Plastic Piping Systems – mysterious, confusing and not trustworthy ?

Posted at March 6, 2014 | By : | Categories : Articles | Comments Off on Plastic Piping Systems – mysterious, confusing and not trustworthy ?

When I first came into this building service industry 60 years ago it was a mind blowing experience of men who had worked and carried out practices on materials and methods of installation that they had been taught by their fathers.

This is the way we do it and always have done!

That was the introduction, metal pipes not even copper, all very heavy, welded and screwed covered in oil ,snags that tore your fingers to pieces ,no gloves they are for cissies.
Stocks and dies for threads,no machines,welding tools hands get burnt,boss white and hemp for joints, lead caulked joints etc,etc….

But when it was finished it was in installation to be proud of after the red lead paint was applied.
But you knew where you were steel tubes had 3 grades light,medium and heavy weight. Black or Galvanised.

The revolution was coming,copper was the thing!!!!

Lighter,easier to joint than steel,although you could burn a building down with misuse of the blow lamp but life was going to be easier,colleges were changing all their methods to teach copper fittings .When finished an installation looked ,dare I say beautiful when polished. Just like an engine room on a ship.

But when there was a world shortage of copper the “clever boys” came in and produced products like “ copper coated steel” that you could solder like copper and have the benefit of rust inside the tube which eventually made the system leak.

Then the turning point “press fit Joints” for thin wall steel pipes.There was a major rush to bring these into the market as they were faster to install,light to handle and easy to prefabricate.
Not really cost effective ,required painting,and good control on the jointing process,no drips but a flood when the joint failed. It was apparently all about the “o” ring joint.

So in the 1980s the word was plastics,at that time PVC,Polybutylene were the fore runners.
Now plastics are extremely good for life, cleanliness, sound insulation, ease of jointing, weight etc.


With steel and copper you knew that the pressure and temperature they could withstand was a fore gone conclusion on general domestic services as well as heating and chilled water. Now when it comes to plastics its not so easy.

Temperature! Plastics require a relationship between temperature,pressure,life,operating periods and expansion to be calculated. Not just a matter of picking up a piece of heavy weight steel knowing it will do the job. Then once installed how about oxygen permeation. We don’t get that on steel!

Twenty years ago I starting selling Plastic tube and fittings.The market was open for it as the price structure was very stable.there was a considerable amount of work in the construction industry and the major contractors went for the whole bag of tricks using plastics on any type of pipe system required in the projects, heating, chilled, domestic services, boosted mains right from the plant room to the final connections.

Today there seems to be a different atmosphere, designs are changing and all we see in plastics is distribution after the plant room and terminating before the end connections as far as pressure piping systems are concerned.

So Mysterious

If the system demands a temperature to run at and a static working pressure surely you can chose a suitable it polypropylene,polybutylene,polyethylene,c.pvc,HDPE,ABS etc.
But different plastics use different jointing principles, solvent welding, butt welding, socket fusion, push fit, press fit Etc,Etc.

Surely the sales team will give you the best suggestion bearing in mind the cost after installation and the promise of the 25 year life in writing.

Some systems demand a costly tool purchase or hire, how about lagging, plastics have good sound and insulation properties, which will calculate and agree the change in thickness.
Everyone always comments that we need more clips to make it look an engineering installation and to control the expansion.

There again another decision do you select reinforced pipe that reduces the expansion which is approximately 2mm per metre at a flow temperature of 75Degc. Non reinforced pipe varies according to the materials but at the same temperature can move up to 10mm per metre.

One cost saving is that plastic pipes do not generally like expansion bellows so the movement has to be controlled by change of direction flexing legs.


It is confusing and can be costly if the wrong choice is made and dangerous if the life is not correct for the working conditions.

Manufacturers will always lead with their products so where do you take the most reliable information from.

Plastics have been used in the Uk for building services since the 60s and changing regularly, so your advice needs to be based on known facts and experience.


I managed the installation of a chilled water distribution system in the deserts of Little Aden cantonment in 1963 with Yorkshire PVC system that worked very satisfactorily in those conditions.
Since that time I have always been working with many types of plastic piping materials up to 1990 when I acted as a consultant for GF and the Instalflex polybutylene system which was the first plastic material able to withstand and work at heating temperatures of 80 Deg C and carried a BS standard.

10 Years owning and using Aquatherm has taken my experience into many areas of application of plastic piping systems and I feel that I have met the majority of problems and benefits that plastic piping can produce.

Those who know me know that I say it as it is. There is always an answer to a selection; it is difficult to get an unbiased one I hope that CTSLplastics is where you find that answer.