Construction is the sector with the highest rate of fatal accidents in Spain. And every summer, that statistic is compounded by a factor that is still not taken seriously enough: extreme heat.
In 2025, record temperatures on site caused dozens of serious incidents — from heat stroke on rooftops to accidents caused by loss of concentration at height. In 2026, with temperatures peaking earlier and regulations beginning to require specific protocols, the sector can no longer keep improvising.
1. Why construction is especially vulnerable to heat
Construction workers are exposed to conditions that multiply thermal risk compared to other sectors:
• Outdoor work with no possibility of climate control• Surfaces that accumulate and reflect heat: metal sheeting roofs, asphalt pavements, concrete facades• Intense physical effort that raises body temperature — excavation, reinforcement work, shuttering• Mandatory PPE (helmet, harness, gloves) that impairs thermoregulation• Difficulty monitoring worker condition on sites with multiple open fronts
The result: a rooftop worker in July may be exposed to effective temperatures above 50°C, combining ambient temperature, direct solar radiation, and heat radiated by materials.
2. The phases of heat stress that no one detects in time
Heat stroke is the outcome — but the problem starts much earlier. On site, warning signs go unnoticed because the work pace does not stop and no one is watching closely.
This is how heat stress progresses in a construction worker:
• Early fatigue: performance drops, movements slow down, and precision errors increase• Heat cramps: muscle spasms in the legs and arms — especially dangerous at height• Heat exhaustion: dizziness, nausea, mild confusion — the worker may still be standing but with compromised reflexes• Heat stroke: body temperature above 40°C, loss of consciousness — immediate medical emergency
The most dangerous moment is the heat exhaustion phase. A worker confused about scaffolding, operating an angle grinder, or driving heavy machinery is an accident in progress. And from the ground, they simply look tired.
3. What changes in regulations in 2026
Regulatory pressure on the sector is increasing. These are the changes that directly affect construction sites in Spain:
• Risk assessments must include heat stress as a specific risk in sun-exposed roles• The Health and Safety Plan must include action protocols linked to AEMET heat alerts• Health monitoring must assess heat tolerance — especially in workers over 45 or with pre-existing health conditions• Companies must document preventive measures taken during heatwaves: schedules, hydration, rotations
The Labor Inspectorate has intensified site visits during summer months. Not having this protocol documented is a serious infringement that can result in the site being shut down.
4. The protocols being used — and why they are not enough
Most construction companies have some form of heat protocol. The problem is that it is almost always reactive and depends on someone activating it manually.
The typical on-site protocol:
• Distributing water and isotonic drinks on site• Setting up awnings or shade areas for rest breaks• Bringing forward the start of the working day to avoid peak heat hours• Stopping work when the site manager decides 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.