Headford
Workshop # 1998 Gothenburg
Jointing Methods for Plastics Pipeline Systems AL Headford (Durapipe S & LP, UK) ee Introduction The basic requirements for pipe Jointing are common to all pipe systems made from any material (including traditional materials), whether they be for sealed pressure usage or non-pressure usage. These are
a) minimal detrimental effect on the performance of the remainder of the system, and b) acceptable cost :a) Minimal detrimental effect on the overall pipe system, in terms of key properties, embracing factors such as the following :
- life expectation
- physical strength
- resistance to internal pressure
- handling and flexibility
- resistance to physical abuse
- able to accept expansion / contraction / axial loading - forces / movement
- influence on flow properties
- influence on fluid quality
- chemical resistance and corrosion
b) Optimum cost combination of any materials or components plus labour.
For example : - component or material cost
- associated assembly equipment costs - ease of use
- time for assembly / make-up
- skills / training requirements
- traceability / ownership cost
- reliability / quality
- replacement / repair cost
- transport costs
- availability
- health and safety considerations -environmental effects For different pipe materials, types of pipe system, and operational conditions, some of the above factors will be more important than others, and this will influence the choice of jointing method.
However there are fundamental reasons why certain jointing methods are the norm for particular pipe materials.
A limiting factor, influencing the choice of jointing metnod, comes into place when it is necessary to connect together entirely different types of materials, for example thermoplastics to metals, when fusion is not feasible. In these cases mechanical methods are used (adhesive bonding is also possible but rarely favoured — except for GRP).
