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Background

During liquified petroleum gas (LPG) tank fires — such as propane — the potential exists for an explosion known as boiling liquid expanding vapor explosion (BLEVE).

The liquified natural gas (LNG) market has evolved significantly in the past decade and the potential also exists for a BLEVE when dealing with LNG tank fires.

Concerns/hazards

If the pressurized vessel containing liquid ruptures, the pressure which prevents the liquid from boiling is lost. This causes a portion of the liquid to "instantaneously" boil, which in turn causes an extremely rapid expansion. The expansion may be so rapid as to be an explosion, with the potential for severe damage and injury or death to firefighters. A BLEVE is an extremely high-risk event for first responders.

Recommended actions

To reduce the risk of BLEVE, firefighters and fire departments should follow the recommendations below.

Incident commanders

Incident commanders should:

  • complete a 360-degree size-up
  • develop an incident action plan including the securing of an adequate water supply
  • implement a strong Incident Command/Management system

Firefighters

Firefighters should:

  • fight fire from the maximum distance possible or use unattended hose holders or monitor nozzles
  • be aware of the differences between LPG and LNG tanks:
    • cool LPG tanks by flooding the outside of the tank (side walls) with large quantities of water to reduce the risk of a BLEVE occurring
    • applying water to LNG tanks or liquid spills may increase the hazard by warming up the cryogenically cooled LNG
  • not direct water at the source of leak or at safety devices (for example. valves or vents, generally located at the top of the tanks); icing may occur which would prevent venting and increase the risk of BLEVE
  • leave the area immediately if there is a rising sound from venting safety devices or discoloration of the tank
  • be aware that when a BLEVE occurs, sections of the tank can fly in any direction

Employers

Employers must:

  • provide information, instruction and supervision to firefighters to protect the health and safety of the firefighter
  • make firefighters aware of the hazard associated with LPG and LNG fires, including BLEVE

Employers should:

  • incorporate these procedures into fire department standard operating procedures and guidelines
  • ensure that fire department code and standard enforcement personnel adhere to the applicable Acts, Codes and Standard for the installation, maintenance, and inspection of LPG and LNG installations

Considerations

Fire departments should consider the following actions to further reduce the risk of BLEVE:

  • familiarize themselves and conduct risk assessments of LPG and LNG installations within their jurisdictions and pre-plan accordingly
  • become familiar with the location(s) of LPG tank installations for home heating purposes
  • have the emergency contact information for the LPG suppliers and service contractors within their jurisdiction

Further considerations to reduce the risk of BLEVE include:

  • for pre-planning and training, consideration should be given to including supplier and contractor representatives
  • the LPG 420 tank, which is a common residential upright tank, can pose a significant risk, as these tanks are often ganged or combined with additional tanks and are quite often directly adjacent to structures

Applicable regulations and acts

Read:

Applicable standards

Read the CAN/CSA-B149.2-05 Propane storage and handling Code guidance on how to safely handle and store natural gas and propane, and the safe and effective installation of related appliances and equipment, and more.

Read the CAN/CSA Z276-01 LNG production, storage and handling standard for information on liquified natural gas.

Related

Read Transport Canada’s Hazardous Goods Emergency Response Guidebook which helps first responders identify hazards based on the material involved in a transportation incident and protect themselves and the public during the initial response to an incident.

Read the requirements for propane storage and handling under the Technical Standards and Safety Act.