Final Study Flashcards
What must the gasfitter make sure to do when leaving a job?
Make sure that all the appliances are in the safe working order
Removing the ground prong on a power tool can?
Kill you
Should an accident occur on a gas installation after taking all necessary precautions, the primary responsibility will be that of the:
Licensed gasfitter
The first thing to do when dismantling a gas appliance is:
Shut off the gas to the appliance
To ventilate a building in event of a propane gas leak:
The upper story windows should be opened and;
The basement windows should be opened
A unit of power or heat rate that is 1000 times the base unit is used to:
Used to rate appliances
A hydrocarbon gas is one that:
Is composed of hydrogen and carbon molecules
The average amount of energy released by burning a gas is given in?
BTU/CF (BTU/ft³)
or
kJ/m³
Manufactured gas is a product of?
Coal gasification
LP gases are so named because they are normally stored and transported as ______.
Liquids
S.T.P. is used in calculation of?
Standard gas volumes
Natural and propane gases are both naturally odorless, naturally colorless, and naturally non-_____ .
Non-toxic
Mercaptan is A) odorless B) colorless C) non-combustible D) tensile
B) colorless
Is liquid propane more dense than water?
No. Liquid propane has a relative density of 0.51
The heating value of natural gas is
1000 BTU/CF or 37500 kJ/m³
The maximum flame temperature of natural gas is: A) lower than propane B) higher than butane C) higher than propane D) (A) and (C) above
A) lower than propane
The maximum flame temperature of natural gas is 3500°F… Lower than that of both propane and butane at 3650°F and 3660°F
Natural gas is: A) A product of decaying organic matter B) A byproduct of refining processes C) distilled from crude oil D) none of the above
A) A product of decaying organic matter
Referring to a gas what does LPG stand for?
Liquified Petroleum Gas
A cubic foot of natural gas weighs?
3/4 oz
The relative density of natural gas is?
0.6
When a fuel gas is burned completely it will make: A) water B) soot C) nitrogen D) all of the above
D) all of the above
Carbon monoxide has a chemical symbol of:
CO
When a substance is combined with oxygen, the process is called:
Oxidation
The most common method of extinguishing Type A fires is to remove the?
Oxygen
The three T’s are?
Necessary for complete combustion:
Time
Temperature
Turbulence
Does nitrogen in the air change in the combustion process?
No. Nitrogen is virtually unchanged in the combustion of gases
The oxygen used for combustion makes up ____% of air
20%
The main cause of incomplete combustion is?
Not enough combustion air
Combustion is best described as:
Rapid oxidation
What are the products of complete combustion?
Heat
Light
H2O
CO2
Three factors necessary for combustion are:
Fuel
Heat
Air
One cubic foot of air at STP weighs?
The density of air is 0.076 lbs/ft³ or 1.25 oz/ft³
To get the same volume of gas per hour through a 1” pipe as through a 1 1/4” pipe:
The velocity has to increase
Air has a density of?
- 076 lbs/ft³ @ STP 60°F at 29.92 Hg absolute
1. 29 kg/m³ @ STP 0°C at 101 kPa
Different types of piping affect pressure dropped because of different: A) Wall thickness B) threads C) surface smoothness D) all of the above
C) surface smoothness
A column of water 12” high will exert a pressure of?
0.434 PSIG
Manifold pressures are read with?
The main burners operating
A pressure of 1 PSIG is equivalent to ____” W.C.
28” W.C.
Standing line pressures are read with the main burners _____.
Off
The operating pressure in a residential propane line is normally _____ than that of natural gas
Less
Pressure in a propane system is at least ____” W.C.
11” W.C.
The main purpose of a gas burner is to?
Mix the gas and air
Burners are categorized by?
Flame pattern
Type of air mixing
Air supply methods
A burner that has air mixed with gas before ignition is known as?
An aerated burner
The primary purpose of a gas burner orifice is to?
Regulate gas volume
To change your burner from burning natural gas to propane gas, what has to be adjusted?
The orifice size only
Before dismantling any gas appliance or piping you should?
Shut off the gas &
Shut off the appliance power supply
The abbreviation MPa indicates?
A unit of pressure
Piping less than ____” shall not be concealed
1/2”
Unthreaded portions of piping must extend through walls and ceilings at least ___”
1”
Every hose and hose fitting must be rated for a minimum working pressure of ____ psig
350 psig
A close nipple is one that?
Has none of the original wall thickness left…. all thread
Which of the following is almost never handled it as a liquid by the gasfitter? A) propane B) butane C) natural gas D) pentane
C) natural gas
What is the maximum pressure allowed for building supply line piping?
2 psig
Soot is produced by?
A lack of primary air
Complete combustion requires
Controlled circumstances and
A proper air to fuel ratio
