RMGA Pipeline Installation 2 — Questions and Answers
Question 1: According to NFPA 99, what is the minimum burial depth required for medical gas piping installed underground inside a healthcare facility?
- 6 inches
- 12 inches
- 18 inches (Correct answer)
- 24 inches
Correct answer: 18 inches
NFPA 99 requires underground medical gas piping inside buildings to be buried at least 18 inches deep to protect against damage.
Question 2: Which type of fitting is prohibited in medical gas pipeline systems according to NFPA 99?
- Wrought copper fittings
- Cast brass fittings
- Brazed socket fittings
- Threaded fittings on copper tubing (Correct answer)
Correct answer: Threaded fittings on copper tubing
Threaded fittings on copper tubing are prohibited in medical gas systems; all joints must use brazed or approved mechanical connections.
Question 3: What is the required color coding for a nitrous oxide pipeline in the United States?
- Green
- Blue (Correct answer)
- Light blue
- Yellow
Correct answer: Blue
Nitrous oxide pipelines are coded blue per CGA and NFPA 99 standards for medical gas identification in the US.
Question 4: When installing copper tubing for medical gas pipelines, which grade must be used?
- Type M copper
- Type L copper
- Type K copper
- Type ACR copper cleaned for oxygen service (Correct answer)
Correct answer: Type ACR copper cleaned for oxygen service
Medical gas piping requires Type K or Type L hard-drawn copper tubing that has been cleaned for oxygen service and labeled accordingly.
Question 5: In a medical gas pipeline system, what is the purpose of a zone valve box?
- To regulate gas pressure to patient outlets
- To isolate a section of the distribution system for maintenance or emergency (Correct answer)
- To measure gas flow to individual rooms
- To prevent backflow of gases between zones
Correct answer: To isolate a section of the distribution system for maintenance or emergency
Zone valve boxes allow specific areas to be isolated from the pipeline system without shutting down the entire facility supply.
Question 6: After brazing joints in a medical gas pipeline, what must be done before pressure testing?
- Painted with a rust-inhibiting coating
- Visually inspected and wiped with a damp cloth
- Blown down with oil-free nitrogen to remove residual flux (Correct answer)
- Wrapped with pipe insulation immediately
Correct answer: Blown down with oil-free nitrogen to remove residual flux
After brazing, lines must be blown down with dry nitrogen to remove flux residue, which is corrosive and could contaminate the gas supply.
Question 7: What is the maximum allowable pressure drop across a medical gas pipeline system during peak demand as specified by NFPA 99?
- 5 psi (Correct answer)
- 10 psi
- 15 psi
- 20 psi
Correct answer: 5 psi
NFPA 99 requires that the pipeline system maintain pressures within ±5 psi (or ±10%) of the operating pressure under peak demand conditions.
RMGA Pipeline Installation 2
According to NFPA 99, what is the minimum burial depth required for medical gas piping installed underground inside a healthcare facility?