Q: What is the distance needed to prevent obstructing medical gas shut-off valves? Is it just not having anything directly in front of the valve itself – or does it have to be a certain distance away on each side?
A: This is a judgment call as there is not a specific distance identified for clearance in front of or to the side of medical gas shut-off valves. Section 184.108.40.206 of the 2000 edition of the NFPA 101 Life Safety Code (LSC) requires medical gas systems to be in compliance with NFPA 99 (1999 edition) Standard for Health Care Facilities. Section 4-220.127.116.11 (d) in NFPA 99 requires zone valves (another name for shut-off valves) to be readily operable, and does not mention any specific clearance requirements in inches or feet. The definition of what is readily operable is left up to the authority having jurisdiction (AHJ) to decide, and our opinions don’t count (unless you are an AHJ!). In my experience, I have observed many AHJs using 3 feet clearance in front of the medical gas shut-off valves as a reasonable definition of readily operable. The 3 feet distance is widely believed to be taken from NFPA 70 the National Electric Code, in describing the clearances required in front of electrical panels.