The purpose of this guideline is to provide guidance on how to recognize, estimate, prevent and treat heat stress at work. Parameters of heat stress are introduced in this guideline to guide employers in avoiding discomfort from hot environment at work. The guideline also elaborates on risk assessment and risk control based on heat stress estimation using wet bulb globe temperature (WBGT). A warm or hot environment can compromise concentration, vigilance, or steadiness of employees.

It is one of the general duties of employer and self-employed person as prescribed under the Occupational Safety and Health Act 1994 [Act 514] to provide a safe working environment and without risk to their employees’ health. Employees also have the duty to take reasonable care for their own safety and health and of others at work. The employers have to take practicable measures to ensure employees are protected from excessive heat exposure while at work.