Construction hot work
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Fire caused by hot work

A guide to loss prevention

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    Hot work is usually defined as any open flame, spark or heat producing activity and is typically associated with cutting, welding, grinding and brazing operations as part of maintenance or construction works.

    Hot work can generate sparks, molten material and other  ignition sources well away from the area of work. In addition,  conducted heat can cause ignition of combustible materials  both locally and remotely.

    Ideally hot work should not be carried out and alternative  methods of work should be investigated. If there is no  alternative, then every effort should be made to relocate  the activity to a designated safe area well away from  buildings and structures or to a properly designed and  constructed workshop area.

    The decision to carry out hot work when the above criteria  cannot be met should be a conscious one after all other  alternatives have been exhausted. At this stage a formal  Hot Work Permit and procedure should be used. This  applies to everyone – staff or contractors alike.

    Hot work has been recognised as a significant fire risk for many years. Despite this, loss statistics show us that it continues to be a major cause of loss within industrial and commercial facilities, particularly during mintenance periods and construction projects.

    It is essential that all hot work activities are properly managed.

    Hot work procedure

    Hot work and timber frame construction

    Hot work on timber frame construction sites should be  minimised. Where hot work cannot be avoided, in addition  to the standard controls for hot work, the area in which the  work has been undertaken must be continually monitored  for at least one hour following completion of the hot works  and be visited two hours after completion prior to closing  the permit.

    Exposed wooden flooring and other items of combustible  material which cannot be removed must be covered with  sand or other non-combustible material.

    All hot work undertaken outside of a designated 'safe' hot  work area or within 15m of buildings, structures or external  storage should fall under a Hot Work Permit.

    This should be fully documented, adopted as a company  standard and applicable to all employees, contractors and  visitors. As a minimum the procedure should contain the  following:

    • Definition of hot work
    • Scope of application of procedure
    • A dedicated permit for the control of hot work activities –  Hot Work Permit
    • Training requirements for Hot Work Permit issuers,  including refresher training timescales
    • A list of those trained and authorised to issue Hot Work Permits
    • Requirement for periodic audit of the Hot Work Control
    • Procedure including live and completed Hot Work Permits

    Hot Work Permits

    The use of a dedicated permit to control hot work activities  forms an essential part of a hot work process, but it is not  the only level of control needed. Many losses have occurred  where permits have been issued but these have not been  properly completed, or the precautions identified have not  been properly implemented, or those issuing the permit do  not recognise all the potential hazards.

    Authority to issue permits should be granted following  successful completion of appropriate training and  demonstration of competence.

    The key criteria for a Hot Work Permit are:

    • Permits should be issued for a specific task in a  specific location.
    • Permits should be issued to a named individual and  only for that individual to carry out the hot work.
    • Permits should not be issued for more than one day  or shift (8 hours).

    Extensions to permits are acceptable provided all necessary  precautions are re-checked and the extension is formally  documented.

    A copy of the issued permit should be available at the  place where the work is being carried out. This allows  those carrying out the work to demonstrate that they  have the appropriate permission. The issued permit also  acts as a checklist to allow review of the conditions under  which the permit was issued. Should any of these  conditions change then work should be suspended.  Resumption of work should only be undertaken when  authorised by the original permit issuer.

    Fire watch

    A fire watch should be posted during the work.  As a minimum this should be one person with a fire  extinguisher or hose, but could require additional  observers if the work is being done close to pits,  trenches or cable trays, or near penetrations through  walls or floor or ceilings, or on tall or combustible  structures. The person doing the hot work should  never be allowed to be their own fire watch. Note that  the fire watch should be maintained during breaks in  the work such as at refreshment breaks.

    Statistically the majority of major losses have occurred  sometime after the hot work has been completed.  Smouldering materials may go unnoticed and develop  into fires when the area or building is unoccupied. A fire  watch should always be undertaken during the work and  following completion of the work. The period of the postwork  fire watch should be based on the hazards present.  The minimum post-work fire watch should be continuous  for 30 minutes then periodic inspection of the work place  and surrounding area (including floors below where the  floor is penetrated) for at least another 30 minutes.  Where there is a significant combustible loading within  the building or combustible construction is present, the  periodic inspections should be extended to 2 hours or  more after the work is completed.

    To ensure an adequate fire watch can be achieved, hot  work should not be allowed within 2 hours of the end of  the normal shift when operations would normally cease  and staff leave for the night.

    Checklist before hot work commences

    • At least 2 suitable portable fire extinguishers should  be available for immediate use within the area of hot  work operations and all persons involved and  undertaking fire watch duties be trained in their use.  Any sprinkler protection should remain fully  operational. Any automatic fire detection systems  should be isolated only in the area where hot works  is undertaken and only for the period of the work.
    • Inspections should be made and combustible materials and flammable liquids should be removed from:
      • an area within 10 metres of the hot work
      • floors above and below, and areas on the other sides of walls, screens or partitions which may be in danger of ignition either directly or from conducted heat.
    • Floors of combustible material in the designated area should be covered with sheets of incombustible protective material or wetted and covered with sand if there are any:
      • combustible materials that cannot be removed
      • holes, gaps in walls, floors or ceilings where sparks could pass through they should be covered by incombustible material.
    • Where work is carried out on building panels, an assessment should be made on insulating or other materials behind or forming the core of the panels.
    • Allow adequate ventilation and ensure enclosed  equipment such as tanks, vessels, etc, are emptied  and tested to ensure that they are free of flammable  or other dangerous materials.
    • Identify any gas pipes or other services adjacent to  or below the area of hot work and isolate and  protect them.
    • All persons carrying out the hot work and  undertaking the fire watch should know how to raise  the fire alarm and be aware of any emergency  procedures.
    • Confirm all other contractors/operators on site are  aware that hot work is being undertaken, and that  there is no application of paints or flammable solvent  based chemicals.


    • FPA RC7 – Recommendations for Hot Work
    • NFPA 241: Standard for Safeguarding Construction, Alteration, and Demolition Operations Current Edition: 2022
    • The Joint Code of Practice on the Protection from Fire of Construction Sites and Buildings Undergoing Renovation, 10th Edition (August 2022)
    Disclaimer: The guidance in this document refers to industry best practice loss control advice. Adoption of the advice contained within this document does not imply  compliance with industry, statutory or HSBEI guidelines, nor does it guarantee that fire related losses will not occur.

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