RMGA Installation Codes & Standards Compliance 3 — Questions and Answers
Question 1: What is the primary purpose of a zone service box (ZSV) in a medical gas system per NFPA 99?
- To boost gas pressure in remote areas
- To isolate gas supply to a specific area for maintenance or emergency (Correct answer)
- To filter particulates from the gas stream
- To regulate flow rate to individual outlets
Correct answer: To isolate gas supply to a specific area for maintenance or emergency
Zone service valves allow staff to shut off gas to a defined area for maintenance or in emergencies without affecting other parts of the system.
Question 2: Per NFPA 99, medical gas zone valves must be located in which type of enclosure?
- Locked stainless steel cabinet
- Labeled, accessible box with a transparent cover (Correct answer)
- Underground vault with access panel
- Ceiling plenum accessible via ladder
Correct answer: Labeled, accessible box with a transparent cover
NFPA 99 requires zone valves to be housed in labeled, accessible enclosures with a transparent or breakable cover so their status is visible.
Question 3: Under NFPA 99, which of the following gases requires a separate, dedicated source of supply and cannot share supply equipment with other gases?
- Medical air (Correct answer)
- Carbon dioxide
- Nitrogen
- Nitrous oxide
Correct answer: Medical air
Medical air must have a completely dedicated source (compressor system) to prevent contamination from other gas sources.
Question 4: According to CGA V-1, which valve type is required at the cylinder connection point of a medical gas manifold?
- Ball valve with padlock
- Check valve to prevent backflow
- Pin-index safety system valve (Correct answer)
- Quarter-turn butterfly valve
Correct answer: Pin-index safety system valve
The Pin-Index Safety System (PISS) uses a specific pin configuration for each gas to prevent accidental connection of wrong gas cylinders.
Question 5: What does NFPA 99 require regarding the labeling of medical gas outlets?
- Outlet label only, no color coding needed
- Color coding and gas name label at each outlet (Correct answer)
- Gas name only in black text on white background
- ISO symbols only, no text labeling required
Correct answer: Color coding and gas name label at each outlet
NFPA 99 mandates both color coding and text labeling of the gas name at each outlet to provide redundant identification.
Question 6: What is the required clearance around a medical gas cylinder storage area per NFPA 55?
- 1.5 m (5 ft) from combustibles
- 1.5 m (5 ft) from open flames and heat sources (Correct answer)
- 3 m (10 ft) from all electrical equipment
- 6 m (20 ft) from patient care areas
Correct answer: 1.5 m (5 ft) from open flames and heat sources
NFPA 55 requires oxygen and oxidizer cylinders to be stored at least 1.5 m (5 ft) from open flames and heat sources to reduce fire risk.
Question 7: According to NFPA 99, what is required at every medical gas riser where it passes through a floor?
- Expansion loop to absorb thermal movement
- Sleeve with firestop material (Correct answer)
- Pressure gauge to monitor riser pressure
- Isolation valve accessible from the floor below
Correct answer: Sleeve with firestop material
NFPA 99 and IBC require that all pipe penetrations through floor assemblies be firestopped to maintain the fire resistance rating of the floor.
RMGA Installation Codes & Standards Compliance 3
What is the primary purpose of a zone service box (ZSV) in a medical gas system per NFPA 99?