We all appreciate that in the average home there are pipes and cables running in all directions. These can include cold water pipes, hot water pipes, grey water drains, sewage drains, electrical cables, communication cables and rainwater drains. In short, there are multiple common services coming both into and out of a home. Many of these services are incorporated into the construction of the house but many can also be retrofitted to existing properties.
Often these services are not good neighbours. Water does not mix with electricity, neither does gas. Communication cables can be impacted by electrical cables. So despite the obvious mismatches it is often surprising that we see common services in very close proximity to each other. For example, penetrations in concrete slabs will on occasion have water, electrical and communication pipes and cables running through them. Potentially fine, if this is a properly constructed and sized service duct, but less than suitable if there is a 10 cm bore hole cut through the slab supporting all of the above.
The same requirements for separation applies within roof frames where it is equally important that all of the common services are appropriately separated. This can be a challenge where pipes and cables need to criss-cross the roof cavity. None the less the rules of separation still apply.
Given the above it is not surprising that there are Australian Service Standards which dictate how close pipes and cables can be to each other. In the main there are different prescribed distances for below ground services and above ground services:
Focusing on the above ground issues (because these can often be seen as opposed to those that are buried) and where the same duct or chase is used for different services the minimum required separation distance must be maintained.
- A separation distance of at least 25mm shall be maintained between any above ground cold water service and an electrical conduit, electrical wire or cable and consumer gas pipes.
- A separation distance of at least 100mm shall be maintained between any above ground pipework associated with heated water service and electrical cables, gas pipes or other services.
- A separation distance of at least 100mm shall be maintained between any above ground drain or discharge pipes and an electrical conduit, electrical wire or cable, consumer gas pipes or water services.
- A separation distance of at least 100mm shall be maintained between any above ground site stormwater downpipe and an electrical conduit, electrical wire or cable, consumer gas pipes, or water services.
WA homes have multiple reticulation systems for power, gas, electricity, communication, water and waste water. It is important that these reticulation systems have appropriate safety distance margins when they are located in close proximity. There are defined distance requirements and these are set out in the Australian Standards and endorsed by the WA Building Commission.
Much of the above information has been sourced from the WA Building Commission Industry Bulletin IB 052/2015.