Recent Developments in Expansion Joints for Plastic Pipe Systems

When I chose a title for this paper nearly two years ago I was aware of projects for several new types of telescopic expansion joints, and of new materials being tested in bellows type joints.
I therefore believed that by September 1982 sufficient progress would have been made for a report such as this to be of considerable interest to the pipe makers and to the installation industry.

Some progress and some new developments have indeed been made but as so often occurs in our industry the ultra-cautious attitude of the domestic side of the business has resulted in a very marked difference between changes in industrial pipework and changes in domestic installations.

It is probable that the main reason for this is that industrial pipe systems normally have space available for large offsets, loops, etc. and that installations, although necessarily highly reliable are often required for comparatively short-term use, i.e. a few years only. I use the expression "short term" purely as a contrast to requirements normally laid down for domestic installations of a minimum guaranteed life of 50 years.
Another limiting factor for domestic installations is that the entire pipe system must be unobtrusive. The plumber quite reasonably wants to do a neat job especially in such locations as kitchens, bathrooms and toilets where the pipe system tends to be in full view at all times; at least that is the case in the U.K.
In Continental Europe and in America the pipework is usually largely concealed behind walls or partitions. In some cases, especially in hotels, hospitals, etc. specially built trunking is set-up to carry all the pipework and sometimes other services as well.