Engineering Controls

If a force acting on a surface is applied in a direction perpendicular to that surface then the force is called: A) Uni-directional force B) Normal force C) Perpendicular force D) Friction force

If a force acting on a surface is applied in a direction perpendicular to that surface then the force is called: A) Uni-directional force B) Normal force C) Perpendicular force D) Friction force

Which of the following is among NFPA's classifications of hazard of contents for a building? A) Conventional hazard B) Ordinary hazard C) Nominal hazard D) Minimal hazard

The correct answer is: B Of these, NFPA defines "Ordinary Hazard" as one of the classifications of the hazard of contents in a building. The other two classifications are "Low Hazard" and "High Hazard". NFPA 101 6.2.2 (Life Safety Code)

Once ergonomic hazards are identified through the systematic worksite analysis, which of the following is the next step? A) Design an Ergonomics Program B) Design out the hazards C) Conduct a verification survey D) Apply Administrative Controls

The correct answer is: B Once the ergonomic hazards are identified, it is appropriate to design out the hazards.

PRP is an acronym for: A) Perpetually Responsible Party B) Potentially Responsible Party C) Principal's Responsibility Provision D) Person Receiving Prison (Sentence)

The correct answer is: B PRP has become a common term in the discussion of responsibility for environmental contamination. In the United States, the EPA allows the use of the word "potentially" in front of the term "responsible party" in the CERCLA context.

Calculate the density of standard air at 200°C and at 0.7 atm: A) 0.10 g/l B) 0.52 g/l C) 0.80 g/l D) 0.95 g/l

The correct answer is: B PV = nRT = mRT/M where: m = mass and M = molecular weight Remember to convert degrees °C to °K (°K = °C + 273) Density is defined as mass per unit volume (m/V) m/V = PM/RT = p (density) p = (0.7 atm * 28.96 g/mole) / (0.08205 l-atm/mole-K * 473°K) (when °K = 273 + °C) p = 0.522 g/L

Why does water pressure increase with depth? A) Water becomes more dense with depth B) H2O exerts more force/unit area C) The force of gravity increases with depth D) Mass of water

The correct answer is: B Pressure is defined as a force per unit area. As the weight of water increases with increasing depth the pressure or force per unit area increases.

If 3500 cfm of air is drawn through an 8 inch diameter duct, what is the velocity in feet per minute? A) 1023 fpm B) 10,230 fpm C) 800 lpm D) 1000 lpm

The correct answer is: B Q=AV A=p r2 V=Q/A A=3.14 * (0.33 ft)2 V=3500/A V=10,230 fpm

A full cylinder of compressed helium was left in the afternoon sun all day. At 4:30 p.m., the temperature of the cylinder is measured at approximately 140ºF. The compressed helium gas supplier claims that its cylinders are always filled to approximately 3,200 psig at around 70ºF. What is the approximate gauge pressure in the helium cylinder that afternoon? Assume that compressed helium at these temperatures and pressures acts as an ideal gas. A) 3,500 psig B) 3,600 psig C) 4,500 psig D) 6,400 psig

The correct answer is: B Remember to convert everything into absolute temperature. When dealing with temperatures in Fahrenheit, convert to Rankine (though you can convert Fahrenheit to Kelvin, it takes an extra step). To convert a Fahrenheit value to a Rankine value, add 460 to the Fahrenheit value. Therefore, the two temperatures are 530 R and 600 R, respectively. Using the ideal gas law, PV = nRT. V, n, and R are constant and can be eliminated from the equation (volume, number of moles, and the Gas Constant do not change in this problem). Therefore, the relationship P = T is left. Pinitial and Tinitial are related to Phot and Thot directly. Therefore, Pinitial / Phot = Tinitial / Thot 3,200 psig / Phot = 530 R / 600 R Phot = 3,623 psig

A punch press guard normally consists of: A) Barrier B) Remote Controls C) Sensing D) Locks

The correct answer is: B Remote controls are the most common guard on punch presses.

Smoke detectors work best where: A) Smoke generation will be difficult to detect B) A good deal of smoke will be generated by the products of combustion C) There is the potential for substantial fumes to be generated D) The products of combustion generated by fire are invisible

The correct answer is: B Smoke detectors respond to the particles of combustion that occur in the second fire phase. Smoke detectors operate on lighting principles. When smoke enters a light beam, it triggers a reaction, the more smoke that enters, the faster the response.

What is the specific gravity of mercury, which is a liquid at 25°C? (density of Hg = 13.5340 g/ml; H2O = 0.997 g/ml) A) 135,340 kg/m3 B) 13.57 C) 135,340 mg/m3 D) 13 mg/mL

The correct answer is: B Specific gravity is the ratio of the density of a substance to that of a reference material. In the case of a liquid, the reference material is water. SG (Hg) = p HG / p H2O = 13.5340 g/mL / 0.99707 g/mL = 13.57377 (unitless)

What is the predominant frequency to be expected from a fan which is directly driven at 3600 rpm, and delivers 2400 cfm @ 1/4 in.? The fan has 60 backward curved blades. A) 3500 Hz B) 3600 Hz C) 2400 Hz D) 900 Hz

The correct answer is: B The frequency is calculated from the number of times/second the blades pass a fixed point. Therefore, 3600 rpm=60r/second. 60 rps * 60 blades= 3600 Hz

Joint and several liability defines a scope of liability in the United States. The practical meaning of joint and several liability is best described as: A) All responsible parties must jointly contribute to clean-up costs, to the extent of their volumetric share of the wastes at the site B) Each and every responsible party could be held individually liable for the entire cost of the clean-up C) NPL sites where there are multiple responsible parties must act jointly, through generator committees, to severally apportion costs amongst themselves D) EPA must allocate costs among responsible parties in a manner that reflects both the volume and toxicity of their wastes, as well as the difficulty of clean-up

The correct answer is: B The liability provisions under Section 107 of CERCLA are strict, joint and several, and retroactive in application.

A Class C fire involves: A) Ordinary combustibles B) Live electrical equipment C) Combustible metals D) Flammable liquids

The correct answer is: B Class A fires invlove ordinary combustibles. Class B fires involve flammable or combustible liquids. Class C fires involve live electrical equipment. Class D fires involve combustible metals.

Class "B" fire doors are used to protect openings in: A) Corridor walls B) Stairwells C) Fire walls D) Exterior walls

The correct answer is: B Class B openings are in enclosures of vertical communication through buildings, such as stairs and elevators. Doors for protection of these openings have a fire protection rating of 1 to 1-1/2 hours.

Class III, Division 1 electrical protection is provided in a plant processing: A) Sugar B) Cotton C) Starch D) Paint

The correct answer is: B Class III, Division 1 locations are hazardous because of the presence of easily ignitable fibers or flyings in processing cotton.

Descriptive statistics can best be defined as statistics that: A) Deal with methods of planning the observation B) Summarize population data C) Make generalizations based on sample data D) Provide information about individuals rather than groups.Descriptive statistics can best be defined as statistics that:

The correct answer is: B Descriptive statistics is the branch of statistics that deals with methods that helps to classify, summarize and present the results of observations in forms that are comprehensible and likely to be suggestive of fruitful hypotheses.

A 50 ft * 190 ft * 20 ft building is supplied with 8,000 cfm. What is the number of air changes per hour in the building? A) 1.4 air changes/hr B) 2.5 air changes/hr C) 3.6 air changes/hr D) 4.7 air changes/hr

The correct answer is: B Determine total building volume: 50 ft * 190 ft * 20 ft = 190,000 ft3 Convert cfm to ft3/hr: 8,000 cfm * 60 min/hr = 480,000 ft3/hr 480,000 ft3/hr / 190,000 ft3 = 2.5 air changes/hr

Boilers and unfired pressure vessels are designed, constructed, tested and installed in accordance with which code? A) NFPA B) ANSI C) ASME D) ASTM

The correct answer is: C Design, construction, testing, and installation of boilers and unfired pressure vessels are covered by applicable sections of the American Society of Mechanical Engineers' (ASME) Boiler and Pressure Vessel code. This ASME code is referenced by applicable OSHA regulations.

Of the following, which is the appropriate type of hood for a welding operation? A) Side hood B) Canopy C) Downdraft bench booth D) Wind tunnel

The correct answer is: C Downdraft bench booth is an appropriate type of hood for a welding operation.

For his protection, how long should a manufacturer keep product records? A) Life of the product B) Life of the product guarantee C) Well beyond life of the product D) Should not keep any records

The correct answer is: C Due to product liability claims, a manufacturer should keep product records well beyond the intended life of the product.

A paint spray operation will be located on the assembly floor. What precautions with regard to ignition sources must be exercised? A) None are needed B) All ignition sources must be eliminated C) All flammable and combustible material must be removed from the area D) All ignition sources should be prohibited within 20 ft of the spraying area

The correct answer is: D There shall be no open flame or spark producing equipment in any spraying area within 20 ft, unless separated by a partition. 29 CFR 1910.107(c)(2)

Water feed valves for boilers that remain open during a control failure to allow boiler to operate and not build up excess pressure are: A) Intrinsically safe devices B) Fail passive devices C) Fail active devices D) Fail operational devices

The correct answer is: D Water feed valves that remain open during boiler control failure, allowing boiler to operate and not build up excess pressure are fail Operational devices.

A form of evaluation in which input is measured in terms of dollars and output is measured in terms of the achievement of some desired objectives, is known as: A) Cost-Effectiveness Analysis B) Cost-Benefit Analysis C) Cost-Effectiveness Ratio D) Cost-Benefit Ratio

The correct answer is: A " Cost-Effectiveness Analysis" as the name implies the input is dollars the outputs can be anything you want to measure. Therefore, the effectiveness of your spending is measured.

In relation to fire protection AFFF defines? A) Aqueous film forming foam B) Aqueous film fire fighting C) Approved flammable fire fabric D) Approved flammable fire fighting

The correct answer is: A "Aqueous Film Forming Foam" means a fluorinated surfactant with foam stabilizer which is diluted with water to act as a temporary barrier to exclude air from mixing with fuel vapor by developing an aqueous film on the fuel surface of some hydrocarbons. This film is capable of suppressing the generation of fuel vapors.

Interlocks provide a form of design hazard control. Identify the appropriate interlock indicated; Sensing of any conductive material, especially steel or aluminium, causes it to operate? A) Radio-frequency inductive B) Electromagnetic sensing C) Conductive Reactance D) Motion Interlock

The correct answer is: A "Radio-frequency inductive" interlock is a type of interlock that senses conductive material.

A specific activity intended to improve one or more aspects of the safety system or contribute to the solution of a specific accident problem, is called: A) Countermeasure B) Mitigation C) Hazard Control D) Safeguard

The correct answer is: A A "Countermeasure" is a specific activity designed to improve or reduce a specific accident problem.

An example of a Fail-passive device is the: A) Fuse B) Emergency generator C) High temperature limit switch D) A and C

The correct answer is: A A fuse would be the best example of a Fail-passive device as its failure brings the system to its lowest energy state ("0" current flow). The other devices do not necessarily bring the system to its lowest energy state given a failure.

An alarm system that transmits water flow alarms from sprinklers and supervisory signals to a central system that is constantly manned by the owner's security force is the description of a: A) Proprietary system B) Central station system C) Auxiliary system D) Remote station system

The correct answer is: A A proprietary system is a normally closed-circuit system with electromechanical devices used to transmit signals to the central supervisory station located in or near the building or groups of buildings being protected. The central supervisory station is constantly manned by qualified personnel hired by the building owner or occupant.

A sound absorption coefficient of 0.6 means that ______ of the sound energy in a wave will be reflected. A) 40 % B) 60 % C) 10(log 0.6/0.4) % D) 0.6 log 10

The correct answer is: A A sound absorption coefficient of 0.6 means that 40 % of the sound energy in the wave will be reflected and 60 % absorbed. The key word in the question was reflected NOT absorbed.

A system of forces is said to be ____ if all the forces are acting on a two-dimensional surface. A) Coplanar forces B) Concurrent forces C) Tangential force D) Normal force

The correct answer is: A A system of forces is said to be coplanar forces if all the forces are acting on a two-dimensional surface.

The reliability of a system is enhanced by adding a component in: A) Parallel B) Series C) Sequence D) Progression

The correct answer is: A The reliability is always enhanced by adding a component in parallel. The additional component, which performs the same function within a given system, makes it redundant (or parallel). Conversely, the reliability of a system is diminished by adding a component in series.

Air sampling data are log normally distributed. To analyze air sampling data using a t-test one must: A) Use the log of the concentration B) Convert to an exponential distribution C) Use a Mantel-Haenzel test instead D) Don't have to make any changes to use the t-test

The correct answer is: A A t-test is used with a normal distribution. To analyze log normally distributed data one must convert the air sampling data to logs to use the t-test. Converting to logs should result in a normal distribution.

Why would 4,000 fpm be maintained in an exhaust duct? A) Prevent settling B) Reduce abrasion C) Minimize noise D) Minimize energy consumption

The correct answer is: A A velocity this high would normally be used only if dust transport were involved.

Which of the following Boolean expressions defines the Idempotent Law ? A) A.A = A B) A.B = B.A C) A.1 = A D) A.0 = 0

The correct answer is: A A.A = A is an identity which is appropriate to the Idempotent Law.

As manager of the safety and health function, you are privy to all the cost data that relate to insurance, medical, wages and operations. How would you determine the total cost of an injury or illness? A) Sum the insured and non-insured costs B) Combine insurance cost for medical and compensation paid to claimant C) Determine the direct cost and multiply it by four D) Determine the direct cost and add 25%

The correct answer is: A Accident costs include both those that are insured and those that are not insured. The insured include medical and compensation costs paid to the claimant by the insurance company. The non insured include time lost by others who observed or rendered assistance at the time of the accident, time lost to investigate the accident, time to train a replacement, cost for damaged materials, etc.

Valve system V1 has the following valve component failure rates: X1 = 0.4 X2 = 0.1 X3 = 0.2 X4 = 0.5 The fault tree of the valve system indicates that valve subsystem SS1 contains series components X1, X2, and X3. Valve component X4 and SS1 are parallel and redundant. What is the anticipated failure rate of V1? A) 0.35 B) 0.65 C) 0.75 D) 0.95

The correct answer is: A Add the series components for the failure rate of SS1. lSS1 = 0.4 + 0.1 + 0.2 = 0.7 Multiply the failure rate of SS1 with redundant valve component X4 to calculate the failure rate of V1. lV1 = 0.5 * 0.7 = 0.35

An example of a non-fail safe device would be: A) Any single point failure B) Deadman switches C) Circuit breaker D) GFCI

The correct answer is: A Any single point failure is an example of a non-fail safe device.

Which of the following is false? A) CFM varies indirectly as fan speed B) SP varies as the square of fan speed C) HP varies as the cube of the fan speed D) TP varies as the square of fan speed

The correct answer is: A CFM varies directly as fan speed not indirectly as stated in choice A). The other listed relations between some operating parameter and the fan are true.

A Class I, Division I hazard includes all of the following EXCEPT: A) A closed loop system of flammable solvent B) An open vat of flammable solvent C) A cleaning operation involving flammable solvent D) A flammable solvent degreasing tank

The correct answer is: A Class I Division I systems involve operations where flammable solvent vapors are always present.

In the identification of fire class occupancies, Class II indicated the presence of: A) Combustible dusts B) Flammable vapors C) Ordinary combustibles D) Ignitable fibers

The correct answer is: A Class II occupancies are locations combustible dust is or may be in suspension in the air continuously, intermittently or periodically. Hazardous dusts are separated into groups: E for metal dust F for carbon black, coal or coke dust G for flour, starch or grain dust.

A generic process of evaluating competing courses of action by examining the dollar costs of certain abatement actions versus the dollar value of the benefits received is called: A) Cost-Benefit Analysis B) Cost Versus Abatement Analysis C) Out-put and In-put Analysis D) Loss-Benefit Analysis

The correct answer is: A Cost-Benefit Analysis is the technique that weighs the costs of a program and the benefits of the program.

As a safety professional, you are asked to provide guidance in the layout of a 5,000 square foot, high hazard facility that will house up to 15 laboratory scientists. The expected configuration of process equipment presents the need for a dead end corridor in the means of egress arrangement. Based on NFPA 101 (Life Safety Code), what is your suggestion regarding the maximum permitted length of the anticipated dead end corridor? A) 0 ft B) 25 ft C) 30 ft D) 50 ft

The correct answer is: A Dead ends are not permitted in high hazard occupancies with an area of more than 200 square feet or an occupant load of more than 3 people. NFPA 101 7.11.4 (Life Safety Code)

What is the density of dry air in units of lbs/ft3 at 70°F, the industrial ventilation design standard? A) 0.075 lb/ft3 B) 0.15 lb/ft3 C) 1.0 lb/ft3 D) 1.5 lb/ft3

The correct answer is: A Density air (or "p") = Pressure air * Mass air / RT air Use Rankine for absolute temperature: (70° F = 529.6° R) p = [17.7 lb/in.2 * 28.96 lb/lb-mol] * 144 in.2 / 1544 lb. ft/mole * 529.6° R = 0.07496 lb/ft3

Which is not appropriate when designing tank farms? A) Different types of tanks and contents should be grouped or diked together B) Tanks should be properly diked or drainage to a remote impounding provided C) Atmospheric storage tanks and pressure vessels should be arranged in rows not more than one or two deep D) Storage tanks should be located at a lower elevation to prevent flow toward structures or equipment

The correct answer is: A Different types of tanks and contents should never be grouped or diked together. This will increase the loss potential due to the possible interaction of the contents.

An enclosure is placed around a worker and a noise source. Why is the sound pressure level experienced by the worker greater than without the enclosure? A) Reverberation B) Impact C) Masking D) Increase in line component

The correct answer is: A Enclosing a noise source always increases the sound pressure level because direct sound is added to the reflected sound.

The term used to describe the extent to which values spread on either side of a mean, median or mode is called: A) Limit B) Range C) Deviation D) Dispersion

The correct answer is: D Dispersion is a measure of the spread of the data with respect to the mean or other measure.

Suppose a company operating as a machine shop doing contract jobs for their customers is in worker's compensation Class 3652. In the company's current state, this worker's compensation Class has a manual rate of $10.50. The company employs 55 people and the average salary per person is $35,000. The company has an adequate safety program and has a current experience modification factor on workers' compensation insurance of 1.1. Next year, it will drop to 0.90. What is the firm's estimated worker's compensation premium for the next year? A) $181,912.50 B) $222,337.50 C) $17,500 D) $21,388.89

The correct answer is: A Estimated premium is calculated in this case by determining the estimated payroll, dividing the estimated payroll by $100 (since rates are based on $100 of payroll), multiplying that number by the rate for machine shops and the experience modifier for the new year. Estimated Premium = [(# Emp * Avg Sal / Empl) / $100] * Manual Rate * Experience Modifier EP = [(55 * $35,000) / $100] * $10.50 * 0.90 EP = 19,250 * $10.50 * 0.90 EP = $181,912.50

You are a safety professional in a plant that manufactures a flammable solvent based ink. The wiring in the processing area should be: A) Class I, Div. 1 B) Class I, Div. 2 C) Class II, Div. 1 D) Class 11, Div. 2

The correct answer is: A Following the requirement of the National Electrical Code, a Class I, Div. 1 rating is required. This high level of protection is required because flammable solvents are used. The vapors can travel and, if no protection were provided, find a source of ignition.

Which of the following is not characteristic of a centrifugal fan? A) High volume - low pressure drop B) Low space requirement C) Often used with particle laden air D) Low to medium noise

The correct answer is: A High volume - low pressure drop are the most notable characteristics of axial flow fans not radial or centrifugal flow fans.

What is the name of the evaluation technique for analyzing randomly obtained observations or evidence to determine the probability of drawing such evidence by random sampling methods under the assumption that the hypothesis is correct? A) Hypothesis Testing B) Placebo Effect C) Post Hoc Test D) Regression Test

The correct answer is: A Hypothesis Testing is a test to determine if what you propose is supported by the data (sample) you have collected, e.g., blood lead levels have increased in battery workers.

A Gaussian distribution implies that approximately 68% of the observations fall above or below the mean plus ____ standard deviation(s). A) 1 B) 2 C) 3 D) 4

The correct answer is: A In a normal (Gaussian) distribution, approximately 68% of the observations will fall above or below the mean by 1 standard deviation.

What is the molar volume at 300°C and 0.95 atmospheres pressure for an ideal gas? A) 49.5 liters B) 40.9 liters C) 49.5 cubic meters D) 33 cubic feet

The correct answer is: A Molar volume @STP = 22.4 liters. For 300°C and 0.95 atmospheres: 22.4 * (573/273) * (1/.95)= 49.5 liters. In general, (22.4)(T1/T2)(P1/P2) where T1=273°K P1=1 atm

A gas inside a sealed drum exerts 15.3 lb/in2 at 25°C. What is the pressure inside the drum when the temperature is 40°C? A) 16.0 lb/in2 B) 14.6 lb/in2 C) Molecular weight of material must be known D) Volume of drum must be known

The correct answer is: A P1 V1 /T1 = P2 V2 /T2 Where: P1 = Initial Pressure P2 = Resulting Pressure V1 = Initial Volume V2 = Resulting Volume T1 = Initial Temperature °K T2 Resulting Temperature °K Substituting: 15.3/323 = P2 /338 P2 = 16.0 lb/in2

What is the appropriate interlock that can detect the presence, absence, excess, or inadequacy of pressure, temperature, flow or other parameters and either permits or stops action? A) Parameter sensing B) Transducer Interlock C) Trip Device D) Proximity Device

The correct answer is: A Parameter sensing interlocks detect the presence of pressure, temperature etc. and either permit or stop an action.

Which natural fiber makes the safest rope? A) Manilla B) Sisal C) Cotton D) Jute

The correct answer is: A Per the "Accident Prevention Manual", manilla rope is the best suited natural fiber rope for slings and capstans.

The best fire protection system advisable in a plant where water damage would result in a serious product loss would be: A) Preaction B) Deluge C) Dry pipe D) Wet pipe

The correct answer is: A Preaction fire protection systems are designed to eliminate the danger of water damage and to counteract the operational delay of conventional dry pipe systems. In preaction systems, the water supply valve is actuated independently of the opening of sprinklers.

The removal of insoluble matter from water is referred to as: A) Primary waste treatment B) Secondary waste treatment C) Tertiary waste treatment D) Activated sludge process

The correct answer is: A Primary waste treatment removes insoluble matter through screening, removal of grit, and primary sedimentation.

A cylinder contains 1000 psi(g). What is the absolute pressure of the contents? A) 1014.7 psi(a) B) 985.3 psi(a) C) 1000 psi(a) D) 900 psi(a)

The correct answer is: A Psi(g) (pounds per square inch gauge) is equal to the absolute pressure minus the atmospheric pressure. IN other words: Psi(g) = psi(a) - psi(atm) 1000 psi = psi(a) - 14.7 psi psi(a) = 1014.7 psi

An industrial furnace that produces radiant heat would be best reduced by: A) Shielding B) Blowing cool air C) Lowering the temperature D) Absorption

The correct answer is: A Radiant heat is best controlled by shielding.

Secondary containment is considered: A) A best management practice B) Necessary to effective wastewater treatment C) Provided by compacted soil barriers D) Unnecessary if hazardous waste tanks and containers are frequently inspected and when releases are directed away from storm sewers

The correct answer is: A Regardless of regulatory requirements, secondary containment is recommended as a best management practice. Secondary containment manages the risks and costs associated with chemical releases. Requirements for secondary containment can be found in both RCRA and CWA regulations. The fines, clean up costs, and litigation expenses associated with oil and chemical releases indicate the necessity for secondary containment.

A light curtain safety interlock system is being proposed for an automatic metal shearing machine. Assuming a standard hand speed of 63 in./sec, and a machine shut down time of 0.5 sec, what is the minimum acceptable distance from the point-of-operation to the sensing field of the light curtain? A) 31.5 in B) 47.3 in C) 63.0 in D) 126 in

The correct answer is: A Simply multiply the standard hand speed by the time necessary for the interlock to shut down the equipment. Distance = 63 in/sec * 0.5 sec = 31.5 in.

To secure a roof antenna three guide wires are required. The wires will make a 35° angle with respect to the roof. How much guide wire is needed if the antenna is 10 feet high? A) 53 feet B) 55 feet C) 60 feet D) 67 feet

The correct answer is: A Sin 35° = Opp / Hyp = 10 / Hyp H = 10 / Sin 35° = 17.43 ft Total = 3 guide wires * 17.43 = 52.29 feet

A system which is arranged to automatically discharge a predetermined concentration of agent into an enclosed space for the purpose of controlling or extinguishing fire is called: A) Total flooding system B) Fixed enclosed system C) Fire suppression system D) Sprinkler system

The correct answer is: A The "Total Flooding System" is defined above and found in 29 CFR 1910.156.

Which of the following is the most important distribution in probability statistics? It represents the case of the continuous variable that is the limiting condition of the discrete, binomial probability function. A) Normal B) Exponential C) Gamma D) Log-Normal

The correct answer is: A The Normal (Gaussian) distribution is the most common distribution in statistics.

A chemical with a molecular weight of 88 evaporates from a chemical process. Where would it most likely accumulate? A) Floor B) Ceiling C) Neither A nor B, it will mix uniformly D) Insufficient information

The correct answer is: A The best answer choice is A because for gases, density is proportional to molecular weight. Air is approximately M.W= 30. Therefore the gas should sink.

The exiting design requirements in the NFPA 101 Life Safety Code are based on classification of the occupancy. These classifications are dependent on the burning characteristics of: A) Contents of the building B) Quantity of combustible materials C) Type of building construction D) The type of flooring materials

The correct answer is: A The contents are evaluated to determine the rate of fire spread, development of products of combustion and components that affect the time available for evacuating the building.

In system safety design, which design philosophy is the closest to "perfect" safety? A) Intrinsically safe B) Fail Safe C) Fail Passive D) Fail Operational

The correct answer is: A The design philosophy which is closest to "perfect" safety is Intrinsic safety. This design philosophy seeks to limit failures to an extremely small percentage. All of the others allow failure, but seek to engineer out the hazard a failure would bring.

Which is the preferred guard for power presses performing piercing, blanking and stamping operations? A) Fixed B) Interlocked C) Adjustable D) Self-adjusting

The correct answer is: A The fixed guard is considered preferable to all other types and should be used in every case unless it has been definitely determined that this type is not at all practical. The fixed guard at all times prevents access to the dangerous parts of the machine. Besides power presses, fixed guards are also on guillotine cutters, drilling machines, gear trains, milling machines and sheet flattening machines.

Given the following sample distribution: 10, 10, 15, 25, 35. Compute the mean: A) 19 B) 17 C) 21 D) 23

The correct answer is: A The mean is the sum of the measurements divided by the total number of measurements i.e. the average value.

In a normal distribution, the mean plus two standard deviations estimates the _____ percentile of the distribution. A) 97.7 B) 95.0 C) Lower 90.0 D) Middle 84.0

The correct answer is: A The mean plus 2 standard deviations will estimate the point at which 97.7% of the observations fall below. If the question asked for the mean minus two standard deviations, then that would be the point at which 2.3% of the observations fall below. To determine this, use the Table of the Normal Distribution and select a "z" equivalent to the number of standard deviations above or below the mean. For this problem, we use a "z" of 2.00. On the far right column, find "2.0". Since we said 2.00, we will use the number in the "0" column immediately to the right of the "z" of 2.0. This number is 0.4772. (Had we asked for 2.09 standard deviations, you would have selected the number in the "9" column at the other end of the "z = 2.0" row (that number is 0.4817). With 0.4772, we now know the area under the curve of plus 2.00 standard deviations. But since we wanted the whole percentile, we need to add everything below the mean to the part we just found above the mean. Therefore, since the mean represents half of the area under the curve, then we must add 0.500 to our number. Area = 0.4772 + 0.500 = 0.9772 = 97.7 percentile

Given the following sample distribution: 10, 10, 15, 25, 35. Compute the mode. A) 10 B) 15 C) 25 D) 35

The correct answer is: A The mode is the sample measurement that occurs most frequently.

Out of 921 serious accidents at a plant, 127 were eye injuries. Of these, 100 were the result of failure to wear approved eye protection. What is the probability of a serious accident due to the failure to wear approved eye protection? A) 0.11 B) 0.22 C) 0.33 D) 0.44

The correct answer is: A The probability of a serious accident due to the failure to wear approved eye protection is 100 / 921 = 0.1085 or .11

Given industry data reveals that out of 883 serious accidents, 24 are the result of vehicular use. What is the probability that a serious accident is due to vehicular use? A) 0.02 B) 0.04 C) 36 D) 40

The correct answer is: A The probability of a serious vehicular accident is 24/883.

A process which requires conditioning agents, which uses sparging fine air bubbles through an oily emulsion, and lifts the oily substance to the surface is called: A) Flotation B) Aeration C) Conditioning D) Agglomeration

The correct answer is: A The process is called Flotation. The term is descriptive as you can see from the question.

Given the following sample distribution 10, 10, 15, 25, 35. Compute the standard deviation: A) 10.8 B) 9.7 C) 6.7 D) 11.9

The correct answer is: A The standard deviation(s) is a measure of the variability of the data. It is calculated using the following formula: s=([nx2-(x)2]/n(n-1))1/2 n= sample size x= observation =sum of ... x2 = 100+100+225+625+1225 = 2275 (x)2=(10+10+15+25+35)2= 952 n=5 (((5 * 2275)-9025)/5(4)))1/2 117.5(1/2) i.e., the square root of 117.5 10.8

Which of the following statements is not true about the static pressure in a given ventilation system? A) Is measured parallel to the direction of flow B) Tends to collapse the duct in an exhaust system C) Acts in all directions D) Is available to do work

The correct answer is: A The static pressure is always measured perpendicular to the direction of flow.

If the public water supply at street level is 95 psig, what will be the pressure at a hose outlet located on the roof of a 50 ft high office building? A) 73.3 psig B) 45.0 psig C) 82.6 psig D) 165.0 psig

The correct answer is: A The weight exerted by a 50 ft high column: 62.4lbs./ft3 = .443 psi/ft * 50 ft 144lbs./ft2 = 21.7 psig, to be subtracted from supply pressure at street level. 95 psig - 21.7 psig

A system that is designed to shut down when one or more critical components fail is called: A) Fail safe B) Interlock C) Circuit breaker D) Fuse

The correct answer is: A There are times when a system, guard, elevator, and other high risk equipment are designed to shut down when one or more critical components fail. When this occurs, it will do so in a safe position or condition without the experience of a major loss.

For event A to occur a preliminary, intentional action B, is needed; for example, lifting the cover that protects a critical switch, permitting it to be thrown. Such a design is called: A) Interlock B) Isolation device C) Lockout D) Lockin

The correct answer is: A This is a description of the concept of an interlock in terms of probabilities and systems terminology.

How many moles are in 60.0 g of chlorine gas? Gram Molecular Weight = 70.9 A) 0.846 moles B) 1.00 moles C) 1.31 moles D) 1.37 moles

The correct answer is: A To calculate moles utilize the following: 60 grams/70.9 grams/mole = 0.846 moles

Whenever flammable or combustible liquids are transferred from one container to another: A) Both containers shall be effectively bonded and grounded B) Only the dispensing container shall be bonded and the other container shall be grounded C) Both containers need only be grounded D) Both containers need only be bonded

The correct answer is: A To prevent discharge sparks of static electricity, it is necessary to both ground and bond each container.

An uncolored sprinkler head is suitable for use in which temperature range? A) 135°F-165°F B) 175°F-212°F C) 250°F-360°F D) 325°F-360°F

The correct answer is: A Use the following table: Ceiling Temp. (°F) Rating Class Color 100 135-170 Ordinary Uncolored 150 175-225 Intermediate White 225 250-300 High Blue 300 325-375 Extra High Red 375 400-475 Very Extra High Green 475 500-575 Ultra High Orange

A tank of helium contains 150 liters of gas at a pressure of 110 atmosphere. What volume would the gas occupy at 1 atmosphere assuming the temperature remains unchanged? A) 1.65 x 104 liters B) 1.65 liters C) 0 liters D) 16.5 liters

The correct answer is: A Utilizing Boyle's law (P1V1 = P2V2) and solving for V2 = P1V1/P2 = (110 atm * 150 liters)/1.0 atm = 1.65 x 104 liters

Given a velocity pressure reading of 0.60 in of water in a circular duct, what is the average velocity in feet per minute? A) 3102 fpm B) 15 fpm C) 29 fpm D) 1023m

The correct answer is: A V=4005 * (VP)1/2 Where VP=velocity pressure V=4005 * (0.60)1/2 V=velocity V=3102 fpm

Which of the following statements concerning various types of air pressure is not true? A) Velocity pressure may be a + or - number B) Static pressure may be + or - number C) SP is exerted on the sides of the duct D) TP = SP + VP

The correct answer is: A Velocity pressure is a measure of kinetic energy and therefore cannot be negative. Static pressure can be negative if the duct is an exhaust duct.

In the application of principles of guarding, what does Zero Mechanical State (ZMS) mean? A) All energy sources neutralized B) All electrical energy off C) Guards are not effective D) All electrical energy locked and tagged out

The correct answer is: A ZMS is discussed in ANSI Z241.1-1981 as the state with all energy sources neutralized.

The tendency of a distribution to depart from symmetry or balance around the mean is called: A) Range B) Skewness C) Mode D) Confidence Level

The correct answer is: B "Skewness" describes the abnormal tails of a distribution. In an ideal situation the tails are symmetrical. This is not true in the real world, therefore a measure of the departure from the ideal shape is needed. This is the source of the descriptions like "the distribution is skewed to the left".

An average of all the deviations about the mean in a sample that is arithmetically defined as the square root of the mean of the squared deviations of measurements from the mean is: A) Sample Distribution B) Standard Deviation C) Statistical Significance D) Skewness

The correct answer is: B "Standard Deviation" is the square root of the sum of the squared deviations from the mean of all the observations. The variance is the square of the standard deviation.

A battery operated smoke detector is an example of what type of design? A) Interlock B) Fail active C) Fail passive D) Fail operational

The correct answer is: B A battery operated smoke detector is an example of a fail active design.

A combustible liquid is best defined by which of the following? A) Any liquid having a flash point above 100°F and below 140°F B) Any liquid having a flash point at or above 100°F C) Any liquids having a flash point above 140°F D) Class II liquids having flash points at or above 100°F and below 140°F

The correct answer is: B A combustible liquid is any liquid having a flash point at or above 100°F. Flammable and combustible liquids are subdivided into classes with combustible being: Class II - flash points at or above 100°F and below 140°F. Class III- flash points at or above 140°F.

A locomotive is traveling at 60 mph. The engineer's reaction time is 0.6 seconds. How many feet will the locomotive travel before the engineer recognizes an emergency situation and actually applies the brakes? A) 45 feet B) 53 feet C) 60 feet D) 75 feet

The correct answer is: B A conversion from mph to feet per second is to multiply mph by 1.47. This conversion factor could also be calculated by: (5280 ft/mi * 1hr/60 min * 1 min/60 sec)=1.47 ft/sec 60 mph * 1.47 = 88 feet/second 88 feet/second * 0.6 seconds = 53 feet

The design of a large office complex requires that a number of partitioned areas opening off a common corridor be sized for 45 occupants. Doors from these rooms: A) Must swing in the direction of exit travel B) May swing in either direction C) Must swing against the direction of exit travel D) Must swing in the direction of exit travel if the occupancy is in a Group 4 earthquake zone

The correct answer is: B A door from a room to an exit or to an exit access shall swing in the direction of exit travel when the room is occupied by more than 50 persons or when used for a high hazard occupancy [29 CFR 1910.37(f)(2)]. The direction of door swing is not defined for other than high-hazard occupancies with fewer than 50 people. 29 CFR 1910.37 (f)(2) and NFPA 101 7.2.1.4.1 (Life Safety Code)

Which of the following designs will NOT allow equipment to operate? A) Fail active B) Fail passive C) Fail safe D) Fail operational

The correct answer is: B A fail passive system shuts the equipment down.

A flammable liquid is best defined by which of the following? A) Any liquid having a flash point below 73°F and a boiling point below 100°F B) Any liquid having a flash point below 100°F and a vapor pressure not exceeding 40 psia at 100°F C) Any liquid having flash points at or above 100°F and below 140°F D) Any liquid having a flash point below 73°F and having a boiling point at or above 100°F

The correct answer is: B A flammable liquid is any liquid having a flash point below 100°F and having a vapor pressure not exceeding 40 psia at 100°F. Flammable and combustible liquids are subdivided into classes with Class I having a flash point below 100°F, Class II having flash points at or above 100°F and Class III having flash points above 140°F.

A good safety design to overcome failures or malfunctions is the: A) Safety margin B) Safety factor C) Maximum foreseeable failure margin D) Maximum permissible failure factor

The correct answer is: B A good safety design to overcome failures or malfunctions is the safety factor. By definition, a safety factor is the ratio of the ultimate (breaking) strength of a member, or piece of material, to the actual working stress or to the maximum permissible (safe load) stress when in use. The magnitude of the safety factor depends on how great the cost of failure will be in terms of life or damage.

A one-story steel framed factory building with a metal roof, concrete floor and masonry exterior/interior walls represents what type of construction? A) Fire-resistive B) Non-combustible C) Ordinary D) Heavy timber

The correct answer is: B A standard classification of buildings into five major types based on the fire-resistance ratings of their component parts was developed by NFPA to help prevent confusion of terms used in various building codes and by insurance companies. Noncombustible construction is entirely of noncombustible materials that either fail to meet the full requirements for fire-resistive construction or are without fireproofing protection for the structural steel elements.

In the design of a noise reducing enclosure, all of the following characteristics are desired EXCEPT: A) Acoustical absorbing material inside the enclosure B) Acoustical absorbing material outside the enclosure C) An enclosure made of solid non-porous material D) An air tight enclosure

The correct answer is: B Acoustical absorbing material on the outside of an enclosure is much less effective than having the sound absorbing material on the inside.

Which of these conversions is NOT true? A) 1 liter water = 1000 gm of water at STP B) 1 cubic meter = 10,000 liters C) 14.7 psi = 760 mm Hg D) 1 liter = 0.001 cubic meters

The correct answer is: B All of the above conversions with the exception of B are true. 1 cubic meter = 1000 liters. You can obtain this same figure by multiplying each side of choice (D) by 1000. Basic conversions like these are valuable for the ASP and CSP exams.

When a vacuum cleaner is used to clean up asbestos containing wastes, it must have ______ _________ exhaust ports. A) Well maintained B) HEPA filtered C) Pressure demand D) Demand only

The correct answer is: B All vacuum cleaners used for asbestos containing material (ACM), MUST have HEPA filtered exhausts.

At 10°C and 4.0 atmospheres pressure a sample of gas occupies 1000 liters. If the gas is reduced in volume to 300 liters and the temperature remains constant, what will the pressure be? A) 10 atm B) 13 atm C) 14 atm D) 23 atm

The correct answer is: B Boyle's law states that at constant temperature pressure and volume are inversely related i.e., as the pressure increases the volume decreases. atm = 4.0 atm * (1000 l/300 l) = 4.0 atm * (3.333) = 13.33 atm

Canopy hoods can best be used when: A) High toxicity materials are used B) Thermal currents can be taken advantage of C) Energy costs are a concern D) Canopy hoods should never be used

The correct answer is: B Canopy hoods are best used where heated materials give off contaminants that tend to rise; where the canopy hood can capture and remove them. The toxicity of the material is less of an issue if the canopy hood is able to keep the concentration below hazardous levels. Canopy hoods do tend to draw a high volume of air, which can lead to higher makeup air and energy costs.

Given that the volume of a gas at 45°C is 79.5 ml, what would the volume be at 0°C? Use Charles' Law to determine new volume. A) 6.83 ml B) 68.3 ml C) 78.3 ml D) 88.5 ml

The correct answer is: B Charles' law states that volume is proportional to absolute temperature i.e. V2=V1 * (T2/T1). In this way if the temperature rises, volume increases. If temperature decreases, the volume will decrease. Using the data given in the problem we get: V2=79.5 ml * (273/318) V2=68.3 ml

A common wastewater treatment concept which involves a process of removing suspended solids by quiescent settling to produce a clear effluent is called: A) Flocculation B) Clarification C) Agglomeration D) Coagulation

The correct answer is: B Clarification is the appropriate process. The remaining three choices above all equate to the flocculation process.

Dilution ventilation is: A) Used to control a contaminant at its source B) Used for controlling vapors having low toxicity C) More economical than local exhaust ventilation D) Is the first consideration for hazard control

The correct answer is: B Dilution ventilation lowers the concentration of a contaminant by adding air to the general work area. Since the air is added to the general work area it will not effectively control exposure to a toxic or highly toxic substance used in a specific location.

A 1000 pound load is lifted with a 2 leg sling whose legs are at a 30° angle with the load. The stress on each leg of the sling is: A) 500 pounds B) 1000 pounds C) 2000 pounds D) 3000 pounds

The correct answer is: B Drawing the sling you will note that the vertical component of each sling supports 500 pounds (1000 pounds/2). Setting up a right triangle with a 30 degree angle solve for the hypotenuse and you will have stress for each sling leg. Sin 30° = 1/2 = opp/hypot = 500/hypot hypot = 1000 pounds

A design that automatically reduces the system to its lowest energy level is considered: A) Fail safe B) Fail passive C) Fail ceased D) Fail non-operational

The correct answer is: B Fail passive is a design that automatically reduces the system to its lowest level.

A large office building currently houses 50 people. If the building HVAC system supplies 8,000 cfm and 90% of the air is recirculated, what is the outdoor air ventilation rate per person? A) 0 cfm/person B) 16 cfm/person C) 25 cfm/person D) 800 cfm/person

The correct answer is: B First determine the amount of outdoor air: 8,000 cfm * 0.1 = 800 cfm Then determine cfm/person: 800 cfm/50 people = 16 cfm/person

Flexible ducting used for moveable exhaust systems has the following advantage over conventional galvanized ducts: A) Decreased resistance B) Maneuverability of hood C) Availability of hood shapes D) Increased static pressure

The correct answer is: B Flexible ducting's principle advantage is its maneuverability. The hood should be located as close as possible to the contaminant source. Once galvanized ducts are installed they are difficult and expensive to move.

The combined frequency and severity role is defined as: A) Accident severity formula B) Frequency severity indicator C) Incident rate D) Frequency rate

The correct answer is: B Frequency severity indicator is the combined frequency and severity role.

In a group of 1000 adults, 630 are women. What is the probability that a person chosen at random from the group will be a man? A) 0.185 B) 0.370 C) 0.555 D) 0.740

The correct answer is: B If 630 people out of the 1000 are women, 1000 - 630 = 370 men. The probability of choosing a man is 370/1000.

In a normal distribution 99% of the observations will fall within approximately ___ standard deviation(s) of the mean. A) 1.96 B) 2.58 C) 3.00 D) 4.40

The correct answer is: B In a normal distribution, approximately 99% of the observations will fall within 2.58 standard deviations of the mean; 95% within 2 standard deviations and 68% within one standard deviation. Approximately 99.7% of the observations will fall within 3.0 standard deviations.

This system safety design reduces the system to its lowest energy level given a failure: A) Intrinsically safe B) Fail passive C) Fail active D) Fail operational

The correct answer is: B In fail passive designs the system is brought to its lowest energy level, given a component failure. The other options do not reduce the system energy level to its lowest potential.

The amount of make-up air volume in most cases is determined by: A) The number of air changes required B) The total volume of air removed C) The required comfort conditions D) Carbon dioxide concentration

The correct answer is: B In most cases, make-up air volume should equal the total volume of air removed from the building by exhaust ventilation systems, process systems and combustion processes. Determination of actual volumes of air removed usually requires an inventory of exhaust locations.

A company sold a product in 1970 that caused an accident in 1983. The company was not insured in 1970, but did have Company "A" insurance in 1983. Who is responsible for losses? A) Company since it had no insurance in 1970 B) Insurance Company "A" C) Both the company and insurer share responsibility D) Nobody is responsible

The correct answer is: B Insurance Company "A" would be responsible for the losses.

Which of the following smoke detectors will accurately detect most fires more rapidly than the others? A) Rate-of-rise thermal B) Ionizing C) Reflected beam photoelectric D) Bulb detection system

The correct answer is: B Ionizing detectors sense fire at the earliest practical detection stage. They sense both visible and invisible products of combustion which enters a chamber containing positive and negative plates and a very minute amount of radioactive material that ionizes the air in the chamber. The movement of ions between plates sets up a small current that triggers an alarm.

Total pressure is: A) The difference between SP and VP B) Measured parallel to the axis of flow C) Normally positive on the suction side D) Measured perpendicular to the axis of flow

The correct answer is: B It is measured parallel to the direction of flow since it contains a Velocity Pressure component. Total pressure is equal to the sum of the static pressure SP and the velocity pressure VP, not the difference as indicated in choice A.

New petroleum underground storage tanks must have the following: spill and overfill protection, proper installation, corrosion protection, and: A) Lightning protection B) Leak detection C) Single-walled fiberglass protection D) Explosion protection

The correct answer is: B Leak detection is the missing item that is required on all new petroleum underground storage tanks.

Molality refers to: A) Number of moles solute/liter solution B) Number of moles solute/1000 grams solvent C) Number of moles/gram of molecular weight D) Number of grams solute/mole solution

The correct answer is: B Molality refers to the number of moles of a solute dissolved per 1000 grams of a solvent. Number of moles solute/liter solution is molarity.

What is the probability that an even number will come up when a single die is thrown? A) 1 B) 1/2 C) 1/3 D) 1/6

The correct answer is: B Of the 6 possible numbers on each face of the die, three are even (2,4,6). The probability is 3/6 or l/2.

In walking through a chemical mixing area, it was noted that the automatic sprinkler heads faced the roof and were color coded blue. What should this tell you? A) It was an intermediate pendent sprinkler head with an operating temperature of 175°F - 212°F B) It was a high upright sprinkler head with an operating temperature of 250°F - 280°F -286°F C) It was an extra high upright sprinkler head with an operating temperature of 325°F - 340°F - 350°F D) It was a high pendent sprinkler head with an operating temperature of 250°F - 280°F - 286°F

The correct answer is: B Sprinkler heads facing up are called upright. When color coded blue, it signifies a high rating with 250°F - 280°F - 286°F operating temperature.

Ignition of flammable vapors, dusts, or fibers by discharge of static electricity can be prevented by any of the following EXCEPT: A) Grounding and bonding B) Insulation C) Humidification D) Ionization

The correct answer is: B Static electricity is non-flowing electricity commonly generated by friction and the effects of the positive and negative charges which have the potential to spark. The static charge which already exists can be removed or allowed to dissipate itself. The acts or conditions which can accomplish this are the same as those which permit the separation of charges to occur. Ignition is prevented by the actions employing humidification, ionization, grounding and bonding. Flammable vapors, dusts or fibers cannot be insulated.

A hazardous location, because of the presence of combustible dust requires electrical protection that meets the requirements of: A) Class I locations B) Class II locations C) Class III locations D) Class IV locations

The correct answer is: B Suspended combustible dust may be present in quantitites sufficient to produce explosive or ignitable mixtures; or be electrically conductive; or be ignitable by a malfunction of electrical equipment.

Interlocks are one of the most commonly used safety devices. Identify the appropriate interlock device below. Nonalignment of two or more parts prevents further action. A) Path Separation B) Position Interlock C) Key Interlock D) Path Coding

The correct answer is: B The "Position Interlock" is the type of interlock described in the question. The word nonalignment was a tip.

A number that expresses the distance from a particular value (X) above or below the mean () in units of standard deviation (S), is called ________. The result of this calculation is used in statistical tests involving normal distributions. A) Variable B) Z-Score C) Variance D) Quartile

The correct answer is: B The "Z-Score" is calculated below Z = (X - )/S It is used to test how likely the observed value X would be observed if the X was drawn from a normal distribution with mean() and standard deviation (S).

"Flame Spread Rating" is a measure of a materials surface burning characteristics. Which test is employed? A) Time/Temperature Curve B) Steiner Tunnel Test C) ASTM E 32 D) FM Calorimetry Test

The correct answer is: B The 25 ft Steiner Tunnel Test, also known as ASTM E84, NFPA 255 and UL 723 was developed at Underwriters Laboratories. In the need for some method for control of interior finishes, the Steiner Tunnel Test was recognized and adopted by ASTM & NFPA as an official standard in 1958.

ANSI recommends the lighting level for corridors in industrial facilities should have a minimum of _____ foot-candles: A) 10 B) 20 C) 30 D) 40

The correct answer is: B The American National Standards Institute (ANSI) Standard Practice for Industrial Lighting (ANSI A22.2-1984) provides minimum lighting levels for safety purposes. The minimum they recommend for corridors in industrial facilities is 20 foot-candles. The Illuminating Engineering Society (IES) publishes a Lighting Handbook which recommends higher illumination levels to maximize productivity.

Which of the following distributions is useful for analog computer approximations of the normal and exponential distributions? It is a continuous function that indicates times to failure of various failure modes. A) Weibull B) Gamma C) Log-Normal D) Poisson

The correct answer is: B The Gamma Distribution is often used to describe times to failure. It is a continuous function.

The National Electrical Code (NEC) utilizes a Class I, II, III etc. hazard identification system. Class II hazards involve: A) Flammable liquids B) Dusts C) Fibers D) Powders

The correct answer is: B The NEC Class I hazard includes flammable liquids or gases, Class II includes combustible dusts, Class III fibers.

During a power failure, the NFPA Life Safety Code (NFPA 101) requires that power operated doors: A) Operate automatically B) Operate manually C) Lock D) Remain motionless

The correct answer is: B The NFPA Life Safety Code requires that power operated doors are capable of being operated manually during a power failure. NFPA 101 7.2.1.9.1 (Life Safety Code) .

What is the duct velocity in a 6 inch duct with an airflow of 1000 cubic ft/min? A) 5000 ft/min B) 5092 ft/min C) 6750 ft/min D) 7225 ft/min

The correct answer is: B The area of a 6 inch duct is 0.1964 sq ft (remember to change inches to feet when calculating the area of the duct). Start with Q=AV solve for V Velocity = Volumetric Flow/Area = 1000/0.1964 = 5092 ft/min

What is the velocity at the face of a 10' by 10' dry type paint booth if the total flow through the opening is 2000 cfm? A) 10 ft/min B) 20 ft/min C) 40 ft/min D) 200 ft/min

The correct answer is: B The basic formula for ventilation calculation is: Q = VA Q, the airflow rate is measured in cfm. V, the velocity is measured in fpm. A, the cross sectional area is measured in ft2. V = Q/A = 2000 cfm/10ft * 10 ft = 20 ft/min

What type of "closed-head" sprinkler system requires a fire detection device in the affected area to activate? A) Dry-pipe system B) Pre-action system C) Deluge system D) Wet pipe system

The correct answer is: B The best answer is a pre-action system. A dry-pipe system relies on sprinkler head operation to trigger water flow. A deluge system uses a fire detection device but the heads are already open.

Which of the following portable fire extinguishers should not be used to extinguish a small fire in a confined space? A) ABC dry chemical B) Carbon dioxide C) Water D) BC dry chemical

The correct answer is: B The break down of CO2 to CO in a confined space could lead to asphyxiation.

One of the means of egress in a two-story business occupancy consists of a 44 in. wide exit access corridor, two 36 in. doors leading to and exiting from the stairwell, and a 44 in. wide corridor in the stairwell itself. What is the maximum number of occupants that this means of egress may serve? A) 120 occupants B) 147 occupants C) 180 occupants D) 220 occupants

The correct answer is: B The most restrictive egress component is the 44 in. wide stairway. The component with the least capacity determines the total egress capacity. COMPONENT CAPACITY FACTOR CAPACITY Door = 36 in. 0.2 in/person 180 persons Stairs = 44 in. 0.3 in/person 147 persons Door = 44 in. 0.2 in/person 220 persons

Which system design is intrinsically safe? A) A non-redundant system B) Double parallel system C) Cost effective system D) Single parallel system

The correct answer is: B The only redundant system listed is a double parallel.

From a deck of 52 cards, one card is drawn at random. What is the probability that the random card is either a ten or a jack? A) 1/13 B) 2/13 C) 1/26 D) 1/52

The correct answer is: B The probability of drawing a ten = 4/52 = l/13. The probability of drawing a jack is 4/52 = l/13. The probability of either a ten or a jack is l/13 + l/13 = 2/13.

Which of the following has the most potential for fire and explosion? A) Acetone B) Acetylene C) Gasoline D) Hydrogen

The correct answer is: B The range of flammable limits for acetylene (2.5 to 81 percent acetylene in air) is greater than that of other commonly used gases, with consequently greater hazard.

In any study involving statistic analysis, the main focus is on sets of numerical data. The entire set of data from which your data came is called the: A) Sample B) Population C) Bell shaped curve D) Normal distribution

The correct answer is: B The sample is what you take. You hope (and assume) that your sample is representative of the population from which it was drawn.

A mathematical representation of real-world phenomena that serves as a plan or pattern from which these phenomena and their interrelationship can be identified, analyzed, synthesized, and altered without disturbing the real-world processes is called: A) Prototype B) Model C) Synthesis D) Inferential

The correct answer is: B The statement above defines a "Model". Models are common in fields such as accident investigation, risk assessment, etc.

Static pressure on the exhaust side of a fan is normally: A) Negative B) Positive C) Neither negative nor positive D) Greater than 100 MPascals

The correct answer is: B The static pressure on the exhaust side of a fan is normally positive, in relation to atmospheric pressure. The static pressure on the suction side of an exhaust fan is negative, compared with atmospheric pressure.

Velocity pressure of a system is always: A) Negative B) Positive C) Equal to total pressure D) Equal to static pressure

The correct answer is: B The total pressure = static pressure + velocity pressure. Since VP is always exerted in the direction of flow, VP is always positive.

Velocity pressure is: A) The velocity of air divided by 4005 (square root of the SP) B) The difference between total pressure and static pressure C) Independent of velocity D) Proportional to the square root of velocity

The correct answer is: B The total pressure in a ventilation system is equal to the static pressure plus the velocity pressure. The velocity pressure, therefore, is the difference between the total pressure and the static pressure. The CFM is equal to the area of the duct multiplied by 4005 (square root of the velocity pressure). The velocity pressure is directly related to the square of velocity of air in the duct.

Whcih of the following types of interlocks requires two simultaneous physical actions by a person - sometimes within a specific time period - to activate the system? A) Timed action interlock B) Two-hand controls C) Sequential controls D) Simultaneous motion interlock

The correct answer is: B The two-hand control requires two simultaneous physical actions to activate the system.

What is the volume of a 0.76 meter column of mercury if the cross sectional area is 1 m2? A) 76 m3 B) 0.76 m3 C) 0.076 m3 D) 7.6 m3

The correct answer is: B The volume of a column can be calculated using: V= h A = 0.76 m (1 m2) = 0.76 m3

In a semi-conductor operation, a random sampling of 100 wafers showed that 3 were faulty. In a sampling of 2500 wafers, how many may be expected to be faulty? A) 30 B) 75 C) 100 D) 150

The correct answer is: B There is a probability of 3/100 = 3% that a wafer may be faulty. (3%)(2500) = 75

A 12 inch diameter duct has an average duct velocity of 3200 fpm. What is Q? A) 1573 CFM B) 2512 CFM C) 2600 CFM D) 2700 CFM

The correct answer is: B To solve problem: Q = VA Q = (3.14 * 6 in * 6in)/144 in2/ft2) * 3200 fpm =2512 CFM

Which of the following temperature ranges concerning fire sprinker heads color coding is correct? A) 100° ceiling temperature - Orange B) 150° ceiling temperature - White C) 375° ceiling temperature - Blue D) 475° ceiling temperature - Uncolored

The correct answer is: B Use the following table: TEMPERATURE RATING CLASS COLOR 100° 135° - 170° Ordinary Uncolored 150° 175° - 225° Intermediate White 225° 250° - 300° High Blue 300° 325° - 375° Extremely High Red 375° 400° - 475° Very, Extremely High Green 475° 500° - 575° Ultra High Orange

The flowing pressure at a fire extinguishing nozzle is 50 psi. What is the velocity of discharge in feet per second? A) 8.5 ft/sec B) 85.5 ft/sec C) 50 ft/sec D) 600 ft/sec

The correct answer is: B Use the formula Q = 12.1 square root of P Q = 12.1 square root of 50 Q = 12.1 (7.07) Q = 85.5 ft/sec

A ¼ in. vertical air conditioning drain pipe is plugged and now filled with water. What is the gauge pressure (psig) at the base of this 100 ft. high pipe? A) 36 psig B) 43 psig C) 62 psig D) 100 psig

The correct answer is: B Water weighs 62.4 lbs per cubic foot. The size (diameter) of the pipe is irrelevant to the question. psi = 62.4 lb/ft3 * 100 ft * (1 ft / 12 in.)2 = 43.3 lb/in 2 = 43.3 psi

For safety reasons, worker identification tags are to be color coded using only five colors. The colors are always to be applied in groups of three, showing three of the five possible hazards which the workers are trained to handle in their work. In how many ways can the five colors be arranged in groups of three? A) 55 B) 60 C) 65 D) 70

The correct answer is: B When the order of selection is significant then it is a permutation. N!/ (N - X)! 5! / (5 - 3)! 120 / 2 = 60 Possible ways these ID tags can be arranged.

When hazards from operating machinery cannot be eliminated, ________ provides protection to the employee from inadvertent contact with a moving or dangerous part. A) Training B) Guarding C) Personal protective equipment D) Administrative controls

The correct answer is: B Where hazards cannot be eliminated, guarding provides protection against potential failure of people to utilize equipment correctly. Both safe design and guarding minimize the effect of individual differences on accident frequency or severity.

The correlation formula is used to evaluate the relationship between two variables of the same interval. Select the best correlation. A) 0.05 B) 0.50 C) 0.92 D) 1.006

The correct answer is: C 1.0 is a perfect positive correlation, -1.0 is a perfect negative correlation, and 0 is no correlation, therefore 0.92 is the best correlation. Correlations above 1 are impossible.

Which of the following Boolean expressions are not appropriate? A) A.1 = A B) A.A = A C) A+A = 1 D) A.B = B.A

The correct answer is: C A + A = 1 is not appropriate; A + A = A

A distribution of data which has more than one concentration of frequency occurring values is called: A) Histogram B) Modal Statistics C) Multimodal D) Interaction Effect

The correct answer is: C A distribution of data which has more than one concentration of frequency occurring values is called "Multimodal."

The following system is an example of a Fail-active design: A) Cylinder with rupture disc B) Class I Division 1 Wiring C) Transformer with back-up generator D) B or C

The correct answer is: C A fail active design normally creates redundancey by the use of standby equipment. A back-up generator is a perfect example of a fail active system. Choice B) is intrinsically safe and choice A) could be considered fail passive.

An MFL wall is: A) An interior partition that acts as a barrier to the spread of fire B) A fire resistant wall designed to prevent the horizontal spread of fire C) A self supporting wall designed to maintain its integrity if the structure on either side completely collapses D) A concrete block, floor to ceiling, wall that protects one fire zone from the other

The correct answer is: C A maximum forseeable loss (MFL) wall is a fire resistant wall designed to prevent the horizontal spread of fire into adjacent areas and by insurance carrier decree, must be self supporting and designed to maintain its integrity if the structure on either side completely collapses. The MFL wall insures that a total fire loss would not extend beyond the wall.

How many g (NH4)2 SO4 per liter in a 2.5 N solution? (N=14, H=1, S=32, O=16) A) 132 B) 66.0 C) 165 D) 12

The correct answer is: C A normal solution = Number of equivalent wts/L MW is 132 g 132 g/2 = amount of equivalent weights = 66 66 * 2.5 = 165 g/ liter

If a material has a sound absorption coefficient of 0.8 that means that ______ percent of the sound energy in the wave will be ___________ . A) 20, absorbed B) 10 log(0.20/0.80), reflected C) 80, absorbed D) 80, reflected

The correct answer is: C A sound absorption coefficient of 0.8 means that 80% of the sound energy in the wave will be absorbed and 20% will be reflected.

Which of the following Boolean expression defines Full and Empty Sets? A) A.A = A B) A+A = A C) A+1 = 1 D) B.A = A.B

The correct answer is: C A+1 = 1, is the correct answer. The whole, expressed by 1, cannot be exceeded.

Anticipating and controlling hazards are best accomplished: A) Twenty-four hours following a workplace inspection B) Any time before a pilot process is closed to production C) All design stages of an activity D) After an accident has occured

The correct answer is: C Anticipating and controlling hazards at the design stages of an activity is the cornerstone of a safety program. The ultimate goal for any safety program (occupation, systems, product) is to design environments and equipment and to set up job procedures so that employee exposure to injury will be either eliminated or controlled as completely as possible.

Which type of hood(s) would you recommend be designed for operations which release sudden surges of hot gases and vapors? A) Down draft B) Enclosed C) Canopy D) Slotted

The correct answer is: C Canopy hoods are effective for the control of hot processes and for those operations which release sudden surges of hot gases and vapors, e.g. where the thermal currents caused by rising hot air funnel the contaminant into the exhaust system.

The function of a slot in a slot hood is to: A) Decrease capture velocity B) Reduce material required to build system C) Obtain proper air distribution D) Increase capture velocity

The correct answer is: C Capture velocity is essentially independent of its slot air velocity. The function of the slot is to provide proper air distribution by making the pressure drop if the slot is large relative to the plenum.

A generic process of evaluating competing courses of action by examining the dollar costs of certain abatement actions versus the dollar value of the benefits received is called: A) Prime cost asssessment B) Cost analysis C) Cost benefit analysis D) Risk management

The correct answer is: C Cost benefit analysis is a generic process of evaluating competing courses of action by examining the dollar costs of certain abatement actions versus the dollar value of the benefits received.

Cost factor equals the total compensation and medical costs incurred per exposure, and is calculated by which of the following? A) CF = Exposure / cost incurred B) CF = Cost * exposure C) Cost incurred * 1000 / total work-hours D) Total work-hours / cost incurred * 100,000

The correct answer is: C Cost incurred * 1000 / total work-hours is the formula for cost factor.

Which floor surface presents the most resistance to a slip/fall accident? A) Steel B) Granite C) Creosote wood D) Tile

The correct answer is: C Creosote wood flooring would provide the most resistance to a slip/fall accident

Manufacturing firms are required, with limited exceptions, to provide secondary containment for which of the following areas? A) 90 day container accumulation areas B) Waste loading and unloading areas C) 90 day accumulation tanks D) Virgin product storage areas

The correct answer is: C EPA regulations currently require secondary containment for hazardous waste storage and accumulation tanks at 40 CFR Parts 264 & 265-Subpart J. Secondary containment for virgin product storage is currently limited to non-transportation related oil storage, as outlined in the Spill Prevention, Control and Countermeasures (SPCC) regulations found at 40 CFR Part 112-Oil Pollution Prevention. There is no current federal requirement that explicitly requires that 90 day container accumulation areas be provided with secondary containment. Secondary containment is strongly recommended, however, as a best management practice.

Automatic sprinkler systems seldom fail to control fires, however, when a failure does occur the dominant cause is: A) Foreign material obstructing the piping system B) Freezing of water in the piping system C) Improperly closed supply valve D) Inadequate supply of water

The correct answer is: C Factory Mutual records cite PIV's, improperly closed valves, to be the dominant cause for automatic sprinkler system failure. This occurs most often because of maintenance related actions that necessitate system shutdown followed by failure to open the valve after work has been completed. Shutting off the supply valves prematurely during a fire is another leading cause for failure.

A design which allows the system to function safely until corrective action is possible is called: A) Fail safe B) Fail passive C) Fail operational D) Fail non-operational

The correct answer is: C Fail operational is a design which allows the system to function safely until corrective action is possible.

A door hinge fails 4 times out of 1,000,000 operations. What is the failure rate? A) 4 x 10-7 B) 4 x 10-9 C) 4 x 10-6 D) 4 x 10-5

The correct answer is: C Failure Rate = 4 failures / 1,000,000 attempts = 4 x 10-6

An exhaust system operating at 25,000 CFM is increased to 30,000 CFM. What is the required increase in the fan horsepower to handle the increased volume? A) 50% B) 66% C) 73% D) 79%

The correct answer is: C Fan horsepower varies as the cube of the fan speed and cube of the fan volume. Therefore, the required ratio of increase in the fan speed is: (30,000 CFM/25,000 CFM)3 = 1.73 The required increase in the fan horsepower is 73%. You must insure that the fan motor horsepower rating is ample. Ask an electrician.

What is meant when a system is said to be "two fault tolerant?" A) The system will fail when it sustains two independent failures. B) The system will fail when it sustains three independent failures. C) The system is designed to tolerate two independent failures and still operate. D) The system is designed to tolerate three independent failures and still operate.

The correct answer is: C Fault-tolerance is a method of designing equipment to sustain one or more independent failures and still operate (or be able to transition into a fail-safe mode). In this case, the system is designed to sustain two independent failures and still function. Fault tolerance has nothing to do with when the system will fail (i.e., the system may sustain more than three independent failures and still function).

Good engineering controls for manual materials handling tasks are based on which of the following principles? A) Anthropometry B) Epidemiology C) Ergonomics D) Physiology

The correct answer is: C Good engineering controls involve designing the workplace to fit the worker is one of the definitions for Ergonomics. The key scientific areas that have been studied for the purpose of developing ergonomic guidelines for workplace design include: anthropometry, biomechanics, epidemiology and physiology.

Experience has indicated the most effective way to reduce accidents is: A) Training employees to be more safety-conscious B) Behavior modification C) Designing safety features into systems D) Job rotation

The correct answer is: C Hazards can be more effectively reduced or eliminated through system design, whereas hazard reduction through changing human behavior is limited and requires continuous reinforcement.

Round ducts are better than square ducts because round ducts: A) Can be made air-tight easier B) Use less material for the same size C) Are stronger D) Have less friction

The correct answer is: C In industrial applications, high velocities, and therefore high SP's, are normally used. This condition results in duct collapses. Circular ducts are more able to withstand this stress.

NIOSH has conducted over 500 indoor air quality investigations. The primary factor responsible for complaints is: A) Building furnishings B) Microbial contamination C) Inadequate ventilation D) Unknown cause

The correct answer is: C Inadequate ventilation was found responsible for 52% of complaints followed by contamination inside the building (16%), unknown (13%), and contamination from outside the building (10%).

Evaluate the following situation: A chemical process uses a flammable material under pressure. The flammable material is pumped into a reactor vessel (a pressure vessel). The pressure vessel is designed in accordance with ASME requirements. As a part of the process control, the safety relief valve is used to regulate pressure. When the vessel pressure is too high, the safety relief valve lifts, and a flammable mixture flows to the flare (the flare is designed to handle substantially more load than this). Which of the following statements best describes this process? A) The process is designed adequately. B) The process is not designed adequately because flammable materials should not be used under pressure. C) The process is not designed adequately because safety relief valves should not be used to control the pressure in any process. D) The process is not designed adequately because the products of the reactor should not be relieved to the flare through a safety relief valve.

The correct answer is: C It is considered poor engineering practice to control a process with its safety systems. Other process controls and design features should be put in place so that the safety system can be used to relieve the system when safety parameters have been exceeded.

The most desirable method of employee protection would be: A) Engineering controls such as ventilation B) Education/training C) Respiratory protection D) Substitution of the process or material

The correct answer is: D Substitution is the best method of employee protection, since it eliminates the hazard. Ventilation, education, and respiratory protection help to protect the worker from the hazard, but elimination of the hazard is the best solution.

Records pertinent to all phases of a company's manufacturing, packaging, procurement, testing, marketing, distribution and final disposition of finished products should be retained: A) For 30 years B) The life of the product plus 10 years C) Indefinitely D) For 5 years

The correct answer is: C It is essential in product safety loss control that information be collected and maintained through all phases of the manufacturing cycle including final dispositon of finished products. In addition, the records should include quality control activities, labeling, warnings, recall plans and all other program elements that would, if needed, be used in court as evidence of the company's efforts to do the right thing. Prudency dictates these records be kept on file for an indefinite period of time.

During an earthquake the building type you would least like to be in would be: A) Wood B) Steel C) Masonry D) B and C

The correct answer is: C Masonry, due to its characteristics is most impacted by earthquakes.

A wastewater treatment that requires an adjustment of the pH of the waste stream may be needed to obtain optimal conditions for the formation and/or settling of solids is defined as: A) Chemical feeding B) Miving C) Neutralization D) Clarification

The correct answer is: C Neutralization is the process in which pH is adjusted for optimal conditions. For example iron hydroxide settles best at a pH of 8.3, but will dissolve completely below a pH of 6.

The main disadvantage of most heat detectors is: A) False alarm rate is high B) They are costly to install C) They are slow in detecting fire D) They have limited application

The correct answer is: C Of the four kinds of fire detectors in use, heat detectors are the slowest in detecting fires. They are widely used because they are the least expensive fire detector and have the lowest false alarm rate.

In a pre-action sprinkler system, the water is: A) Admitted to the piping by the use of a pressure actuated valve B) Contained in the piping system similar to that of a wet system C) Admitted to the piping through an automatic water control valve that has been activated by a zoned heat responsive system D) Held back from the sprinkler piping by a deluge valve

The correct answer is: C Pre-action systems are designed to protect properties where there is danger of serious water damage as a result of damaged automatic sprinkler heads or piping. The pre-action system is similar to a standard dry-pipe system. To it is added a water supply valve that is opened by the operation of an automatic fire detection system.

In a mine opening you found a total flow of 2000 cfm. The opening was 10' x 10'. What is the velocity of the air in the entrance? A) 3000 fpm B) 2 fpm C) 20 fpm D) 3 cfm

The correct answer is: C Q= VA 2000 cfm = 100 ft2 * Velocity solving for V; V= 20 fpm.

A total flow of 800 cfm was measured in a large duct 5' x 5'. What is the average velocity of the air at the entrance of the duct? A) 2000 ft/min B) 160 ft/min C) 32 ft/min D) 32 cfm

The correct answer is: C Q=AV Area= 5 ft * 5 ft = 25 sq ft Q=800 cfm 800 cfm = (25 sq ft) * V V = (800 cu ft/m)/25 sq ft V = 32 ft/m

If 500 CFM are needed to capture air contaminants six inches from a hood, what volume of air is needed to capture contaminants 12 inches from the hood face? A) 150 CFM B) 550 CFM C) 2000 CFM D) 4000 CFM

The correct answer is: C Required CFM varies as the square of the distance from the contaminant source. A source twice as far away will require (2*2) 4 times the CFM.

Maintenance grounds-keepers often use self-propelled machines to assist them with their work. The most protective type of guard used for this equipment is the: A) Self-adjusting B) Adjustable C) Interlocked D) Fixed

The correct answer is: C Self-propelled lawn mowers and snow blowers are interlocked with the source of power so that the machine cannot be operated without all guards in place. The interlocking guard prevents operation of the control that sets the machine in motion until the guard is moved into position, so that the operator cannot reach the point of operation or the point of danger.

Why would a lead oxide particle settle faster than a silica particle? A) Shape B) Size C) Density D) Diffusion

The correct answer is: C Settling velocity is directly proportional to particle density hence, the lead particle will settle faster because it is has a higher density.

In many cases, canopy hoods are not considered very good because: A) More material needed to construct system B) Larger fans are needed C) Contaminant is drawn thru breathing zone D) Are always considered good

The correct answer is: C Since canopies are above the worker the contaminant must travel very close to, and most of the time through, the worker's breathing zone.

Which is considered a secondary containment method for underground storage tanks? A) Single-walled tanks in sand B) Single-walled tanks in solid ground C) Single-walled tanks in a concrete vault D) Single-walled tanks with high reliability

The correct answer is: C Single-walled tanks in a concrete vault is the only choice that is considered secondary containment.

When applied to electrical apparatus, the term "explosion proof" means: A) Capable of withstanding external explosions B) Capable of excluding the intrusion of explosive gas or vapor C) Capable of containing an internal explosion D) A and B combined

The correct answer is: C The National Electric Code (NEC) defines explosion proof as, "Apparatus enclosed in a case that is capable of withstanding an explosion of a specified gas or vapor which may occur within it and preventing the ignition of a specified gas or vapor surrounding the enclosure by sparks, flashes, or explosion of the gas or vapor within and which operates at such an external temperature that a surrounding flammable atmosphere will not be ignited."

The simplest form of redundancy is the replication of single components in parallel circuits A and B. An output will result if A, B, or both A and B operate. Since reliability is a probability, the reliability of the system is expressed by: A) R (system) = R(A) + R(B) * R(A)R(B) B) R (system) = R(A) + R(B) + R(A)R(B) C) R (system) = R(A) + R(B) - R(A)R(B) D) R (system) = R(A) - R(B)

The correct answer is: C The appropriate expression is: R (system) = R(A) + R(B) - R(A)R(B) Classic probability of parallel events, that are mutually exclusive.

In product safety, the safety professional must give consideration to the design parameters involving malfunctions, operator errors, environmental differences and: A) Safety margins B) Ergonomics C) Loss minimization D) Structural failure

The correct answer is: C The design factors that must be considered include: minimizing loss, malfunctions, operator error and environmental conditions. MINIMIZING LOSS is a provision of protective methods which can be applied to product safety for the purpose of containment and damage minimization. Examples include bumpers, seat belts, explosion barriers and other forms of energy absorbing mechanisms or personal protective safety devices.

This System Safety design philosophy, given a failure, keeps the system energized in a safe mode until corrective or overriding action can take place: A) Intrinsically safe B) Fail passive C) Fail active D) Fail operational

The correct answer is: C The fail active design philosophy keeps the system energized and in a safe mode until corrective action or an override can take place. Intrinsic safety eliminates failure, fail passive knocks system to lowest energy level and fail operational allows system to operate without interruption.

Baffles are put on the canopy of a shake out hood because: A) Channel dust to hopper B) Prevent plugging of grid C) Provide better air distribution D) Lowers noise level

The correct answer is: C The function of the baffles is to provide for better air distribution and hence better control of the air contaminant from this foundry operation.

Risk is usually expressed as the frequency of an event multiplied by the consequence of the event. Usually, consequence is expressed in units of currency (e.g., dollars) to permit comparison of risk across different areas. Which of the following scenarios has the higher annual risk? Scenario A: Minor employee injuries occur about twice per month and cost the company about $3,750 in lost work productivity and $1,800 in medical and insurance compensation. Scenario B: Catastrophic accidents occur about once every 30 years and cost the company about $1,500,000 in lost work productivity and equipment damage, and $2,500,000 in legal fees and other compensation.

The correct answer is: C The minor accidents cost the company $133,200 annually ($5,500 per incident multiplied by 24 times per year ). The major accidents only happen once every 30 years, but cost $4,000,000 when they do happen. Dividing this over 30 years yields and annual risk exposure for the catastrophic accident of $133,333. These are essentially equivalent.

Class B portable fire extinguishers are rated by the size of the fire that a novice can extinguish and are identified by a red square containing the letter "B". The numeral preceding the "B" in the rating indicates: A) Number of seconds it will take to dispense the contents of the extinguisher B) Number of times the extinguisher may be used C) Number of square ft of burning liquid that can be extinguished D) Number of times the unit is effective compared with one gallon of water

The correct answer is: C The numeral preceding the letter "B" indicates the number of square feet of burning liquid that the novice can extinguish with that extinguisher. For example a 20B rating indicates the novice can extinguish 20 square feet of burning liquid fire.

When controlling noise, the following are all proven techniques EXCEPT: A) Substituting the process B) Minimizing sound emitting areas C) Providing adsorption panels D) Eliminating leakage path

The correct answer is: C The panels need to absorb the sound waves, not adsorb them. Process substitution can provide alternative technologies that are less noisy. Reducing the areas that radiate noise will also reduce exposure.

Given two independent events, the probability of their joint occurrence is the product of the independent probabilities. What is the probability of getting two sixes rolling a pair of dice? A) 0.1 B) 0.01 C) 0.028 D) 0.28

The correct answer is: C The probability of getting any one number on a die is 1 in 6. Therefore, the probability of getting two sixes is (1/6)(1/6)=1/36=0.028

What is the probability of getting two heads in three successive tosses of a Lincoln penny? A) 1/8 B) 3/16 C) 3/8 D) 1/4

The correct answer is: C The probability of getting two heads in a particular order is: 1/2 * 1/2 * 1/2 = 1/8 There are three ways of arranging two heads (and only two heads) in three positions, therefore 3 (1/8) = 3/8.

Diesel fuel is pumped into a tank at a rate of 150 gpm. If the tank has a diameter of 18 ft and is 27 ft high, what will be the duration of the filling process if the tank started empty? A) 45 minutes B) 1.3 hours C) 5.7 hours D) 22.9 hours

The correct answer is: C The tank has a volume of 6,871 ft3 . This volume converts to 51,564 gallons (note that there are slightly more than 7.5 gallons per cubic foot). If the tank is filling at a rate of 150 gpm, then the filling process will take nearly 344 minutes, or 5.7 hours.

Air pollution control laws and regulations have generally specified the amounts of pollutants that may be discharged from a source, but not the particular technology or method the source had to use to reduce or eliminate the discharge. The term MACT defines which of the following? A) Minimal Acceptable Control Technology B) Maximum Acceptable Control Technology C) Maximum Achievable Control Technology D) Minimal Achievable Control Technology

The correct answer is: C The term MACT defines the Maximum Achievable Control Technology.

The maximum travel distance in an industrial occupancy fully protected with automatic sprinklers is: A) 200 ft B) 150 ft C) 250 ft D) 300 ft

The correct answer is: C The travel distance to at least one exit shall not exceed 200 ft in industrial occupancies NOT equipped with a sprinkler system or exceed 250 ft in industrial occupancies protected throughout by an approved, supervised sprinkler system. NFPA 101 40.2.6.1 (Life Safety Code)

In an assembly of 4,321 adults, 1,792 are college graduates. What is the probability (to the nearest tenth) that a person chosen at random from this group is not a college graduate? A) 0.4 B) 0.5 C) 0.6 D) 0.7

The correct answer is: C There are 4,321 - 1,792 people who are college graduates. The probability of choosing one of these people is: 2529/4321 = 0.6 to the nearest tenth.

If a bus is going 60 miles per hour, how many feet per second does this equal? A) 66 feet/second B) 77 feet/second C) 88 feet/second D) 99 feet/second

The correct answer is: C To convert 60 miles per hour to feet per second, you must manipulate conversions. 60 miles/hour * 5,280 feet/mile * 1 hour/60 minutes = 316,800/3,600 = 88 feet/second. To check: note that all units cancel except feet/second.

A fire protection standpipe 110 ft high is filled with water. What is the gauge pressure at the bottom of the pipe? A) 33 psig B) 38 psig C) 48 psig D) 62 psig

The correct answer is: C To determine the pressure at the bottom of the pipe, obtain the density of water from the OHST/CHST Examination Reference Handout and multiply it by the height of the standpipe. Convert the units to obtain pounds per square inch (psi). Water has a density of 62.4 lbs./ft3. 110 ft (62.4 lbs./ft3)(1 ft/12 in.)2 = 47.67 psi To obtain the absolute pressure, add 14.7 psi to the gauge pressure.

You passed the ASP Core Examination with a score of 192. The cumulative statistics for this examination are as follows: Mean 180, standard deviation 32. How many safety professionals taking the exam have scored higher than you? A) 47% B) 56% C) 35% D) 40%

The correct answer is: C Use the formula: z = X - / s = 192 - 180 / 32 = 0.375 = 0.646 (from table) 1 - z = 35% scored higher

The tendency of a liquid to vaporize at room temperature determines its: A) Rate of evaporation B) Vapor pressure C) Volatility D) Flammable range

The correct answer is: C Volatility is the tendency or ability of a liquid to vaporize. Alcohol and gasoline are examples of liquids, and because of their tendency to evaporate rapidly, are called volatile liquids.

A 10 part block and tackle is used to lift a load of 3 tons. Neglecting shear friction, what is the force required? A) 100 pounds B) 200 pounds C) 300 pounds D) 600 pounds

The correct answer is: D A 600 pound force is required. 3 tons * 2000 pounds/ton = 6000 pounds 6000 pounds / 10 = 600 pounds

A system safety design concept that allows functions to continue safely given a failure is: A) Intrinsically safe B) Fail active C) Fail passive D) Fail operational

The correct answer is: D A fail operational design allows a system that is experiencing a failure to continue to operate safely until corrective action is possible. Limited disruption, if any, is experienced.

A system of forces is ____ if all the forces have a common line of action. A) Concurrent B) Tangential C) Coplanar D) Collinear

The correct answer is: D A system of forces is collinear if all the forces have a common line of action.

A system of forces is ____ if the lines of action of the forces have a common point of intersection. A) Combined B) Normal C) Non-concurrent D) Concurrent

The correct answer is: D A system of forces is concurrent if the lines of action of the forces have a common point of intersection.

The typical "scrubber" used in a factory for acid vapor emissions control is: A) Filter B) Electrostatic precipitator C) Cyclone D) Wet collector

The correct answer is: D A wet collector controls emissions through absorption of the air stream with a caustic liquid.

Which of the following is not an appropriate Boolean expression? A) A+B+C = 1 B) A+A+1 = 1 C) A+0+1 = 1 D) A+A+A = 1

The correct answer is: D A+A+A = 1 is not appropriate; A+A = [A], therefore, [A]+A = A A+A+A = A

Fail-safe designs try to ensure that a failure will leave the product unaffected or will convert it to a state in which no injury or damage will occur. Which design does NOT meet this criteria? A) Fail passive arrangements B) Fail active design C) Fail operational arrangements D) Fail mode design

The correct answer is: D All of the following designs may be considered fail-safe. FAIL PASSIVE ARRANGEMENTS are similar to fuses and circuit breakers; they reduce the system to its first level. FAIL ACTIVE DESIGN maintains any condition that will keep the system in a safe mode until corrective or overriding action occurs. FAIL OPERATIONAL ARRANGEMENTS allow functions to continue safely until corrective action is possible.

A router made by X Corp. is sold to Y company by ABC Corp. An employee is injured utilizing the employee modified router. Who is potentially liable? A) X Corp B) Y Company C) ABC Corp D) All parties are potentially liable

The correct answer is: D All parties involved are potentially liable in this situation.

Which of the following engineering controls would be the most appropriate for a worker exposed in a steel mill to air temperatures exceeding 105°F? A) Use of increased general ventilation B) Use of cooling fans C) Provision of cooling fans D) Application of radiant heat shielding

The correct answer is: D Although increasing general ventilation, using cooling fans, or providing spot cooling would result in some improvement, the application of radiant heat shielding is more appropriate. A steel mill (or forge shop, foundry, glass manufacturing plant) is a hot, dry industry, where the thermal load on the worker is increased by the sensible heat given off by the process equipment. The major heat source is radiant heat from molten metals and cherry red ingots, while that of the surrounding hot air is secondary. Radiant heat has no appreciable heating effect on the air it passes through, but its energy is absorbed by any object it strikes. Therefore, the application of a shield to either absorb or reflect the radiation from the heat source would be an appropriate engineering control.

Non-regulatory consequences of failure to adequately clean up chemical releases include all EXCEPT: A) Decreased property values B) Difficulties in selling the affected property C) Reduced collateral value of the property in borrowing situations D) Reduced charges to waste disposal budget

The correct answer is: D Answers A, B, and C are possible. Answer D is not - most likely, costs will increase. Chemical contamination can cause a property to have a negative economic value because the costs of remediation exceed the market value of the property, once remediated. There are legal/regulatory consequences as well.

How many molecules does 0.8 moles of chlorine gas contain? MW=70.9 A) 2.4 x 1023 molecules B) 3.6 x 1023 molecules C) 3.8 x 1023 molecules D) 4.8 x 1023 molecules

The correct answer is: D As one mole of anything contains 6.02 x 1023 molecules, use the following calculation: 0.8 moles x 6.02 x 1023 molecules/mole = 4.8 x 1023 molecules

The first step following primary treatment may be the addition of ingredients to effect a chemical or physical change in pollutants in the wastewater is: A) Mixing B) Clarification C) Neutralization D) Chemical feeding

The correct answer is: D Chemical feeding is the step following primary treatment the function of which is to effect a chemical or physical change in the wastewater.

The fall season has arrived at a New England office facility and with it, a rash of complaints, that did not happen during the summer, concerning the HVAC system. Which trouble-shooting step should be first? A) Determine if the dampers are operating properly B) Check the inside/outside temperature controls C) Determine if the air distribution is balanced to specifications D) Check the make-up air system

The correct answer is: D During the warm months of the year, large volumes of air of relatively high velocities are welcome by the workers. During the fall or winter months, care must be taken to make sure that air blowing over the occupants is kept within acceptable values, (comfort conditions) suitable for the work situation.

All of the following are decomposition products of Halon 1301 EXCEPT: A) Hydrogen Fluoride B) Hydrogen Bromide C) Bromide D) Ethylene

The correct answer is: D Ethylene is a gaseous olefinic compound resulting from the cracking of either selected petroleum fractions or natural gas.

What is the specific gravity of a 1 lb can of beans when it weighs 0.75 lbs submerged in water? A) 0.75 B) 1.33 C) 1.75 D) 4.00

The correct answer is: D First, determine the weight of the water displaced. 1 lb - 0.75 lbs = 0.25 lbs. Next, divide the original weight of the can of beans by the weight of the water displaced. 1 lb / 0.25 lbs = 4. Specific gravity is the density of the item / density of water.

What material should be used to provide shielding against gamma rays? A) Aluminum sheet B) Paper C) Pyrex D) Lead

The correct answer is: D Gamma rays must be shielded by dense materials such as lead. The thicker and denser the material the better.

In general which of the following operations would require the greatest capture velocity to achieve effective exposure control? A) Evaporation from open surface tanks B) Spray booths C) Welding D) Grinding

The correct answer is: D Grinding operations release contaminants at high initial velocities. The other operations release contaminants with low velocities. Higher capture velocities are required to entrain the releases from the grinding operations.

All the following secondary hazards should be considered as a result of discharge of Halon 1301 EXCEPT: A) Noise B) Dislodgement of objects C) Frostbite burns to skin D) Heat

The correct answer is: D Heat is not a secondary hazard as a result of discharge of Halon 1301.

If four coins are tossed simultaneously, what is the probability that all four coins will be heads? A) 1/2 B) 1/4 C) 1/8 D) 1/16

The correct answer is: D If one coin is tossed, the probability of heads is 1/2. For four coins it is: 1/2 * 1/2 * 1/2 * 1/2 = 1/16.

A successful research study is characterized by which of the following? A) The study must involve random samples B) The study and control groups must show the same results C) Variables for study and control groups must be controlled by one person D) Evidence of the study must be reproducible by others

The correct answer is: D If results of a study cannot be reproduced by other researchers, the study has questionable validity.

Any of the following are major cause(s) of electrical shock EXCEPT: A) Ungrounded frames or inadequate grounding of frames on noncurrent-carrying parts of electrical machinery and tools B) Inadequate protection of exposed current-carrying parts of electrical installations C) Inadequate insulation of electrical conductors D) GFCI

The correct answer is: D Listed are the three major causes of electrical shock as reported by OSHA in their student manual "Guide to Voluntary Compliance". The National Electric Code (NEC) provides instructions for eliminating shock hazard from the workplace. GFCI stands for Ground Fault Circuit Interrupter and prevents electrical shocks.

Means of egress, as defined by the National Fire Protection Association in their Life Safety Code, consists of three separate and distinct parts. Which of the following should be excluded? A) Exit access B) The exit C) The exit discharge D) The exit doorway

The correct answer is: D Means of egress is a continuous and unobstructed way of exit travel from any point in a building or structure to a public way and consists of three separate and distinct parts, namely, exit access, the exit and exit discharge.

Means of Egress as defined in the NFPA Life Safety Code (NFPA 101) include all of the following EXCEPT: A) Exit access B) Exit C) Exit discharge D) Exit doorway

The correct answer is: D NFPA 101 (Life Safety Code) states that a means of egress involves the exit access, exit and exit discharge. These components of the means of egress are further defined in the NFPA's Life Safety Code Handbook. NFPA 101 3.3.121 (Life Safety Code)

What is not an acceptable method of controlling static discharge? A) Grounding B) Bonding C) Conductive flooring D) Open Circuits

The correct answer is: D Open circuits are not an acceptable method of controlling static discharge.

The most common cause of indoor air quality problems is: A) Off-gassing from building materials and furnishings B) Cigarette smoking C) Processes using volatile chemicals D) Poor ventilation

The correct answer is: D Poor ventilation is the most common cause of indoor air quality problems because air contaminants from sources such as cigarette smoke, processes, and off-gassing build-up can cause hypersensitivity in employees. The other answers contribute to the cause, but poor ventilation is usually the root of the problem.

Secondary containment should be considered for all EXCEPT: A) 90-day container accumulation areas B) Chemical and waste loading and unloading areas C) Virgin product storage areas and tanks D) Immersion heaters

The correct answer is: D Secondary containment of chemical and waste storage and transfer areas is a best management practice and should be seriously evaluated even where not currently required by federal, state, or local regulations. Immersion heaters present a fire hazard in electroplating operations but do not require secondary containment.

What is the annual electricity cost to operate a 100 W light bulb all day for every day of the year? Electricity in this jurisdiction costs 10.2 cents per kWh. A) $10.20 B) $19.96 C) $24.22 D) $89.35

The correct answer is: D Simply determine the total power consumption over the year. 100 W/ 1,000 W per kWh * 24 h/day * 365 days/yr * $0.102 per kWh = $89.35

A three-legged sling is supported from a single point and attaches to a 1000 lb. steel cylindrical object at three equidistant points along the cylinder's circumference (i.e., the attachment points on the steel cylinder are 120 degrees apart). The center of gravity of the cylinder runs through its center. When attached to this steel cylinder, each leg of the sling creates a 30 degree angle with respect to the load. What is the tension in each leg of the sling? A) 333 lbs B) 385 lbs C) 577 lbs D) 667 lbs

The correct answer is: D Tension (one leg) = 1/3 of Total load/sin 30° Tension (one leg) = 1/3 of 1,000 lbs/sin 30° Tension (one leg) = 333.3/0.05 Tension (one leg) = 667 lbs. When you have the angle of each leg of the sling with respect to the load (or with respect to the horizontal), divide the load by the sine of the angle.

The minimum width of any exit access for new construction shall be no less than: A) 28 inches B) 30 inches C) 32 inches D) 36 inches

The correct answer is: D The NFPA Life Safety Code (NFPA 101) states that the minimum width of any exit access shall be as specified for individual occupancies, but in no case shall such width be less than 36 inches (91 cm). In existing buildings, the minimum width shall not be less than 28 inches. NFPA 101 7.3.4.1 (Life Safety Code)

Use of the binomial distribution is extremely difficult when n is large or p or q is small. It is often advantageous to approximate the probability of occurrences by the use of: A) Gaussian B) Weibull C) Gamma D) Poisson

The correct answer is: D The Poisson distribution is often used in these instances. Poisson distributions describe rare events.

As a safety professional, you are asked to recommend a fire detector for use in a Class I, Division 2 work area. Which of the following would you select? A) Fixed temperature B) Rate compensated thermal C) Rate-of-rise thermal D) Bulb detection system

The correct answer is: D The bulb detection system is completely mechanical thereby avoiding the use of electricity and a potential source of ignition in an area where volatile flammable liquids or gases are used.

A device that separates slurries or liquids of different densities is called: A) Filter press B) Rotary vacuum filter C) Strainer D) Centrifuge

The correct answer is: D The centrifuge is the device that separates materials based on their densities.

Strict liability can refer to the standard of liability in the United States. The practical implications of strict liability in cases of environmental contamination are best described as: A) The liability applies regardless of fault, and the government does not have to prove intent or negligence on the part of the responsible party B) Compliance with laws and regulations in effect at the time of disposal does not matter C) The government does not need to prove that a responsible party's waste at the site actually was released or caused harm D) All of the above

The correct answer is: D The liability provisions of CERCLA are found at Section 107, and are strict, joint and several, and retroactive.

In a 25 ft high assembly area designed for fire safety, a 6 ft metal curtain has been affixed to the bar joists. What is the least likely fire safety purpose ? A) Delays and limits the horizontal spread of heat, gases and smoke B) Assists in making the venting more effective C) Provides a horizontal confinement to obtain a stack effect D) Delays and limits the vertical spread of heat, gases and smoke

The correct answer is: D The metal curtain is a draft curtain that functions to delay and limit the horizontal spread of heat, gases and smoke by providing a horizontal confinement to obtain a stack effect. The placement of draft curtains makes the venting more effective in that the volume of hot gases and smoke discharged by thermal updrafts through a vent, varies directly with the height of the gas or smoke column.

All of the following are examples of malfunctions which cause an impact to a system EXCEPT: A) Structural B) Mechanical C) Power D) Human

The correct answer is: D The potential malfunctions in any system include structural failure, mechanical malfunctions, power failures, and electrical malfunctions. The human component, though critical, is not considered to be a malfunction.

Ventilation systems are designed for any of the following EXCEPT: A) Supply oxygen B) Remove contaminants C) Provide comfort D) Supply carbon dioxide

The correct answer is: D The purpose of ventilation includes removal of contaminants, dilution of contaminants and supplying make up air.

What major code(s) are utilized in the design and construction of pressure vessels in the United States? A) ASME B) API Standard 620 C) CFR D) Two of the above

The correct answer is: D The two major codes in use today are ASME (American Society of Mechanical Engineers) Code and the API (American Petroleum Institute) Standard 620. An earlier code discontinued in 1956 was the API-ASME Code.

Which of the following interlock can sense the presences of nonporous materials? A) Radio-frequency inductive B) Magnetic sensing C) Photoelectric device D) Ultrasonics

The correct answer is: D Ultrasonic interlocks are used to sense the presence of nonporous materials.

An exhaust duct static pressure is -1.50 inches. Total pressure is -0.75 inches. What is the standard air velocity pressure? A) -0.25 inches B) -0.50 inches C) -0.75 inches D) .75 inches

The correct answer is: D Using the equation SP + VP = TP TP = -.75 inch, SP = -1.50 inch VP = -.75 -(-1.50) = 0.75 inch

An exhaust duct static pressure is -1.50 in.. Total pressure is -0.75 in.. What is the standard air velocity pressure? A) -0.25 in. B) -0.50 in. C) -0.75 in. D) 0.75 in.

The correct answer is: D Using the equation SP + VP = TP TP = -0.75 inch SP = -1.50 inch Substituting and rearranging we get: VP = -0.75 - (-1.50) = 0.75 in

A gas occupies a volume of 2.75 liters at 87°C and 150 torr. What volume will the gas occupy at 25°C and 745 torr? A) 0 liters B) 0.13 liters C) 0.23 liters D) 0.46 liters

The correct answer is: D Utilizing the combined gas law equation (P1 V1 /T1 = P2 V2 /T2 ) and converting all temperatures to Kelvin (°K =°C + 273), the equation is: V2 = [(150 torr)(2.75 liters)(298°K)] / (745 torr)(360°K) = 0.46 liters

What is the name of the data collection technique in which the population is divided into subclassifications, or strata, from which a certain number of cases is drawn by chance (taking random samples from each subclassification)? A) Stratified Random Sampling B) Variance Sampling C) Random Sampling D) Validity Random Sampling

What is the name of the data collection technique in which the population is divided into subclassifications, or strata, from which a certain number of cases is drawn by chance (taking random samples from each subclassification)? A) Stratified Random Sampling B) Variance Sampling C) Random Sampling D) Validity Random Sampling