Cylinders in Fires

Gas cylinders are designed and constructed to safely contain a gas under pressure.

All cylinders contain gases which are stored under pressure, this can vary from a low pressure to a very high pressure.  This pressure can result in significant stored energy being contained within the cylinder.

Different gases may have different properties, each with its own associated hazards, for example, flammable, oxidising, inert, toxic, etc.

If involved in a fire, a cylinder will heat up.  This heat will have an effect on the materials the cylinder is manufactured from and it will increase the temperature, and therefore the pressure, of the gas.  If exposed to extreme heat all gas cylinders are at risk of failure and may suddenly rupture due to over pressure.  The presence of flammable or oxidant gases can have a significant effect on the severity of the fire.  Other gases may introduce an additional hazard(s) in the local area.

Acetylene. Exceptionally, dissolved acetylene has distinct properties which requires specific post fire actionsThe direct heat of a fire may, in extreme circumstances, initiate decomposition of acetylene.  This is an exothermic (heat creating) reaction, which can cause a dissolved acetylene cylinder to reheat after the initial fire is extinguished.

The Fire and Rescue Service have procedures to manage acetylene, as well as all other gas cylinders involved in a fire.

BCGA Leaflet 6 provides information for managing cylinders involved in fires.

When not in use, gas cylinders should always be stored in a well ventilated, secure gas cylinder store compliant with BCGA CP 44. When in use, they should always be managed in accordance with your work place risk assessment.  This should implement controls to minimise the risk of a gas cylinder being involved in a fire.

If a gas cylinder has been in a fire incident involving the Fire and Rescue Service, they will advise when it is safe to approach the cylinder.

Do not use any cylinders which have been involved in a fire, or which may have been subjected to excessive heat.  Some may have obvious damage, some may have had their mechanical properties affected by heat, not all damage will be noticeable to the naked eye.

Always inform the owner (gas supplier) of a gas cylinder which has been in a fire or subjected to excessive heat.  They will provide advice on the next action to take, which will vary depending on the circumstances.

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Managing acetylene cylinders involved in a fire

Acetylene is the most flexible oxy-fuel gas and is used across multiple welding and metal cutting applications. Put simply, there is no direct replacement for acetylene. When handled, stored and transported correctly, acetylene is perfectly safe and has been invaluable to industry for over one hundred and sixty years.

From 2003 until November 2012, and only in the UK, the Fire and Rescue Services had what has since proven to be a somewhat excessive precaution for managing dissolved acetylene cylinders involved in a fire. This included water cooling them for at least 24 hours, during which a hazard zone of 200 metres radius was usually maintained throughout. This often led to major disruption, which, in turn, prejudiced safety away from the incident.

To resolve some of the concerns held over managing acetylene cylinders in a fire, BCGA co-ordinated a major research project involving five stakeholder parties, namely BCGA, the Health and Safety Executive (HSE), the Chief Fire Officers Association (CFOA), the Department for Transport (DfT) and Transport for London (TfL).  This was conducted during 2008 and 2009 by the German Federal Institute for Materials Research and Testing (BAM).  BAM is world renowned in acetylene science and research.

Their task was to find out, with certainty, after how many hours of realistic cooling to a dissolved acetylene cylinder can we be sure that no decomposition can be ongoing and that therefore 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 a temperature of at least 350 °C has been reached, meaning that only an acetylene cylinder which has been exposed to least this temperature can be a hazard from decomposition;
  • polymerization reactions of acetylene can occur at temperatures below 300 °C, but these are pressure-reducing reactions and therefore not of direct concern to the Fire and Rescue Service.
  • confirmation that the previous 24 hour cooling had been very excessive and that, realistically, one hour cooling was more than enough in the vast majority of acetylene incidents.

The BAM work was discussed extensively with the Fire and Rescue Service and with (the Government department responsible at that time) the Department for Communities and Local Government’s (DCLG) expert panel of consultant Professors.  A recommendation was accepted that one hour cooling, followed by a further one hour monitoring as a precaution would be more than prudent. This agreed with the empirical evidence found at real incidents.

On completion of the project BAM produced a comprehensive report.  A copy of the BAM Executive Summary and BAM’s opinion on the new protocol are available.

The findings of the BAM research are of global significance, providing a scientific basis to the procedures adopted by our Fire and Rescue Service.  BCGA strongly recommend that this UK protocol is adopted in other countries to help mitigate any needless disruption.

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Fire and Rescue Service Guidance

The Fire and Rescue Service initially published their revised guidance, the Fire and Rescue Service, Operational guidance, Incidents involving hazardous materials, in November 2012.

The findings from the BAM research, which advised a 1 hour cooling, plus a 1 hour monitoring protocol for acetylene cylinders which have been exposed to direct fire, were incorporated into the guidance.

This Fire and Rescue Service National Operational Guidance for hazardous materials is regularly updated (but the 1 + 1 hour protocol for acetylene cylinders remains unchanged)

The National Operational Guidance is of primary interest to operational firefighters. Section 3 is the main source of information for gases.

The Acetylene Safety (England and Wales and Scotland) Regulations (SI 2014 No. 1639) regulate the use of acetylene.  The regulations include a provision which MANDATES the use of flashback arrestors on oxy-acetylene sets.

The HSE provide guidance on the safe use of acetylene, along with a range of additional information, on their website.

BCGA CP 7  sets out the minimum safety standards required for the assembly, examination, inspection, maintenance and use of cylinder oxy-fuel gas equipment.

 

Fire & Rescue Service Acetylene Training Video

BCGA worked with CFOA and the Fire Service College to produce this training video

Publications

Publications

CP44 The storage of gas cylinders. Revision 1: 2022

17/06/2022 Codes of Practice CP44

This document defines the principles of safe practice for the storage of gas cylinders and bundles. It promotes the use of an outdoor store, with good natural ventilation, in a secure location, which meets the required separation distances.

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GN13 DSEAR risk assessment guidance for compressed gases. Revision 1: 2021

14/01/2021 Guidance Notes GN13

Provides guidance on the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) which require all sites, where there are gas containers, to undertake a risk assessment and, where necessary, to implement appropriate controls.

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TIS15 Model risk assessment for the storage and use of gas cylinders for oxy-fuel applications. Revision 1: 2015

18/11/2015 Technical Information Sheets TIS15

This document has been withdrawn, refer to Code of Practice 7, The safe use of oxy-fuel gas equipment (individual portable or mobile cylinder supply).

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TIS32 Acetylene or propane (for welding, cutting and allied processes). Revision 3: 2024

23/07/2024 Technical Information Sheets TIS32

This document provides technical information on the different properties of acetylene and propane to help the user make an informed choice when choosing a fuel gas for welding, cutting and allied processes.

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L6 Cylinders in fires. Revision 6: 2022

22/04/2022 Leaflets L6

BCGA Leaflet L6 provides advice on the actions to take in the event of a fire on or near gas cylinders.

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BCGA publish several publications providing advice on managing gas cylinders. All BCGA publications are accessible via the Publications page.