SAIT PLUMBING SUPPLEMENT CODE APPENDIX STANDPIPE CLOTHES WASHERS

Summary

The transcript discusses different methods for installing clothes washing machine standpipes in residential plumbing, focusing on two common approaches. The first method is a standard installation with a 2-inch standpipe and a vertical cleanout, which has been the typical practice for years. The second method involves connecting the washing machine's drain directly into the laundry tray's fixture outlet, disregarding additional hydraulic load considerations. The script also introduces an alternative wet venting technique and explains how fixture units and venting play a role in ensuring proper drainage for these installations.

Takeaways

• 😀 Minimum standpipe size for clothes washers should be 24 inches (2 feet) in length and 2 inches in diameter.
• 😀 A vertical cleanout must be installed in the standpipe, and it should have an individual and continuous vent.
• 😀 The standard fixture unit load for a clothes washer connected to a standpipe is 2 fixture units.
• 😀 The '22 and 2 rule' applies: 2 feet in length, 2 inches in size, and 2 fixture units in hydraulic load.
• 😀 Clothes washer discharge into a laundry tray may disregard the washer's hydraulic load because the tray handles it.
• 😀 A laundry tray’s P-trap can handle the hydraulic load from a clothes washer if the washer is connected to the tray’s fixture outlet pipe.
• 😀 The hydraulic load for the laundry tray itself is 1.5 fixture units, while the clothes washer contributes 2 fixture units.
• 😀 Wet venting of a clothes washer is allowed through the laundry tray's system, with legal configurations of both laundry tray and washer venting together.
• 😀 Alternative methods, such as wet venting, have been effective in residential applications for years, even if not explicitly outlined in the NPC appendix.
• 😀 The alternative wet venting method involves venting the washer through a red pipe below the laundry tray's P-trap, maintaining proper functionality.

Q & A

What is the minimum size of the standpipe for draining a clothes washing machine?

The minimum size of the standpipe for draining a clothes washing machine is 2 inches in diameter.

What is the typical fixture unit load for a clothes washing machine according to Table 2493?

The typical fixture unit load for a clothes washing machine is 2 fixture units.

What is the minimum developed length of the standpipe for a clothes washing machine?

The minimum developed length of the standpipe for a clothes washing machine is 24 inches, or 2 feet.

What does the '22 and two rule' refer to in the context of standpipes for clothes washers?

The '22 and two rule' refers to a standpipe that is 2 feet in length, 2 inches in size, and has a hydraulic load of 2 fixture units.

How is the second example of cloth washer installation different from the typical one?

In the second example, the clothes washing machine is tied directly into the laundry tray's fixture outlet pipe, using the laundry tray's P-trap as its own, unlike the typical standpipe installation.

When can the hydraulic load from a clothes washer be disregarded in plumbing calculations?

The hydraulic load from a clothes washer can be disregarded if it discharges into a laundry tray, as the tray is designed to handle the load from the washer.

What does Table 2493 say about laundry traps and floor drains in relation to clothes washers?

Table 2493 indicates that when calculating the hydraulic load on a drainage pipe, the load from a clothes washer can be ignored if it discharges into a laundry tray.

What does the 'wet venting' method for clothes washers involve?

The 'wet venting' method involves venting the clothes washer through the red pipe between the Ty below the laundry tray P-trap, using the laundry tray's vent system.

Is the 'wet venting' method recognized in the National Plumbing Code (NPC)?

The 'wet venting' method for clothes washers is not explicitly recognized in the NPC appendix, but it has been used effectively for many years in residential applications.

What fixture unit loads are associated with the laundry tray and clothes washer in the 'wet venting' example?

In the 'wet venting' example, the laundry tray is worth 1.5 fixture units, and the clothes washer is worth 2 fixture units.