The safety of plastic pipes at petrol stations - Conductive Piping - A solution looking for a problem?
A recent article in African Petrochemicals 1. attempts to postulate that conductive plastic piping as used for delivery of petroleum on forecourts is somehow ‘safer’ than non-conductive plastic piping.
The article implies that the safety of non-conductive piping is compromised by unnamed accidents around what could or might be considered risk factors associated with non-conductive pipe only and that the use of conductive pipe mitigates these purported risks and is therefore safer. The article was originally written by Dr Harold Walmsley of Walmsley Electrostatics, in 2012 (Published issue 58 of Insight Magazine – Spring 2013) and is incorrectly attributed to Mr Mike Welman of Colvic in the African Petrochemical article.
Despite the fact that the article fails to cite any references for the claims made, it also does not definitively identify any actual, documented, independent conclusion that any accident anywhere could be attributed solely to the installation of non-conductive pipe. The use of words such as ‘may’ or ‘might’ to imply a firm conclusion really does not inspire confidence that any purported conclusion could be relied upon as fact.
Non-conductive piping systems have been extensively used, globally, for over thirty years. Millions of meters of fiberglass, flexi hose, PE pipe – all non-conductive - have been installed worldwide and these systems are now widely adopted in many major oil company’s design standards to the extent that 95% of all non-metallic pipe installed world-wide is classed ‘non-conductive’. All of these systems have to meet stringent UL and European safety standards before they may be used – and no safety agency has isolated any inherent risk with the use of properly installed non-conductive systems.
What is also known is that in the petrochemical industry, all serious safety events are rigorously investigated, with conclusions and learning’s circulated. It is quite simply fanciful to surmise that were there real evidentiary conclusion that there is an inherent safety issue with non-conductive piping per se, that global oil companies would continue using it and that official standards agencies would continue to allow their specification.
A further rather obvious commercial corollary is if there were either a real safety problem with non-conductive piping or a definite advantage to conductive piping, then manufacturers themselves, if they were of the opinion that conductive systems offered either a safety advantage or that non-conductive systems posed a risk, then they would not develop their own conductive systems? The simple answer to that is no – none of them are.
An extension of this point is that the sole manufacturer behind conductive plastic pipe systems continues to manufacture and sell non-conductive pipe, despite their published comments seeking to cast doubt on non-conductive systems. Surely, if they were that concerned about the safety of non-conductive systems, then they would immediately cease production and sale of those products?
This last point really illustrates the real purpose of the debate - to seek commercial advantage, with tenuous evidence to try and cast doubt in the mind of the market around the ‘safety’ of non-conductive pipe per se and not to focus on what has been factually established.
What seems not to be in dispute on both sides of the debate is that there is a risk, particularly in unearthed terminations such as filler boxes of electrostatic charge building up as a result of fuel frictional velocity, particularly in metallic components and that these must always be sufficiently earthed, regardless of whether conductive or non-conductive piping systems are present. It would also appear from the available evidence that in the few ignitions that have occurred, there has been compromised earthing at the exposed ends of pipe runs, typically in areas such filler boxes. The rating agencies all stress the importance of proper grounding of components, regardless of whether conductive or non-conductive pipe systems are in use.
Both sides of the debate are also clear that piping systems must be properly installed as per manufacturer’s specifications, including proper earthing at exposed terminations and the use of end-caps on weld pins and conductivity across the entire length of pipe in conductive systems. The consequences of improper installation in conductive systems, resulting in compromised conductivity actually renders a higher risk of ignition than in earthed non-conductive systems. The non-conductive portion of the pipework then acts as a capacitor, with all of the possible consequences that could result.
This subject has been rigorously debated within the industry, and should the reader wish to be further informed then both sides of the debate, for the sake of transparency, can be found on our website at www.petrolpumps.co.za/nonconductivepipesystems-electrostaticsafety
Southern Africa Master Distributors
1. Article: African Petrochemicals - August 2014 - The safety of plastic pipes at petrol stations - conductive vs non conductive.
Dr. Harold Walmsley Insite Article conductive versus non conductive
Electrostatic Safety of a Non-conductive Pipe System
FFS-0179_UPP Pipe Non-Conductive Whitepaper
FFS-0190 Cutting Through the Static Brochure 05-11 web