ARE 5.0 Study - Building Systems
TRUE or FALSE: In cold climates, direct gain spaces may be mechanically heated in wintertime.
TRUE
Mechanical air conditioning can remove both sensible and latent heat. TRUE or FALSE?
TRUE. Mechanical air conditioning can remove both sensible and latent heat while it sensibly cools the air. The removed moisture condenser on the evaporator coil and is the source of the dripping often seen coming from window AC units.
It is determined for a conditioned interior space that the design heating load - to be delivered to the space in the winter via 145 degree F hot air from an air handling unit (AHU) - is 40,000 BTU/hr. Furthermore, the design cooling load - to be delivered to the space via 50 degree F cool air in the summer from the same AHU - is also 40,000 BTU/hr. Which condition, HEATING or COOLING, will most likely control the size of the duct tasked with carrying that air?
The COOLING condition will most likely control the size of the duct tasked with carrying the air. It is easier for a building's mechanical system to to make the air very hot in the heating season than it is for a system to make the air very cool in the cooling season.
Is the dew point located on the WARMER or COLDER side of a surface?
The dew point is always on the WARMER side of a surface.
An office are has an average continuous lighting load of 1,000 watts. What is the energy cost of providing lighting to this area for a 12 hour day, based on a unit cost of 8 cents per kilowatt hour?
.96 cents. 1 KW for 12 hours = 12 KW hours. 12 KW hours x .08 cents per KW hour = .96 cents
Does a FLAT ROOF or a SOUTH WALL receive the most radiant heat in the United States during the summer?
A FLAT ROOF receives the most radiant heat. In the summer, when the sun is high, horizontal surfaces approach perpendicular relative to the direction of the sunlight. In the morning and afternoon, the sun is in the east and west. It is then in the winter that the sun is low in the southern sky, and a south wall becomes a good source for solar gains and sunlight.
A structural insulated panel (SIP) does not have structural members that make contact with both the exterior face and the interior face of the panel. Why? A. To provide a thermal break B. To minimize air infiltration C. To provide both structural independence and low embodied energy D. To provide an air gap
A. A SIP does not have these members in order to provide a thermal break. Structural members that make contact with both the exterior and interior surfaces of a building can create a thermal bridge, which would short circuit an efforts to insulate.
Two bodies in direct contact with each other will transfer heat primarily by the mechanism of... A. Conduction B. Convection C. Radiation D. Evaporation E. None of the above
A. Conduction is the mode of heat transfer through solids, including building elements like walls and roofs. This is measured with metrics like U-value and R-value. Convection involves heat transfer within a fluid, or between a solid and a fluid. Radiation describes heat moving through electromagnetic energy. It can't move through opaque materials. Human bodies radiate heat.
Where the water can be shut off for maintenance, what type of valve would be used? A. Gate valve B. Globe valve C. Check valve
A. Gate valve.
The sun's positioning the sky along the vertical axis is called it's... A. Altitude B. Solar angle C. Azimuth
A. It's called the altitude. The solar altitude describes the sun's angle above the horizon. The azimuth describes the position of the sun relative to the cardinal points and is usually measured in degrees-from-south.
Waste from which of the following is classified as greywater? Select three. A. Lavatories B. Waterless urinals C. Composting toilets D. Washing machines E. Kitchen sinks F. Showers
A. Lavatories, D. Washing machines, F. Showers. Greywater may only originate from fixtures that do not drain food waste or human waste, and it may be reused in water closets, urinals, and sprinklers. Wastewater containing human waste or food waste is called blackwater.
Which would best describe a building material with high thermal mass... A. Porous material B. Dense, heavy material
A. Porous material. It is the small air pockets found in fiberglass, foam, mineral wool, and cotton that give these materials their high thermal resistance. Dense materials can provide a measure of thermal mass, which stores heat and doesn't interrupt the heat flow through the building envelope like a porous material does.
For a south facing window (temperate climate, northern hemisphere), which building type would benefit more from the use of glass with a higher solar heat gain coefficient (SHGC)"? A. A skin-load dominated building B. An internal-load dominated building
A. Skin-load dominated buildings have a lot of surface area relative to their volume. It will have a high heat gain to the south and a low heat gain to the north. Internal-load dominated buildings are like hospitals, office buildings, and schools with a lot of people, lighting, and equipment.
In the compression refrigeration loop (air conditioning), which is likely to be warmer? A. Condenser coil B. Evaporator coil
A. The condenser coil is likely to be warmer.
On hot days, a cooling tower cools... A. Water from the condenser B. Refrigerant as it moves through the compressor C. Refrigerant from the evaporator
A. The cooling tower water loop removes heat from the condenser side of the chiller and deposits it into the air.
Doubling the thickness of a given homogeneous wall material will... A. Halve the wall's U-value B. Double the wall's U-value C. Not alter the wall's U-value
A. The wall's U-value would be halved if it's thickness was doubled because it would impede the transfer of heat, just as doubling the thickness of a blanket limits the transfer of your body heat through that blanket
Which of the follow types of copper pipe would be the best choice for a line buried as an underground water supply. A. Type K B. Type L C. Type M D. Type DWV
A. Type K is the heaviest type of copper pipe, thus most appropriate for underground water supply. Type L is thinner and is most common for water supply lines in building systems. Type M is the thinnest and is best for low-pressure water supply. Type DWV is only used for drainage, waste, or vent piping.
What is a vacuum breaker used for? A. To prevent wastewater from contaminating supply water B. To limit water pressure at a fixture C. To purify well water D. To pump water
A. Vacuum breakers prevent back flow in fixtures like hose bibs and toilets, blocking non-potable water from entering the potable water supply. They allow air to enter the water system if a siphon attempts to form, checking water looking to reverse direction.
When designing an art gallery, which of the following metrics would be most relevant to your lighting strategy? A. Color temperature B. Color rendering index C. Lamp lumen depreciation D. Lamp life
B. The color rendering index (CRI) would be the most relevant. The CRI measures the size of the range of color frequencies emitted by a lamp. The higher the CRI value, the better the visual perception of color in a space.
At its widest point, the width of an A-17 incandescent lamp is... A. 2" B. 2 1/8" C. 2 1/2"
B. The widest point is 2 1/8" or 17/8" wide. In lamp nomenclature, the number (17 in this example) corresponds to the number of eighths of an inch wide it is. An A-17 is therefor 17/8" wide.
If the unit price of a central air conditioning system is $1,000 per ton, what would be the total cost of a system able to provide cooling (refrigeration) for 96,000 BTU/h? A. $800.00 B. $8,000 C. $80,000 D. $96,000
B. $8,000. 1 ton of cooling equals 12,000 BTU/h. 96,000 BTU/h / 12,000 BTU/h = 8 tons. 8 tons x $1,000 = $8,000
What does a lamp and fixture photometric curve describe? A. Efficiency over time B. The distribution of light in space C. Spectral light distribution D. All of the above
B. A lamp and fixture photometric curve describes how it distributes light in space. Polar-coordinated graphs describe the light output from a lamp and fixture combination where the distance from the center represents the candlepower in that direction. This is known as the photometric curve or isolux values.
Which of the following can be used most effectively to limit low-frequency sounds in an HVAC system? A. Turning vanes B. Duct lining C. Mufflers D. Dampers
B. Duct lining, though C. Mufflers could also be an acceptable answer.
Where the water is variable or frequently controlled, such as a faucet, what type of valve would be used? A. Gate valve B. Globe valve C. Check valve
B. Globe valve.
Single family residences typically provide appropriate air quality through the process of... A. Mechanical ventilation B. Infiltration through cracks in construction
B. Infiltration through cracks in construction.
Between design development and construction document phases, it is discovered that a building requires more water supply fixtures units (WSFU) than previously calculated. This most likely requires... A. More pipe elbows (and therefor more pipe friction) B. Larger supply lines
B. It would require large supply lines. We size water supply lines by available pressure and required flow - a fixture unit is a unique number for each water fixture, expressing required flow.
Which likely has a longer duct run to the spaces it serves? A. Fan coil unit (FCU) B. Air handling unit (AHU)
B. Most AHUs are remote and ducted to the space they serve, and most FCUs are found in the space they serve. FCUs may not use ducts at all.
The U-value of a wall assembly includes resistance allowances for each of the following except... A. Air spaces B. Orientation C. Interior air film D. Exterior air film
B. Orientation
Where water is allowed to flow in only one direction to combat water supply contamination, what type of valve would be used? A. Gate valve B. Globe valve C. Check valve
C. Check valve.
If the set point temperature is 70 degrees F, the buildings balance point temperature is 55, and the outdoor temperature is 70, which is the mechanical system most likely to be doing? A. Heating B. Cooling C. Neither heating nor cooling
B. When the outdoor temperature is warmer than the balance point temperature, cooling is required. The set point temperature is the design indoor temperature or the temperature to which the thermostat is set. Because the set point temperature is already accounted for when calculating a buildings balance point temperature, it is not relevant in coming to a correct response to the question.
What is a typical requirement for illumination, in foot candles, of a building interior? Select two. A. 0.1 B. 1 C. 10 D. 100
C. 10 and D. 100. Typical interior illuminance levels range between 10 and 100 foot candles. A minimum of 1 foot candle at the floor is required for egress. Outdoor daytime illuminance levels commonly range from between 100 and 10,000 foot candles.
A waste line on sloping lot must run a horizontal distance of 75 feet. The vertical rise has been calculated to be 9.75 feet. The percent grade of the waste line will be? A. 9% B. 11% C. 13%
C. 13% (9.75 / 75 = .13)
Flush control for a handicapped accessible urinal is a maximum of how many inches above the floor? A. 36 B. 40 C. 44 D. 48
C. 44
What makes a well an artesian well? A. It can be utilized in a gravity down-feed system B. It is part of a municipal water supply C. It comes from an aquifer under positive pressure D. It produces naturally soft water
C. An artesian well comes from an aquifer under positive pressure. They are naturally under pressure, sometimes enough that pumps are not needed in order to bring the water to the surface.
A machine that uses a reversible compression refrigeration loop, so that both coils may take the role of either evaporator or condenser is called a... A. Heat sink B. Air handling unit C. Heat pump D. None of the above
C. It is a heat pump.
If the set point temperature is 70 degrees F, the buildings balance point temperature is 55, and the outdoor temperature is 55, which is the mechanical system most likely to be doing? A. Heating B. Cooling C. Neither heating nor cooling
C. Neither heating or cooling.
Which of the following terms is defined as "water tested to be suitable for bathing, cooking, and consumption by humans"? A. Well water B. Groundwater C. Potable water D. Grey water
C. Potable water
When comparing the output of a source with a color temperature of 5,000 K to one with a color temperature of 3,500 K... A. The 5,000 K source appears warmer than the 3,500 K source B. The 5,000 K source appears flatter than the 3,500 K source C. The 5,000 K source appears cooler than the 3,500 K source D. The 5,000 K source appears brighter than the 3,500 K source
C. The 5,000 K source appears cooler than the 3,500 K source. The color of light goes from warm to coo, as it moves from the 3,000 Kelvin range to the 5,000 Kelvin range. Standard fluorescent lamps fall within the 3,500 K to 4,500 K range. Noon sunlight falls in the 5,000 K range. Sunrise is about 2,000 K.
For a building with 277/480 volt, three phase, four wire service, typically the electric lighting runs on... A. 120 volts B. 240 volts C. 277 volts D. 480 volts
C. The buildings electrical lighting most likely runs on 277 volts. 277/480 volt, three phase, four wire power service is specified for large buildings with heavy lighting and equipment loads. 277volt lighting is installed, and small transformers are used to step power down to 120 volts for process loads, like phone chargers.
120/240 volt single phase service requires how how many wires? A. 1 B. 2 C. 3 D. 4
C. This type of service requires 3 wires: two hot 120 volt wires, plus one neutral.
Electrical receptacles in a residential bathroom are required to be installed... A. No lower than 4 feet above the floor B. Below the level of toilet or lavatory fixtures C. With ground fault circuit interrupter protection D. At a minimum of 6 feet from a tub or shower
C. With ground fault circuit interrupter protection.
Lightning protection can be provided to a building by which of the following... A. A system of lightning rods and conductors extended to the ground B. An overhead grid of wire conductors extended to the ground C. A system of lightning rods connected to the buildings steel frames and then to the ground D. All of the above
D. All of the above
The thermal resistance (R-value) of a typical insulating material used in buildings would be... A. 0.01 B. 0.1 C. 1 D. 10
D. An R-value of 10 would best represent the thermal resistance of a typical insulating material. Nominally, single pane windows have an R-value of 1, double pane windows have an R-value of 2, three inches of glass fiber insulation has an R-value of 10, and 12 inches of insulation has an R-value of 40.
An area that generally has cool summers is likely to have... A. Many heating degree days (HDD) B. Few heating degree days C. Many cooling degree days (CDD) D. Few cooling degree days
D. An area that generally has cool summers is likely to have few cooling degree days.
When found in a buildings indoor air, carbon monoxide, radon, formaldehyde, and nicotine are all classified as... A. Ventilation components B. Hydrocarbon fuel emissions C. Building material emissions D. Indoor air contaminants
D. Indoor air contaminants
Which piping material has the highest coefficient of thermal expansion? A. Steel B. Cast iron C. Glass D. Plastic
D. Plastic
The most effective method of limiting plumbing noise in buildings is to... A. Use plastic rather than metal waste pipes B. Avoid over sizing water supply lines C. When practical, put fixtures on upper floors where the supply water pressure is lowest D. Resiliently mount piping so that it makes no rigid contact with the building structure.
D. Resiliently mount piping so that it makes no rigid contact with the building structure. Pipes and fixtures are by themselves poor radiators of noise. Rather, sounds are amplified when a noisy or vibrating plumbing system is coupled with efficient noise radiators, such as wall's, ceilings, and floors. For this reason, decoupling the plumbing system from the structure offers the best chance of mitigating plumbing noise.
Which of the following types of copper pipe would be installed as a stack vent? A. Type K B. Type L C. Type M D. Type DWV
D. Type DWV for drainage, waste, or vent piping.
Which of the following plumbing fixture types is not permitted to connect to a waste stack vent? A. Bidet B. Utility sink C. Lavatories D. Water closets
D. Water closets. A waste stack vent is synonymous with sources of greywater (no human or food waste). That means, it must never connect to a source of sewage/soil line.
For a temperate climate (warm summers and cold winters), heat transfer for conduction (Q) is more of a concern in the SUMMER or WINTER?
Heat transfer would be more of a concern in the WINTER because the delta T (temperate difference between interior and exterior) is much higher than it is in the summer. Latent heat and solar heat gain are a concern in the summer.
An energy recovery ventilator (ERV) CAN or CANNOT remove moisture from intake air in the summertime?
It CAN. Moisture condenses from the intake air if the device cools the air beyond its dew point. This is most common when conditions outside are humid. For this reason, a drain is required with this device.
A roof-mounted, south-facing, active solar panel only used for heating a pool in the summer season should be sloped MORE STEEPLY or LESS STEEPLY compared to one used for heating a concrete floor in the winter?
It should be sloped LESS STEEPLY. The sun is low in the south winter sky, which makes it necessary for a steeper pitch to maintain a geometry so that the active solar panel is close to perpendicular relative to the suns rays. Conversely, when the sun is high in the summer sky, a shallow pitch maxi,Ives solar gain.
Name three sources of off-gassing in buildings.
Paints, adhesives, composites, wood, furniture, seals, stains, and carpeting.
Does Low E glass boast a HIGH or LOW solar heat gain coefficient (SHGC)?
Low E glass boasts a LOW SHGC. High SHGC means that a lot of heat goes through through (.07 to .09). Low SHGC falls in the range of 0.2 to 0.4.
