For buried piping, the minimum backfilled cover is 36 inches. It may be reduced to ______ inches where physical damage is prevented.

For buried piping, the minimum backfilled cover is 36 inches. It may be reduced to ______ inches where physical damage is prevented.

• A. 20 in
• B. 24 in
• C. 18 in
• D. 16 in

Answer: (C)

The key idea is that burial depth for medical gas piping can be reduced when there are effective protections against physical damage. Normally, a 36-inch cover provides robust protection, but if you implement safeguards—such as concrete encasement, a protective sleeve, or routing the pipe in a protected area—the minimum cover can be lowered while still keeping the line safe from damage. 18 inches is the depth allowed under those protective conditions. It reflects that the added physical protection compensates for the shallower burial, maintaining safety and integrity of the piping. So, 16 inches wouldn’t meet the protection-based allowance, while 20 or 24 inches are deeper than necessary when protection is in place.

The key idea is that burial depth for medical gas piping can be reduced when there are effective protections against physical damage. Normally, a 36-inch cover provides robust protection, but if you implement safeguards—such as concrete encasement, a protective sleeve, or routing the pipe in a protected area—the minimum cover can be lowered while still keeping the line safe from damage.

18 inches is the depth allowed under those protective conditions. It reflects that the added physical protection compensates for the shallower burial, maintaining safety and integrity of the piping.

So, 16 inches wouldn’t meet the protection-based allowance, while 20 or 24 inches are deeper than necessary when protection is in place.