Working in Hot Weather: A Summer Measures Checklist

What does the legislation say about working in hot weather?

In the first hot week of June, the question most often heard on a construction site, on a roof or in a warehouse with a metal roof is the same: "At what temperature do we stop work?" Our legislation has no such threshold for working in hot weather. Instead, the regulations give the employer the duty to assess the risk arising from heat and take measures.

Three provisions in Annex I of the Regulation on Health and Safety Measures in Workplace Buildings and Annexes relate directly to this topic:

Item 64: For work carried out outdoors, risks are assessed and workers are protected in particular against adverse weather conditions.
Item 20: If the nature of the work makes it necessary to work continuously in a very hot environment, measures are taken to protect workers from excessive heat.
Item 46: In workplaces with ten or more workers, a suitable rest area is provided.

Behind these provisions lies the general rule of Law No. 6331 on Occupational Health and Safety: the employer carries out a risk assessment, or has one carried out, and takes all measures necessary for health and safety (Art. 4, Art. 10). In other words, summer should be a separate line in your risk assessment: which jobs are in the sun, which departments are hot, who is more vulnerable and which measure is whose responsibility?

This article focuses on seasonal measures. We explain measurement for year-round hot work such as at furnaces, kilns and boilers in our article on heat stress at foundries and furnaces (WBGT), and symptoms and first response in our article on heatstroke symptoms and response.

Outdoor heat: the thermometer alone does not determine the risk

The temperature in a weather app is only part of the heat load a worker is actually exposed to. The same 33 °C may be bearable for desk work in the shade; for a worker stripping formwork on a concrete slab in the sun, it is an entirely different load. In the summer assessment, consider the following factors together:

Factor	Why does it matter?	How is it recognised on site?
Humidity	Sweat cannot evaporate, the body cannot cool down	Sweat is dripping but clothes do not dry, the air feels "heavy"
Direct sun and radiation	Roofs, asphalt, concrete and sheet metal surfaces radiate heat back	Surfaces cannot be touched by hand, the air shimmers on the roof
Air movement	Cooling is reduced in areas without wind	Inside enclosed formwork, pits, inside tanks, sheltered facades
Workload	Heavy work generates extra heat in the body	Lifting, digging, fixing rebar, carrying materials
Clothing and PPE	Overalls, chemical suits and face shields prevent heat loss	Quick fatigue when wearing protective clothing
Personal condition	Chronic illness, certain medicines, age, fatigue, fasting	Health information known to the workplace physician, worker's own statement

Fill in this table job by job in the risk assessment. For example, on a construction site, roof waterproofing, formwork and rebar work, asphalt and concrete pouring are classed as "high", and paperwork done in the site container as "low". If you are not sure whether the heat creates a health risk in a particular job, we plan measurement with accredited laboratories; turning the result into a work-rest plan is a separate step.

Water, shade and breaks: the foundation of workplace safety in summer

The three most effective measures for workplace safety in summer are the simplest. Yet on site they often remain on paper: there is water but 300 metres away, there are breaks but in the sun, there is shade but only in the supervisor's vehicle.

Water: Place cool drinking water where workers can reach it without leaving their work and walking a long way. For a team working on a roof, water should be given before they go up. Personal named water bottles reduce sharing and hygiene problems. A practical starting point for how much water to drink is in the recommendations section of our WBGT article; what matters here is that drinking regularly without waiting to feel thirsty becomes a shift rule.

Shade: Set up a shaded rest area on outdoor sites: an awning, a site container, a tent or the side of a building out of the sun. The shaded area should be large enough for the whole team to sit at the same time. Indoors, the rest area should be separate from the hot process area and ventilated.

Breaks: Art. 68 of Labour Law No. 4857 sets out the minimum rest breaks; on hot days this may not be enough. If the risk assessment calls for short, frequent cooling breaks for heavy work, put this in writing and give the supervisor the authority to apply it.

Hot weather working hours: move heavy work to cooler hours

The most effective measure on working hours in hot weather is to move heavy work and work exposed to the sun to the cooler hours of the day. This does not require changing the whole shift; in most businesses, changing the order of work is enough.

Job	Can it be moved to cooler hours?	Work that can be done in the midday heat
Roof insulation, roof covering	Started early in the morning and finished by midday	Material preparation in the shade
Concrete pouring, formwork	Pouring planned for the morning	Interior work on enclosed floors
Unloading and carrying materials	Deliveries moved to the morning or late afternoon	Organising inside the warehouse
Outdoor maintenance and repair work	Sequenced during the day according to shade	Preparing parts inside the workshop

When shifting hours, do not forget two legal limits. First, under Art. 69 of Law No. 4857, the period between 20:00 and 06:00 is the night period, and night work may not, as a rule, exceed seven and a half hours. Moving work before 06:00 in the morning puts part of the work into the night period. Second, permanent changes to working hours relate to employment contracts and internal rules; plan any change in hours together with the human resources and legal departments. For other aspects of night work, see our article on working night shifts.

Acclimatisation: new starters and workers returning from leave

The body adapts to heat within a few days: sweating starts earlier and the heart is under less strain for the same work. A worker who has not acclimatised is the most vulnerable to heat-related illness in the first few days. Seasonal workers hired in summer, subcontractor teams newly arriving on site and workers returning from annual leave are in this group.

The US National Institute for Occupational Safety and Health (NIOSH) criteria document on hot environments recommends a gradual acclimatisation plan:

Workers who have done this work before: On the first day, no more than 50 per cent of the usual heat exposure time, 60 per cent on the second day, 80 per cent on the third day and the full time on the fourth day.
New workers: No more than 20 per cent on the first day, increasing by 20 per cent each following day.

For other causes of accident risk among new starters, see our article on accident risk among new starters. For Ramadan falling in the summer months, also consider the recommendations in our article on fasting workers.

Summer measures for indoor areas

Heat is not only a problem for outdoor sites. Warehouses with sheet metal roofs, poorly ventilated production halls, textile departments with stenters and dryers, and loading docks also create heavy conditions indoors in summer. For indoor areas, follow this order:

Isolate the heat source. Insulate hot process equipment, extract hot air at source; move heat-emitting equipment away from workstations.
Check the ventilation. If the annual periodic inspection and filter maintenance of mechanical ventilation and air conditioning systems are scheduled before summer, loss of capacity is noticed before the hot days.
Reduce heat from the roof. Roof insulation, light-coloured roofing and roof ventilation are long-term solutions.
Do not rely too much on fans. When the air temperature approaches body temperature, the cooling effect of fans decreases; they should not be seen as a solution on their own.
Do not forget the loading dock. On a dock that gets the sun while the door is open, forklift operators and the dispatch team work in the hottest conditions; the order of work should be arranged accordingly.

In environments such as offices and shops, the issue is comfort rather than health risk; for this, see the summer adjustments in our article on thermal comfort measurement.

Hot weather working checklist

Before summer begins, at the end of May, review this list together with supervisors and the OHS specialist:

Have heat-related jobs and vulnerable workers been identified separately in the risk assessment?
Has cool drinking water and a personal water bottle been provided close to every workstation?
Has a shaded rest area large enough for the whole team been set up on outdoor sites?
Have heavy jobs exposed to the sun been planned for the morning and late afternoon?
Is there a written acclimatisation plan for new starters and workers returning from leave?
Have workers been informed about the symptoms of heat exhaustion and heatstroke?
Has the supervisor been given the authority to remove a worker showing symptoms from work and to reduce the pace of work?
Has the workplace physician's opinion been obtained for workers with chronic illnesses or taking medication?
Does the emergency plan include a heat-related scenario, cooling supplies and the rule to call 112?
Have ventilation and air conditioning in indoor areas been serviced before summer?
Have options for light-coloured, breathable workwear and, where needed, hard hats with neck protection been considered?
Are weather warnings being followed and the work programme reviewed on hot days?

To start summer preparation on the same date every year, you can add the end of May to the OHS calendar. At construction sites and production facilities in Bursa and the surrounding provinces, we address heat-related work as part of the risk assessment and carry out the assessment of vulnerable workers together with our workplace physician service. For other site-specific checks, see our construction site OHS checklist article.

Frequently Asked Questions

At what temperature is work stopped?

The legislation has no fixed temperature value at which work stops. The decision is made through the risk assessment, considering temperature, humidity, sun, workload and clothing together. For heavy work, the work-rest plan and, if necessary, measurement results are the basis; a worker showing symptoms is removed from work immediately.

Is it mandatory to give outdoor workers extra breaks in hot weather?

The rest break in the law is a minimum. If the risk assessment shows that the heat creates a health risk in heavy work, extra cooling breaks become one of the measures the employer must take. These breaks need to be taken in the shade or in a cool place.

How many days does acclimatisation take?

According to NIOSH's recommendation, a four-day plan is applied for workers who have done the work before, and for new workers a plan starting at 20 per cent and increasing by 20 per cent each day. A worker returning from long leave should also be put on a gradual plan.

What should be done if a worker shows signs of heatstroke?

If there is confusion, incoherent speech, staggering or fainting, call 112 and cool the worker immediately while waiting for the ambulance. For detailed steps, see our article on heatstroke symptoms and response.