Chapter 13 - Mechanical and Electrical Systems Flashcards
Mechanical systems include:
heating, cooler, plumbing, and fire protection
Electrical systems include
power, lighting, telephone, and other communication systems
The two primary methods of heating and cooling systems are:
- Air
- Water
All air systems cool or heat spaces by _________
conditioned air alone heat is transported to the space with supply and return air ducts
Common example of an all-air system?
residential forced-hot-air-furnace
return ducts collect the cooled air and return it to the furnace for reheating
For commercial buildings, there are several variations of systems, including Variable Air Volume (VAV), high-velocity dual duct, constant volume and reheat, and multizone systems. All types require ______, _____, and _____ in all spaces.
supply air ductwork, registers, and return air grilles
Registers are connected to the supply air ductwork and can be adjusted to ____________ and ____________
- control the direction of air flow - control the volume of air coming through them
If fire-rated partitions extend above the suspended ceilings, then ____ and ____ must be provided.
supply air ducts and openings for return air
At locations where the fire wall is penetrated, fire dampers are required. What do these do?
they automatically close in the even of a fire
All-water heating systems use ______
a coil unit called a CONVECTOR in each space through which hot water is circulated. the hot water heats the fins of the coil unit, and air is heated as it is drawn over the fins. Air may be circulated by CONVECTION
What are terminal reheat systems?
combination systems that use ductwork for supplying fresh air but use water to heat or cool the air before it is introduced into the conditioned space
In residential construction, small ducts and plumbing pipes run ________.
within the walls and floor joists
In commercial construction, horizontal ducts are normally run _________ and vertical ducts are normally run ___________.
in the plenum within their own chases
A _________ is an enclosed vertical space used only to accommodate ducts or pipes.
chase
A ______ adjusts the quantity or temperature of air going into a space from the main air supply line(s), reduces the velocity of air, and attenuates noise
mixing box
What is connected to a mixing box?
lines from thermostats
With variable air volume systems (VAVs) what varies the quantity of air?
VAV box
Most common use for a raised access floor? but it can also be used for?
electrical, communication, and computer wiring HVAC ductwork
A _________ consists of two runs of studs separated by several inches, the exact dimension being determined by the largest pipe or duct that has to be concealed
chase wall
A _____ is a steel framework that is bolted to the floor inside a pipe chase and carries the weight o wall-hung toilets
toilet carrier
Access doors need to be provided for:
valves, fire dampers, heating coils, mechanical equipment, electrical junction boxes, communication junction boxes, and similar devices
Who determines the location of the thermostats?
mechanical engineer
Who should coordinate the location of supply air diffusers and return air grilled with other ceilings items, such as lights, sprinkler heads, smoke detectors, speakers, and the like?
interior designer
In commercial construction, does it matter where window treatments are placed?
yes–it can affect the heating and air conditioning in the space. they should be placed at least 2” from the glass to avoid heat build up between the window covering and the glass
There are several types of conductors that supply power throughout a building. Most common type for: Residential (or commercial under 3 stories) Commercial
Romex (two or more plastic-insulated conductors and ground wire surrounded by a moisture-resistant plastic jacket
Individual plastic-insulated conductors must be placed in metal conduit
What is the purpose of metal conduit?
supports and protects the wiring, serves as a system ground, and protects surrounding construction from fire if the wire overheats or shorts
In residential construction, outlets must be spaced no more than ____ feet apart and on ______
12’ and on each wall surface where furniture might be placed so lamp cords and the like do not have to be stretched across door openings
What is grounding?
a separate wire in addition to the two that provide power. The grounding of an electrical system prevents a dangerous shock if someone touches an appliance with a short circuit and simultaneously touches a ground path such as a water pipe
Where are GFI’s required?
bathrooms, garages, accessory buildings at or below grade, outdoors, crawl spaces, unfinished basements, countertop receptacles in kitchens, laundry and utility rooms, boathouses
What is an AFCI?
The AFCI (Arc Fault Circuit Interrupter) protects against fires caused by arcing faults
Where are AFCIs required?
family rooms, dining rooms, living rooms, libraries, dens, sunrooms, rec rooms, closets, hallways, and similar rooms
Where are telephone and communication systems shown?
on the same plan as the power
Plumbing systems consist of two or more major components:
water supply and drainage
Is it easier to place water supply or drainage pipes?
supply pipes because they work off of pressure and can be placed in walls or in ceilings. drainage pipes are more difficult because they require gravity
two reasons drainage pipes are more difficult to place?
- need to be sloped to carry waste
- need vent pipes
______ are pipes connected to the drainage system at various locations, open to the outside air, and designed to serve two purposes.
vents
Two main purposed of vent pipes:
- allow built up sewage gases to escape
- allow pressure in the system to equalize so discharging waste does not create a siphon that would drain the water out of the traps
soil stack vs waste stack
human waste: soil stack waste stack: anything other than human waste
Plumbing plans are drafted by the _____
mechanical engineer
Fire containment is achieved through
building materials, compartmentation, and smoke control
Fire suppression is achieved through
fire detection and alarms, sprinkler systems, standpipes, and other methods
Compartmentation is a critical concept in fire and life safety. The basic idea is to ______
contain a fire and limit its spread (to get occupants out safely and the parts of the building not yet subject to the fire)
Compartmentation works especially well in ____ building
high-rise buildings where occupants may not be able to evacuate immediately. instead there is a place of refuge where occupants can wait until the fire is extinguished or until they can exit safely
On a smaller scale of compartmentation, ____ are isolated to protect the building from collapsing
structural members are isolated
What’s an example of compartmentation in residential construction?
Fire stops
More deaths and injuries occur in fires due to __________ than ________________.
inhalation of smoke and other gases than due to flame and heat exposure
What is one of the most important aspects of fire protection?
smoke control
Why is smoke a big deal in fires?
Because is travels so quickly (through stairways, elevator shafts, mechanical shafts, and atriums and is exacerbated by HVAC systems
Fire and smoke detector devices should be shown on the
RCP
Four types of fire detection devices
- ionization detectors
- photoelectric detectors
- rise-of-temperature detectors
- flame detectors
ionization detectors
responds to products of combustion-ionized particles (not smoke)
these are early warning detectors
photoelectric detectors
respond to smoke (which obscures a light beam in the device )
rise of temperature detectors
sense the presence of heat
major disadvantage is that usually flames must be present before the alarm temperature is reached
flame detectors
respond to infrared or ultraviolet radiation given off by the flames.
downside: they do not give an early warning of smoldering fires
Many buildings have a ________ of fire detectors
combination
Where should fire detectors be located?
- near fire doors
- in exit corridors
- in individual hotel rooms
- in bedrooms
- in place of public assembly (sometimes required in main air ducts)
Most common type of fire supression system?
sprinkler system
When are upright sprinkler heads used?
with exposed ceilings
_______ are pipes that run the height of a building and provide water outlets at each floor to which fire fighting hoses can be connected
standpipes
standpipes are typically located
within the stairway
A unit or device that radiates heat from water to the surrounding air, usually through closely spaced fins. These are usually placed against a wall under a window.
Convector
