ABS plastic has several characteristics that makes it the material of choice for many specialist applications. ABS has a high ductility, which is the ability to deform and reform to the items original shape. The best known application of this is in the use of ABS for making LEGO bricks. The high ductility enables the “snap together” locking mechanism to deform and reform every time it is snapped together and pulled apart. In pipe systems this makes ABS an attractive material as it is very resistant to mechanical damage (unlike PVC which can crack easily if hit with a heavy blow). When struck, the plastic deforms, absorbing the blow, and then reforms rather than cracking.
The ductility also helps if there is an overpressure situation. In this instance, the deformation reaches the point where the pipe wall is thinner and a split appears. In the same situation PVC is likely to shatter, causing a potential health and safety issue. The ductility also has benefits at low temperatures as it means that ABS pipe systems are suitable for use as low as -40oC (-40oF). Whereas at temperatures below freezing, material like PVC can become increasingly brittle.
Like PVC, ABS is very easy to assemble with only basic tools required. A solvent cement process bonds pipe to socket fittings and the pipe is easily cut with a hand or electric saw. Where ABS does differ in the assembly process to PVC is in the joint cure time. With PVC there is a window of several seconds where, once fully inserted, the pipe and/or fitting can be rotated and aligned. With ABS there is no such luxury. The joint stiffens very quickly and the installer only has a second or so for adjustment. To avoid errors, this means that much more careful measurement and marking is required before assembly.
The applications where ABS pipe systems are most widely used is in cooled liquid (such as glycol and chiller circuits) and compressed air circuits (up to the specified operating pressure of the pipework).
We are often asked the question whether ABS can be glued/ cemented to PVC. The layman’s answer is yes as long as PVC glue is used, but the bond will never be as good as PVC to PVC or ABS to ABS. We would recommend using flanges or threaded fittings to connect, but if this cannot be avoided, then it should be ensured that the pipework is well clamped either side of the joint. A composite (ABS:PVC) joint is unlikely to leak, but if not clamped to deny pipe movement on either side, could blow apart at higher operating pressures.