ABS pipe systems are most commonly chosen over the more common PVC in applications where low operating temperatures are expected, or where the chemical compatibility of PVC is unsuited. ABS is quite a ductile material and this means, as far as we pipefitters are concerned, that it is less brittle at lower temperatures than PVC. It is for this reason that ABS is the plastic of choice for cold process lines such as chiller circuits with glycol and those carrying ice slurries, such as ice cream and chilled food factories.
ABS Pipe is a mid to light grey in colour, as opposed to the dark grey of PVC. Care should be taken when identifying by colour alone however, as some older PVC (up until the late 1990s) was also manufactured in a light grey.
ABS pipe and fittings are joined together in three different ways:
Flanges or threads are often used to join the pipe to other materials (such as brass or other metals and plastics) and to connect to equipment such as pumps, blowers, filters etc.
Solvent welding is the process used for the majority of the ABS pipe and fittings. With solvent weld, a "glue" is brushed onto the cleaned fitting and pipe and the two are then pushed together in one swift movement. The joint is very rapidly made and there is little room for any rotational movement of the fitting, once pushed together
The rapid reaction of ABS to the solvent cement is often something as a surprise for fitters who are more used to working with PVC. The latter gives a window of a few seconds, when the fitting can be lined up, however with ABS, this window is reduced to almost zero. It is therefore vitally important that pipes are properly measured, and that both pipes and fittings are properly marked prior to gluing together. ABS pipe systems can be assembled dry as a trial run, but ensure that they have not been cleaned with any solvents or cleaner first. The cleaner will key and soften the plastic and make it almost impossible to disassemble.