NFI Gas Test questions and answers
with solutions
Air weight is 1, NG, Propane Weight?
Natural Gas .4 .to .8 or .64 , Propane 1.52
What is the ignition temperature for natural gas?
NG 1,150F
What is the ignition temperature range for propane?
Propane min 920-1120F
You need these three things for fuel to ignite?
(1) ignition temperature = sufficient heat (2) flammability limits = fuel to air limits
(3)combustion ratio = air to fuel mixture
Flammability Limit for NG and PG (gas to air ratio?)(% range)
NG 4 % -14 % gas to air , PG 2.15 - 9.6% (fuel gas in mixture)
Fuel Combustion Ratio - Air to fuel ratio (NG and LPG)( ( cubic feet of air to fuel)
NG 10 to 1 (air to natural gas cubic feet)
LPG 24: 1
Name the safety odorant added?
mainly mercaptan
Define 1 BTU
Amount of energy to raise 1 pound of water 1 degree F at sea level
How are appliances rated?
BTUs per hour
What happens if the main burner orifice is underrated?
incomplete burn and carbon monoxide
What happens if the main burner is overrated?
,Too much heat
What the rule for derating an orifice for altitude?
4 % for each 1,000 ft of altitude some over 1k others over 2k ) .
You do not de-rate an orifice for an unvented fireplace. What is the typical unavoidable result?
Fireplace may be subject to nuisance outages or frequent maintenance.
1 cubic foot NG equals how many BTUs?
1,000 BTUs
1 cubic foot Propane equals how many BTU's?
2.5k BTU
1 cubic foot Butane equals how many BTUs?
3.2k
Gases are nontoxic. This health risk is that it does what?
displaces all the oxygen
Natural gas pressure when transported in pipes across the country? (pounds per inch?)
1,500 pounds per inch
NG pressure when entering the home is?
per inch 7 to 11 inches of water column WC
One psi equals how many water columns of pressure?
28
NG pressure after the valve and before the main burner?
3.5 water columns of pressure
Above what temperature does propane vaporize?
-44 F (boiling point)
Propane storage tanks filled this percentage to make room for vapor expansion?
80%
Propane BTUS drop as it gets
, colder outside
Home WC reduced to
11-14 for propane incoming
The name of the liquid portion of the tank that absorbs heat from the outside?
Wetted Surface
The act of joining two electrical conductors together, whether they are wires, wire and pipe, or
two pieces of equipment. This is called what?
Bonding
The process of making an electrical connection to the general mass of the earth is called?
Grounding
Gas piping is considered to be bonded when it is connected ________________ and
____________________ ________________________ that are connected to the
appliance/equipment grounding connector of the circuit supplying the appliance.
appliance, electrical components
Each above-ground portion of a gas piping system that is likely to become energized must be
_______________ and ___________________ to an effective ground-fault path (page 24)
electronically continuous, bonded
For CSST - 2009, the fuel gas code requires piping systems to be _____________ to the electrical
service grounding electrode system at the point where the ____________ service enters the
______________. (page 24)
bonded, gas , building
The 2012 fuel gas codes, however, specify that the bonding jumper must connect to a
____________________ pipe or _____________________ between the point of delivery and
the first downstream CSST fitting.
metallic, fitting
Longest Run method used to determine _____________ ______________. Add all the linear
feet together for each run and every calculation.
piping size
with solutions
Air weight is 1, NG, Propane Weight?
Natural Gas .4 .to .8 or .64 , Propane 1.52
What is the ignition temperature for natural gas?
NG 1,150F
What is the ignition temperature range for propane?
Propane min 920-1120F
You need these three things for fuel to ignite?
(1) ignition temperature = sufficient heat (2) flammability limits = fuel to air limits
(3)combustion ratio = air to fuel mixture
Flammability Limit for NG and PG (gas to air ratio?)(% range)
NG 4 % -14 % gas to air , PG 2.15 - 9.6% (fuel gas in mixture)
Fuel Combustion Ratio - Air to fuel ratio (NG and LPG)( ( cubic feet of air to fuel)
NG 10 to 1 (air to natural gas cubic feet)
LPG 24: 1
Name the safety odorant added?
mainly mercaptan
Define 1 BTU
Amount of energy to raise 1 pound of water 1 degree F at sea level
How are appliances rated?
BTUs per hour
What happens if the main burner orifice is underrated?
incomplete burn and carbon monoxide
What happens if the main burner is overrated?
,Too much heat
What the rule for derating an orifice for altitude?
4 % for each 1,000 ft of altitude some over 1k others over 2k ) .
You do not de-rate an orifice for an unvented fireplace. What is the typical unavoidable result?
Fireplace may be subject to nuisance outages or frequent maintenance.
1 cubic foot NG equals how many BTUs?
1,000 BTUs
1 cubic foot Propane equals how many BTU's?
2.5k BTU
1 cubic foot Butane equals how many BTUs?
3.2k
Gases are nontoxic. This health risk is that it does what?
displaces all the oxygen
Natural gas pressure when transported in pipes across the country? (pounds per inch?)
1,500 pounds per inch
NG pressure when entering the home is?
per inch 7 to 11 inches of water column WC
One psi equals how many water columns of pressure?
28
NG pressure after the valve and before the main burner?
3.5 water columns of pressure
Above what temperature does propane vaporize?
-44 F (boiling point)
Propane storage tanks filled this percentage to make room for vapor expansion?
80%
Propane BTUS drop as it gets
, colder outside
Home WC reduced to
11-14 for propane incoming
The name of the liquid portion of the tank that absorbs heat from the outside?
Wetted Surface
The act of joining two electrical conductors together, whether they are wires, wire and pipe, or
two pieces of equipment. This is called what?
Bonding
The process of making an electrical connection to the general mass of the earth is called?
Grounding
Gas piping is considered to be bonded when it is connected ________________ and
____________________ ________________________ that are connected to the
appliance/equipment grounding connector of the circuit supplying the appliance.
appliance, electrical components
Each above-ground portion of a gas piping system that is likely to become energized must be
_______________ and ___________________ to an effective ground-fault path (page 24)
electronically continuous, bonded
For CSST - 2009, the fuel gas code requires piping systems to be _____________ to the electrical
service grounding electrode system at the point where the ____________ service enters the
______________. (page 24)
bonded, gas , building
The 2012 fuel gas codes, however, specify that the bonding jumper must connect to a
____________________ pipe or _____________________ between the point of delivery and
the first downstream CSST fitting.
metallic, fitting
Longest Run method used to determine _____________ ______________. Add all the linear
feet together for each run and every calculation.
piping size
