Q1. The Minnesota Fuel Gas Code is primarily based on which national model
code?
A) Uniform Plumbing Code (UPC)
B) International Fuel Gas Code (IFGC)
C) National Fire Protection Association (NFPA) 54
D) Minnesota State Building Code
Answer: B – International Fuel Gas Code (IFGC)
Explanation: Minnesota adopts the IFGC as the foundation for its fuel gas
regulations, with amendments. NFPA 54 is a related standard but not the
adopted model.
Q2. What is the minimum test pressure for gas piping systems less than 10 psi,
according to the Minnesota Fuel Gas Code?
A) 3 psi
B) 5 psi
C) 10 psi
D) 15 psi
Answer: B – 5 psi
Explanation: Piping systems operating at less than 10 psi must be tested at not
less than 5 psi for 15 minutes with no pressure drop.
Q3. Which of the following materials is NOT approved for use as gas piping
inside buildings?
A) Black steel
B) Copper (if allowed by code amendment)
C) PVC plastic
D) Corrugated stainless steel tubing (CSST)
Answer: C – PVC plastic
Explanation: PVC is prohibited because it cannot handle fuel gas safely. Black
steel, CSST, and sometimes copper are permitted.
,Q4. What is the primary purpose of a gas regulator?
A) Increase pressure to appliances
B) Reduce and control gas pressure to safe operating levels
C) Prevent backflow of gas
D) Allow air mixing for combustion
Answer: B – Reduce and control gas pressure
Explanation: Regulators ensure appliances receive gas at the proper pressure
for safe operation.
Q5. Gas shutoff valves for appliances must be located:
A) Anywhere on the gas line
B) Within 6 feet of the appliance and in the same room
C) At the gas meter only
D) Behind the appliance, hidden
Answer: B – Within 6 feet of the appliance and in the same room
Explanation: Code requires each appliance to have a shutoff valve accessible
in the same room and within 6 feet.
Q6. What is the minimum burial depth for underground metallic gas piping in
Minnesota?
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Answer: C – 18 inches
Explanation: Underground metallic piping must be buried at least 18 inches
below grade to protect from damage.
Q7. Corrugated stainless steel tubing (CSST) must always be:
A) Buried directly in soil
B) Electrically bonded
C) Painted to prevent corrosion
D) Installed only outdoors
,Answer: B – Electrically bonded
Explanation: CSST must be bonded to the electrical grounding system to
reduce the risk of lightning-induced damage.
Q8. The maximum pressure allowed inside most residential buildings for
natural gas piping is:
A) ½ psi (14 inches water column)
B) 2 psi
C) 5 psi
D) 10 psi
Answer: A – ½ psi
Explanation: Standard residential appliances are designed for low pressure
(around 7" WC). Higher pressure systems require special regulators and piping.
Q9. The volume of combustion air required for a gas appliance is generally
based on:
A) Gas line size
B) Appliance input rating (BTU/hr)
C) Appliance height
D) Regulator size
Answer: B – Appliance input rating
Explanation: Combustion air requirements are calculated by the total input in
BTU/hr of all appliances in the space.
Q10. A Category IV appliance vent is:
A) Non-condensing, natural draft
B) Non-condensing, forced draft
C) Condensing, positive pressure
D) Wood-burning
Answer: C – Condensing, positive pressure
Explanation: Category IV appliances produce condensate and require sealed
venting to withstand positive pressure and corrosion.
Q11. When sizing gas piping, the main factors considered are:
A) Pipe material and wall thickness
, B) Gas pressure, pipe length, and total load (BTU/hr)
C) Appliance brand
D) Size of regulator only
Answer: B – Gas pressure, pipe length, and total load
Explanation: Proper pipe sizing ensures enough flow at acceptable pressure
drop to supply all appliances.
Q12. Which type of joint is prohibited in concealed gas piping?
A) Threaded steel pipe joint
B) Brazed copper joint
C) Compression fitting
D) Welded steel joint
Answer: C – Compression fitting
Explanation: Compression fittings are not allowed in concealed locations
because they may loosen or leak over time.
Q13. What is the minimum clearance between a gas vent termination and an
operable window or door?
A) 6 inches
B) 12 inches
C) 3 feet
D) 5 feet
Answer: C – 3 feet
Explanation: Vent terminations must be at least 3 feet horizontally from
operable doors or windows to prevent flue gas re-entry.
Q14. Manifolded gas appliances (e.g., multiple furnaces on one line) require:
A) Individual shutoff valves for each unit
B) One shared shutoff valve
C) Higher pressure regulators
D) Isolation from combustion air
Answer: A – Individual shutoff valves
Explanation: Each appliance must have its own shutoff for safety and service
purposes.
code?
A) Uniform Plumbing Code (UPC)
B) International Fuel Gas Code (IFGC)
C) National Fire Protection Association (NFPA) 54
D) Minnesota State Building Code
Answer: B – International Fuel Gas Code (IFGC)
Explanation: Minnesota adopts the IFGC as the foundation for its fuel gas
regulations, with amendments. NFPA 54 is a related standard but not the
adopted model.
Q2. What is the minimum test pressure for gas piping systems less than 10 psi,
according to the Minnesota Fuel Gas Code?
A) 3 psi
B) 5 psi
C) 10 psi
D) 15 psi
Answer: B – 5 psi
Explanation: Piping systems operating at less than 10 psi must be tested at not
less than 5 psi for 15 minutes with no pressure drop.
Q3. Which of the following materials is NOT approved for use as gas piping
inside buildings?
A) Black steel
B) Copper (if allowed by code amendment)
C) PVC plastic
D) Corrugated stainless steel tubing (CSST)
Answer: C – PVC plastic
Explanation: PVC is prohibited because it cannot handle fuel gas safely. Black
steel, CSST, and sometimes copper are permitted.
,Q4. What is the primary purpose of a gas regulator?
A) Increase pressure to appliances
B) Reduce and control gas pressure to safe operating levels
C) Prevent backflow of gas
D) Allow air mixing for combustion
Answer: B – Reduce and control gas pressure
Explanation: Regulators ensure appliances receive gas at the proper pressure
for safe operation.
Q5. Gas shutoff valves for appliances must be located:
A) Anywhere on the gas line
B) Within 6 feet of the appliance and in the same room
C) At the gas meter only
D) Behind the appliance, hidden
Answer: B – Within 6 feet of the appliance and in the same room
Explanation: Code requires each appliance to have a shutoff valve accessible
in the same room and within 6 feet.
Q6. What is the minimum burial depth for underground metallic gas piping in
Minnesota?
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Answer: C – 18 inches
Explanation: Underground metallic piping must be buried at least 18 inches
below grade to protect from damage.
Q7. Corrugated stainless steel tubing (CSST) must always be:
A) Buried directly in soil
B) Electrically bonded
C) Painted to prevent corrosion
D) Installed only outdoors
,Answer: B – Electrically bonded
Explanation: CSST must be bonded to the electrical grounding system to
reduce the risk of lightning-induced damage.
Q8. The maximum pressure allowed inside most residential buildings for
natural gas piping is:
A) ½ psi (14 inches water column)
B) 2 psi
C) 5 psi
D) 10 psi
Answer: A – ½ psi
Explanation: Standard residential appliances are designed for low pressure
(around 7" WC). Higher pressure systems require special regulators and piping.
Q9. The volume of combustion air required for a gas appliance is generally
based on:
A) Gas line size
B) Appliance input rating (BTU/hr)
C) Appliance height
D) Regulator size
Answer: B – Appliance input rating
Explanation: Combustion air requirements are calculated by the total input in
BTU/hr of all appliances in the space.
Q10. A Category IV appliance vent is:
A) Non-condensing, natural draft
B) Non-condensing, forced draft
C) Condensing, positive pressure
D) Wood-burning
Answer: C – Condensing, positive pressure
Explanation: Category IV appliances produce condensate and require sealed
venting to withstand positive pressure and corrosion.
Q11. When sizing gas piping, the main factors considered are:
A) Pipe material and wall thickness
, B) Gas pressure, pipe length, and total load (BTU/hr)
C) Appliance brand
D) Size of regulator only
Answer: B – Gas pressure, pipe length, and total load
Explanation: Proper pipe sizing ensures enough flow at acceptable pressure
drop to supply all appliances.
Q12. Which type of joint is prohibited in concealed gas piping?
A) Threaded steel pipe joint
B) Brazed copper joint
C) Compression fitting
D) Welded steel joint
Answer: C – Compression fitting
Explanation: Compression fittings are not allowed in concealed locations
because they may loosen or leak over time.
Q13. What is the minimum clearance between a gas vent termination and an
operable window or door?
A) 6 inches
B) 12 inches
C) 3 feet
D) 5 feet
Answer: C – 3 feet
Explanation: Vent terminations must be at least 3 feet horizontally from
operable doors or windows to prevent flue gas re-entry.
Q14. Manifolded gas appliances (e.g., multiple furnaces on one line) require:
A) Individual shutoff valves for each unit
B) One shared shutoff valve
C) Higher pressure regulators
D) Isolation from combustion air
Answer: A – Individual shutoff valves
Explanation: Each appliance must have its own shutoff for safety and service
purposes.
