Heat Stress

What heat stress means

Heat stress (الإجهاد الحراري) is the load placed on a worker’s body when the heat it gains from the working environment and from physical effort exceeds the body’s capacity to get rid of that heat. It is an occupational hazard that exists both in work under direct sun and in hot enclosed environments, such as a workshop, a kitchen or a warehouse without adequate ventilation.

Heat stress is a condition of the body, not a temperature. The measure is not the temperature reading on its own but that reading combined with humidity, air movement, the intensity of the effort, the type of clothing and the length of exposure. So heat stress can occur on a day of moderate temperature when the effort is heavy and the protective clothing is thick, and it may not occur on a hotter day when the work is light and is done in shade with good ventilation.

That combination is why a single figure on a thermometer cannot tell a supervisor whether a crew is safe. Two teams on the same site at the same hour can carry different loads: one lifting materials in full protective clothing, the other checking instruments in a shaded cabin with moving air. The concept of heat stress therefore looks at the work as well as at the weather, and any response to it has to look at both.

Heat stress and the duties in the Labor Law

In the Articles of the Saudi Labor Law (نظام العمل) that we reviewed, none carries the name heat stress. What applies is the general duty of occupational safety and health set out in Part Eight of the Labor Law, and three of its provisions bear directly on work in heat:

• Article 122 of the Labor Law. It requires the employer to take the necessary precautions to protect workers from the hazards and diseases arising from the work, and to post the instructions on work and worker safety in a visible place in the establishment, in Arabic and, where needed, in another language the workers understand. In hot environments the language of those instructions is a practical matter, not a formality: a worker who cannot read a warning gains nothing from it. The same Article of the Labor Law bars the employer from charging workers, or deducting any sum from their wages, for providing this protection.
• Article 123 of the Labor Law. It is written in two sentences. In the first, before the worker starts work, the employer must inform the worker of the hazards of their occupation and oblige them to use the protective means prescribed for it. In the second, which carries no such timing, the employer must provide suitable personal protective equipment for the workers and train them in its use.
• Article 121 of the Labor Law. It requires the employer to keep the establishment in a healthy and clean state and to secure water for drinking and for washing. Where heat stress is concerned, that water is a standing duty, not a favour granted to workers.

Article 121 of the Labor Law also refers the rules, procedures and levels of protection, safety and occupational health to a decision of the Minister, so the detailed standard is not set in the statute. In the sources we reviewed, we found no copy of that decision, and we attribute no temperature threshold or exposure limit to it.

Royal Decree M/44, which amended the Labor Law with effect from 19 February 2025, did not amend Articles 121, 122, 123 or 134 of the Labor Law. None of those four Articles carries an amendment note from that decree in the consolidated text published by the Ministry of Human Resources and Social Development.

The summer rule on heat stress and its dates

The rule that circulates in this area is a ban on work under the sun during part of the day in specified summer months. We found no such rule in the provisions of the Labor Law on occupational safety; it is attributed instead to controls issued under a separate instrument. In the sources we reviewed, we found neither the text of those controls nor the instrument that issues them. For that reason we give no start date, no end date, no starting hour and no finishing hour for the ban.

Leaving the dates out is deliberate. The wording of the rule in circulation can change from one year to the next, it can be copied between websites without a source, and the version a reader remembers may be the text of a past year. A summer work schedule built on a figure recalled from memory, or copied from a secondary text, rests on something whose current status is unknown. The window and its hours are taken from their official source before each season, not from a glossary definition and not from any other secondary text.

The same caution applies to the planning around the ban. A rota that moves outdoor work into the early morning, a contract schedule that assumes a shorter working day in summer, or a quotation that prices in lost hours all depend on the window being right. Each of them is checked against the official source in the season it covers, rather than carried forward from the year before.

The heat stress violation in the Schedule of Violations and Penalties

The Schedule of Violations and Penalties (جدول المخالفات والعقوبات) for the Labor Law and its Implementing Regulation (اللائحة التنفيذية), issued by Ministerial Decision No. 112377 dated 21/8/1447H, lists in its first category, the general violations for all activities, the employment of a worker under direct sun or in bad weather without the required precautions. The Schedule classes that violation as grave (جسيمة), and its fine is multiplied by the number of workers concerned.

So the existence of the violation, its class and its multiplication by the number of workers are settled in the Schedule. The required precautions against which the violation is measured have their source outside the Schedule, in the controls whose text we did not find. The fine in that row is SAR 1,000 in each of the three columns the Schedule sets by establishment size, as Ministerial Decision No. 112377 dated 21/8/1447H prints it, so an establishment with five workers exposed without the required precautions faces that amount five times over.

What an establishment does about heat stress, whatever the time window

The time ban is a minimum tied to a season and to set hours. Heat stress can occur outside both, so an establishment has work to do in every case:

• Water within reach of the work site. It needs to be at the site itself, not in a building some distance away, because distance can cancel availability in practice.
• Shade on site. It gives workers somewhere to rest, with rest breaks organised before symptoms appear, not after them. The statutory limits on rest periods during the working day are set out in our guide to working hours and the weekly rest.
• Gradual acclimatisation. It applies to a new worker, or to one returning after a break, because such a worker may tolerate heat less well than colleagues who are used to the conditions, and may be at greater risk of heat stress as a result.
• Briefing supervisors and workers on the early symptoms. It connects with the duty to inform the worker of the hazards of their occupation before starting work, set out above.
• Reviewing when the heaviest tasks are done. It means moving the most demanding work to the coolest hours of the shift and spreading it across the crew.

The effect of these measures falls on field roles, including blue collar workers in contracting, transport and maintenance. An establishment that has formed a safety committee can include these measures among the matters the committee follows up, so that water, shade and the timing of heavy tasks are checked on the site rather than assumed from a written plan.

Heat stress and work injury

Cases of heat stress that do occur are dealt with under the rules on work injury. Article 134 of the Labor Law provides that an injury is a work injury as defined in the Social Insurance Law (نظام التأمينات الاجتماعية), so what counts as a work injury is referred to that law.

The definition of heat stress does not say that any particular case counts as a work injury. That question is decided by the provisions of the law to which Article 134 of the Labor Law refers, and by the medical report, not by a glossary definition.

Before each summer, the controls on work in hot weather are checked against their official source, because a definition of the concept cannot stand in for them.

This is an explanation of the concept and of the statutory provisions cited, not legal advice.

Related terms

• Health and Safety Officer
• Hazard Pay
• Safety Committee
• Work Injury
• Schedule of Violations and Penalties