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10-11-2009, 08:51 AM #1
Sprinkler backflow piping above grade
Does anyone have a reference to when it is required (height above grade/material/pipe size/etc.) to secure the piping that goes above grade where the back flow preventer is installed. I see these of varying heights throughout my area. Some look pretty darned flimsy.
10-11-2009, 12:08 PM #2
Re: Sprinkler backflow piping above grade
One back up basis is the supporting and securing specified in Table P2605.1.
- P2605.1 General. Piping shall be supported in accordance with the following:
- - 1. Piping shall be supported to ensure alignment and prevent sagging, and allow movement associated with the expansion and contraction of the piping system.
- - 2. Piping in the ground shall be laid on a firm bed for its entire length, except where support is otherwise provided.
- - 3. Hangers and anchors shall be of sufficient strength to maintain their proportional share of the weight of pipe and contents and of sufficient width to prevent distortion to the pipe. Hangers and strapping shall be of approved material that will not promote galvanic action. Rigid support sway bracing shall be provided at changes in direction greater than 45 degrees (0.79 rad) for pipe sizes 4 inches (102 mm) and larger.
- - 4. Piping shall be supported at distances not to exceed those indicated in Table P2605.1.
Also, don't forget this:
- P2603.6 Freezing. In localities having a winter design temperature of 32°F (0°C) or lower as shown in Table R301.2(1) of this code, a water, soil or waste pipe shall not be installed outside of a building, in exterior walls, in attics or crawl spaces, or in any other place subjected to freezing temperature unless adequate provision is made to protect it from freezing by insulation or heat or both. Water service pipe shall be installed not less than 12 inches (305 mm) deep and not less than 6 inches (152 mm) below the frost line. (Jerry's note: The first line in the above is referring to Appendix D in the IPC, which establishes what I call "the freeze line", which is approximately along Interstate Highway 10 across the top of Florida, through Texas, and up to California.)
Many AHJ require the back flow device to be supported as the piping is not intended to support anything other than itself.
By the way, Houston is 32 degrees, you are south of Houston, so the last part may not apply until you get north of Houston - however, San Antonio is listed as 30 degrees, so that section would apply there.