Ventilation and temperature

Regulation 7 of the UK’s Workplace (Health, Safety and Welfare) Regulations 1992 requires that ‘during working hours, the temperature in all workplaces inside buildings shall be reasonable’. It is recommended that, in the typical workplace, the temperature should be at least 16°C unless much of the work involves severe physical effort, in which case it should be at least 13°C. These temperatures would be considered by most to be below comfort levels. However, the ACoP defines a reasonable temperature as one that should secure the thermal comfort of people at work, allowing for clothing, activity level, radiant heat, air movement and humidity.

For air-conditioned buildings in the UK, CIBSE recommends a dry resultant temperature of between 21°C and 23°C during winter and between 22°C and 24°C in summer for continuous sedentary occupancy. It is recognised that room temperatures in buildings without artificial cooling will exceed the summer values for some of the time but should not exceed 25°C for more than 5% of the annual occupied period (typically 125 hours).

There is currently no maximum temperature for a workplace, a bone of contention for many indoor workers during summer time, when temperatures rise in buildings to conditions that are uncomfortable.

Regulation 6 requires that ‘effective and suitable provision shall be made to ensure that every enclosed workplace is ventilated by a sufficient quantity of fresh or purified air’.

It should be noted that this Regulation covers general workplace ventilation, not local exhaust ventilation for controlling specific hazardous materials or substances hazardous to health. Workplaces should be sufficiently well-ventilated so that stale air, and air that is hot or humid because of processes or equipment, is replaced at a reasonable rate. In many cases, natural ventilation through windows may be sufficient, but mechanical ventilation or air conditioning may also be required.