Between June and September, outdoor temperatures on our Gulf sites regularly pass 45 °C, with humidity on coastal sites pushing the heat index far higher. Since 2020 we have logged wet-bulb globe temperature (WBGT) every hour on every Gulf project. Six summers and roughly 410,000 readings later, the data has changed how we plan work.
Why we started measuring
In 2019 we recorded nine heat-related illness cases requiring first aid or medical treatment across our UAE and Qatar sites. None was a lost-time injury, but each was a warning. Air temperature alone was not telling us when conditions became dangerous — a 39 °C morning in Lusail with 70% humidity is a very different risk from a 44 °C dry afternoon inland.
We installed WBGT monitors at the workface on every site, linked them to the site HSE dashboard, and set action thresholds that trigger mandatory changes to work-rest cycles.
What the data shows
- Mornings are not always safe. On coastal sites, 31% of readings above our high-risk threshold occurred before 10:00, when humidity peaks.
- The workface is hotter than the weather station. Readings on exposed slabs averaged 3.4 °C WBGT higher than at the site entrance.
- Week one is the riskiest. 58% of heat-related cases since 2020 involved workers in their first ten days on site, before acclimatisation.
- Night shifts work — with planning. Moving concrete pours to night shifts cut high-risk exposure hours by 44% without affecting programme.
“The single most effective control was not water or shade. It was moving the work.”
The controls we now apply
Every Gulf site runs a heat-stress management plan, approved before mobilisation and reviewed weekly from May to October. Alongside the mandatory regional summer midday work bans — which we treat as a minimum, not a target — the plan sets out:
- WBGT-based work-rest cycles enforced by supervisors, with four action levels from normal work to stop work.
- Acclimatisation schedules for all new arrivals: reduced exposure over the first seven days, with buddy assignments.
- Re-sequenced programmes that move heavy and exposed activities — pours, rebar fixing on open decks, roofing — to night or early-morning shifts.
- Shaded, cooled rest areas within 50 m of every workface, with electrolyte drinks and supervised hydration checks.
- Daily heat briefings in the five most common languages on site, including symptom recognition.
The results
- Heat-related cases, 2019
- 9
- Heat-related cases, 2025
- 1
- Gulf summer man-hours, 2025
- 3.2m
- Programme days lost to heat
- 0
We have not had a heat-related lost-time injury in six summers, while summer man-hours on Gulf sites have grown by more than 60%. Re-sequencing work has a cost — night-shift premiums and lighting — but it has been consistently lower than the productivity lost by forcing exposed work through the hottest hours.
What's next
This summer we trialled wearable core-temperature sensors with 120 workers on two sites in Riyadh and Doha. Early results are promising, and we will share them once the trial is independently reviewed. We are also sharing our WBGT thresholds and plan template with subcontractors free of charge — contact our HSEQ team if you would like a copy.
Key takeaways
- Measure WBGT at the workface, not the gate.
- Treat regulatory midday bans as the minimum control.
- Protect new arrivals with structured acclimatisation.
- Re-sequence exposed work before adding more water and shade.