Medical Gas Certification Exam (ASSE
6010/6005/6020 Style) – 2026/2027 Actual
Exam-Format Questions with 100% Verified
Correct Answers Latest Version – Graded
A+ – Pass Guaranteed
Q1 According to NFPA 99 (2024 edition – current in 2026/2027), what is the minimum required
pressure test for medical gas piping after brazing but before final connection to terminal units?
Answer: Initial pressure test at 150 psig for 24 hours
Rationale: NFPA 99 § 5.1.12.2.6 requires an initial pressure test of 150 psig (or 50% above
normal operating pressure, whichever is greater) held for 24 hours with no more than 5 psig
drop.
Q2 What is the required purge gas when brazing medical gas copper piping?
Answer: Nitrogen (oil-free, dry)
Rationale: NFPA 99 § 5.1.10.4.4.2 mandates the use of oil-free, dry nitrogen as the purge gas
during brazing to prevent internal oxidation (scaling).
Q3 Which brazing alloy is permitted for joining medical gas copper tubing?
Answer: BCuP-5 (silicon-free, 15% silver)
Rationale: NFPA 99 § 5.1.10.4.5 requires brazing filler metals to be BCuP series (phosphorus-
copper) with no more than 0.05% cadmium and no flux. BCuP-5 is the most common approved
alloy.
Q4 What is the maximum allowable pressure drop permitted during the standing pressure test for
medical gas systems?
, Answer: 5 psig over 24 hours
Rationale: NFPA 99 § 5.1.12.2.6 allows no more than a 5 psig drop during the 24-hour initial
pressure test.
Q5 Which gas is used for the final purge of medical gas piping before placing it into service?
Answer: Nitrogen
Rationale: NFPA 99 § 5.1.12.2.9 requires a final purge with oil-free, dry nitrogen to remove
residual brazing flux and debris before system use.
Q6 What is the required labeling for medical gas piping?
Answer: Color-coded labels every 20 feet, at each branch, and at all outlets
Rationale: NFPA 99 § 5.1.11.1 requires permanent labels with name of gas and color code at
intervals not exceeding 20 feet, at all branches, and at each terminal unit.
Q7 Which type of copper tubing is required for medical gas systems?
Answer: ASTM B819 Type L, specially cleaned and capped
Rationale: NFPA 99 § 5.1.10.1 mandates ASTM B819 Type L copper tubing that is cleaned for
oxygen service, plugged/capped, and labeled.
Q8 What is the minimum required separation between medical gas piping and electrical conduit?
Answer: No minimum – they may be installed in the same chase if properly supported
Rationale: NFPA 99 does not require a specific separation distance between medical gas piping
and electrical conduit as long as both are properly supported and protected.
Q9 During the system verification test, what is the required purity level for oxygen in a new
medical gas system?
6010/6005/6020 Style) – 2026/2027 Actual
Exam-Format Questions with 100% Verified
Correct Answers Latest Version – Graded
A+ – Pass Guaranteed
Q1 According to NFPA 99 (2024 edition – current in 2026/2027), what is the minimum required
pressure test for medical gas piping after brazing but before final connection to terminal units?
Answer: Initial pressure test at 150 psig for 24 hours
Rationale: NFPA 99 § 5.1.12.2.6 requires an initial pressure test of 150 psig (or 50% above
normal operating pressure, whichever is greater) held for 24 hours with no more than 5 psig
drop.
Q2 What is the required purge gas when brazing medical gas copper piping?
Answer: Nitrogen (oil-free, dry)
Rationale: NFPA 99 § 5.1.10.4.4.2 mandates the use of oil-free, dry nitrogen as the purge gas
during brazing to prevent internal oxidation (scaling).
Q3 Which brazing alloy is permitted for joining medical gas copper tubing?
Answer: BCuP-5 (silicon-free, 15% silver)
Rationale: NFPA 99 § 5.1.10.4.5 requires brazing filler metals to be BCuP series (phosphorus-
copper) with no more than 0.05% cadmium and no flux. BCuP-5 is the most common approved
alloy.
Q4 What is the maximum allowable pressure drop permitted during the standing pressure test for
medical gas systems?
, Answer: 5 psig over 24 hours
Rationale: NFPA 99 § 5.1.12.2.6 allows no more than a 5 psig drop during the 24-hour initial
pressure test.
Q5 Which gas is used for the final purge of medical gas piping before placing it into service?
Answer: Nitrogen
Rationale: NFPA 99 § 5.1.12.2.9 requires a final purge with oil-free, dry nitrogen to remove
residual brazing flux and debris before system use.
Q6 What is the required labeling for medical gas piping?
Answer: Color-coded labels every 20 feet, at each branch, and at all outlets
Rationale: NFPA 99 § 5.1.11.1 requires permanent labels with name of gas and color code at
intervals not exceeding 20 feet, at all branches, and at each terminal unit.
Q7 Which type of copper tubing is required for medical gas systems?
Answer: ASTM B819 Type L, specially cleaned and capped
Rationale: NFPA 99 § 5.1.10.1 mandates ASTM B819 Type L copper tubing that is cleaned for
oxygen service, plugged/capped, and labeled.
Q8 What is the minimum required separation between medical gas piping and electrical conduit?
Answer: No minimum – they may be installed in the same chase if properly supported
Rationale: NFPA 99 does not require a specific separation distance between medical gas piping
and electrical conduit as long as both are properly supported and protected.
Q9 During the system verification test, what is the required purity level for oxygen in a new
medical gas system?
