ASP Exam - Domain 3 (Ergonomics)

Action Limit and Maximum Permissible Limit in manual lifting

- AL: Meets spinal compression force limits and has low incidence of injury. Most people can lift AL loads (75% of women, 99% of men) - MPL: Increases injury rates, requires engineering controls (1% of women, 25% of men) - e.g., repackaging materials into lighter loads, raising pallet, lowering conveyor, get adjustable pallet lift - Between AL and MPL: Admin controls required at minimum (training, worker strength training, teaching manual lifting concepts)

What are the minimum elements of stress prevention program?

- Build general awareness about job stress (causes, costs, control) - Secure top management commitment and support - Incorporate employee involvement in all phases - Establish technical capacity to conduct program (e.g., hire specialized consultants or hold specialized training)

Significant control

- Condition requiring precision placement of the load at the destination of the lift - Worker has to regrasp load, momentarily hold object, carefully position/guide at the destination

What are some ergonomic factor risks associated with the aging workforce? What are some controls?

- Decreased capacities in strength, range of motion, duration of activity, vision and hearing - Underscores the need for a well-planned return to work program - Workers who are older actually tend to experience fewer workplace injuries - Controls: Match tasks to abilities, reduce repetition

Controls for heat-related issues

- Engineering controls, physical conditioning, acclimatization, fluid and salt replacement, training, adherence to work/rest cycle Engineering - Air conditioning, ventilation, convection fans, heat shields, chillers and mechanical refrigeration Administrative and Work Practice - Acclimatization takes about 2 weeks - expose 20% on each day for 5 days - Fluid and salt replacement - eat normal meals, avoid extremely cold drinks - Work/rest cycle - determine Wet Bulb Globe Temperature Index and average metabolic rate of person

What is Heinrich's law?

- For every 1 major injury, there are 29 minor injuries and 300 accidents without injuries - Not basis of modern behavior-based safety

What are the elements of every behavior-based safety program?

- Identify/target behaviors that affect safety - Define those behaviors precisely enough to measure them reliably - Develop and implement mechanism for measuring those behaviors to determine current status and set reasonable goals - Provide feedback and reinforce progress

4 principles of workstation layout

- Importance: Most important component is directly in front of the operator - Frequency of use - Functional: Things that are functionally related should be grouped together (all electrical systems together and all hydraulic systems together) - Sequence of use

What are some risks for workers who perform concrete grinding, cutting, and jackhammering?

- Inhaling respirable crystalline silica - silicosis/pneumoconiosis - Use wet polishing to cool diamond abrasives (grinding/polishing), use local exhaust ventilation (concrete saw), use water-spray attachment (can reduce dust exposure by 70-90%)

What factors contribute to occupational and non-occupational ergonomic (musculoskeletal) risks?

- Magnitude/force, frequency/repetition, duration, posture, vibration, cold temperatures, machine-paced work, insufficient rest breaks - Segmental vibration: Affects part/segment of body (arm, hand while using jackhammer) - vascular insufficiency resulting in interference with sensory receptor feedback --> carpal tunnel syndrome - Whole body vibration: E.g., truck drivers and lower back pain Non-occupational ergonomic risk factors: Age, gender, arthritis, endocrinological disorders, obesity, pregnancy, diabetes, acute trauma

Ropes, Chains, Slings (Rigging) Hazards and controls

- Main hazards are overloading, deterioration or wear, exposures, improper rigging/abuse - Factors that affect rigging risks - type of hitch, angle formed by the legs - Controls include fitting hooks with retainers, selecting correct rigging materials, regular inspection, reading load capacity charts

Wet Bulb Globe Temperature

- Measures hotness felt by people depending on air temperature, speed of air movement, radiant heat from hot objects, solar power, body cooling due to sweat evaporation - Uses ACGIH TLV

Compressed air systems/pneumatic tools hazards and controls

- Powered by compressed air - chippers, drills, hammers, sanders - Compressed air cannot be used for cleaning unless reduced to less than 30 psi

5 controls to manage storage of material hazards

- Proper stacking, cross ties to interlock materials, stepping back rows, retaining walls, racks and protective barriers at bottom to prevent vehicle collision

What is the difference between pursuit and compensatory control tracking?

- Pursuit: Both target and controlled element move (driving) - Compensatory: Either controlled element or target is fixed, and remaining element moves in response to control (aircraft instrument landing system, "pong" game)

Lifting Index

- Relative estimate of level of physical stress associated with particular manual lifting task - Answers: "How significant is the risk?" LI = Object Weight (L) / RWL

Conveyors hazards and controls

- Roller, belt, screw, bucket, chain, wheeled carts, hoppers - Overhead moving loads - use protection plate, mesh, net, etc. - Use fixed guards (surrounding, barrier/fixed distance, fixed in-running nip guards), interlocking guards, interlocked guards with guard locking

What is involved with work hardening? How is it different from work conditioning?

- Work hardening: Highly structured, individualized, job-specific program with the goal of return to work using real/simulated activities. Multi-disciplinary and includes job coaching, ergonomic evaluation, etc. 1. Exercise and strengthening 2. Work simulation 3. Building cardiovascular work endurance - Work conditioning: restore the performance skills of workers recovering from long-term injury or illness Job rotation - structured interchange of workers between different jobs, requiring workers to rotate between different workstations or jobs at certain time intervals - increases the variety of tasks required as the worker takes on more duties, enlarging the physical demands and adding variety to the job

What are the 2 primary causes of job stress?

- Worker characteristics - Working conditions (NIOSH-favored view)

What are some types of slings and their uses?

1.) Chains: Strength and ability to adapt to shape of load; sudden shock may damage alloy chains 2.) Wire rope: Fiber core is flexible but more prone to environmental damage. Wire rope core is stronger and is resistant to heat damage 3.) Metal mesh: Used for abrasive and hot loads 4.) Fiber rope and synthetic web: Primarily used for temporary work (construction, painting, marine), good for expensive loads, highly finished parts, fragile parts

What is the safety factor for manila rope in block and tackle assembly?

10

What is the maximum amount of flammable and combustible liquids in a room or single fire area?

25 gallons

Voluntary muscle is controlled at will and comprises what percentage of body weight?

40%

How do you enhance or diminish reliability of a system?

Adding components in parallel, redundancy, or series Diminish - designing complementary components

What is the rule of thumb for angle as related to sling legs?

Angles of legs increase (becomes wider) -> leg tension increase -> carrying capacity decreases Sling where both legs is vertical is strongest. In another words: Tension on each leg increases as angle of lift from horizontal decreases (inverse relationship)

What is the most common hazard when using pneumatic tools?

Being hit by tool attachment or fastener

What information is required to document training occurred?

Both worker and trainer need to certify: Worker name, date, subject Worker demonstrated safe procedures to standard All questions were answered to worker's satisfaction Worker will comply with safe procedures as condition of employment

What does the Ergonomics Job Hazard Analysis do?

Breaks job into various elements or actions Describes them Measures and quantifies ergonomic risk factors inherent in the elements Identifies conditions contributing to the risk factors Determines corrective measures

What is the primary hazard for operating gas-powered industrial trucks in an unventilated space?

Carbon monoxide

What are cold-related stresses and injuries?

Chilblains: aka pernio/perniosis Itchy and tender red/purple bumps caused by blood vessels shutting down in the cold - Occur several hours after exposure Hypothermia: Body temp dips below 95F; impacts to cerebral, musculoskeletal, cardiac functions Frostbite: Exposure to env temperatures below zero - Depends on wind chill, temperature, length of exposure - Do not rub frostbitten parts or pour hot water directly. Immerse body part in warm water (105 maximum). Do not warm skin if it will be cold again.

Human-machine interface design principals should incorporate:

Compatibility, coding, and arrangement

Drills, belt sanders, and chainsaws all have this safety feature in common.

Constant pressure switches and controls (shuts off when pressure is released)

If the air temperature is above the skin temperature you should ________ the air velocity to reduce the convective load.

DEcrease If the air temperature is above the skin temperature, increasing the air velocity will increase the convective load, however it may increase the heat loss by evaporation.

The three basic choices for applying anthropometric data to the design of the work place include:

Design for the average, extremes, and range to allow for adjustability - Design so things are adjustable for different users - Design for the 95th percentile male to fit and 5th percentile female to reach to allow most people to fit - Know the population you are designing for

What is Reynaud's syndrome?

Disorder of the blood vessels, usually in the fingers and toes and affected area turns blue - aka white finger syndrome Due to cold temperatures and vibration, such as from operating a jackhammer

What are some examples of commercial behavior-based safety systems?

Dupont STOP, SafeStart, Aubrey Daniels, Check 6

What are different types of power tools?

Electric: Abrasive grinders, jig saw, circular saw, belt sanders, electric drills, paint spray guns Hazards include electrical burns, shock, heart failure Pneumatic: Chippers, drills, hammers, sanders Hydraulic: Jackhammer, riveting machines, breaker, hydraulic jack Liquid fuel: chain saws, lawn mowers, concrete saws, and brush cutters Powder: Hilti gun, Ramset gun (types of nail guns)

What are the goals of ergonomics training?

Enable workers, supervisors, and managers to identify aspects of job tasks that may increase a worker's risk of MSDs Recognize signs and symptoms of MSDs Participate in development of strategies to control them

Only these employees may be in the fall zone while operator is moving a suspended load

Engaging in hooking, unhooking, guiding load Engaged in initial attachment of the load to component or structure Operating concrete hopper or concrete bucket

What are 3 major types of human factors elements that cause accidents?

Environmental (noise, cold, distractions) Internal (personal problems, emotional stress) Situational (unclear instructions, new trainer)

What are some rules for using portable tools (e.g., abrasive wheels, belt sanders, circular saw, abrasive grinder)?

Exposure to the wheel cannot exceed maximum 180 degrees Top half of wheel must be enclosed Vertical "right" angle grinders need 180 degree guard between operator and wheel

What are hazards associated with portable abrasive wheel tools?

Flying objects, abrasions, cuts

Powered vehicles

Forklifts, backhoes, bulldozers Hazards: Visibility, load limits, power source, high center of gravity Controls: Rollover protection system (ROPS) (forms operator compartment, may have 4 columns and crossbars), falling object protection system (FOPS) - managed by Society of Automotive Engineers

What are principles of forklift loading?

Fulcrum principle Stability triangle Center of gravity Moment

Hand-operated materials handling vehicles

Hand trucks, trollies, wheelbarrows Hazards: Load shifting, tipping Controls: Push than pull, large diameter wheels or pneumatic tires for easier maneuvering, limit load height for visibility, ensure handle and tongue extend further so the feet are not run over

What handle style is best for high force tasks?

Handle length longer than the widest part of your hand (4-6 inches)

What are the heat-related issues?

Heat rash: Hot, humid environment where sweat remains trapped on skin because of poor evaporation and hygiene. Heat cramps: Occurs when a person drinks large quantities of water but doesn't replace body salts - causes loss of electrolytes Heat syncope: Fainting caused by mild overheating with inadequate water or salt. Can exhibit normal body temperature - Main cause is pooling of blood in legs and skin from prolonged static posture Heat exhaustion: Loss of large amounts of fluids and salts through excessive sweating. Person still sweats but is exhausted and fatigued. Pale, clammy skin and nausea Heat stroke: MEDICAL EMERGENCY. Body's temp regulation system fails, sweating becomes inadequate or stops. Symptoms include hot/dry skin, chills, euphoria, irritability, shivering, erratic behavior - Core body temp above 104F

2 main power sources for powered industrial trucks are

Internal combustion (LPG, compressed natural gas, gasoline, diesel) Electric

What are examples of hydraulic power tools? What is a requirement for the fluid operating hydraulic power tools?

Jackhammer, riveting machines, breaker, hydraulic jack Must be approved fire-resistant fluid and retain its operating characteristics at the most extreme temperatures

What are hoisting apparatus safety controls?

LIDS: Load Indicating Devices - used for cranes to measure the load and provide operator with reading load or warning - Ensure chains and ropes are free of kinks, ensure stability (outriggers for boom cranes, anchoring cables for tower cranes), ensure safe load (know boom length and angle)

What is the best natural fiber for a rope?

Manila rope for slings and capstans

What are the 3 motivation theories?

Maslow - needs Herzberg - two factors Vroom - expectancy a) Maslow: - Looks at individual for variables that affect desired performance - humans are motivated by unsatisfied needs - Lower needs must be satisfied before next-higher level serves as a motivator 1.) Physiological 2.) Safety 3.) Social needs, love, belonging 4.) Esteem (ongoing): confidence, achievement, respect of others, respect by others, personal need to contribute 5.) Self-actualization (ongoing): Can accept human nature addressing shortcomings and failures; focus on solving problems for the greater good - problems considered "task that they must do" b) Herzberg - enrich a work environment so that it allows self-motivation - Hygiene factors (affect level of dissatisfaction): Physical working conditions, interpersonal relationships, policies and rules, supervisor quality, salary - cyclical in nature, new becomes the norm. Hygiene is used in a sense that they are "maintenance" factors that are necessary to avoid dissatisfaction. Should only be considered as ways of minimizing job dissatisfaction. - Motivation factors (affects job satisfaction): Achievement, advancement, recognition, responsibility, work itself, personal growth c) Vroom - mental processes regarding choice - Expectancy theory: Valence (how deeply someone wants the outcome - reward must be valuable), Expectancy (belief that one's effort will result in attainment of desired performance goals), Instrumentality (trust and belief that reward will be given once goal is met) - People can be motivated to perform when there are clear links between behavior and reward - individuals are going to select their behaviors based on the outcomes that they expect as a result of those behaviors

When does twisting amplify the forces on the lower back during a lift?

Middle of the lift

Abrasive wheels and grinders hazard controls

Must be ring- or vibration tested Ring: Evaluates sound coming from wheel when lightly tapped with non-metallic material. Tap the wheel about 45 degrees on each side of the vertical line. Undamaged wheel sends clear ringing tone. Vibration test: Evaluates how sand moves on side of a vibrating wheel. If stable, sand will remain evenly spread on the wheel.

NIOSH Lift Equation/Recommended weight limit (RWL)

NIOSH Lift Equation/Recommended weight limit (RWL) - Assess physical stress of 2-handed manual lifting tasks THAT CAN BE LIFTED/LOWERED BY 90% OF AMERICAN INDUSTRIAL WORKERS - Assumes non-lifting manual handling is minimal (e.g., non-lifting = holding, pushing, pulling, carrying) - Defined for specific set of task conditions as the weight of the load that nearly all healthy workers could perform over substantial period without increased risk of developing low back pain or injury - Answers: "Is this too heavy for the task?" RWL = LC x HM x VM x DM x AM x FM x CM LC - load constant HM - horizontal multiplier VM - vertical multiplier DM - distance multiplier AM - asymmetric multiplier FM - frequency multiplier CM - coupling multiplier

What is the rule for stacking lumber?

No more than 16 feet high if handled manually, 20 feet if using a forklift

How is wind chill factor defined?

Number of calories lost in 1 hour from a square meter of a surface kept at 91.4F Function of air temperature and wind speed

What is the most effective approach to managing work stress?

Organizational change and stress management

What are 4 basic sources of heat to the body?

Radiation, convection (thermal energy is transferred via heated fluids), conduction (thermal energy is transferred between 2 objects in contact), metabolic

What are the 4 ways that heat is lost through a body?

Radiation, convection, conduction, evaporation

What is DeQuervain's syndrome?

Repetitive strain injury that affects tendons on the thumb. Use Finkelstein's test for diagnosis

What is the most harmful variation of vibration?

Resonant frequency vibration

Which power tool causes most injuries on the job?

Saws, drills, nail guns

6 elements in the human-machine interface

Sensing, Information Processing, Action Controls, Machine Operation, Displays

What are the 4 methods for creating control resistance?

Springs, friction, viscous damping, inertia

What is an interlock? What are some examples?

Switch intended to prevent access to energized equipment or dangerous location - makes the state of two mechanisms or functions mutually dependent

What are some job conditions that may lead to stress?

Task design Management style Interpersonal relationships Work roles Career concerns Environmental conditions

What are the ancillary structures of the human skeleton?

Tendons, cartilage and ligaments

What is the rated test load for cranes?

Test loads shall not be more than 125 percent of the rated load unless otherwise recommended by the manufacturer (in order to rate a crane to 100 percent of the design intended loading)

What elements in incident management procedure are key to stress management?

Training and preparedness

Types of basic hitches

Vertical hitch: can use full lifting capacity. Never for unbalance loads. Choker hitch: achieve only about 75% of their potential capacity, cannot be used for loose bundles of materials - provide greater contact area to better secure the load, increase control during movement, and prevent slippage from the sling Basket hitch: Avoids twisting but cannot be used with loads that are difficult to balance. has twice the lifting capacity of a single leg vertical hitch when the legs are in a true 90° vertical fashion

What are some examples of powder-actuated tools? A powder-actuated tool must not be able to operate until...

What are some examples of powder-actuated tools? A powder-actuated tool must not be able to operate until...

When are bent handles better to use than those with single handles?

When the force is applied horizontally in the same direction as straight forearm and wrist

Where should repetitive lifts occur?

between knuckle and shoulder height

What is hand-arm vibration syndrome?

neurological disorders, vascular and musculoskeletal loss of sensibility, blanching, and decreased grip force in the hands - Avoid cold exposure, stop smoking

Kinematic analyses are based on the relationships between

position (displacement), velocity, and acceleration, which are vector quantities.

What does a "Bird Cage" in a wire rope usually signify?

subjected to a sudden release of tension