Plastics terminal fittings and pipework for domestic use

The British Waterworks Association is an advisory body to the water authorities in the United Kingdom and as well as advising on Legal and Parliamentary matters relating to the affairs of the water industry, it operates a testing station.
The testing station undertakes the examination and test, on behalf of the members of the Association, of fittings against the requirements of the Model Water Byelaws.
All test criteria are set to determine whether or not the fittings comply with the requirements of the Byelaws, namely, whether or not they will lead to waste, mis-use, contamination, undue consumption, reverberation or erroneous measurement. The work in this respect covers an immense field ranging from kitchen taps to 3000 gal calorifiers, from haemodialysis machines to industrial storage tank; of 100,000 gal capacity. The tests are primarily secondary research, but in some cases they relate to pre-production environmental tests on old concepts constructed from new materials and particularly in the field of plastics. This pap.er does not deal with the technicalities of the new raw materials, but with the problems of setting up suitable test criteria and environmental rigs to evaluate such developments.
From the beginning, the Association has been involved in the development of plastics domestic terminal fittings and ancillary -pipe work : I have chosen acetal copolymer as my subject, used in the field of domestic fittings, and thought it could be interesting to give some background to the development work on this material for use in the water industry.
The Association, for a good number of years, has accepted plastics terminal fittings in the form of diaphragm type ball valves and at a later date, pillar taps, bathroom and kitchen sink mixers.
In the early days when the materials were derived as by-products, many problems were met, which is inevitable in any new development', and the work which has gone on has led to properly engineered materials, which if carefully selected for their right application and design features, will, in my opinion, be beneficial to the water industry.
The manufacturers in the early days of development took as their guide line the BS 1010 specification, and from that standard took as much of the design as could be practically used; namely the size, length etc., of the connections, but had to develop different closing