January 22, 2024

Toolbox Talk: Portable Heaters

Insights UK Regional Division
Risk Management

In the winter months, the use of portable heaters in otherwise unheated areas of premises naturally increases, especially in buildings where fixed heating is impractical. They are typically small electrical, gas or liquid-fuelled units and, by their nature, transportable.  

There are various types of portable heaters but, in general terms, electric appliances are less hazardous from a fire inception perspective than their liquid-fuelled, or gas-fired counterparts. We look at the various types, the hazards and the safety measures that should be taken to avoid potential fires and damage to premises. 

Electric Heaters  

  • Portable electric heaters should carry the British Electrotechnical Approvals Board (BEAB) safety mark.  
  • Convection or infrared heaters are preferable to appliances with radiant elements.  
  • Flexible leads should be as short as practicable, protected against mechanical damage and inspected regularly to ensure they remain in good condition.  
  • The use of electrical extension leads in conjunction with portable electric heaters should be avoided, as this can cause overloading and fire.  
  • Electric heaters should be checked periodically under the client’s portable appliance inspection and testing regime.  
  • Cabinet-type heaters with integral gas cylinders are preferable to those connected to a freestanding gas cylinder by a trailing hose.  
  • Direct-fired, fan-assisted heaters are particularly hazardous due to the presence of a naked flame and should be avoided.  
  • Indirect-fired heaters have an enclosed combustion chamber and are considered safer than direct-fired types.  

Liquid-Fuelled Heaters  

  • Generically known as ‘oil fired’, these heaters use either diesel (also known as gas oil/35- second oil), kerosene (heating oil/28-second oil) or paraffin (a refined version of kerosene); all are flammable liquids, having flash points below 60°C.  
  • Direct- and indirect-fired types are again available, and the latter preferred.  
  • The burning of waste oil in portable heaters is not acceptable. This practice is sometimes encountered at motor trade premises in particular.  

Inherent Hazards  

  • Easily moved to be in proximity to, or contact with, combustible items or flammable/explosive vapours.  
  • Potential for the unit to be knocked over, causing the sudden release of fuel which could then ignite.  
  • Mechanical damage to the unit, potentially causing fuel leakage and subsequent ignition.  
  • Typically used infrequently, often stored for long periods without use and consequently not always adequately maintained.  

Acceptability of Portable Heaters  

The use of portable heaters — other than electrical appliances in offices and similar low-risk areas — is normally only considered acceptable where the fixed system has broken down and is necessary to maintain a suitable working environment. Once the fixed system has been repaired, portable heaters should be removed from the premises, together with any liquid fuel or gas cylinders.  

However, other operational or practical circumstances may apply, and insurance underwriters will need to consider the use of portable heaters on individual merit.  

Control Measures  

Where the use of portable heaters cannot be avoided and is accepted by underwriters, the following control measures should be implemented (where applicable):  

  • Liquid-fuelled and gas-fired portable heaters should only be operated by trained, authorised persons and in accordance with the manufacturer’s instructions.  
  • Heaters should: 
    • Be in good condition and regularly maintained by a competent person.  
    • Located on a noncombustible surface in a designated position clearly identified by floor markings or fencing of noncombustible construction and with a minimum clear space of 2 metres maintained from any combustible materials.  
    • Positioned away from traffic, circulation and escape routes where they could be knocked over or impede egress in an emergency.  
    • Not be used where flammable liquids or vapours may be present.  
    • Not be moved whilst alight or switched on.  
    • Not be refuelled whilst alight or switched on.  
    • Not be left unattended whilst in operation. Formal procedures should be implemented to ensure heaters are safely switched off at the close of business.  
    • Not be fitted with timer switches allowing them to be turned on whilst the premises are unattended (typically to pre-heat work areas before employees arrive at the start of the day).  
  • The correct fuel should always be used with liquid and liquefied petroleum gas (LPG)-fuelled portable heaters.  
  • Where practicable, portable liquid and LPG-fuelled heaters and gas cylinders in use should be securely fixed in position.  
  • The number of fuel gas cylinders held should be kept to the minimum practicable. Spare and empty cylinders should be kept secure, well-ventilated external store away from potential ignition sources and sheltered from direct sunlight.  
  • Liquid fuel should be kept in a suitable container and safe location away from potential ignition sources.  
  • Where practicable, portable liquid and gas-fuelled heaters should be guarded by a stout mesh guard fixed to the heater and extending at least 50cm from each side and 1 metre to the front, in order to prevent the guard from overheating.  
  • There should be adequate provision of suitable fire extinguishers in the immediate vicinity. 
  • The client’s fire risk assessment should be reviewed and updated to ensure it adequately covers the introduction of portable heaters.  

Where potentially explosive atmospheres may arise and/or LPG cylinders are held on the premises, the Dangerous Substances and Explosive Atmospheres Regulations (or DSEAR) will also apply.  

Should any uncertainty arise in connection with portable heaters, it is best to consult with risk control specialists.