Factory heating and minimum working temperatures

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There is no single legal minimum working temperature for a factory written into UK law. Regulation 7 of the Workplace (Health, Safety and Welfare) Regulations 1992 says that "During working hours, the temperature in all workplaces inside buildings shall be reasonable." HSE's Approved Code of Practice (L24) puts a figure on that: the temperature "should normally be at least 16 degrees Celsius", or "at least 13 degrees Celsius" if work involves rigorous physical effort. In a factory, which figure is the sensible benchmark depends on the work done at each area, not on the building as a whole. HSE accepts that some areas, such as loading bays open to the outside or chilled product areas, cannot reach those figures, but expects them to be as close as practical. For most factories, staying at a reasonable temperature through winter comes down to well-chosen, well-maintained heating: warm air heaters, radiant tube heaters or boiler-fed systems serviced at the manufacturer's intervals by a competent engineer. This guide covers what the guidance says for production areas, how to measure in high-bay buildings, the heating options and how to keep them working.

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Commercial heating tips and advice · 12 November 2026 · Fast Commercial Boiler Help, Gas Safe 985448

13°C or 16°C: which applies on a factory floor?

Paragraph 61 of L24 reads: "The temperature in a workplace should normally be at least 16 degrees Celsius. If work involves rigorous physical effort, the temperature should be at least 13 degrees Celsius. However, these temperatures may not necessarily provide reasonable comfort, depending on other factors such as air movement, relative humidity and worker clothing." HSE's temperature pages give the same figures and say 13°C applies "if much of the work involves rigorous physical effort".

The lower figure is tied to the work, not the type of building. Most factories mix activities: heavy manual handling in one bay, seated assembly, inspection or packing at benches in another, plus offices, canteens and welfare areas. A practical approach for a production or facilities manager is to:

List the main work areas and what people do there for most of the shift.
Use 16°C as the starting benchmark for sedentary or light work, such as bench assembly, quality control, machine minding and packing lines, and 13°C only where much of the work really is rigorous physical effort.
Remember paragraph 60: the temperature "should provide reasonable comfort without the need for special clothing." Heavy coats at a packing bench are a sign the heating is not keeping up.
Treat welfare areas separately. L24 paragraph 66 says toilets and rest facilities should be at a reasonable temperature, and changing rooms and shower rooms "should not be cold."

The legal status of the Code, and how the duty works in offices, are covered in our guide to office heating and the law on workplace temperature. Factory offices follow the same 16°C benchmark.

Factory minimum working temperature: where the guideline can't be met

Factories have areas that ordinary heating cannot keep at 13°C or 16°C. L24 paragraph 62 says the temperature guidelines "do not apply where it would be impractical to maintain those temperatures, for example in rooms which have to be open to the outside, or where food or other products have to be kept cold. In such cases, the temperature should be as close to those mentioned in paragraph 61 as is practical."

For areas that must stay cold for products or processes, paragraph 63 lists measures to apply as appropriate, including "keeping chilled areas as small as possible", "providing insulated duckboards or other floor coverings where workers have to stand for long periods on cold floors", "excluding draughts from workstations, eg by using baffles" and "installing self-closing doors where such measures are practical and would reduce discomfort." Paragraph 67 adds that temporary heating and other control measures should be provided for employees who have to work in normally unoccupied rooms, "such as storerooms", for more than short periods where there is a risk of working below the paragraph 61 temperatures.

So a goods-in bay with roller shutters open half the day does not have to hit 13°C, but it should not simply be written off either. Fixed workstations near open doors are where local heating, screens and good door discipline make the most difference.

Measuring temperature in high-bay buildings

Factory readings go wrong easily. A thermostat on a column, a BMS sensor near the roof or a thermometer under a radiant heater can all give a figure that has little to do with the person on the line. L24 says "Temperature readings should be taken close to workstations, at working height and away from windows" (paragraph 61), and that thermometers "should not be located directly in front of windows or near radiant heat sources" (paragraph 68).

In high-bay buildings that means taking readings at the workstations people actually use, at bench or machine height, and noting where they were taken. HSE's thermal comfort guidance explains why the figure on the thermometer is only part of the story: "Air temperature alone is not a valid or accurate indicator of a comfortable workplace temperature or heat stress." It lists six factors, including radiant temperature, air movement, humidity, clothing and work rate. In a factory, draughts from doors, cold floors and how hard people are working all change how warm the same reading feels.

Keep a simple log: date, time, location, reading, outside conditions and whether doors were open. If a heater or zone is not keeping up, that log gives your engineer something concrete to work from, and it shows you were monitoring.

Heating options for factories and high bays

Most factories use one or more of the following. Choosing, sizing or changing the system is design work for a competent heating engineer, but it helps to know what you have.

Gas-fired warm air heaters. A burner heats a heat exchanger and a fan blows warm air into the space, either from the heater or through ducts. Powrmatic's LNVx manual is a useful example of the limits on where these can go. It says the units are designed to operate within an ambient range of -10 to 25°C, and that heaters "should not be installed in hazardous areas or areas where there is a foreseeable risk of flammable or corrosion inducing particles, gases or vapours being drawn into the combustion air or main fan circuits." It lists areas needing special consideration, including where de-greasing solvents are present, where paint spraying is carried out, where petrol engine vehicles are stored or maintained, and where dust is present, for example woodworking or joinery shops. Our guide to warm air heater heat exchanger inspection covers why the annual inspection matters.
Gas-fired radiant tube heaters. Overhead tubes and reflectors direct heat down onto people, floors and surfaces below. The AmbiRad Vision VS manual sets recommended mounting heights for each model and minimum clearances to combustible materials which, in its words, "MUST be adhered to at all times." That matters in factories where stock, pallets or racking get moved around under the heaters. BS 6896 covers the installation and maintenance of gas-fired overhead radiant heaters in industrial and commercial premises. See our guide to radiant tube heater maintenance for reflectors, clearances and dust.
Boiler-fed systems. Low temperature hot water from a boiler plant feeding unit heaters, fan convectors or radiators, often with the boilers also serving offices and welfare areas. When the boilers lock out, every zone they serve goes cold, so the boiler plant needs the same attention as the heaters on the shop floor.
Local heating at fixed workstations. L24 paragraph 65 says that "If a reasonably comfortable temperature cannot be achieved throughout a workroom, local heating or cooling (as appropriate) should be provided." In large, draughty buildings, local heating at fixed positions can be part of the answer.

Whatever the system, regulation 7(2) of the Workplace Regulations says a method of heating "shall not be used which results in the escape into a workplace of fumes, gas or vapour of such character and to such extent that they are likely to be injurious or offensive to any person." L24 paragraph 78 says fixed heating systems "should be installed and maintained so that the products of combustion do not enter the workplace", and that any heater which produces heat by combustion "should have a sufficient air supply to ensure complete combustion." Paragraph 79 notes the Regulations do not prevent proprietary unflued heating systems "designed and installed to be used without a conventional flue", which is why the ventilation designed for unflued heaters must be kept as the installer left it. IGEM/UP/10 is the industry standard for installing flued gas appliances in industrial and commercial premises.

Keeping factory heaters serviced and working

A heater that is not working cannot keep anyone at a reasonable temperature, so servicing is where the temperature duty and the maintenance duty meet. The manufacturers are clear on frequency:

The AmbiRad Vision VS manual says the heaters "should be serviced annually by a competent person to ensure safe and efficient operation. In exceptional dusty or polluted conditions more frequent servicing may be required."
Powrmatic's LNVx user instructions say: "To maintain efficient, reliable and safe operation of the heater it must serviced annually by a qualified person."

Factory dust, fibres, oil mist and process fumes are the reason the "dusty or polluted conditions" wording matters. If your site is dusty, ask your engineer whether a shorter service interval is needed and record the answer.

The law on gas work in factories. Regulation 2(4) of the Gas Safety (Installation and Use) Regulations 1998 takes factories, within the meaning of the Factories Act 1961, out of most of those Regulations (regulations 37, 38 and 41 still apply). That does not remove the need for competent people. The Health and Safety at Work etc. Act 1974 still applies, and HSE's catering guidance CAIS23 says that "In premises where GSIUR does not apply, such as canteens in factories, employers need to ensure that any staff doing such work are competent. In practical terms, Gas Safe registration is the clearest way of demonstrating competence." Offices, shops and other workplaces on the same estate that are not factories come under GSIUR regulation 35, which requires gas appliances, pipework and flues at a place of work under the employer's control to be "maintained in a safe condition so as to prevent risk of injury to any person." Our guide to warehouse heater servicing explains this in more detail.

What site staff can do between services. Look, keep clear and report:

Keep the area around each heater clear. Powrmatic's user instructions say "Free access must be maintained to and around the heater for servicing purposes and the air supply to the heater must not be restricted in any way. Combustible materials must not be stored adjacent to the heater."
Keep stock and racking out of radiant heater clearance zones, and tell your engineer before changing racking layouts or stacking heights under heaters.
Report any visible damage. The Powrmatic manual notes that where a heater could suffer external mechanical damage, for example from overhead cranes or fork lift trucks, "it must be suitably protected." A dented flue, casing or guard after a forklift strike needs an engineer, not a quick restart.
Don't keep resetting a heater that locks out. The AmbiRad user instructions say that if lockout occurs three times consecutively, switch off and isolate the gas and electricity supplies and call a service engineer. Powrmatic says that, unless the cause of an overheat fault is readily obvious, "a service engineer should be contacted." Our boiler lockout log sheet shows what to record.

Site staff should not remove burner covers, adjust gas valves, alter safety devices or work on flues. That work is for a competent Gas Safe registered commercial engineer.

When the factory heating fails: practical steps

HSE's page on managing workplace temperatures lists practical steps when people are too cold. They include "Provide adequate workplace heating, such as portable heaters, to ensure work areas are warm enough when they are occupied", "Design processes that minimise exposure to cold areas and cold products", "Reduce draughts while still keeping adequate ventilation", "Provide insulating floor coverings or special footwear when workers have to stand for long periods on cold floors" and "Provide appropriate protective clothing for cold environments". HSE also suggests job rotation and enough breaks "to allow workers to get hot drinks or warm up in heated areas". L24 paragraph 69 adds that suitable protective clothing and rest facilities should be provided where local heating fails to give reasonable comfort.

A sensible order for a production or facilities manager:

Take and log readings at the affected workstations, at working height.
Work out what has failed: one heater, one zone or the whole building? Is there a lockout or fault light on a heater or the boiler, or has a time clock or controller lost its settings after a power cut? Note any fault codes, but don't keep resetting.
Report it to whoever looks after the plant, with your readings and the fault details.
Put temporary measures in place: move people from the coldest positions where you can, close doors that don't need to be open, add breaks and warm-up areas, and provide suitable clothing.
Get a Gas Safe registered commercial engineer to the heaters or boiler plant.

Take care with temporary heaters on a factory floor. L24 paragraph 78 says to "Ensure that portable paraffin and liquefied petroleum gas heaters do not produce fumes which will be harmful or offensive", and paragraph 80 says to "Take care when siting temporary heaters to prevent burns from contact with hot surfaces". Follow the heater manufacturer's instructions and your fire risk assessment, and keep heaters well away from stock, packaging and anything else combustible. If you suspect a gas leak at any point, HSE's advice for employers is to turn off the supply and immediately phone the National Gas Emergency Service on 0800 111 999 (or your LPG supplier, for LPG), and if in doubt, evacuate the building.

Factory heating and temperature checklist

Check	Who	When
Work areas listed with the type of work done, and the benchmark (16°C or 13°C) agreed for each	Production or facilities manager	Before the heating season, and when layouts or processes change
Thermometers at suitable locations, away from radiant heat sources and windows; readings at working height logged	Facilities manager or supervisors	When people report being cold, and more often in cold spells
Cold areas (loading bays, chilled areas, storerooms in use) reviewed for draught screens, door closers, floor coverings and local heating	Employer	Before winter
Warm air and radiant heaters serviced; dusty sites asked about shorter intervals	Competent Gas Safe registered commercial engineer	At least annually, per the manufacturer's instructions
Boiler plant serving unit heaters, offices and welfare areas serviced	Competent Gas Safe registered commercial engineer	At the manufacturer's intervals and your maintenance schedule
Heaters clear of stock and racking, air supply unobstructed, no combustibles stored next to them	Site staff	Daily or weekly walk-round
Forklift or crane damage, repeated lockouts and fault lights reported, not reset again and again	Site staff and supervisors	As they happen
Temporary heating plan ready, with safe siting and fire risk assessment checked	Employer	Before winter

Factory heating not keeping up?

Our Gas Safe registered engineers (985448) work on warm air heaters, radiant tube heaters, boiler plant and controls in factories and warehouses. See our factory and warehouse heating repair page, warm air and radiant heater repair, and commercial boiler servicing or planned preventive maintenance to keep the plant serviced. For breakdowns, see commercial boiler repair or our emergency commercial boiler repair page. Call 0800 0996 007, WhatsApp 07947 578332 or email [email protected]. Photos of the heater's rating plate and any fault lights help us prepare.

Safety note

Under the Gas Safety (Installation and Use) Regulations 1998, gas work must be carried out by a Gas Safe registered engineer, and we apply that rule on every site. Don't attempt DIY work on gas appliances, burners, flues or safety devices. On pressure systems, trained site staff should stick to visual and gauge checks, log the readings and report anything abnormal. Never adjust, cap, plug or test-lift a relief valve yourself.

Talk to a Gas Safe commercial engineer

Fast Commercial Boiler Help is a Gas Safe registered (985448) commercial heating business based at 4 Market Hill, Clare, Sudbury, Suffolk CO10 8NN. Our team of over 10 local engineers covers East Anglia and East London, working on commercial boilers, plant rooms, water heaters, and warm air, radiant and unit heaters. We work on commercial premises only.

Call 0800 0996 007

Call or WhatsApp 07947 578332 (a photo of the appliance data plate or the fault display helps) · Email [email protected]

Frequently asked questions

What is the minimum working temperature in a factory in the UK?

The law (regulation 7 of the Workplace (Health, Safety and Welfare) Regulations 1992) says indoor workplaces must be at a reasonable temperature during working hours. HSE's Approved Code of Practice L24 says that should normally be at least 16°C, or at least 13°C where work involves rigorous physical effort.

Does the 13°C figure apply to the whole factory?

No. It applies where the work involves rigorous physical effort. Areas where people do sedentary or light work, such as bench assembly, inspection, packing or offices, should normally be at least 16°C. Assess each work area separately.

What about loading bays and cold stores?

L24 says the guidelines do not apply where it would be impractical to maintain them, such as rooms that have to be open to the outside or where products have to be kept cold. The temperature should then be as close to the guideline as is practical, with measures such as draught screens, self-closing doors, insulated floor coverings and protective clothing.

How often should factory warm air and radiant heaters be serviced?

The manufacturers' manuals we cite say annually by a competent or qualified person. The AmbiRad Vision VS manual adds that more frequent servicing may be needed in exceptionally dusty or polluted conditions.

Do the Gas Safety (Installation and Use) Regulations apply in factories?

Regulation 2(4) takes factories within the meaning of the Factories Act 1961 out of most of GSIUR, though regulations 37, 38 and 41 still apply. Employers still need competent people for gas work under general health and safety law, and HSE says Gas Safe registration is, in practical terms, the clearest way of demonstrating competence.

What should we do when factory heating breaks down?

Log temperatures at the affected workstations, note any heater or boiler fault lights, report the fault and put temporary measures in place, such as moving people from the coldest positions, extra breaks and suitable clothing. Site temporary heaters safely, away from stock. Gas heater and boiler repairs must be done by a competent Gas Safe registered engineer. If you smell gas, call 0800 111 999.

Sources and further reading