Hot Weather Work Arrangements: A Hong Kong Employer's Guide to Heat Stress and Rest Breaks
Updated: Aug 30
Hot Weather Work Arrangements: A Hong Kong Employer's Guide to Heat Stress and Rest Breaks
During Hong Kong's summer, employees in outdoor work, logistics, cleaning, construction, property management, food delivery and non-air-conditioned workplaces may face prolonged exposure to heat, humidity and direct sunlight. The Labour Department has reminded employers that, when the Heat Stress at Work Warning is in force, they should assess employees' heat-stress risks and, so far as reasonably practicable, implement heat-control measures and suitable rest arrangements.
For a business, the issue is not simply whether everyone should stop work whenever temperatures rise. The key is whether there is a clear, workable process: which roles are affected, who monitors the warning, how breaks are determined, how supervisors redeploy staff, and what happens when an employee feels unwell.
Key point: The Heat Stress at Work Warning mainly applies to outdoor work and indoor workplaces without air-conditioning. Employers should determine suitable work/rest arrangements by considering the warning level, work intensity, heat sources and ventilation, heat-control measures already in place, and individual employee risks—not merely whether it feels hot on a particular day.
What Is the Heat Stress at Work Warning? How Is It Different from a General Hot-Weather Alert?
The Heat Stress at Work Warning is issued by the Labour Department, with technical support from the Hong Kong Observatory. It draws on the Hong Kong Heat Index (HKHI) and the “Very Hot Weather” special announcement, and has three levels: Amber, Red and Black. These indicate increasing heat stress and health risks for employees working outdoors or indoors without air-conditioning.
The warning is updated hourly and may be updated earlier if heat stress reaches a higher level. The Labour Department states that employers should make adjusted rest arrangements within the hour immediately following the publication of a warning, or an hourly update confirming that it remains in force, having regard to work intensity, existing control measures and other heat-stress risks.
Employers and supervisors can receive alerts through the Hong Kong Observatory website, the MyObservatory app and the iAM Smart app.
Which Roles Should Receive Priority Heat-Stress Risk Assessment?
Heat stress is not relevant only to construction workers. Employers should also prioritise assessment for:
• construction, maintenance, landscaping and engineering work;
• delivery, manual handling, warehousing and logistics;
• street cleaning, security and property management;
• outdoor promotion, events, car parks and food delivery;
• non-air-conditioned kitchens, workshops, renovation sites and poorly ventilated indoor spaces; and
• work near heat sources or requiring impermeable protective clothing.
Five Factors to Consider in a Heat-Stress Assessment
1. Work intensity: Is the work light, moderate, heavy or very heavy? Lifting, pushing, pulling, prolonged walking and repetitive physical work all increase heat stress.
2. Work environment: Is there direct sunlight, shade, ventilation, air-conditioning or a place where employees can cool down during breaks?
3. Nearby heat sources: Stoves, welding, flame cutting, machinery and other heat-generating equipment can raise environmental heat.
4. Clothing and equipment: Impermeable protective clothing can impede heat dissipation and should be considered together with PPE requirements.
5. Employee condition: New employees, returning employees, or employees who have not worked in a hot environment for more than two weeks may need additional arrangements while adapting.
Six Actions Employers Should Take When the Warning Is in Force
1. Identify affected roles and employees on duty immediately
Businesses should designate who monitors the warning, such as HR, an operations manager, site supervisor or duty manager. Once a warning is issued, identify outdoor, non-air-conditioned and heat-source-related work taking place that day, then notify the relevant supervisors to activate the planned arrangements.
2. Set work and rest periods according to risk
Appendix 4 of the Labour Department's Guidance Notes on Prevention of Heat Stroke at Work provides recommended work/rest arrangements for different warning levels and work intensities. Actual break arrangements should be adjusted for site-specific risks and controls already implemented.
Breaks may be split rather than taken in a single block, but the total rest time within each hour should not be less than the assessed requirement. Even if the adjusted hourly rest requirement is zero, the guidance recommends:
• at least 10 minutes' rest after every two hours of light to moderate work; and
• at least 15 minutes' rest after every two hours of heavy to very heavy work.
A break should provide access to water and a place to cool down—not merely standing aside briefly.
3. Reschedule work and reduce intensity during hotter periods
Consider moving physically demanding, sun-exposed or heat-source-related tasks to earlier or later periods. Job rotation, additional staffing, trolleys, lifting equipment and other mechanical assistance can reduce continuous physical exertion.
For example, logistics teams can stagger manual-handling tasks; property-management teams can reschedule non-urgent outdoor patrols; and restaurants or workshops can review extraction and ventilation around high-heat processes.
4. Provide practical, usable heat-control measures
Heat protection should not exist only in a notice. Depending on the workplace, employers may provide:
• shaded areas, canopies or umbrellas that cover most of the body;
• readily accessible drinking water and hydration arrangements;
• fans, misting fans, portable fans or other cooling equipment;
• areas for cooling down, resting and drinking water;
• suitable breathable workwear and sun/heat protection; and
• tools and work methods that reduce lifting, pushing, pulling and repetitive physical work.
The Labour Department's guidance notes that shade or indoor work away from direct sunlight, enhanced air circulation/cooling equipment and reduced work intensity can affect the hourly rest time required. These measures must be effective in practice and reflected in the risk assessment.
5. Take extra care of employees not acclimatised to heat
Employees who are newly recruited, newly transferred from a cooler environment to outdoor work, or who have not worked in a hot environment for more than two weeks may need time to re-acclimatise. Employers should increase work progressively, arrange suitable rest and strengthen supervisor observation and communication.
The Labour Department identifies lack of acclimatisation or the need to re-acclimatise as a personal factor that may require additional rest time.
6. Give clear instructions, keep records and prepare for emergencies
Supervisors should clearly explain the warning level, that day's work arrangements, rest locations, hydration arrangements and who employees should contact when unwell. Businesses should retain records of heat-stress assessments, measures adopted, work/rest arrangements and relevant instructions.
There should also be a simple emergency process. If an employee experiences dizziness, nausea, weakness, unusual sweating, palpitations or confusion, the relevant work should stop immediately. Arrange for the employee to rest and cool down in a cooler place, and seek medical assistance where appropriate. Supervisors should never ask employees to skip breaks simply to meet a deadline.
When May More Rest Time Be Needed?
The following factors increase heat stress. The Labour Department's guidance indicates that, where the relevant risk is not effectively controlled, each factor may generally add 15 minutes to the hourly rest requirement:
Risk factor | Example |
|---|---|
Obvious heat source with inadequate insulation or extraction | Working near kitchen stoves, welding, flame cutting or heat-generating equipment |
Inadequate ventilation | Enclosed rooms or boarded renovation areas without effective ventilation |
Impermeable protective clothing | Work requiring protective clothing that hinders heat dissipation |
Lack of heat acclimatisation | New employees, returning employees or employees not recently exposed to hot conditions |
Where multiple risk factors are present, additional rest time may accumulate. The guidance states that if all four factors above are present, the rest requirement may reach 60 minutes per hour—which means the work should stop for that hour. Conversely, effectively controlling heat sources, ventilation, clothing and acclimatisation can reduce the need for additional rest.
Important: These are practical guidance arrangements based on the Labour Department's risk-assessment approach. A single number should not be applied mechanically to every role; each workplace should assess its actual process, environment and staffing situation.
HR and Operations Checklist
• [ ] A person has been designated to monitor the Heat Stress at Work Warning.
• [ ] All outdoor, non-air-conditioned, heat-source-related and high-intensity roles have been identified.
• [ ] A workplace heat-stress risk assessment has been completed or updated.
• [ ] Work/rest arrangements have been set for Amber, Red and Black warnings.
• [ ] Shade, ventilation, drinking water and cooling/rest locations have been confirmed.
• [ ] Arrangements for new, returning and non-acclimatised employees have been reviewed.
• [ ] Clear instructions have been issued to supervisors and employees.
• [ ] A process for reporting discomfort, immediate cooling and seeking help is in place.
• [ ] Risk assessments, daily arrangements and communications are retained.
Need Help Putting Hot-Weather Arrangements into Practice?
A general heat-stress guideline still needs to become a day-to-day work arrangement. Get More can help your business translate the guidance into practical rosters, rest and water arrangements, supervisor instructions, communication steps and records for review.
We can help you identify:
which roles or work locations require closer planning;
how managers should respond when conditions change;
what should be recorded and communicated; and
whether HR consultancy, HR outsourcing or a clearer policy workflow is needed.
Contact Get More to discuss the next step:
Let Get More become your strategic HR partner and support your company in making the right decisions.
Further Reading
Frequently Asked Questions
Must work stop whenever the Heat Stress at Work Warning is issued?
Not necessarily. A warning indicates higher heat stress for employees working outdoors or in non-air-conditioned environments. Employers should set suitable work and rest arrangements based on the warning level, intensity, workplace conditions, measures already taken and other risks. If the risk assessment shows heat stress cannot be effectively controlled, the work may need to be suspended or deferred.
Can shade and fans reduce the rest time needed?
Shade, indoor work away from direct sunlight, cooling equipment and reduced work intensity can reduce the hourly rest time required—but only where the measures are actually effective and adjustments are made in accordance with the Labour Department's guidance and the site risk assessment.
Do non-air-conditioned kitchens and workshops also need heat-stress assessment?
They should be considered. Non-air-conditioned indoor work is also affected by hot weather, and heat stress may be higher where stoves, heat-generating equipment or inadequate ventilation are present.
What should a supervisor do if an employee feels dizzy or unwell?
Stop the relevant work immediately, arrange for the employee to rest, hydrate and cool down in a cooler place, and seek medical assistance where appropriate. Businesses should give supervisors clear reporting and emergency-support instructions in advance.
Can an employer ask employees to miss a break to meet a deadline?
No. The Labour Department's guidance stresses that employers should ensure employees comply with rest arrangements, while employees should take breaks as instructed rather than skipping them to finish work sooner.
References
Disclaimer
This content is for general informational purposes only and does not constitute legal advice. For specific workplaces, occupational-safety-and-health responsibilities or employment arrangements, please consult a qualified HR consultant, occupational safety and health professional or legal professional.
