ELECTRONIC LEAK DETECTION OF MEMBRANES NOW APPROVED BY AUCKLAND COUNCIL
WHAT IS ELECTRONIC LEAK DETECTION?
Electronic leak detection is an alternative method to flood testing a membrane roof or deck for leaks, using a low voltage test system. It is now approved by Auckland Council as an alternative to the flood testing under the Producer Statement Construction (PS3) Waterproofing.
Electronic testing is now recognised by the Waterproof Membrane Association Inc.(WMAI). The WMAI 2008 Code of Practice only requires flood testing but we understand this may change in the future.
We are unaware of any NZBC Acceptable Solutions direct requirements for flood testing (and certainly not electronic testing), but BCA's often have a requirement for flood testing. Some BCA's may be unaware of electronic leak detection as an option, this may need to be discussed with the BCA.
HOW DOES IT WORK?
An electric field is formed by wetting the membrane surface, and readings are taken with specialised equipment of the electric flow travelling across the membrane. Changes in the electrical field enables breaches to be located with pinpoint accuracy.
WHAT IS REQUIRED?
Electronic leak detection requires that the membrane being tested is laid on a conductive and earthed substrate. A non-conductive lightweight roof substrates, such as plywood or insulation, require a stainless steel detection grid and ancillary terminals to be installed on the substrate prior to the membrane being placed. However, reinforced concrete structures are usually earthed through the reinforcing steel and therefore do not normally require a grid if the membrane is directly applied to the concrete. A grid will be required if the concrete is separated from the membrane by insulation or similar.
Most membranes can be tested however certain types, such as Butyl rubber and EPDM cannot be tested by this method, check with the test providers.
The benefits of Electronic Leak Detection are;
- Testing is relatively quick.
- The membrane areas do not have to be horizontal.
- The entry point of the breach can be pinpointed.
- Allows testing of membranes covered by other material (e.g. green roofs, paving etc).
- Testing can be carried out a number of times over the membranes life (including immediately after laying and at completion).
- With some (critical) installations constant monitoring may be possible.
WHAT ARE MASTERSPEC DOING
This month we are introducing the new ILD section 4481LD INTERNATIONAL LEAK DETECTION SYSTEM, but over the next few months Masterspec will modify all appropriate membrane sections with the added generic option for electronic leak testing.