For a 2 inch pipe, the maximum distance from fixture trap to vent is?

For a 2 inch pipe, the maximum distance from fixture trap to vent is?

• A. 3 Feet 6 Inches
• B. 6 Feet
• C. 4 Feet
• D. 5 Feet

Answer: (C)

Venting must be close enough to the trap to prevent siphon when the fixture drains. The distance from the trap to the vent, called the trap arm, is limited by pipe size. For a 2-inch pipe, the maximum trap-to-vent distance is four feet. This keeps the vent within reach to relieve negative pressure and keep the trap from siphoning. The other distances either are shorter than the maximum or exceed what a 2-inch trap arm is allowed, so they’re not correct for this size.

Venting must be close enough to the trap to prevent siphon when the fixture drains. The distance from the trap to the vent, called the trap arm, is limited by pipe size. For a 2-inch pipe, the maximum trap-to-vent distance is four feet. This keeps the vent within reach to relieve negative pressure and keep the trap from siphoning. The other distances either are shorter than the maximum or exceed what a 2-inch trap arm is allowed, so they’re not correct for this size.