NFPA 99 MEDICAL GAS & ELECTRICAL
SAFETY TIMED MOCK EXAM (2026–
2027) CERTIFICATION PRACTICE TEST
WITH ANSWERS
NFPA 99 Practice Test – Set 1 (Questions 1–160)
Category Risk Assessment (Category 1–4)
1. NFPA 99 Category 1 systems are defined as:
A. Systems with no impact on patient care
B. Systems where failure could result in minor injury
C. Systems where failure could result in major injury or death
D. Systems used only for diagnostics
Answer: C
Rationale: Category 1 = highest risk (life support systems).
2. Which is an example of a Category 1 space?
A. Waiting room
B. Operating room
C. Administrative office
D. Storage closet
Answer: B
3. Category 2 systems failure would result in:
A. Death
B. Minor injury
C. Severe injury
D. No impact
Answer: B
4. Who is responsible for determining system category?
A. Contractor
B. AHJ (Authority Having Jurisdiction)
,C. Nurse manager
D. Manufacturer
Answer: B
5. Category 4 systems have:
A. High risk
B. Moderate risk
C. No impact on patient care
D. Life support function
Answer: C
Medical Gas Systems
6. Medical gas piping must be made of:
A. PVC
B. Copper Type K or L (cleaned for oxygen service)
C. Steel
D. Aluminum
Answer: B
7. Copper tubing used must be:
A. Painted
B. Coated internally
C. Cleaned for oxygen service
D. Flexible
Answer: C
8. Nitrogen purging during brazing is required to:
A. Cool pipes
B. Prevent oxidation inside tubing
C. Increase pressure
D. Reduce cost
Answer: B
9. Acceptable brazing material must have a melting point of at least:
A. 500°F
,B. 800°F
C. 1000°F
D. 1200°F
Answer: C
10. Oil contamination in oxygen systems can cause:
A. Corrosion
B. Fire or explosion
C. Leakage
D. Pressure drop
Answer: B
DISS Connectors
11. DISS stands for:
A. Direct Internal Safety System
B. Diameter Index Safety System
C. Digital Integrated Supply System
D. Dual Intake Safety Standard
Answer: B
12. Purpose of DISS connectors:
A. Increase flow
B. Prevent gas misconnections
C. Reduce pressure
D. Improve aesthetics
Answer: B
13. Each gas has:
A. Same connector
B. Color-coded pipe only
C. Unique threaded connection
D. Same pressure rating
Answer: C
, 14. Oxygen DISS fittings are:
A. Interchangeable
B. Gas-specific
C. Universal
D. Optional
Answer: B
15. Improper DISS use can result in:
A. Noise
B. Gas cross-connection
C. Lower pressure
D. Pipe corrosion
Answer: B
Alarm Systems
16. Master alarm panels must be located:
A. Mechanical room
B. Nurse station
C. Roof
D. Storage
Answer: B
17. Area alarms monitor:
A. Entire facility
B. Specific zones
C. Only vacuum
D. Electrical only
Answer: B
18. Alarm systems must be:
A. Optional
B. Continuously monitored
C. Battery-free
D. Manual only
Answer: B
SAFETY TIMED MOCK EXAM (2026–
2027) CERTIFICATION PRACTICE TEST
WITH ANSWERS
NFPA 99 Practice Test – Set 1 (Questions 1–160)
Category Risk Assessment (Category 1–4)
1. NFPA 99 Category 1 systems are defined as:
A. Systems with no impact on patient care
B. Systems where failure could result in minor injury
C. Systems where failure could result in major injury or death
D. Systems used only for diagnostics
Answer: C
Rationale: Category 1 = highest risk (life support systems).
2. Which is an example of a Category 1 space?
A. Waiting room
B. Operating room
C. Administrative office
D. Storage closet
Answer: B
3. Category 2 systems failure would result in:
A. Death
B. Minor injury
C. Severe injury
D. No impact
Answer: B
4. Who is responsible for determining system category?
A. Contractor
B. AHJ (Authority Having Jurisdiction)
,C. Nurse manager
D. Manufacturer
Answer: B
5. Category 4 systems have:
A. High risk
B. Moderate risk
C. No impact on patient care
D. Life support function
Answer: C
Medical Gas Systems
6. Medical gas piping must be made of:
A. PVC
B. Copper Type K or L (cleaned for oxygen service)
C. Steel
D. Aluminum
Answer: B
7. Copper tubing used must be:
A. Painted
B. Coated internally
C. Cleaned for oxygen service
D. Flexible
Answer: C
8. Nitrogen purging during brazing is required to:
A. Cool pipes
B. Prevent oxidation inside tubing
C. Increase pressure
D. Reduce cost
Answer: B
9. Acceptable brazing material must have a melting point of at least:
A. 500°F
,B. 800°F
C. 1000°F
D. 1200°F
Answer: C
10. Oil contamination in oxygen systems can cause:
A. Corrosion
B. Fire or explosion
C. Leakage
D. Pressure drop
Answer: B
DISS Connectors
11. DISS stands for:
A. Direct Internal Safety System
B. Diameter Index Safety System
C. Digital Integrated Supply System
D. Dual Intake Safety Standard
Answer: B
12. Purpose of DISS connectors:
A. Increase flow
B. Prevent gas misconnections
C. Reduce pressure
D. Improve aesthetics
Answer: B
13. Each gas has:
A. Same connector
B. Color-coded pipe only
C. Unique threaded connection
D. Same pressure rating
Answer: C
, 14. Oxygen DISS fittings are:
A. Interchangeable
B. Gas-specific
C. Universal
D. Optional
Answer: B
15. Improper DISS use can result in:
A. Noise
B. Gas cross-connection
C. Lower pressure
D. Pipe corrosion
Answer: B
Alarm Systems
16. Master alarm panels must be located:
A. Mechanical room
B. Nurse station
C. Roof
D. Storage
Answer: B
17. Area alarms monitor:
A. Entire facility
B. Specific zones
C. Only vacuum
D. Electrical only
Answer: B
18. Alarm systems must be:
A. Optional
B. Continuously monitored
C. Battery-free
D. Manual only
Answer: B
