Construction is the sector with the highest rate of fatal accidents in Spain. And every summer, a factor is added to that statistic that is still not taken seriously: extreme heat.
In 2025, record temperatures on construction sites caused dozens of serious incidents — from heat stroke on roofs to accidents due to loss of concentration when working at height. In 2026, with peak temperatures approaching and regulations beginning to require specific protocols, the sector cannot continue improvising.
1. Why construction is especially vulnerable to heat
Construction workers are exposed to conditions that multiply the thermal risk compared to other sectors:
• Work outdoors without the possibility of air conditioning• Superficies que acumulan y reflejan calor: cubiertas de chapa, pavimentos de asfalto, fachadas de hormigón• Intense physical effort that raises body temperature — excavation, rebar, formwork• Mandatory PPE (helmet, harness, gloves) that make thermoregulation difficult• Difficulty in supervising the status of workers in construction sites with multiple open fronts.
The result: a worker on deck in July can be exposed to effective temperatures of more than 50°C, combining ambient temperature, direct solar radiation and heat radiated by materials.
2. The phases of thermal stress that no one detects in time
Heat stroke is the outcome — but the problem begins much earlier. On site, previous signals go unnoticed because the pace of work does not stop and no one supervises closely.
This is how thermal stress progresses in a construction worker:
• Early fatigue: performance declines, movements become slower and accuracy errors increase• Heat cramps: muscle spasms in the legs and arms — especially dangerous when working at height• Thermal exhaustion: dizziness, nausea, mild confusion — the worker may remain standing but with compromised reflexes• Heat stroke: body temperature above 40°C, loss of consciousness — immediate medical emergency
The most dangerous moment is the thermal exhaustion phase. A confused worker on a scaffold, operating a radial or driving heavy machinery is an accident in the making. And from the ground, it looks like he's just tired.
3. What changes in the regulations in 2026
Regulatory pressure on the sector is increasing. These are the changes that directly affect the works in Spain:
• Risk assessments should include thermal stress as a specific risk in positions exposed to the sun.• The Health and Safety Plan must contemplate action protocols linked to AEMET heat alerts.• Health surveillance should assess heat tolerance — especially in workers over 45 years of age or with pre-existing health conditions.• Companies must document the preventive measures adopted in the event of heat waves: schedules, hydration, rotations
The Labor Inspection has intensified visits to construction sites during the summer months. Not having this documented protocol is a serious infraction that can lead to work stoppage.
4. The protocols that are applied — and why they are not enough
Most construction companies have some type of heat protocol. The problem is that it is almost always reactive and depends on someone manually activating it.
The usual protocol on site:
• Distribute water and isotonic drinks on site• Place awnings or shaded areas for rest• Advance the start of the day to avoid central hours• Stop the work when the construction manager considers that it is too hot
The failure of this model is structural: depends on human perception at the time. No construction manager can simultaneously supervise 20 workers distributed across 4 floors and detect who is beginning to suffer thermal stress.
5. Continuous monitoring on site: from reaction to prevention
Computer vision is coming to the construction industry and changing how safety is managed in real time. Not as science fiction — as an operational tool that is already deployed in great works.
A system like Safe can detect thermal warning signs on site before they become an incident:
• Abnormal behavior: slow movements, unstable postures, pauses out of pattern• Workers without rest in areas of high sun exposure for too long• Absence of hydration — detection of work areas where no stops are being made• Automatic alerts to the construction manager when a worker has spent more than the maximum recommended time in direct exposure
The system does not replace the construction manager. multiplies it- Gives you visibility over the entire job site simultaneously, with real-time alerts before the incident occurs.
In construction, most heat accidents don't happen because no one knew it was hot. They occur because no one detected in time that that specific worker, at that point in the work, had exceeded his limit.
6. How to structure a thermal risk protocol for construction in 2026
An effective protocol for the construction sector must cover these four levels:
• Prior evaluation: identify positions and phases of work with greater sun exposure and physical effort, and define alert thresholds for temperature and humidity• Preventive measures: schedule planning adapted to AEMET alerts, shaded rest areas, accessible hydration on each floor and specific PPE for heat• Real-time detection: visual monitoring systems that detect risky behavior without relying on manual supervision• Response protocol: clear communication chain in the event of an alert, thermal first aid training for managers and evacuation procedure
The big gap in the sector is in the third level. Evaluation and preventive measures are already in place for the majority. Real-time detection, almost none.
Conclusion: Summer 2026 is not the time to improvise
Temperatures will continue to rise. The regulations will continue to be tightened. And heat accidents on construction sites will continue to occur as long as the supervision model depends on someone seeing them with their own eyes.
Construction companies that implement continuous monitoring this year will not only reduce accidents — they will be one step ahead of inspections and their competitors.