The constant evolution of climatic conditions towards global warming is now a real problem for outdoor workers. Whether they are roofers, construction workers, roadworks crews, railway workers, energy network operators, or those working on public spaces, etc., adopting a range of workwear adapted to high temperatures and heat waves is essential. This guide will help you understand the regulations, alert thresholds, and personal protective equipment necessary to guarantee the safety of workers.
Breathable clothing and appropriate footwear: the guide to working safely this summer
On a construction site in the middle of summer, the heat isn't just a discomfort: it's a serious occupational hazard. Heatstroke, dehydration, decreased alertness, premature fatigue… the effects of prolonged sun exposure without proper equipment can have serious consequences. However, solutions exist to stay cool while still meeting safety requirements.
Working in extreme heat: what the regulations require
Since July 1, 2025, the French Labor Code has strengthened employers' obligations regarding extreme heat. As soon as a Météo France weather alert (yellow, orange, or red) is issued, specific measures must be implemented on construction sites.
The employer's legal obligations from the moment vigilance is activated
Hydration: minimum 3 liters of fresh drinking water per worker per day, provided by the employer.
Adjusting working hours: staggering shift start times to early morning to avoid heat peaks between 11am and 3pm.
Appropriate PPE: The employer has an obligation to adapt personal protective equipment if climatic conditions require it. This includes work clothes.
Single document (DUERP): the heat risk must be integrated into it with the associated prevention measures according to alert level.
Warning signs to be aware of in the field
Unusual fatigue, headaches, nausea, and muscle cramps are the first signs of heat exhaustion. Heatstroke, however, is an absolute medical emergency: body temperature exceeding 40°C (104°F), confusion, burning and dry skin, and absence of sweating. These conditions can develop much more quickly than one might imagine when clothing does not allow for adequate heat dissipation.
Choosing the right work clothes for the heat
The first instinct is often to undress: take off your shirt, work in a tank top, roll up your sleeves. This is a mistake. Skin directly exposed to sunlight heats up faster and burns more easily. Lightweight technical clothing creates a barrier between the skin and the sun while facilitating the evaporation of perspiration.
Key materials: lightweight, breathable and quick-drying
Technical synthetic fabrics (high-performance polyester, lightweight polycotton blends) are far superior to regular cotton in summer. Cotton retains moisture, becomes heavy and clumpy when wet with sweat, and takes a long time to dry. Technical fabrics wick away moisture, regulate body temperature, and dry quickly, even during intense activity in the sun.
Also, opt for light colors (beige, light grey, white) which reflect sunlight rather than absorbing it.
Summer work trousers: stretchy, breathable and multi-pocketed
In summer, the ideal work trousers combine an ultra-lightweight, breathable, and water-repellent U-4 4-way stretch fabric. UPower's Horizon and World models have been specifically designed for summer conditions: a functional slim fit, an adjustable elastic waistband, and technical finishes that wick away moisture for optimal comfort all day long.
Discover our range of UPower work trousers suitable for all seasons.
Work t-shirt and polo shirt: the first layer of protection against heat
The upper body is the area most exposed to perspiration on a physically demanding worksite. A technical work polo shirt or t-shirt made of breathable fabric is essential. It should be loose-fitting to allow air to circulate, with short or long sleeves depending on sun exposure, and resistant to frequent washing. If the worksite requires wearing a vest or jacket, it serves as the breathable base layer.
Safety footwear in summer: lightness, ventilation and heat resistance
Safety footwear is often the most uncomfortable item in hot weather. Weight, non-breathable materials, soles that overheat on asphalt… poorly chosen, it quickly becomes a source of fatigue and risk. The market now offers models specifically designed for summer conditions.
Understanding HRO and HI markings: essential on hot construction sites
HRO (Heat Resistance Outsole): The outsole withstands thermal contact up to 300°C for 60 seconds. Essential for hot asphalt construction sites, roofs in summer, industrial areas with hot floors, or railway ballast.
HI (Heat Insulation): Thermal insulation is provided across the entire sole, protecting the foot from heat conduction. Complementary to the HRO marking, it provides lasting protection against very hot floors.
SRC: combination of the SRA (resistance on wet tiles) and SRB (resistance on steel with glycerol) markings. Recommended for all types of construction sites to prevent slips, including in dry and hot weather where some surfaces become slippery due to expansion.
S1, S1P, S2, S3: which category in summer?
The EN ISO 20345 standard defines the categories of safety footwear according to their basic level of protection:
S1 and S1P: basic protection (steel or composite toecap, antistatic, energy absorption in the heel). The S1P adds a puncture-resistant midsole. Very lightweight, they are suitable for low-risk worksites where lightness is a priority. The Vortix UPower model (490g) is a good example, ideal for summer.
S3 + HRO + HI: Maximum protection for hot environments: puncture-resistant sole, lightweight composite toecap, thermal contact resistance, and insulation. The Bulls, Depp, Gravel, and Trail UPower models combine these markings for the most demanding construction sites.
Discover our complete range of UPower safety footwear, categorized by use and condition.
High visibility and heat: solutions for not having to choose
The requirement to wear high-visibility clothing does not disappear with rising temperatures. On road construction sites or in the presence of machinery, the EN ISO 20471 standard remains applicable regardless of the season. The challenge in summer is therefore to find high-visibility clothing that does not trap heat.
High-visibility summer vests made of mesh or breathable fabric meet visibility requirements (classes 2 and 3) while maximizing airflow around the body. High-visibility summer softshell jackets made of lightweight stretch fabric also offer an alternative to heavy winter parkas.
Find all our EN ISO 20471 professional high-visibility clothing to equip your teams in full compliance.
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