OBJ 4.2

Question 1

You are designing a building with a floor-to-floor height of 12′0″. Maximum riser height is 7 inches. How many risers and how many threads do your stairs need?

Answer 1

12′0″ x 12 = 144″. 144″/7 = 20.57. Round up to 21 risers. There is always one less tread than there are risers, so 21 risers and 20 treads.

Question 2

Radiant flooring

Answer 2

Flooring that has small concealed tubes within the slab that have hot water running through them to provide heat.

Question 3

Air curtain

Answer 3

A mechanical device used to prevent air or contaminants from entering into a building or from moving from one space to another. Typically used at thresholds between spaces that are different temperatures (e.g., at a vestibule, from inside to outside).

Question 4

Overflow drain

Answer 4

A roof drain located at a higher elevation than the primary roof drain to allow water to drain from the roof in the event of failure from a primary roof drain. Overflow drains are required to prevent water build-up on a roof and to prevent structural failure. Most codes require that the water draining from an overflow roof drain be visible so the owner knows there is a problem with one or more primary roof drains

Question 5

Walk-off mat

Answer 5

Typically located at the entry of the building, it is an area for people to remove grime and environmental hazards from their shoes. It can be a movable furnishing that is surface applied or integrated and recessed into the floor slab.

Question 6

Bearing heights

Answer 6

The point in elevation at which the steel or structure sits. Typically, the height is provided to the structural engineer by the architect.

Question 7

Surface runoff

Answer 7

Water flow that occurs when soil is infiltrated to full capacity.

Question 8

Drain tile

Answer 8

Perforated pipe surrounded by granular fill used to release hydrostatic pressure from the foundation of retaining walls.

Question 9

Trap

Answer 9

Keeps methane gas from entering a building while also catching grease and small jewelry or contacts before going down the sanitary system.

Question 10

Cleanout

Answer 10

An entry point into home drainage systems so clogs can be removed or a camera inserted to inspect the system. They’re usually located on the large vertical pipes—otherwise known as the main drain—in a basement or crawl space.

Question 11

Interceptor

Answer 11

A plumbing device (a type of trap) designed to intercept most greases and solids before they enter a wastewater disposal system.

Question 12

Floor-to-floor height

Answer 12

Measured from finish floor to finish floor. Includes the depth of the clear floor-to-ceiling height plus the depth of the floor–ceiling construction. Important for determining overall building height and efficiency in the vertical dimension. Also called story height.

Question 13

Some considerations on choosing a structural system

Answer 13

Structural systems are often chosen for their impact on other systems. Examples include interior columns, which are not advantageous because they restrict the location of other elements such as walls, doors, corridors, and furniture. Load-bearing walls are often chosen for structures that have relatively unchanging use, such as apartment buildings. Deep spanning members can make for an inefficient building in the vertical dimension. Structure can be part of a building’s skin, serving also as a thermal and waterproof layer, or separate from it.
Columns placed in a multi-story building’s outside skin have a major impact on how the building looks.

Question 14

Circulator pump

Answer 14

A circulator pump is a specific type of pump used to circulate gases, liquids, or slurries in a closed circuit. They are commonly found circulating water in a hydronic heating or cooling system.

Question 15

Air gaps

Answer 15

An air gap, as it relates to the plumbing trade, is the unobstructed vertical space between the water outlet and the flood level of a fixture. Water can easily flow from the faucet into the sink, but there is no way that water can flow from the sink into the faucet without modifying the system. This arrangement will prevent any contaminants in the sink from flowing into the potable water system by siphonage, and it is the least expensive form of backflow prevention.

Question 16

Anode

Answer 16

Piece of metal placed in a water tank to attract mineral deposits so they don’t form on the tank or equipment.

Question 17

Lateral

Answer 17

Common sewer that receives wastewater only from building sewers.

Question 18

Thermosiphon

Answer 18

A method of passive heat exchange, based on natural convection, that circulates a fluid without the necessity of a mechanical pump. Thermosiphoning is used for circulation of liquids and volatile gases in heating and cooling applications such as heat pumps, water heaters, boilers, and furnaces.

Question 19

Drain down

Answer 19

Open-loop system that drains water from the collectors when the outside temperature is freezing. The water is wasted, however, so this is best in mild climates that don’t freeze much.

Question 20

Drain back

Answer 20

Indirect system where water collects heat and is pumped into a heat exchanger, where a coil of domestic hot water is heated. At low temps, the pump is turned off and water is drained back to a solar storage tank.

Question 21

Vacuum breaker

Answer 21

A device used in some fixtures to accomplish the same thing as a trap. The attachment is placed on a hose connection valve or toilet/urinal valve to prevent water from being sucked backward into the public water system.

Question 22

Fixture units (FU)

Answer 22

Used to define the probability demands on plumbing fixtures.
One FU = 1 unit flow rate of 1 gallon/minute.

Question 23

Street main pressure

Answer 23

Minimum fixture flow rate + pressure lost due to height + pressure lost by friction in piping + pressure lost by flow through meter.

Question 24

Thermal expansion (L)

Answer 24

((Length) x (coefficient of expansion, k)) x (final temperature − original temperature).

Question 25

Frost line

Answer 25

The maximum depth of frost penetration in the ground in a given area. Water piping must be buried below the frost line so pipes don’t freeze.

Question 26

Sweating

Answer 26

Method of soldering copper plumbing, or the condensation of water on cold pipes and building materials.

Question 27

Water hammer

Answer 27

The noise caused by a sudden pressure increase in a pipe when a valve or faucet is closed.

Question 28

Leader

Answer 28

Vertical pipe used to conduct water from a roof drain or gutter to the ground.

Question 29

Circuit vent

Answer 29

Any vent that serves two or more traps in a sanitary drainage system.

Question 30

Polyethylene PE

Answer 30

Most common type of plastic used in pipes and tubing.

Question 31

Plant systems

Answer 31

Scale varies, from a room air conditioner to a plant for a whole college campus.
• Plants originally started as heat/steam only. With the development of air-conditioning, they became sources for chilled water, too.

Question 32

Freon

Answer 32

Freon is a harmful chlorofluorocarbon (CFC) found in many older air-conditioning units.

Question 33

Evaporator

Answer 33

The part of a refrigeration system in which the refrigerant evaporates and absorbs heat from the medium to be cooled.

Question 34

Air handling unit (AHU)

Answer 34

A machine which manages a building’s climate. As it moves air through a building, it filters and exhausts air, brings in fresh air, and regulates temperature and humidity.

Question 35

Home energy rating systems (HERS)

Answer 35

A standardized system for rating the energy efficiency of residential buildings. A score between 0 and 100 indicates the relative energy efficiency compared to a HERS-efficient home.

Question 36

Integrated part load value (IPLV)

Answer 36

A single-digit figure of merit, based on part load EER or COP, expressing part load efficiency for air conditioner and heat pump equipment.

Question 37

Building automation system

Answer 37

Computer-based integrated system used to monitor and control building systems.

Question 38

Building commissioning

Answer 38

The process of inspecting, testing, starting up, and adjusting building systems to verify that they’re working in accordance with the contract documents.

Question 39

Direct expansion system

Answer 39

A direct expansion (DX) air-conditioning system uses a refrigerant vapor expansion/compression (RVEC) cycle to directly cool the supply air to an occupied space. DX systems (both packaged and split) directly cool the air supplied to the building because the evaporator is in direct contact with the air supply.

Question 40

Air mixing plenum

Answer 40

The mixing plenum normally combines two air streams and includes three sets of dampers: one for the fresh air, one for the exhaust air, and a mixing damper between the two air streams. The mix of fresh air and recirculated air can thus be adjusted to suit the needs of the building’s occupants.

Question 41

Boiler blowdown

Answer 41

Boiler blowdown is water intentionally wasted from a boiler to avoid concentration of impurities during continuing evaporation of steam. The water is blown out of the boiler with some force by steam pressure within the boiler.

Question 42

Feedwater

Answer 42

Boiler feedwater is an essential part of boiler operations. The feedwater is put into the steam drum from a feed pump. In the steam drum, the feedwater is turned into steam from the heat. After the steam is used, it is then dumped to the main condenser.

Question 43

Specialty engineer

Answer 43

An engineer employed by a manufacturer who designs an engineered product, such as for a pre-engineered metal building.