PLUMBING Flashcards
A 60 US gallon water heater weighs 52.5lbs when its empty. How much does it weigh when its full?
552.3lbs
60usgal x 8.33lbs/usgal = 499.8lbs
499.8lbs + 52.5lbs= 552.3lbs
What is installed either as part of a grease interceptor or immediatly at the inlet connection point to make it more efficient?
Flow control device
What would be the result of a partially plugged bypass orifice in a flushometer?
Long flush cycle
The inner dimmension of a grease interceptor measures 9’ long, 4’6” wide and 5’ deep with a required 20% free board. What is the liquid capacity in the interceptor in Imp gallons?
9’ x 4.5’ x 5’ = 202.5cubic feet
202.5cubicft x 0.8(20%) =162cubicft
162cubicft x 62.4lb/cubicft =10108.8lb
10108.8lb / 10impgal/lb = 1010.88impgal
When cutting borosilicate glass tube what lubricant should be used?
Water
What length of cast iron soil pipe should be removed when installing an MJ wye?
1/4” to 1/2” longer than the wye
What method, in addition to concrete thrust blocks, can be used to further restrain spigot PVC water service joints from seperating?
Serrated harnesses with lugs
What is the required flow rate for a system that has a total heat loss of 175000 BTU and a DELTA T of 15°F?
(175000 BTU/hr) / (8.33lb/usgal x 15°F x 1 BTU/lb/°F)
After units cancel
175000 (hr) / (8.33 (usgal) x 15)
175000 (hr) / 124.95 (usgal)
= 1400.56 USgal/hr
(1400.56USgal/hr) / (60min/hr)
= 23.3 GPM
What effect would a larger DELTA T have on an appliance?
BTU output would increase
- increase water temp
- decrease air temp
A hydronic heating system requires an in-line flow switch. Where would this type of switch be located?
Supply main
What is required when installing long, straight horizontal or vertical runs of copper domestic hot water piping?
Expansion joint
What is the ideal DELTA P for compressed air systems?
15 psi
Intercoolers are installed with which style of compressor?
On two stage compressors
Air intakes for compressor systems should be located where?
In the coolest place possible
The inspector can ask for a minimum of ___ fittings in a medical gas to be removed and inspected to see if there is oxidation present?
3
Where is the in-line high pressure sensor for a medical gas system located?
Downstream of the pressure regulator
Freeze packs are designed to work on ______ water
Standing
What is the minimun size of copper tube permitted for medical gas distribution systems?
1/2”
If performing hot work on a frozen line what must be done?
Re apply freeze pack to the site every 15 minutes
All medical gases must be tested for the purity of the gas. What concentration must those gases be at?
100% oxygen, nitrogen and nitrous and 21% for medical air
If you have a medical gas system with with an anticipated operating pressure of 125 psi what pressure test would it need to maintain to pass inspection?
- 5 psi for 24 hours
1. 5x operating
Which fixtures and appliances must be installed with a shut-off valve in a public building?
All fixtures and appliances
Private (residential) only requires water closet, building iso and hot water tank
What water treatment equipment is required if coliforms are detected in a water supply?
Chlorinator
If there is a pressure of 50 psi at street level, how high will the pressure lift water contained in a 2” veritcal water pipe?
50psi x 2.31psi/foot = 115.5’
A jet pump was seen operating properly at instllation. The installer properly set the cut in and cut out to 30-50psi. Months later the owner is seeing pressures as high as 70 psi before the pump shuts down. What is most likely the reason?
Obstructed or slightly kinked pressure switch tubing
What is the minimum size water service?
3/4”
Polybutylene piping should not come in contact with what?
Chlorine
What is your grade % if you have 216” of drop and 500’ of run?
500’ x 12” = 6000”
6000” / 216” = 0.036
0.036 x 100 = 3.6%
How many GPG does soft water have?
Less than 1 gpg (hardness)
Where a 4” building trap is installed in a system what provisions must be met?
- it must have a cleanout upstream and downstream of the building trap
- must have a 4” fresh air inlet not more than 1.2m upstream of the building trap
What is a class K fire extinguisher used for?
Grease
What device is installed on the downstream side of a high pressure steam safety valve that vents to the roof?
Drip pan elbow
What is the purpose of an insulated service valve insatlled on gas pipe exiting the ground and entering the building?
It breaks the contact between the ground and the building piping
How should you properly prepare a CPVC end?
Deburr and bevel
Regarding DWV piping, what is the maximum plus or minus pressure allowed in a system?
1” WC
A PVC DWV system is running horizontally for 136m, how many clevis hangers will need to be ordered?
PVC/ABS hanger spacing = 1.2m
136m / 1.2m = 113.333333
Round up add 1
=115
What can be installed to correct periodic discharge from a reduced pressure principle backflow preventer when the water distribution pressure is expected to fluctuate?
Install a swing check upstream of the RP
What would the size of the required yoke vent be in a high rise if the vent stack is 2” and the waste stack is 3”?
11/2”
1 size smaller than smallest connected pipe
The base of a soil stack is 6” in diameter and the stack vent on top of it is 3” in size. The stack is required to have a nominally horizontal offset greater than 1.5m. The offset relief vent required on either side of the offset will be required to be what size?
2”
1 size smaller than the stack vent
What is the minimum sized vent that must be provided for any future installations in a building?
11/2”
A flat roof that measures 25m x 50m with a perpendicular wall that is 7m x 50m will require what size leader if local rainfall intensity is 20mm for 15 minutes?
25m x 50m = 1250m
7m x 50m = 350m
- Take 50% of perpendicular wall area
350m x 0.5 = 175m
1250m + 175m = 1425m
1425 x 20(rainfall intensity) = 28500
Size off of 2.4.10.11 (6” leeder)
What fitting would be used to attatch a field cut glass tube to a non-field cut glass tube?
Bead to Plain
What decice is required on a water supply connecting to the bottom of a commercial hot water heater?
Vaccume relief valve installed at least 6” above the tank
What provision must be made for a gas room heater insatalled in a hallway in a seniors home?
Must be vented type
Applicable in any public place
How should a threaded joint be made between threaded galvanized steel piping and copper tubing?
Brass MIP
What determines the minimum size of a suction pipe on a well pump?
Size of the inlet of the pump
What is the sacrificial anode in a hot water tank manufactured from?
Magnesium
Steel piping comes in what usual lengths?
6m
21 feet in the real world
What color codes are type k, l and m copper?
K (kermit) = green
L (lake) = blue
M (murder) = red
What type of thread is on acetylene fittings?
Left
A 3/4” extracted tee may be formed from?
1” type K
Tee is 1 size smaller than pipe size and always use type K
What force would be exerted on a 9” blind flange at the base of a 30’ column filled with water?
Convert feet to psi
30’ x 0.433psi/foot = 12.99 psi
Find surface area of flange
A= 3.14(4.5)Squared
A= 63.585
63.585 x 12.99 = 825.98psi
How do you convert height into pressure?
How do you convert pressure into height?
feet x 0.433
What should the relief valve on a compressed air receiver tank be set to discharge at if the cut out pressure of the compressor is set to 45psi?
55 psi
10psi above cut out
What size is the cleanout on a 6” sanitary building drainas it exits a building?
4”
What backflow preventer is not testable?
DuC
Dual check valve
How do you determine maximum trap arm length?
Fall of 1 pipe diamter
What is the maximum practical lift of a shallow well pump?
25’
What provision must be made for an autopsy table that receives potentially dangerous bio-hazard waste?
Must be installed with a cleanout above flood level rim
How should piping in a pneumatic system be installed?
Graded towards the oulets with branches rising up off the mains
A combined building sewer has a sanitary hydraulic load of 549 fixture units and 8 rainwater leaders with 2750 litres each. What size is the sewer graded at 1%?
2750L x 8 = 22000L
549 FU X 9.1L/FU = 4995.9L
22000L + 4995.9L = 26995.9
Size according to 2.4.10.9 (10”)
How many pounds are in a US gallon?
8.33 lb/gal
Example…
60USgal x 8.33 lb/USgal = 499.8lb
How much does 1 cubic foot of water weigh?
62.4 lb/cubicft
How many litres are in an imperial gallon?
4.54 l/impgal
How do you calculate linear expansion?
Table A-2.3.3.9.
Length change = original length x coefficient of expansion x temp change
The waste for the closed coupled tank type W.C. is roughed in at?
305 mm (12”) from finished wall
A blowout W.C. cannot be?
Horizontally wet vented
A floor drain can be protected from back flow by a?
Gate valve
Screw cap
The minimum distance permitted between two shower heads is?
750mm
A relief vent is most closely related to a?
Vent stack
Not more than how many showers can be served by one drain?
6
A yoke vent is required when the soil or waste stack extends through a number of storeys. An additional circuit vent is also required when?
More than 8 fixtures are installed between vents
The minimum air break for an indirect waste pipe that is 1 ¼” is?
1 1/4”
Which does not require a vent?
a) Lavatory trap
b) Trap forming part of an indirect drainage system
c) Trap on a subsoil drainage system
d) Sewage sumpe
Either b) or c)
Answer: c)
