[D2L] Final Review Flashcards
How many BTU’s in any kind of residential, commercial, or industrial gas system, including any gas appliance does a (B) gas fitter adhere to?
Does not exceed 400,000 BTU
What combustible component of natural gas is typically 95%?
methane
What are oil, natural gas and coal classed as?
hydrocarbon
All gas contains water, which must be removed at the wellhead because it would freeze forming “hydrates”.
True
How many BTU’s are required to heat a 40Gal HWT from 55F to 130F
30,000
What range is the operating pressures of transmission pipe lines?
300 psi - 1500 psi
Which substance is added to natural gas to provide its odor?
mercaptan
What does LPG stand for?
liquefied petroleum gas
What temperature does natural gas need to be at atmospheric pressure need to be in order to liquefy?
-258 F
What is the boiling point of propane at atmospheric pressure?
-44 F
What is the natural state of natural gas?
gas
What is the heating value of natural gas?
1000 btu/cubic foot
How much combustion air is needed for perfect combustion of one cubic foot of propane?
24 cubic feet
Regulators of propane tanks drop the pressure between 5-10psi. What pressure does the home regulator reduce the pressure to?
11” wc
Each atom of natural gas (methane) is made up of carbon and __________.
hydrogen
What pressure is gas distributed in most areas of the city?
12 - 80 psig
What is the Canadian Natural Gas and Propane installation code book?
CSA-B149.1
When gas burns properly, the hydrogen combines with the oxygen of the air to produce water vapour. What is produced when the carbon combines with the oxygen?
Carbon Dioxide(CO²)
How many cubic feet of natural gas are required to produce 400,000 btu?
400
How much combustion air would be required for perfect combustion of 250,000 btu of natural gas?
2500 cubic feet
What are the rough in piping pressure testing requirements for most residential piping systems (2 psi max pressure and less than 200 feet of piping)?
15 psi for 15 minutes
An “A” gasfitter can work on
appliances and Piping downstream of the gas meter
What is natural gases range of flammability?
5% to 15%
What is the chemical formula for natural gas?
CH4
Is natural gas lighter or heavier than air?
Lighter
Propane gas, as a vapour, has a relative density of 1.5 lb/Ft3. Is it heavier or lighter than air?
Heavier
What is the structure of a molecule of Propane?
Three carbon atoms and eight hydrogen atoms
The Maximum Flame Temperature for Nat. Gas is 1000F
False
What is the minimum size of pressure gauge when pressure testing rough in piping?
3”
Where and how is standing pressure obtained from a gas furnace system?
Between the meter and the appliance with no gas flowing
Where and how is manifold pressure obtained from a gas furnace system?
Between the appliance control valve and the burner while the appliance is firing
What are the manifold pressures for natural gas and propane?
Natural Gas is 3.5”wc and propane is 11.0”wc
What is the purpose of an air shutter on a mid efficient gas burner?
Control the amount of primary air entering the burner
What is the purpose of aldehydes?
Nothing; they are a product of incomplete combustion and means carbon monoxide is likely present
What are the three components of the combustion triangle?
Air, fuel and heat
What would cause a roaring and lifting flame?
Too much primary air
What are the three factors used to determine if a gas flame has the correct characteristics?
Colour, shape and size
What pressure of natural gas is delivered from a service regulator to piping inside a home?
7”-14” wc
How many cubic feet of propane gas is required to produce 350,000 BTU?
140
What pressure is finish piping tested to?
working pressure
How much is 1 psig equal to?
28” wc
Vent gases are made up of:
Dilution Air and Flue Gases
How much does 10 Imp Gal of water weight?
100 lbs
How many hours will it take for 2000 cubic feet of propane to operate a construction heater with a rated input of 40 000 Btu per hour, if the heater operated continuously?
125
What happens if we don’t remove Sulphur from gas?
the gas produces acid rain when burned
Propane’s volume increases by how much when changing from a liquid to a vapour?
270x