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Sauna Fire Safety [Hardfacts]


Saunas are now found in a wide range of premises, typically constructed mainly of timber, housing a sauna heater (reaching temperatures of up to 95°C) which are usually electrically operated and thermostatically controlled.

Some large fires have been attributed to saunas so the risk to life, property, and business interruption resulting from such fires must be recognised.

The precautions below apply to all types of sauna and heater (including hidden varieties).

Main Hazards

  1. The Sauna itself
  2. Management controls and housekeeping procedures 
  3. User operation and general abuse in use.

Causes of Fire

  • Poor Housekeeping - combustible materials left in the vicinity of the heater e.g. robes or towels
  • Heaters left ‘on' and unattended for prolonged periods. Also a failure to turn power to the sauna 'off' on cessation of business - inadvertent or deliberate. 
  • Failure to turn power to the sauna ‘off' on cessation of business - inadvertent or deliberate
  • Thermostat failure
  • Defective timer switches
  • Lack of or inadequate inspection regimes during times of operation
  • Deliberate interference - tampering with thermostats to stop the heater switching off once safe operating temperatures are reached. Often saunas are run at too high a temperature by users
  • Lack of maintenance 
  • Close proximity of heating elements in a combustible structure
  • Heater overheating, by using incorrect or insufficient stones or packing too tightly
  • Electrical faults e.g. internal sauna lighting 
  • Being operated at too high a temperature too high for prolonged periods resulting in the drying out of internal timber linings leading to pyrolysis and ignition
  • Use of excessive water or incorrect water (e.g. chlorinated pool water) on the heater stones leading to thermal shock of the heating elements
  • Using neat essence on the heater stones
  • General wear and and abuse of use 
  • Heaters or thermostats - not installed in accordance with manufacturers instructions
  • Incorrect electrical wiring which is not suitable for use in such temperatures

Fire Safety Precautions

Precautions which can be taken to help remove or reduce possible hazards include:

Fire Risk Assessment (FRA)

Ensure the FRA includes the sauna and supports appropriate controls. Keep the assessment under review particularly if changes have been made.

Fire Action Plan

Provide clear and precise instructions covering:

  1. Raising the alarm
  2. Building Evacuation
  3. Calling the Fire Brigade
  4. Tackling the fire - only if safe to do so!


  • All employees, including temporary staff or staff providing temporary cover, are aware of what is expected of them especially if they have special duties e.g reception to call the fire brigade 
  • The Fire Brigade is called. Dependence should not be placed on any fire alarm activation (automatic or otherwise) providing Brigade response- confirmation calls are needed and the procedure for summoning the Brigade should form part of the FRA and should be known to all staff on site  
  • Staff assume any fire alarm activation is a 'true' alarm and take the appropriate action


        Saunas need to:

  • Be constructed and installed in accordance with the manufacturers instructions
  • Have the electrical installation strictly in accordance with BS7671 IEE 17th Edition Regulations (special regulations for saunas were new in the 16th Edition
  • Consider the provision of a remote ‘ON/OFF' switch housed within a lockable safety cover.

Residual Current Device

Use circuit breakers to protect all sauna equipment.


Maintenance must be carried out in accordance with the manufacturer's instructions. Service periods of 6 or 12 months are usual, depending on usage and should include:

  • Check general wear and tear of the structure
  • Check the electrical installation (e.g. thermostats, high temperature safety thermostats, heating elements, timers, RCD's, fuses) - replacing as necessary
  • Check and replace damaged or broken stones with similar or recommended stones.

Management Controls and Inspections

Provide signed/dated/timed recorded checklists to ensure equipment has been inspected and any remedial items have been fulfilled. Such inspections should take place by senior staff.

Start of day inspection

Always check prior to switching the sauna ON:

  • The sauna is empty of combustible items particularly on, around or under the heater e.g. towels, robes etc. 
  • Benches, backrests and duckboards are correctly positioned clear of the heater. 
  • Heater stones cover the heating elements but are not too tightly packed 
  • The heater is fixed securely to the wall or if floor mounted is level and stable also the casing is in good condition 
  • Heater guard rail is securely fixed in place 
  • Timbers in sound condition (not scorched) 
  • Thermostat sensors inside the sauna are safely secured and clear of foreign items 
  • Electrical connections are visually safe

Two hourly intervals

Check during operation of the sauna that:

  • No towels or any items have been left inside the sauna by previous users and particularly that no items are left on the heater or its guard rail 
  • Benches, backrests and duckboards have not been moved close to the heater. 
  • Thermostat sensors inside the sauna have not been tampered with.

End of day

Checks when the sauna is switched OFF:

  • The power supply is switched ‘OFF' and any timer is in the ‘OFF' position. 
  • Working thermostats are ideally turned to the low setting 
  • No items left inside the sauna particularly on the heater or its guard rail 
  • Benches, backrests and duckboards have not been moved close to the heater 
  • Internal timbers are in good condition, not showing signs of scorching 
  • Thermostat sensors within the sauna have not been tampered with 
  • Electrical connections appear safe
  • When ‘OFF' leave the door to the sauna cabin open

General housekeeping

Regularly clean saunas to remove any build up of dust or hair.


Operators and all staff must all be trained and understand all the sauna hazards.

User Safety

Ensure all users are aware of safety instructions, fire safety issues and how to operate the sauna. Usage guidelines should be read in conjunction with a ‘Do' and ‘Don't' list of safety instructions also clearly displayed at the entrance to the sauna cabin.

Fire Extinguisher
Provide an appropriate extinguisher in a suitable position to be used by trained staff.

Other Fire Protection Measures

Automatic Fire Alarm

Install a system or maintain an existing system using a competent firm with appropriate third party accreditation, to BS5839-1:2013.
Consider the provision of remote signalling to an approved Alarm Receiving Centre, where timers switch the heater ‘on' out of hours.

Fire Suppression Systems

Consider protection of the sauna using a suitable fire suppression system, such as watermist.

Any fire suppression system should be interfaced into the fire alarm and/or BMS system (including provision of any remote signalling on detection/activiation) and should be interfaced with the sauna to shut down and heating element on detection/activiation.

Any fire suppression system is to be designed, installed and commissioned by a third party certificated company and any proposed specification is to be supported by independent fire test reports and certificates that have been based upon similar end use application (seek advice from your Insurer).  


The area of the premises where the sauna is located ideally should be in a room or enclosure that can provide at least 60 minutes fire resistance.

Key Action Points

  • Ensure the Sauna is in the Fire Risk Assessment and it is up to date
  • Review the Fire Action Plan
  • Effectively communicate the Fire Risk Assessment and Fire Action Plan to staff 
  • Provide recorded inspection checklists
  • Maintain Saunas, associated equipment and Fire Protection measures regularly.

Next Steps:

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