Under what condition can multiple floor drains share a single trap?

Under what condition can multiple floor drains share a single trap?

• A. In the same room, not located where they can receive food or organic matter
• B. Never allowed
• C. Only if each drain leads to separate traps
• D. Only in parking garages

Answer: (A)

The idea being tested is how trap sharing works with floor drains. A single trap can serve multiple floor drains only when those drains are in the same room and they don’t receive waste that could contain food or organic matter. The reason this is allowed is that with drains in the same space serving clean-water floor areas, the risk of siphoning the trap or letting solids foul the seal is reduced, and venting can be arranged more effectively to maintain the trap seal. If any drain could receive food waste or organic matter, sharing a trap would increase the chance of clogging, odor, and trap-seal loss, so separate traps (with proper venting) would be needed.

The idea being tested is how trap sharing works with floor drains. A single trap can serve multiple floor drains only when those drains are in the same room and they don’t receive waste that could contain food or organic matter. The reason this is allowed is that with drains in the same space serving clean-water floor areas, the risk of siphoning the trap or letting solids foul the seal is reduced, and venting can be arranged more effectively to maintain the trap seal. If any drain could receive food waste or organic matter, sharing a trap would increase the chance of clogging, odor, and trap-seal loss, so separate traps (with proper venting) would be needed.