watcoFINAL.pdf
1/19/10
3:57:16 PM
PLUMBING
Join The Green Scene
continued from page 26
Numerous situations have occurred in high-rise buildings where sewer gases were detected after a fan shutdown when yoke venting was not installed properly. Except for a specific exclusion, the NPC explains that where a soil-or-waste stack receives discharge from fixtures located on more than 11 storeys, a yoke vent is required for each section of five storeys, or part thereof, counted from the top down, as well as at or immediately above each offset or double offset. A yoke vent needs to be connected to the vent stack at least one metre above the floor level of the lowest storey in the section, and to the soil-or-waste stack by means of a drainage fitting at or immediately below the lowest soil-or-waste pipe from the lowest storey of the section. A yoke vent is not required if the soilor-waste stack is interconnected to the vent stack in each storey of the section by means of a vent pipe that is equal in size to the branch or fixture drain, or 1-1/2”, whichever is smaller.
C
M
Y
Image courtesy of SAIT
CM
MY
As stated earlier, yoke venting is no joke. If yoke vents are not installed there will be problems in the soil, waste and vent stacks. Yoke venting must be installed correctly for the building mechanicals to operate with as few problems as possible.
CY
CMY
K
New WatcoFlex Bath Waste ...installs faster/easier TM
Special patent pending PVC flexible tubing. Eliminates four field joints. Innovator overflow parts assemble by hand. No screws. Approved by IAPMO. It’s green. You’ll get used to seeing it. Just ask your wholesaler
A yoke and the offset The second required location of a yoke vent mentioned by code is at the offset in a soil or waste stack. An offset is the horizontal distance between two vertical sections of a stack. In addition to offsets in stacks, double offsets may be installed to realign a stack around an obstacle, and then pipe it back to its original location. If it is required, a yoke vent must be installed at, or immediately above, each offset or double offset.
WATCO
Horizontal stack offsets are constructed with two 90° elbows. When a horizontal offset is installed in a soil or waste stack, the DWV piping must be sized as horizontal piping. ®
Code states, “No soil or waste pipe that is of minimum size required by this Code for the purpose for which it is installed shall be so connected as to drain to other drainage pipe of lesser size.”
The Bath Drain Company WATCO MANUFACTURING COMPANY 1220 South Powell Road, Independence, MO 64057-2724 Phone 816-796-3900 • FAX 816-796-0875 www.watcomfg.com
This is important to note as the fixture unit rating of vertical and horizontal pipe differ, and the size of the stack may be affected.
A Division of WCM Industries, Inc.
28
M e c h a n i c a l
B u s i n e s s
0 8 . 1 3