Worksite testing AI to provide early high heat alerts to keep workers safe

SINGAPORE – A major traffic worksite in Pasir Ris recently began using artificial intelligence to alert its 400 workers to high heat stress levels hours in advance.

Weather forecasts and the previous day’s heat stress data from an automated meter are fed into an AI software which then churns out the prediction for the next day’s heat conditions.

The AI system will also recommend cooling solutions for workers based on Ministry of Manpower (MOM) guidelines. This information will be automatically sent to supervisors via WhatsApp.

If the wet bulb globe temperature (WBGT) – a measure of heat stress – is forecast to reach a high of 33 deg C at 2pm, supervisors will remind their workers in advance to hydrate frequently and rest for 15 minutes after every hour of work.

Updated forecasts are churned out a few times a day to ensure accuracy.

This AI-based system was rolled out as a trial at the Loyang Viaduct site two months ago.

Beyond providing early warnings, it also made heat monitoring more efficient because workers do not need to manually check the WBGT every hour as required by MOM, said Mr Lim Eng Boon, project director at Hwa Seng Builder.

Offering AI-powered alerts, makeshift showers and cooling vests are among the additional measures that the construction firm has undertaken – beyond following MOM requirements – to protect its outdoor workers from rising heat.

Visiting the Pasir Ris worksite on May 11, Minister of State for Manpower Dinesh Vasu Dash said Hwa Seng Builder has been progressive and proactive in implementing its measures.

“Even when... we don’t see very many heat stress cases in worksites, it is still important to make sure that our workers are protected, and that we are ahead of the curve,” he added.

Since 2023, MOM has rolled out heat-safety rules for outdoor worksites. For example, if the WBGT hits high heat stress levels of 32 deg C and higher, workers doing physically intense work are required to rest for at least 10 minutes every hour.

Workers should also hydrate at least every hour, with a recommended intake of 300ml each time.

Between 2021 and 2025, MOM recorded 24 heat-related cases and zero fatalities. Among the 24 cases, 22 were related to outdoor work, and fewer than half involved hospitalisation, said MOM in a parliamentary reply in February.

While most worksites like Hwa Seng’s are compliant, Mr Dinesh noted that his ministry took action against 151 employers in 2024 and 62 in 2025 for flouting heat-safety rules. Figures for 2026 are not available yet with site inspections ongoing, as Singapore is currently in the traditionally hotter months of the year.

MOM took enforcement measures such as issuing stop-work orders and notices of non-compliance, as well as imposing fines, against the breaches.

Some of the worksites inspected in the past two years did not have WBGT meters installed. Such meters are required for all major construction sites, shipyards and process manufacturing plants.

The WBGT takes into account air temperature, humidity levels, wind speed and solar radiation.

Stressing that heat illnesses are preventable, Mr Dinesh said: “Maybe there is a lack of awareness of what (meters) are available. Maybe they fear it might be too expensive.

“And to have certain implementations like shaded areas for workers to rest in – it’s not beyond the capability of our employers. We hope to see a declining trend of heat-related issues within our worksites.”

Beyond worksite measures, Mr Dinesh added that a conducive and cooler dormitory environment is needed to ensure that workers are well rested and recover after a day of physical work.

He cited the recently opened NESST Tukang Dormitory, which has pandemic-ready features and rooms that are north-south facing, with larger windows for more daylight and to improve natural airflow. 

Hwa Seng Builder decided to implement additional cooling and heat-safety measures because these improved the workers’ productivity, said Mr Lim.

“The cost of the AI was not a lot, a few thousands. It is not about the immediate cost. It is the long-term operation cost that we are saving over the years.”

Many of its additional cooling measures were based on workers’ feedback, added Mr Lim.

Employees had mentioned that the metal-roof rest area was still hot despite the installation of fans.

This prompted Hwa Seng Builder to cover the metal roof with insulated sheets to prevent heat absorption. Sprinklers were also set up above the roofing to dampen the temperature further.

Workers also have access to ice cubes and a simple shower inside a tent, in case they need to cool down quickly.

Next, the site’s supervisors are looking to develop solar-powered “cooling vests” with fans and metallic cooling pads embedded inside the fabric. Current prototypes are powered by batteries, which heat up and are not safe.