Heat in the workplace: room temperature under ASR A3.5 and what to do above 26 °C
In summer, temperatures in offices and halls quickly rise above 30 °C. When the employer must act under German rules, which measures work and what applies to outdoor work.
Last updated on 7 min readAMS Go editorial team
Key points at a glance
- The air temperature in work rooms should not exceed 26 °C (ASR A3.5). If it gets warmer despite sun protection, additional measures should be taken.
- Above 30 °C, effective measures according to the risk assessment are mandatory, including suitable drinks. Above 35 °C, a room is not suitable as a work room without further measures.
- Technical measures such as sun protection and ventilation take priority over organisational ones such as flexitime; personal measures come last.
- There is no entitlement to “heat leave” (hitzefrei). Outdoor work requires its own protective measures, including against UV radiation.
What ASR A3.5 requires
The German Workplaces Ordinance requires a room temperature that is conducive to health. The technical rule for workplaces ASR A3.5 “Room temperature” describes what this means: it sets minimum temperatures depending on how strenuous the work is – for example 20 °C for light, seated office work – and a tiered model for heat:
up to 26 °C
What appliesTarget value. Windows and skylights need sun protection if sunlight would otherwise heat the room above 26 °C.
above 26 °C
What appliesIf the outside temperature is above 26 °C and sun protection is in place, the employer should take additional measures. With heavy work, protective clothing or health conditions, they may already be necessary.
above 30 °C
What appliesEffective measures according to the risk assessment are mandatory – including suitable drinks such as drinking water.
above 35 °C
What appliesWithout further technical, organisational or personal measures as for heat work, the room is not suitable as a work room for as long as the temperature is exceeded.
Measures against heat
As with all protective measures, the order applies: technical before organisational before personal measures. Proven examples:
Technical
Examplesexternal sun protection, ventilating in the cool morning and night hours, fans, air conditioning, switching off equipment that is not needed as a heat source
Organisational
Examplesflexitime for an early start, additional breaks in cooler rooms, moving heavy work to the morning, relaxing the dress code, working from home where possible
Personal
Examplessuitable drinks such as drinking water, breathable workwear, cooling vests for heat work
Which measures fit belongs in the risk assessment – ideally in spring, not during the first heatwave.
Is there a right to stop work because of heat?
Employees in Germany have no legal entitlement to time off because of heat. The employer must, however, implement the measures of ASR A3.5. If a room is above 35 °C and no effective measures can be taken, it is not suitable as a work room for that time – then other rooms, working from home or shifting working hours are needed.
Risk assessments in AMS GoAssess heat as a hazard for offices, halls and outdoor work and define measures for hot days with owners and deadlines.Employees at particular risk
- pregnant and breastfeeding employees
- young people, older employees and people with cardiovascular conditions
- employees wearing protective clothing or respiratory protection
- employees doing physically heavy work
- people taking certain medicines
For them, measures may be needed below 30 °C. The company doctor advises on this, and employees can consult them as part of a requested health check.
Outdoor work: heat and UV radiation
On construction sites, in grounds maintenance or delivery services, ASR A3.5 does not apply – it covers work rooms. Heat and UV radiation outdoors must still be considered in the risk assessment. Proven measures:
- shade from sun sails, umbrellas or canopies
- moving work to cooler hours and avoiding the midday heat
- enough drinking water and breaks in the shade
- headwear with neck protection, long, light clothing, sunscreen and sunglasses
- instruction on the signs of heat exhaustion and heatstroke
Emergency: heat exhaustion and heatstroke
Headaches, dizziness, nausea, cramps and confusion can indicate a heat-related illness. Heatstroke is life-threatening.
- 1
Get out of the heat
Take the person into the shade or a cool room immediately.
- 2
Cool down
Loosen tight clothing, cool with damp cloths, fan with air.
- 3
Give water
If fully conscious, give water in small sips.
- 4
Call for help
In case of impaired consciousness, confusion or very high body temperature, call the emergency number 112 immediately and give first aid.
Checklist: heat in the workplace
- Heat considered as a hazard in the risk assessment
- External sun protection on sun-exposed windows
- Room temperature measured and documented on hot days
- Plan of measures defined for above 26, 30 and 35 °C
- Drinking water or other suitable drinks provided
- Flexitime, breaks and dress code for hot days agreed
- Employees at particular risk taken into account
- Protective measures for outdoor work defined
- Employees instructed on heat illnesses and first aid
Free templates for this guide
As PDF and Excel, no sign-up – free to use in your own company.
Frequently asked questions
At what temperature must the employer act?
Above 26 °C, they should take additional measures; above 30 °C, they must take effective measures according to the risk assessment. Above 35 °C, a room is not suitable as a work room without further measures (ASR A3.5).
Do employees get time off above 30 degrees?
No, there is no entitlement to time off because of heat. The employer must, however, take effective measures – such as providing drinks, shifting working hours or providing cooling.
Does the employer have to provide drinks?
At room temperatures above 30 °C, yes – suitable drinks such as drinking water are then among the measures. For heat work and outdoor work, this is common practice anyway.
Does the employer have to install air conditioning?
Not necessarily. ASR A3.5 requires effective measures, not a particular technology. Air conditioning is one option; external sun protection, night ventilation and organisational measures are often enough.
Does ASR A3.5 also apply to outdoor work?
No, it applies to work rooms. Heat and UV radiation outdoors must still be considered in the risk assessment; with intense UV exposure, a health check must be offered.
Terms from the glossary
This guide gives a general overview of German occupational safety law and does not replace legal advice. The regulations in force and the rules of the statutory accident insurance institutions are authoritative.
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