Division 5: Project Development & Documentation

Question 1

What are the five major variables that influence the space needed for mechanical equipment?

Answer 1

Scope of the system (local, centralized, or district), type of HVAC system, building size, building type, and passive systems use.

Question 2

What is a local system in HVAC?

Answer 2

Generally, a system that only serves one zone, typically used for small buildings or for specific areas of a building.

Question 3

What are some examples of a local system in HVAC?

Answer 3

A residential furnace, a window-mounted air conditioner, and commercial gas-fired heaters.

Question 4

What is a centralized system in HVAC?

Answer 4

Generally, a system that serves multiple zones from one location, typically used in moderate- to large-sized commercial and institutional buildings.

Question 5

What is a district system in HVAC?

Answer 5

Generally, a single plant that provides heating and/or cooling services to several buildings.

Question 6

What are the three most common types of HVAC systems?

Answer 6

All-air, all-water, and air-water systems.

Question 7

Which type of HVAC system requires the most space and why?

Answer 7

All-air system, because of the size of air handling units and the ductwork needed to distribute air throughout the building then return it to the central plant.

Question 8

Which type of HVAC system requires the least space and why?

Answer 8

All-water system, because water pipes are smaller than air ducts and there are no supply air ducts.

Question 9

Why do laboratories and hospitals generally need more mechanical equipment space than offices or apartments do?

Answer 9

Individual control is needed in many spaces and special provisions for ventilation and positive pressure are required in specific rooms.

Question 10

In a medium- to large-sized building with an all-air or air-water system, what is the preliminary size range of the mechanical room?

Answer 10

3% to 10% of the total building area being served

Question 11

In a medium- to large-sized building with an all-water system, what is the preliminary size range of the mechanical room?

Answer 11

1% to 3% of the total building area being served

Question 12

What is an air handling unit (AHU)?

Answer 12

Mechanical equipment that uses water from boilers and chillers to heat and cool air

Question 13

An air handling unit (AHU) is rarely purchased and placed as a ready-to-use assembly. True or false?

Answer 13

False

Question 14

Why is it ideal to locate an air handling unit (AHU) near an exterior wall?

Answer 14

The amount of ductwork required to bring in fresh air and remove exhaust air is minimized

Question 15

When locating a high rise building’s mechanical equipment, what are two factors to consider when deciding between the ground floor and the rooftop?

Answer 15

Structural requirements and noise control

Question 16

Between round and rectangular ducts, which shape is better at maintaining air pressure?

Answer 16

Round

Question 17

Between round and rectangular ducts, which shape is better at utilizing the available space?

Answer 17

Rectangular

Question 18

What is static head (or static pressure) in HVAC?

Answer 18

The amount of pressure, measured in inches of water, that must be applied to overcome frictional resistance (between moving air and duct components) and make air flow

Question 19

What is the preliminary cross-sectional area range for low-pressure duct space?

Answer 19

10 square ft to 20 square feet per 10,000 square feet of floor space served

Question 20

What is a chase in HVAC?

Answer 20

A fully enclosed shaft that contains only ducts and piping

Question 21

What is a mixing box in HVAC?

Answer 21

A component that controls the air that flows into a space from the main air supply line by adjusting quantity, velocity, temperature, and noise and is informed by signals from a thermostat

Question 22

What are the size ranges of a mixing box in HVAC?

Answer 22

Height ranges from 6” to 18”, length ranges from 24” to 60”, and width ranges from 14” to 66”