Cylinders in Fires
- BCGA GN 13 - DSEAR risk assessment
- BCGA TIS 15 - Model risk assessment for the storage and use of gas cylinders for oxy-fuel applications
- BCGA L 6 - Cylinders in fire
Gas cylinders are designed to safely contain a gas inside a closed container. If exposed to extreme heat, all gas cylinders are at risk of failure and may fail with an explosive force. Fire and Rescue Services (FRS) are aware of this and have safe methods for dealing with gas cylinders involved in fires.
If the contained gas is flammable, or is oxygen, this can considerably increase fire loads. But disolved Acetylene (DA) has distinct properties which require special precautions. The direct heat of a fire may, in extreme circumstances, initiate decomposition of Acetylene. This is an exothermic (heat creating) reaction, which can cause a DA cylinder to reheat after the fire is extinguished.
From 2003 until November 2012, and only in the UK, FRS had what has since proven to be a somewhat excessive precaution for DA cylinders, which involved water cooling them for at least 24 hours, during which a hazard zone of 200 metres radius was usually maintained throughout. Whilst very safe, this often led to major disruption, which, in turn, prejudiced safety away from the incident.
Acetylene is the most flexible oxy-fuel gas and is used across multiple welding and metal cutting applications.
Put simply, there is no replacement for it and when handled, stored and transported correctly, Acetylene is perfectly safe and has been invaluable to industry for over one hundred and sixty years.
What could Acetylene suppliers do?
BCGA members offered various initiatives to help:-
In 2006, BCGA bought together senior members of the Fire Service, together with various Government Departments and Agencies, to work together towards a solution, which led on to the BAM research project detailed below.
BCGA have developed a document providing advice on dealing with cylinders in fire - BCGA L 6
Special retro-reflective marking tape is being applied to DA cylinders, to help the FRS identify DA more easily.
The UK's DSEAR (Dangerous Substances Explosive Atmospheres) Regulations require users to undertake a comprehensive risk assessment that mandates the use of flashback arrestors (it is not clear that all users are fully aware of DSEAR). BCGA fully endorses the mandatory use of flashback arrestors.
BCGA has developed a simple risk assessment model for oxy-acetylene users - BCGA TIS 15
A full DSEAR risk assessment model is summarized in BCGA GN 13.
BCGA has made agreement with EBAY to ban the sale of DA cylinders through their site as a way of restricting access to the product by untrained and unskilled individuals.
BCGA will continue to help the Fire and Rescue Services by providing expert advice and emergency response on acetylene incidents from member companies Competent Persons.
BCGA has also advised on the potential effects of mechanical impact to Acetylene cylinders, which will help Police and Highways Agency staff when dealing with road traffic incidents. In summary, cold impact to an unheated Acteylene cylinder CANNOT initiate decomposition.
The new Acetylene Safety (England and Wales and Scotland) Regulations - SI 2014 No. 1639 - came into force on 1 October 2014 and included a very important new provision which MANDATES the use of proper flashback arrestors on oxy-acetylene sets.
The Health & Safety Executive (HSE) provide guidance on the safe use of acetylene, along with a range of additional information, on their website.
A copy of the regulations can be downloaded here.
Five Stakeholder parties, namely BCGA, DfT, HSE ,TFL and, latterly, CFOA funded major research conducted over 2008 and 2009, by BAM, the German Federal Institute for Materials Research and Testing. BAM is world renowned in Acetylene science and research.
Their task was to find out, with certainty - after how many hours of realistic cooling can we be sure that no decomposition can be ongoing and therefore that it is safe to close out an incident completely?
The results from the BAM work may be summarised as follows:-
- Mechanical impact alone CANNOT initiate acetylene decomposition.
- Decomposition of acetylene cannot be initiated until at least 350°C, meaning that only a cylinder which has been exposed to direct fire impingement can be at any risk.
- Polymerization reactions of acetylene can occur at temperatures below 300°C, but these are pressure-reducing reactions and therefore not of concern to FRS.
- BAM confirmed that the previous 24 hour cooling had been very excessive and that 1 hour cooling was more than enough in the vast majority of Acetylene incidents.
The BAM work was discussed extensively with the Fire Service and with DCLG's expert panel of consultant Professors and a recommendation was accepted that 1 hour cooling, followed by a further 1 hour monitoring precaution would be more than prudent. This agreed with the empirical evidence found at real incidents.
The Executive Summary report on BAM's work may be viewed by clicking here.
And BAM's Opinion on the revised 1+1 hour protocol may be viewed by clicking here.
The conclusions of the BAM work were incorporated into new UK FRS HazMat guidance published in November 2012. The gases section of this guidance may be viewed by clicking here.
The findings of the BAM Research is of Global significance to both Fire and Rescue Services and others alike and we trust that the new UK protocol may be adopted in other countries too and thereby mitigate needless disruption.
FRS Acetylene Training Video
And finally, in the early part of 2015, BCGA cooperated with The Fire Service College and CFOA to produce a new FRS Acetylene Training DVD, which may be viewed below.