SAIT PLUMBING SUPPLEMENT CODE APPENDIX WET VENTING SYMETRICAL FITTINGS AND MULTI STOREY WET VENTING

Summary

This video explains the basic principles of wet venting, focusing on symmetrical fittings like double sanitary T and Y-fittings for both vertical and horizontal wet vent pipes. It outlines rules such as ensuring water closets are connected at the same level and the maximum fixture load from any story above the first should not exceed four fixture units. The video also details the sizing of wet vented waste stacks, factoring in lavatories, kitchen sinks, and stack venting calculations using codebook tables. This thorough guide ensures compliance with plumbing codes for multi-story systems.

Takeaways

• 😀 Rule 1 of wet venting: Use symmetrical fittings like a double sanitary T with a side outlet for vertical wet vent pipes and a double Y fitting for horizontal wet vent pipes.
• 😀 Rule 2 of wet venting: When a wet vent extends through multiple stories, the total discharge from any single story above the first must not exceed four fixture units.
• 😀 Two water closets must be connected at the same level using a double sanitary T-fitting for vertical pipes and a double Y fitting for horizontal pipes.
• 😀 The bathtub's hydraulic load, when symmetrically connected, is not included in the fixture unit load for sizing the wet vent.
• 😀 A double sanitary T with a side outlet is used for symmetrical connections, as shown in the animation for vertical wet vent pipes.
• 😀 A double Y fitting is used for horizontal wet vent pipes, as shown in the zoomed-in image for horizontal connections.
• 😀 When sizing a wet vented soil or waste stack, the four lavatories count for four fixture units and the two kitchen sinks count for three fixture units.
• 😀 The total fixture unit load draining into the wet vent stack is seven fixture units, according to table 2493 in the codebook.
• 😀 The wet vent's nominal pipe size for seven fixture units is 3 inches, as shown in table 2581.
• 😀 When calculating the stack vent, count the fixture units drawing air from the stack vent, which should total 16.5 fixture units.
• 😀 For the stack vent, the developed length is 8 meters, and the base of the stack is 3 inches in size, as indicated in the codebook.

Q & A

What is the purpose of using symmetrical fittings in wet venting?

Symmetrical fittings, such as a double sanitary T with a side outlet for vertical pipes and a double Y for horizontal pipes, ensure that water closets are connected at the same level for proper drainage and venting.

What is the rule regarding wet vent discharge when it extends through multiple stories?

The total discharge from any single story above the first must not exceed four fixture units when a wet vent extends through multiple stories.

Are bathtub hydraulic loads included in fixture unit load calculations for sizing the wet vent?

No, the bathtub's hydraulic load is symmetrically connected but is not included in the fixture unit load when sizing the wet vent.

What are the fixture unit values for lavatories and kitchen sinks in the example?

In the example, the four lavatories are worth four fixture units, and the two kitchen sinks are worth three fixture units.

How is the size of the wet vented soil or waste stack determined?

The size of the wet vented soil or waste stack is determined by checking the total fixture units draining into it and referring to Table 2581, which indicates that 7 fixture units require a 3-inch nominal pipe size.

Why are the two water closets and the bathtub excluded from the fixture unit load in this calculation?

The two water closets and the bathtub are excluded because they drain into the stack below and are not counted in the fixture unit load for the wet vent.

How is the stack vent calculated?

The stack vent is calculated by counting the fixture units drawing air from the stack vent and referring to Table 2584 in the codebook. In this example, it totals 16.5 fixture units.

What is the developed length given for the stack vent in this example?

The developed length for the stack vent in this example is 8 meters.

What nominal pipe size is required for the wet vent in this example?

For the wet vent with 7 fixture units, the required nominal pipe size is 3 inches, as indicated by Table 2581.

What should you do if you encounter confusion while calculating wet vent sizes or stack vents?

If confusion arises, it's recommended to refer to the code, as it usually provides the necessary information for accurate calculations.