Hot work

Hot work using open flames, heating, hot air, welding, cutting, soldering and/or grinding equipment is a fire hazard and can induce allergies or toxicity.

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Here you can find *a guide on hot work* (Arbeidstilsynet - in Norwegian).

Before starting hot work, the unit must conduct a risk assessment, plan the work and initiate necessary measures to ensure that people and buildings are safe. Additional information can be found in the Regulations concerning the Performance of Work, chapter 5.

Hot work should take place in suitable rooms. Soldering must never be done in an office.

Additionally, you must make sure that:

  • Openings in the floor, walls or ceiling are sealed with wet cloths, rock wool or something similar.
  • Approved fire extinguishers, a minimum of 2 x 6 kilo ABC portable or foam extinguishers or a fire hose with a minimum 3/4 inch diameter with water applied to the hose pipe, are easily accessible at the work site.
  • Active fire protection measures such as detectors and loops are disabled. Contact the building services (in Norwegian).
  • A minimum of two emergency exits are available and unblocked.
  • If the nature of the work requires a fire watcher, the fire watcher must be present during work, breaks and at least one hour after the work has been concluded.
  • Those who perform the work must not leave the work site before all sparks or fires are extinguished.
  • Accidents or near misses must be reported in the NTNU nonconformity system.

Hot work in explosive rooms

  • Before hot work in explosive rooms: Contact the fire protection manager to go through the work.
  • Possibly flammable gasses must be measured immediately before and continuously during the work.
  • Acetone/oxygen containers must not be brought into the facility.
  • Make sure to provide proper ventilation.

Hot work outside designated, specially prepared work sites (welding shops)

Hot work should preferably be performed in designated, specially prepared work sites (welding shops).If you need to work elsewhere, the unit must conduct a risk assessment. Measures must be taken to reduce the risks. You can use the Guidelines for hot work (in Norwegian) (the Norwegian Labour Inspection Authority) as a basis for your risk assessment.

If you perform hot work and use open flames, welding, cutting and/or grinding equipment outside a designated, specially prepared work site, you must have a certificate for working in high temperatures.

Hot work performed by an external company

The line manager is considered the contractor, and is responsible for giving the external company permission to perform hot work. See Work permit for hot work (in Norwegian).

The unit must conduct a risk assessment, plan the work and implement necessary measures. Additionally:

  • Those who perform the work must have a valid certificate for hot work.
  • The contractor must prepare a work permit before commencement of the work.
  • The work permit must be available to be presented at the work site upon request.
  • The contractor must have a copy of the work permit.
  • Those who do the work should consider notifying affected users.

Follow-up after hot work

  • A follow-up control of the work site and the adjacent area must be performed, in order to prevent any danger of a fire.
  • Loops and detector(s) must be enabled. Notify the building services (in Norwegian).
  • The working equipment must be placed in safe distance from the work site.
  • Inform the night watch on 981 97 373 (mobile phone).

Medical examination

If the risk assessment determines that employees can be exposed in a manner that can lead to health damages, the employee must undergo a medical examination. The Norwegian Labour Inspection Authorities have made a guide to hot work (in Norwegian), in which there is information about health damaging exposures that may occur. Contact the Occupational Health Services if you have questions.

Questions regarding the HSE process

  • How does the unit provide fire protection for hot work?
  • Are there any forms of required certifications, applications, notification requirements or permits regarding the unit's hot work?
  • Can exposure to waste gases from or materials used during the unit's hot work induce allergies or toxicity?
  • How does the unit work to reduce exposure to waste gases from the unit's hot work to people and adjacent areas?
  • Which procedures does the unit have to ensure that a medical examination is offered in case of suspected adverse health effects?
  • Who has the adequate qualifications to issue a work permit for hot work (to an external company)?


NTNU regulations




Approved by Director of HSE - December 7th 2012 - HMSR29E - ePhorte 2013/11295