Maximum Length of Remaining Branch
Maximum Length of Remaining Branch
(OP)
We are removing the existing standpipe system from the existing domestic water piping. The remaining branch lines have been capped, but vary in the length of pipe remaining between the cap and the main. There is a concern with stagnant water in these pipes promoting bacteria and backfeeding into the main water distribution system.
Are there any regulation / codes that mandate what the maximum length of dead end water services acceptable are?
Are there any regulation / codes that mandate what the maximum length of dead end water services acceptable are?





RE: Maximum Length of Remaining Branch
Regards,
RE: Maximum Length of Remaining Branch
From experience, it is common to have dead ends in domestic water piping, mainly for future expansion. Even in renovation projects, it is common to leave fairly long sections of dead pipe because it is never known whether or when future renovation will require water piping in the area again.
Also, typically when installing water piping, the contractor has to disinfect the piping system. Therefore, there should be no bacteria in the dead end pipes. The only way to get bacteria in a dead end pipe would be coming from the mains, so the problem of bacteria going from the dead end pipe to the mains is probably highly unlikely.
Hope that helps.
RE: Maximum Length of Remaining Branch
You should avoid dead end at all, and if you have some pipe lenght left for future extension the only practicable way of retaining it (if pipe diameter is large enough to justify this action) is to make recirkulacion pipe up to end of dead branch. It can be very small diameter pipe, and it should end near some frequently used tap.
Sometimes we use to connect recirculation pipe to nearest outside hydrant (fire network valve) as regular hydrant network flushing is mandated.
RE: Maximum Length of Remaining Branch
The use of providing a dead end of pipe for future expansion is a common practice. The dead end might not be very long, but it does exist.
Adding a recirculation loop to prevent stagnant water in the domestic pipe could add a lot of cost to a job. I is done for the hot water, but I have never seen it for the cold side of things.
All that being said, if there are no plans for future expansion which those dead end pipes could be used, then the pipes should be removed back to the main and capped. But if there is a possibility of expansion, you would save yourself a lot of cost by leaving them in place.
RE: Maximum Length of Remaining Branch
Also, regardless of how clean your cold (or hot) water system is, the bacteria, etc that come in with the mains water supply will colonise it if there is limited water turnover, etc.
Regards,
Brian
RE: Maximum Length of Remaining Branch