Fire Safety · Mandatory · Construction

RAMS — Temporary Heating and Drying Operations

A risk assessment and method statement for temporary heating and drying operations on construction sites, covering LPG heaters, diesel space heaters, and dehumidifiers. Addresses fire risk from proximity to combustibles, LPG storage under DSEAR 2002, CO monitoring, end-of-day shutdown checks, and insurance conditions for temporary heating.

Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. MHSWR 1999 / RRO 2005 remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.

Legal basis	MHSWR 1999 / Regulatory Reform (Fire Safety) Order 2005 / DSEAR 2002
Key risk	Temporary heating fires are one of the most common causes of major construction site fires
Clearance	Minimum 1 m clearance from all combustible materials at all times
Supervision	Never leave temporary heating equipment unattended — all heaters must be supervised while in operation
CO monitoring	Carbon monoxide monitoring is required in all enclosed or partially enclosed spaces where fuel-burning heaters are in use
Enforcing authority	HSE, Fire and Rescue Service

1. Temporary Heating RAMS — Controlling One of the Most Common Fire Causes

LPG torpedoes pointing at timber frames, polystyrene insulation, or packaging waste are one of the most common causes of significant fires on construction sites. The combination of high-output radiant heat and the abundance of combustible materials in a partially completed building creates a risk profile that has resulted in multi-million-pound losses and, in the worst cases, fatalities.

Insurers impose specific conditions on the use of temporary heating equipment, and failure to comply can void site insurance cover entirely. Many policies prohibit the use of LPG torpedo heaters inside buildings under construction unless the insurer has given explicit written consent. The RAMS for temporary heating must address not only health and safety law but also the conditions imposed by the site’s insurance policy.

Critical rule

NEVER leave LPG heaters running in unoccupied areas or overnight. All temporary heating equipment must be switched off and isolated when the work area is unoccupied. End-of-day shutdown checks must be formally recorded.

2. RAMS Content — Temporary Heating & Drying Operations

The following table sets out the content that the RAMS for temporary heating and drying operations must cover. Each element must be specific to the site, the equipment in use, and the areas where heating is required.

RAMS element	Detail required
Heating equipment	Type, make, model, output rating (kW), fuel type (LPG, diesel, electric). Serial number and inspection/service date. Only equipment in good condition with current PAT or gas safety certificate.
Locations of use	Specific areas where heating is authorised. Floor plans showing heater positions. Identify combustible materials in proximity and confirm minimum 1 m clearance maintained.
Fire risk assessment ref	Cross-reference to the site fire risk assessment. Confirm that the FRA has been updated to reflect the introduction of temporary heating and any additional fire precautions required.
Combustibles proximity	All combustible materials within 1 m of heater positions must be removed or protected with non-combustible shielding. Timber framing, polystyrene insulation, packaging, and waste are the highest-risk materials.
Supervision	Heaters must be supervised at all times while in operation. Nominate responsible person for each heating zone. Never leave heaters running in unoccupied areas.
Ventilation	Fuel-burning heaters (LPG, diesel) require adequate ventilation to prevent CO buildup. CO monitoring must be in place in enclosed or partially enclosed spaces. Minimum ventilation rate per heater output.
Firefighting provision	Appropriate fire extinguisher immediately adjacent to each heater position. Type matched to fuel — dry powder for LPG, foam for diesel. Personnel trained in extinguisher use.
LPG storage	All LPG cylinders stored outside in a designated compound, away from ignition sources, ventilated, and secured. NEVER store LPG cylinders inside buildings. Minimum separation distances per HSG168.
End-of-day check	Formal end-of-day shutdown procedure. All heaters switched off and isolated. Area inspected for signs of overheating or smouldering. Recorded on daily checklist.
Before leaving site	Final check that all temporary heating equipment is off, fuel supplies isolated, and no signs of heat damage or smouldering. Signed off by nominated responsible person.
Workers informed	All workers in the heating zone briefed on heater locations, exclusion zones, CO symptoms, emergency procedures, and the prohibition on repositioning heaters without authorisation.

3. Common Mistakes

Using LPG heaters in areas with inadequate ventilation

Fuel-burning heaters consume oxygen and produce carbon monoxide. In enclosed or partially enclosed spaces without adequate ventilation, CO can accumulate to dangerous or fatal concentrations within minutes. CO is odourless and colourless — workers will not detect it without monitoring equipment. Every year, construction workers are hospitalised or killed by CO poisoning from temporary heaters in poorly ventilated spaces.

Storing LPG cylinders inside buildings

LPG cylinders must NEVER be stored inside buildings under construction. Cylinders must be stored outside in a designated, ventilated compound away from ignition sources and separated from oxygen cylinders. A leaking LPG cylinder inside a building creates an explosive atmosphere that can be ignited by a spark from any source — electrical switching, static discharge, or a tool striking metal.

4. Frequently Asked Questions

What is DSEAR and when does it apply to temporary heating?▾

The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) apply wherever dangerous substances — including LPG — are present in the workplace. DSEAR requires an assessment of the risk from flammable or explosive atmospheres. For temporary heating on construction sites, DSEAR applies to: LPG storage areas, the connection and disconnection of LPG cylinders, and the use of LPG heaters in enclosed or partially enclosed spaces. The DSEAR assessment must identify hazardous zones, eliminate or reduce the quantity of dangerous substances, and implement controls to prevent ignition sources within those zones.

Can electric heaters be used as a safer alternative?▾

Electric fan heaters and radiant panels eliminate CO risk and are generally preferred where adequate electrical supply is available. However, they still require minimum clearance from combustibles, must not be left unattended, and must be PAT tested. Industrial electric heaters draw significant current — the temporary electrical installation must be designed to accommodate the load without overloading circuits, which is itself a fire risk.

What CO monitoring is required?▾

Where fuel-burning temporary heaters are in use in enclosed or partially enclosed spaces, personal CO monitors should be worn by all workers in the area. Fixed CO detection with audible alarm should be installed where heaters are used regularly in the same location. The workplace exposure limit for CO is 20 ppm (8-hour TWA) and 100 ppm (15-minute STEL). Any alarm activation requires immediate evacuation, ventilation, and investigation before work resumes.

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