Chapter 14 - Building Automation Systems

Question 1

___ controllers use DDC for a wide variety of control sequences and are typically used for HVAC and EMS applications.

a. Pneumatic
b. Electric
c. Electronic
d. Microprocessor-based

Answer 1

d. Microprocessor-based

p 14-9

When using DDC, the microprocessor unit in the controller provides the computation for the sequences. Therefore, the term digital in DDC refers to digital processing of data.

Question 2

Lighting may account for up to ___ percent of the electrical operation costs in a commercial building.

a. 15
b. 30
c. 40
d. 45

Answer 2

c. 40

p 14-14

Question 3

Is a type of lighting control ___ allows lighting levels to be varied according to the type of space or the requirements of occupants in the space.

a. Demand Limiting
b. Occupancy-Based - Time of Day
c. Fixed Power Reduction
d. Vacancy-Based

Answer 3

c. Fixed Power Reduction

p 14-14

It provides sufficient light for the areas or tasks being performed in the building, but it uses less power than the full light output of the system. This configuration provides consumption and demand savings directly proportional to the power level setting.

Question 4

Vacancy sensors save ___ energy than occupancy sensors because the occupants determine when lighting is needed, reducing power consumption when rooms are occupied and automatic turn on is not necessary.

a. Less
b. More
c. The same

Answer 4

b. More

p 14-15

Question 5

Lighting control ___ allows time-delayed dimming can be accomplished by signaling the lighting controller to dim the lights a predetermined amount when the kilowatt demand exceeds a predetermined kilowatt rate.

a. Demand Limiting
b. Fixed Power Reduction
c. Daylight Harvesting
d. Fluorescent Lamp Lumen Depreciation Compensation

Answer 5

a. Demand Limiting

p 14-15

The controller responds to the signal by gradually dimming the lights (e.g., time-delayed dimming) to a predetermined point. When the kilowatt demand level drops below the kilowatt set point, the lighting control
system gradually increases the lighting power to the normal level.

Question 6

Building automation systems (BAS) _____ are typically designed for DDC of unitary equipment and specific HVAC, EMS, and access control application requirements.

a. System-level controllers
b. Sensor-level processors
c. Management-level processors
d. Field-level controls

Answer 6

d. Field-level control

p 14-19

Field-level controllers are typically designed for DDC of unitary equipment and specific HVAC, EMS, and access control application requirements.
These controllers can:
• Provide limited port capacity for direct connection of sensors and devices.
• Support and execute resident DDC programs and EMS software.
• Initiate sequences that provide processing of specific device data.
• Usually operate with limitations in a stand-alone manner.

Question 7

In most midsized to large buildings, energy management is an integral part of the ___ system.

a. Lighting
b. HVAC
c. Telecommunications
d. Intelligent Building

Answer 7

b. HVAC

p 14-11

In most midsized to large buildings, energy management is an integral part of the HVAC system with optimized control performed at the system level and with management information and user access provided by the BAS host.

Question 8

In a BAS system, horizontal cables should be limited to one device per cable run to provide maximum flexibility for future changes, but they may contain as many as ___ devices per run to reduce cabling costs and provide for future flexibility.

a. 3
b. 5
c. 7
d. 12

Answer 8

b. 5

p 14-25

Multiple horizontal cables can also be bridged or chained at the HC (FD) located in the TR or HCP.

Question 9

In building automation systems (BAS), when cross-connections are used at the horizontal connection point (HCP), a BAS outlet/connector should be installed as part of the horizontal cabling link.

a. True
b. False

Answer 9

b. False

p 14-34

When cross-connections are used at the HCP, a BAS outlet/connector should NOT be installed as part of the horizontal cabling link. This requirement ensures that the
horizontal channel contains no more than four connections.

Question 10

Software at the management level normally communicates with all system- and field-level processors in a ___ configuration.

a. Poll-response
b. Peer protocol
c. Peer-to-peer
d. Master/slave token passing

Answer 10

c. Peer-to-peer

p 14-21

The trend for software at the field- and system-level controllers is to communicate using a peer-to-peer configuration, but these levels may communicate using master/slave token passing. Software at the management level communicates with all system- and field-level processors in a peer-to-peer fashion.

Question 11

Typically, 24 AWG balanced twisted-pair cable has the capacity to handle ___ A of current draw per conductor with a maximum of ___ A per 4-pair cable under
maximum ≈25 °C (77 °F) operating temperature.

a. 0.5, 3.3
b. 1.0, 3.3
c. 1.0, 3
d. 1.5, 3

Answer 11

b. 1.0, 3.3

p 14-23

Typically, 24 AWG balanced twisted-pair cable has the capacity to handle 1 A of current draw per conductor with a maximum of 3.3 A per 4-pair cable under maximum ≈25 °C (77 °F) operating temperature.

Question 12

A typical 24 AWG balanced twisted-pair cable has ___ ohms of resistance per ≈304.8 m (1000 ft).

a. 27
b. 57
c. 77
d. 107

Answer 12

b. 57

p 14-24

The current (e.g., signal) leaves the equipment at a specific voltage level chosen because the receiving device requires a certain voltage level to operate. As the signal travels through the cabling, the voltage drops because of resistance. A typical 24 AWG balanced twisted-pair cable has ≈57.2 ohms of resistance per ≈304.8 m (1000 ft) or ≈0.1876 ohms per m (0.0572 ohms per ft).

Question 13

If a 12 V device requires 0.05 A of current to operate and the allowable voltage drop is ± 10 percent, the maximum circuit distance using 24 AWG balanced twisted-pair cable is ___ feet

a. 200
b. 350
c. 420
d. 480

Answer 13

c. 420

p 14-24

1. Calculate the circuit resistance (in ohms) by dividing the voltage drop (in volts) by the current draw (in amperes):
   Drop/draw = Circuit resistance
   Example:
   1.2 V/0.05 A = 24 ohms
2. Calculate the maximum operating distance (m/ft) by dividing the circuit resistance (in ohms) by the resistance for one m (ft) of cable (in ohms):
   Circuit resistance/1 m/ft of cable resistance = Maximum distance
   Example:
   24 ohms/0.1876 ohms = ≈128 m
   24 ohms/0.0572 ohms = ≈420 ft

Question 14

A ___ typically manages the BAS; however, the telecommunications manager manages voice and data.

a. Building or facilities manager
b. ICT distribution designer
c. Owner
d. BAS manager

Answer 14

a. Building or facilities manager

p 14-25

It will require the cooperation of these departments, or direction from upper management, to perform systems
integration using the telecommunications cabling distribution system.

Question 15

Using the ___ approach may reduce each BAS equipment vendor’s bid by eliminating individual cabling systems and pathways furnished with a traditional BAS installation.

a. Top down
b. Checklist
c. Specific scope
d. System integration

Answer 15

d. System integration

p 14-29

When possible, use the same cable and component manufacturers between BMS and data/voice systems for warranty, maintenance compatibility, and overall cost reductions of the structured cabling systems.

Question 16

BAS coverage area for commercial retail space is:

a. 54 ft2
b. 248 ft2
c. 538 ft2

Answer 16

b. 248 ft2

p 14-33 see table 14.1

Question 17

BAS coverage area for commercial indoor parking is:

a. 54 ft2
b. 248 ft2
c. 538 ft2

Answer 17

c. 538 ft2

p 14-33 see table 14.1

Question 18

BAS coverage area for factory/manufacturing is:

a. 54 ft2
b. 248 ft2
c. 538 ft2

Answer 18

c. 538 ft2

p 14-33 see table 14.1

Question 19

BAS coverage area for mechanical room is:

a. 54 ft2
b. 248 ft2
c. 538 ft2

Answer 19

a. 54 ft2

p 14-33 see table 14.1

Question 20

BAS coverage area for hotel/guest room is:

a. 54 ft2
b. 248 ft2
c. 538 ft2

Answer 20

b. 248 ft2

p 14-33 see table 14.1

Question 21

When using the open office cabling approach for a BAS system, a spare horizontal capacity of ___ to ___ percent should be included to compensate for additional points (e.g., additional data connectors, fax machines, modems).

a. 5, 10
b. 10, 35
c. 15, 25
d. 20, 50

Answer 21

b. 10, 35

p 14-34

When using the open office cabling approach, a spare horizontal capacity of 10 to 35 percent should be included to compensate for additional points (e.g., additional data connectors, fax machines, modems).

Question 22

When using a combined CP/HCP configuration, voice/data services should be assigned starting with the ___ port; BAS services should be assigned starting with the ___ port.

a. last, first
b. first, last

Answer 22

b. first, last

p 14-35

See Figure 14.7 for cabling topologies when using coverage areas and HCPs.

Question 23

Traditional BAS use copper balanced twisted-pair conductors ranging from ___ AWG to ___ AWG.

a. 16, 22
b. 18, 22
c. 16, 24
d. 18, 26

Answer 23

a. 16, 22

p 14-35

However, the larger diameter conductors of the cable allow more BAS devices to be connected to a horizontal cable run, resulting in the use of less horizontal cable.

Communications bus lengths up to ≈1219.2 m (4000 ft) are common when using a combination of the horizontal and backbone cabling without the use of extenders or repeaters.

Hint - “DJ Nun”

Question 24

Communications bus lengths up to ___ ft are common when using a combination of the horizontal and backbone cabling without the use of extenders or repeaters.

a. 1000
b. 2000
c. 3000
d. 4000

Answer 24

d. 4000

p 14-35

Communications bus lengths up to ≈1219.2 m (4000 ft) are common when using a combination of the horizontal and backbone cabling without the use of extenders or repeaters. When repeaters are used, extensions of up to three or four times this distance are possible.

Question 25

Each different BAS function (e.g., FA, security, HVAC, and EMS) should use separate 4-pair cables with a minimum of four, 4-pair cables for applications that include all four functions. Category ___ cabling or better is recommended.

a. 3
b. 5E
c. 6
d. 6A

Answer 25

d. 6A

p 14-35

Each different BAS function (e.g., FA, security, HVAC, and EMS) should use separate 4-pair cables with a minimum of four, 4-pair cables for applications that include all four functions. Category 6A/class EA cabling or better is recommended.

Question 26

Horizontal cables should be limited to one device per cable run to provide maximum flexibility for future changes, but they may contain as many as ___ devices per run to reduce cabling costs and provide for future flexibility.

a. 2
b. 3
c. 4
d. 5

Answer 26

d. 5

p 14-35

Horizontal cables should be limited to one device per cable run to provide maximum flexibility for future changes, but they may contain as many as five devices per run to reduce cabling costs and provide for future flexibility. Multiple horizontal cables can also be bridged or chained at the HC (FD) located in the TR or HCP.

Question 27

A typical BAS power supply will have four outputs that deliver up to ___ A per tap.

a. 1
b. 2
c. 3
d. 4

Answer 27

b. 2

p 14-44

A typical BAS power supply will have four outputs that deliver up to 2 A per tap. When using 24 AWG balanced twisted-pair, the circuits should be designed and fused to draw no more than 1 A per tap.

Question 28

Open office horizontal cabling (e.g., zone cabling) can typically reduce ___ to ___ percent and up to 30 percent for the construction cost of cabling and pathways.

a. 5, 10
b. 10, 15
c. 15, 20
d. 20, 25

Answer 28

b. 10, 15

p 14-45

It is possible to reduce both the initial construction costs (typically 10 to 15 percent and up to 30 percent for cabling and pathways) and ongoing operational costs (typically 25 to 40 percent and up to 60 percent) for MACs by:

• Providing open office horizontal cabling (e.g., zone cabling).
• Incorporating voice, data, video, and BAS services in the horizontal.
• Providing a cabling distribution system that meets international standards.
• Consolidating cable pathway and delivery methods for all BAS and telecommunications systems.
• Incorporating the horizontal cabling for lighting and receptacles in a common divided pathway.
• Providing modular connections in the pathway for all services.

Question 29

Distributed intelligence can be accomplished using a centralized equipment approach. This approach, which is not typically used in traditional BAS implementation, works best with system-level controllers incorporating a minimum of ___ ports.

a. 12
b. 16
c. 32
d. 48

Answer 29

c. 32

p 14-47

Large capacity system-level controllers may not be available through some BAS manufacturers, but this strategy can be accomplished using smaller sized controllers.

Question 30

The technique of daylight harvesting provides energy consumption savings of approximately ___ percent for an average building.

a. Two
b. Four
c. Six
d. Eight

Answer 30

b. Four

p 14-15

The technique of daylight harvesting provides energy consumption savings of approximately four percent for an average building.

Question 31

In heating, ventilation, and air-conditioning (HVAC) systems, _____ controls can be used to ensure safe operation of system equipment and prevent injury to personnel.

a. Limit
b. Automatic

Answer 31

a. Limit

p 14-8

Examples of limit controls are:
• Low-limit temperature controllers, which help
prevent water coils or heat exchangers from freezing
• Flow sensors for safe operation of some equipment (e.g., chillers)

Question 32

___ controls are used whenever a variable condition must be controlled.

a. Limit
b. Automatic

Answer 32

b. Automatic

p 14-8

Automatic controls are used whenever a variable condition must be controlled. In HVAC systems, the most commonly controlled conditions are:
• Pressure.
• Temperature.
• Humidity.
• Rate of flow.
• On, off, or variable fan speed.

Question 33

The light output of fluorescent lamps deteriorates over a period of three years and stops at a level approximately ___ percent of the light output of a new lamp.

a. 30
b. 40
c. 50
d. 60
e. 70

Answer 33

e. 70

p 14-15

This is called lumen depreciation.

The lumen depreciation compensation strategy provides comfortable light levels at all times and can produce an energy savings averaging 13 percent per year over a three-year period.

Question 34

Many EMS programs may be integrated into microprocessor-based controllers. One of these is _____, which assures that only the minimum amount of cooling or heating energy is use to satisfy load requirements.

a. Alarm monitoring
b. Load reset
c. Distributed power demand
d. Zero band energy

Answer 34

b. Load reset

p 14-13

Load reset—Assures that only the minimum amount of cooling or heating energy is used to satisfy load requirements

Question 35

A minimum of category 5e/class D balanced twisted-pair cabling should be utilized for all approved building automation systems (BAS) applications

a. True
b. False

Answer 35

b. False

p 14-35

Category 6A/class EA cabling or better is recommended

Question 36

For building automation systems (BAS), there should be no more than _____ horizontal connection point(s) placed in a single horizontal cabling link.

a. Four
b. Three
c. Two
d. One

Answer 36

d. One

p 14-34

No more than one HCP should be placed in a single horizontal cabling link—a BAS outlet is typically not needed when using an HCP.

Question 37

The centralization of building automation systems (BAS) controllers may significantly increase the distance between a BAS device and the sensed variables.

a. True
b. False

Answer 37

a. True

p 14-48

The centralization of BAS controllers may significantly increase the distance between a BAS device and the sensed variables. Check the distance limitations associated with the BAS equipment before implementing this design option.

Question 38

The costs of cabling-related changes in a new or renovated facility can usually be reduced by _____ percent by using a total systems integration approach.

a. 35 to 60
b. 25 to 40
c. 10 to 20
d. 20 to 35

Answer 38

b. 25 to 40

p 14-5

Additional expenses may include installing devices for energy management strategies that optimize power consumption. However, the costs of cabling-related changes can usually be reduced by 25 to 40 percent by using a total systems integration approach.

Question 39

Many EMS programs may be integrated into microprocessor-based controllers. One of these is heat content, which:

a. Maintains a low- or high-temperature limit during unoccupied periods by closing outside damper and cycling air handling unit
b. Assures that only the minimum amount of cooling or heating energy is use to satisfy load requirements
c. Selects the air source, a combination of return and outdoor air that requires the least total heat removal for cooling
d. Uses cool, night outdoor air to pre-cool the building before mechanical cooling is turned on

Answer 39

c. Selects the air source, a combination of return and outdoor air that requires the least total heat removal for cooling

p 14-13

Heat content—Selects the air source, a combination of return and outdoor air that requires the least total heat removal for coolin

Question 40

Within a commercial office building of 2300 sq m (25000 sq ft), how many building automation system (BAS) devices are required?

a. 50
b. 75
c. 100
d. 125

Answer 40

c. 100

p 14-32

Coverage area or BAS device every ≈23 m2 (250 ft2) or 25,000ft2/250ft2 = 100

Question 41

What is the expected luminance value, in watts, of a 200 watt fluorescent lamp after three years?

a 120 watts

b. 140 watts
c. 160 watts
d. 180 watts

Answer 41

b. 140 watts

p 14-16

The light output of fluorescent lamps deteriorates over a period of three years and stops at a level approximately 70 percent of the light output of a new lamp.