Guidelines For Water Connection to Photo-processors

These guidelines are a summary of the recommendations developed by another PIC/Water UK working group for a Code of Practice for water supply connections to prevent contamination of the public water supply.

The local Water Company must be advised of any work being carried out in order that they can make arrangements for their inspector to visit the premises. Reference Water Supply (Water Fittings) Regulations 1999 Regulation 5, paragraphs 1 – 5.

New Installations

Much of the photo-processing process equipment currently available is less dependent on a permanent water supply connection to facilitate its process than the items of equipment manufactured in the past. Manufacturer’s equipment with no requirements for a permanent connection are usually filled manually from adjacent facilities. However, developer process units which do require a permanent connection from the water supply, may incorporate an inlet to a tank which can become submerged and therefore create a potential risk where back-siphonage of its contents can occur.

Equipment incorporating such filling arrangements must be protected to prevent the effects of back siphonage by the provision of a physical and visible air gap at the point of use or the water supply must be from a storage cistern.

Other fittings can, however, give cause for concern. For example, laboratory and hose union draw off taps from which a flexible hose is attached for swilling down purposes. All draw off points of a similar pattern should be considered as a potential risk to the quality of water supply due to the possibility of back-siphonage and therefore must be afforded the appropriate “point of use protection”. For further details see the Water Supply (Water Fittings) Regulations 1999, schedule 2, section 6.

Existing Installations

Existing water supply systems can of course vary considerably. Hence, prior to remedial work or new work being carried out, it is important that a comprehensive survey of the pipework installation is carried out. Installation of any new equipment or fittings associated with a film developing process, should be undertaken with the requirements of the Water Supply (Water Fittings) Regulations 1999. In particular, the provision of “point of use protection” (schedule 2, section 6) being considered as paramount.

Water Connection Matrix

The Schedule for all photo-processing laboratories should be referred to for information. It is expected that the laboratory will identify the types of fittings and record the potential risk of the liquids in use on a scale of 1 (High Risk), 2 (Medium Risk) or 3 (Low Risk) and give the installation options for protection against back-flow into the water supply system.

More information: www.wras.co.uk