What are the regulations regarding using a gas tracer for leak detection in a drinking water network?
The regulations do not prohibit the use of a hydrogen/nitrogen mix or helium as tracer gases to detect leaks in a drinking-water network, provided they are used in a timely manner and that the gases are food grade in accordance with the European guidelines (E949 for hydrogen and E939 Helium.These guidelines specify that every bottle must have its own certificate of analysis as provided by the manufacturer at the time of purchase.
This certificate must contain the following information:
Amount of CnHn which must be below 0.1 PPM).
Traceability of the operations undertaken:
Bottling date and location,
Type of gas and lot number.
Start and end time of bottling operation.
A safety data sheet (FDS) must accompany the certificate of analysis specifying all the elements related to safe use of the gas (inert, flammable, explosive…). This data sheet will usually also provide all the certificate details (purety, Cnhn...)
FYI: An additional study requested by Veolia Water and performed in 2007 by the Anjou Recherche laboratory (Veolia Environment) focused on the impact of tracer gas with chlorine and on removal of the biofilm. The results in the lab indicate there are no problems in this regard.
In 1999, the Health Department issued a certificate for the use of helium for leak detection in a drinking water system to a private company, but this document is no longer really valid given the regulatory changes since.
There are no guidelines for using gas tracers in drinking water networks.
The gases usually used to check pipe integrity are helium (used pure) or hydrogen (used mixed). They must be food grade according to the E939 code for helium and the E949 code for hydrogen. To guarantee the quality, the gas used must have a certificate of analysis. This certificate must specify at a minimum :
- the purity of the gas used,
- the quantity in CnHn (which must be below 0.1 ppm).
Traceability must also be assured in order to avoid an audit by the sanitation authority. Minimum specifications  that would seem useful in addition to the certificate are:
- Date of detection test,
- Start and end time,
- Type of gas and lot number
- Gas concentration,
- Location of test.
Answer posted by the community manager for Eryck Couffy