With so many choices of piping materials now available selecting the most appropriate for any given project is of paramount importance. Therefore we, as pipework contractors, need to know as much about the plant process as possible. Questions need to be asked and answered before the pipework and any valve specification can be agreed on. For example is the material available in the size and thickness required? Will it be the most cost effective choice or is there a better alternative? Seamless or welded? Will it tolerate the maximum temperature and pressure? Will the process fluid cause corrosion or mechanical breakdown of the material over time?
Regarding the last question it could be that the best approach to corrosion control may not require the use of corrosion resistant materials. Adequate life can be obtained from even standard carbon steel pipework dependent on operational and control variables. However when handling process fluids at elevated temperatures or which are by definition highly corrosive there will be no alternative to using corrosive resistant materials.
So who specifies the pipework material – Pipework Contractors or the Plant Engineers?
It falls as much to the pipework contractor as to the plant manager to ensure that correct choices are made early in the pipework selection process to avoid pitfalls later on. No one wants a pipework installation to fail prematurely because poor decisions were made at the design stage. If carbon steel pipework has been deemed unacceptable from a corrosion point of view then there are two main choices open. Stainless or Plastic.
Thin wall stainless steel tubing is becoming more popular within the process pipework industry owing to its high strength and lower weight per metre when compared to carbon steel. Additionally thin wall stainless tubing has long been approved by the Pressure Equipment Directive (PED) for use in the chemical, food & pharmaceutical industry getting on for over 40 years now. As a result its pretty much the default piping product for use in the water treatment industry. With regard to the jointing process the most common method is TIG welding and argon purging which means hot work permits for any site work.
There is an alternative however from Gerberit who offer the ‘Mapress Pipework System‘, a stainless steel, thin wall pipework system that utilises a compressed joint sealing process. Another alternative to traditional carbon steel pipework installation is plastic. Two main types are available PVCU or ABS. The former can be adversely effected by hydrocarbons and other chemicals so can become brittle over time, the latter is more costly but is more able to withstand chemical degradation. Again before specifying any type of pipework installation your pipework contractor should be in a position to work with you to fully comprehend the long term needs of your process.
Linmar Pipework Services have been working in the pipework installation industry for over fifty years. Based centrally in Sheffield Yorkshire we are familiar with most process pipework plant ranging from chemical, oil, water, food or the specialist needs of the construction industry. We possess extensive pipework fabrication and pipe bending expertise gathered from many projects over more years than we care to remember so why not give us a call here so we may quote you on your next pipework contract?