RMGA TEST UPDATED QUESTIONS AND ANSWERS
Which of the following is the chemical formula for natural gas? - CORRECT ANSWER✅✅✅CH4
What is the best method to locate a gas leak? - CORRECT ANSWER✅✅✅Combustible Gas Detector
Is natural gas heavier than air? - CORRECT ANSWER✅✅✅Yes
What is 2-4 times heavier than air? - CORRECT ANSWER✅✅✅Gasoline
What component make Natural Gas "sour gas"? - CORRECT ANSWER✅✅✅Hydrogen Sulfide
What is added to Natural Gas to give it an identified odor? - CORRECT ANSWER✅✅✅Butyl
Mercaptan/Thiophene
T/F? When Natural Gas comes out of the ground, it has no odor? - CORRECT ANSWER✅✅✅True
What is the flammability of Natural Gas? - CORRECT ANSWER✅✅✅4%-14%
What temperature does Natural Gas ignite at? - CORRECT ANSWER✅✅✅1200 degrees
How toxic is Natural Gas? - CORRECT ANSWER✅✅✅Non-toxic
When can combustion air be taken inside a home with tight construction? - CORRECT
ANSWER✅✅✅Never
How many inches of free area are required for horizontal ducts into a mechanical room? - CORRECT
ANSWER✅✅✅1 in.(squared) per 2,000 BTUH
, How many inches of free area are required for vertical ducts into a mechanical room? - CORRECT
ANSWER✅✅✅1 in. (squared) per 4,000 BTUH
What percentage of a wood grill is considerate to be free area? - CORRECT ANSWER✅✅✅25%
What is the smallest single duct that would be large enough to supply air into a mechanical room with a
153,000 BTUH? - CORRECT ANSWER✅✅✅7 in. x 8 in. duct
What is required when converting 2 horizontal ducts to a single duct? - CORRECT ANSWER✅✅✅A
clearance of 1 in. on the back and sides and 6 in. to the front of all appliances
What is the smallest size that will meet a 43 in. (squared) free area? - CORRECT ANSWER✅✅✅6 in. x
8 in. duct
T/F? Vertical ducts are sized the same as horizontal ducts. - CORRECT ANSWER✅✅✅False
What size metal grill would be the smallest needed to provide a 140 in. (squared) of free area? -
CORRECT ANSWER✅✅✅14 in. x 14 in duct
If combustion air is obtained from a crawl space, how large must the grills be? - CORRECT
ANSWER✅✅✅1 square inch per 4,000 BTUH of all appliances in the space
What size horizontal ducts would be the smallest required for a mechanical room with TWO 120,000
BTUH furnaces and a 45,000 BTUH water heater? - CORRECT ANSWER✅✅✅12 in. x 12 in. duct
how many inches of free area would be needed for vertical combustion air ducts supplying a 110,000
BTUH furnace and a 42,000 BTUH water heater? - CORRECT ANSWER✅✅✅38 in. (squared)
An upper combustion air duct must always...? - CORRECT ANSWER✅✅✅Slope upwards
Which of the following is the chemical formula for natural gas? - CORRECT ANSWER✅✅✅CH4
What is the best method to locate a gas leak? - CORRECT ANSWER✅✅✅Combustible Gas Detector
Is natural gas heavier than air? - CORRECT ANSWER✅✅✅Yes
What is 2-4 times heavier than air? - CORRECT ANSWER✅✅✅Gasoline
What component make Natural Gas "sour gas"? - CORRECT ANSWER✅✅✅Hydrogen Sulfide
What is added to Natural Gas to give it an identified odor? - CORRECT ANSWER✅✅✅Butyl
Mercaptan/Thiophene
T/F? When Natural Gas comes out of the ground, it has no odor? - CORRECT ANSWER✅✅✅True
What is the flammability of Natural Gas? - CORRECT ANSWER✅✅✅4%-14%
What temperature does Natural Gas ignite at? - CORRECT ANSWER✅✅✅1200 degrees
How toxic is Natural Gas? - CORRECT ANSWER✅✅✅Non-toxic
When can combustion air be taken inside a home with tight construction? - CORRECT
ANSWER✅✅✅Never
How many inches of free area are required for horizontal ducts into a mechanical room? - CORRECT
ANSWER✅✅✅1 in.(squared) per 2,000 BTUH
, How many inches of free area are required for vertical ducts into a mechanical room? - CORRECT
ANSWER✅✅✅1 in. (squared) per 4,000 BTUH
What percentage of a wood grill is considerate to be free area? - CORRECT ANSWER✅✅✅25%
What is the smallest single duct that would be large enough to supply air into a mechanical room with a
153,000 BTUH? - CORRECT ANSWER✅✅✅7 in. x 8 in. duct
What is required when converting 2 horizontal ducts to a single duct? - CORRECT ANSWER✅✅✅A
clearance of 1 in. on the back and sides and 6 in. to the front of all appliances
What is the smallest size that will meet a 43 in. (squared) free area? - CORRECT ANSWER✅✅✅6 in. x
8 in. duct
T/F? Vertical ducts are sized the same as horizontal ducts. - CORRECT ANSWER✅✅✅False
What size metal grill would be the smallest needed to provide a 140 in. (squared) of free area? -
CORRECT ANSWER✅✅✅14 in. x 14 in duct
If combustion air is obtained from a crawl space, how large must the grills be? - CORRECT
ANSWER✅✅✅1 square inch per 4,000 BTUH of all appliances in the space
What size horizontal ducts would be the smallest required for a mechanical room with TWO 120,000
BTUH furnaces and a 45,000 BTUH water heater? - CORRECT ANSWER✅✅✅12 in. x 12 in. duct
how many inches of free area would be needed for vertical combustion air ducts supplying a 110,000
BTUH furnace and a 42,000 BTUH water heater? - CORRECT ANSWER✅✅✅38 in. (squared)
An upper combustion air duct must always...? - CORRECT ANSWER✅✅✅Slope upwards
