Chapter 13 Mechanical and Electrical Systems Flashcards
(37 cards)
What are HVAC all-air systems and all-water systems?
All- air systems: cool or heat a space by conditioned air transported to the space with supply and return air ducts
All-water systems: use some type of coil unit called a convector in each space through which hot l water is circulated. The hot water heats the fins of the coil unit which heats the air as it is drawn over from the fins.
Where are ducts and plumbing run typically in residential and commercial construction?
Residential - walls and floor joists
Commercial - the plenum and chases
What is a chase?
An enclosed vertical space used only to accommodate ducts or pipes, it will run continuously through floors on multistory buildings
When a project is to retain an existing HVAC system, what needs to be considered when designing the ceiling?
Large ducts leave little room for recessed lighting
What is a mixing box?
Mixing box located in the plenum adjusts the quantity or temperature of air going into a space from the main air supply line; reduces velocity of air and attenuates noise
What is a variable air volume system? (Vav)
HVAC system that supplies air at varying levels or amounts at a constant temperature
When thinking of a plenum consisting of layers, what is located at each level?
building structure (Uppermost level)
Ducts, mixing boxes, other hvac approx sixe of large rest duct under largest structural element
Sprinkler and plumbing approx 4”-6”
Recessed lighting (lowest level) approx 9”-12”
What height are thermostats located?
48” AFF
What are the minimum clearance of a window treatment with exterior glass? (Commerical)
1 1/2” min between window header and top of window treatment
1 1/2” min between window ledge and bottom of window treatment
2” min between glass and window treatment
1 1/2” min between wall and window treatment
ADD PIC PG. 13-6
What are the three common types of air-supply diffusers?
In-lay diffuser ( inserted into suspended ceiling system)
Residential / gypsum air diffuser (uses trim flange that snaps onto diffuser and cover ceiling cut out
Slot diffuser (used when space is limited or appearance wants to be minimized
On a HVAC plan, how are piping and ductwork represented?
With single lines
What is a junction box?
Steel or approved plastic box to which the conduit or cable system is attached
In residential construction, outlets must be placed no farther than______ ft apart
12 ft
What are “dedicated circuits “?
Special power outlets placed on their own circuit to prevent various types of electrical interference from sensitive electrical equipment
What are three types of protection provided in electrical wiring? Describe them.
Grounding: a separate wire in addition to the two that provide power which prevents a dangerous shock if someone touches an appliance with a short circuit and a ground path at the sense time.
Ground fault circuit interrupters (GFCI’s or GFI’s) : devices that detect small current leaks and disconnect the power to circut or appliance.
Arc-fault circuit interrupter(AFCI) :device that provides protection from the effects of arch faults by recognizing characteristics unique to arcing and functioning to de-engegize the circuit when this fault is detected
What are the two major components of plumbing system?
water supply: cold and hot water supplied under pressure to individual plumbing fixtures
Drainage: sloped drain pipes which carry away waste through gravity. Comprised of vents, traps, stacks
What is a trap, vent, and soil waste stack in a plumbing drainage system?
Trap: located at every fixture, catch and hold water to provide a seal that prevents gases from the sewage system from entering the building
Vent: pipes connected to the drainage system open to outside air allowing built-up sewage gases to escape and allow the pressure in the system to equalize
Soil /waste stacks:
soil stack carries human waste
waste stack carries all other waste.
What is a wet column?
Usually at a structural column where hot water, cold water, and drainage risers are located for tenants to easily tap into.
Fire protection in buildings is accomplished by?
Preventing fires
early fire detection and alarm
providing quick exiting
containing fire
suppressing the fire
What is the basic idea of “compartmentation” in fire safety
Contain a fire and limit it’s spread both to allow occupants to escape and protect other parts of the building that are not initially subject to the fire.
How is the spread of smoke during a fine contained?
Devices such as fire dampers, gaskets on fire doors, automatic closing fire doors seal opening in fire walls.
What are the 4 basic types of fire detection devices? Now do they work?
Ionization detector -responds to products of combustion-ionized particles
Photoelectric detector - responds to smoke
Rise-of-tempeature detector- senses presence of heat
Flame detector- responds to infrared or ultraviolet radiation given off by flames
What are the disadvantages of rise-of-temperature detectors and flame detectors?
They do not give early warning signs of soldering fires/smoke
IBC states buildings over______ ft tall require sprinkler systems
75ft
