Risk Assessment of Heat Stroke | Health, Safety and Environment Office - The Hong Kong University of Science and Technology

Workplace Heat Stress Risk Assessment

UNDERSTANDING THE KEY INFORMATION OF GUIDANCE NOTES (GN)

The Labour Department has updated the "Guidance Notes on Prevention of Heat Stroke at Work"(GN), which has been officially effective since 15 May 2023 (info.gov.hk). Labour Department stated that the GN can serve as an important reference for employers and employees (see news.gov.hk, other news and press releases). Representative of Labour Department has also presented the GN in a Webinar organized by Construction Industry Council (Replay).

Work with a higher risk of heat stroke or related illnesses

The GN is applicable to work that needs to be carried out under hot weather or in high-temperature environments, such as:

Work conducted in outdoor locations without shelters.
Work conducted in indoor locations without air-conditioning system installed.
Work conducted near heat sources or heat-generating facilities.

(Section 2.1 of the GN)

Examples on campus include outdoor construction, cleaning, security guard patrols and landscaping, and working in kitchens, close to boilers or in electrical and mechanical plant rooms without air conditioning systems.

Responsibilities of the employers, employees and occupiers

Employers or the persons responsible for a workplace* are required to conduct risk assessments on the heat stress of employees at work, and take appropriate measures based on the assessment results to prevent employees from getting heat stroke at work. If the employer does not have control over the workplace, he must maintain good communication with the occupier of the workplace and ensure that the heat stroke preventive measures are properly implemented. Employees must also abide by the system or work method established by the employer, use any equipment provided by the employer, and comply with relevant prevention and control measures to reduce the risk of heat stroke. (Section 1.2 of the GN)

*Note: Employers or the persons responsible for a workplace are defined in Cap. 509 Occupational Safety and Health Ordinance.

According to Section 3 of the GN, the risk assessment should be conducted by a person who is familiar with the working conditions of the workplace and has basic occupational safety and health knowledge about heat stress. Heat Stress Assessor training courses organized by other organizations, such Occupational Safety and Health Council, are not an absolute requirement for the heat stress assessors to conduct risk assessments.

To ensure the safety of all personnel involved in works with a risk of heat stroke, the HKUST Departments in charge of such works are responsible for conducting risk assessments for their respective HKUST staff. In the case of outsourced works, contractors are responsible for conducting their own risk assessments. The HKUST Safety and Environmental Protection Manual, specifically Chapter 1 and Charter 2, provide general information on HSEO's function to coordinate efforts in advising the Departments on EHS issues, as well as the Departments' roles and responsibilities.

What are the essential steps?

Conducting Risk Assessment of Heat Stress

The risk assessment should cover Environmental, Work and Personal Factors and could be conducted by using one of the two methods below:

Rest Time Calculator of “Prevention on Heat Stroke at Work in a Hot Environment” Thematic Website published by OSHC and Labour Department; or
Workplace Heat Stress Risk Assessment Form (Appendix 2 of the GN) and referring to the Physical Workload Categories, Light, Moderate, Heavy and Very Heavy, and Examples (Appendix 1 of the GN).

According to Section 3 of the GN, the risk assessment should be conducted by a person who is familiar with the working conditions of the workplace and has basic occupational safety and health knowledge about heat stress. Heat Stress Assessor training courses organized by other organizations, such Occupational Safety and Health Council, are not an absolute requirement for the heat stress assessors to conduct risk assessments.

To ensure the safety of all personnel involved in works with a risk of heat stroke, the HKUST Departments in charge of such works are responsible for conducting risk assessments for their respective HKUST staff. In the case of outsourced works, contractors are responsible for conducting their own risk assessments. The HKUST Safety and Environmental Protection Manual, specifically Chapter 1 and Charter 2, provide general information on HSEO's function to coordinate efforts in advising the Departments on EHS issues, as well as the Departments' roles and responsibilities.

Paying attention to the Heat Stress at Work WarninG LEVEL

The real-time Heat Stress at Work Warning level, coded Amber, Red, and Black, is developed and issued by the Labour Department, via the Hong Kong Observatory to indicate the level of heat stress that workers face when working outdoors or in indoor environments without air conditioning system:

Notes: The technical term, the Hong Kong Heat Index (HKHI) is a heat stress index developed through joint research by the Hong Kong Observatory and the Faculty of Medicine of the Chinese University of Hong Kong, which is detailed in Section 3.2.2 of the GN. The real-time HKHI is published on the Hong Kong Observatory website, and via the notification of "MyObservatory" Mobile Application (Click here to see how to enable “Heat Stress at Work Warning” notification), which can appropriately reflect the health risks posed to the entire population in Hong Kong as a result of the heat stress. Although Section 3.2.1 of the GN describes Measuring Heat Stress in the Workplace as an alternative, employers or responsible persons may simply refer to the values of the HKHI as an easier and more convenient means of assessing the risk of heat stroke faced by employees at work.

Appendix 4 of the GN lists out the recommended hourly rest periods for employees working outdoor at different levels of physical workload (as defined in Appendix 1 of GN) under different Heat Stress at Work Warning levels. These recommendations are based on the outdoor working environment and physical workload of employees without regard to other risk factors that may affect the required rest periods (Section 5.4 of the GN), and the heat stroke preventive measures (Section 5.3 of the GN) that have already been taken.

Refer to Appendix 4 of the GN, Rest Arrangements for Outdoor Work in Times of Heat Stress at Work Warning:

Notes:

The above rest arrangements assume that the employees are working outdoors without any preventive measures.
If the employer has conducted a risk assessment for employees in advance and has adopted suitable preventive measures, the above arrangements can be adjusted accordingly.

Various factors can increase or decrease the rest time based on the result of the risk assessment. Refer to Sections 5.3 and 5.4 of the GN to implement the preventive measures to reduce the required hourly rest time for workers and to avoid the conditions which could increase the rest time:

Implementation of Hourly Rest Arrangements

Rest breaks should be arranged for affected workers every hour as far as is reasonably practicable based on the hourly rest time after adjustment, the real-time update on the Heat Stress at Work Warning level, and whether the employees are unacclimatized or need to re-acclimate to hot work environment (Section 5.4.4 of the GN):

Recognition and Treatment of Heat-Related Illness

Heat-related illnesses (including heat cramps, heat syncope, heat exhaustion, and heat stroke) are health damage and symptoms that arise when the body’s physiological mechanism in temperature regulation is overwhelmed in hot weather or high temperature environments. Appropriate precautions should be taken to avoid heat-related illnesses when working in hot environments. For details of Recognition and Treatment of Heat-Related Illness, please refer to Section 6 of the GN.