Are contractors obliged to stop work during heatwaves?

An image of the sun set against a blue sky (Image: Dreamstime)
Are contractors obliged to stop work during heatwaves? (Image: Dreamstime)

With temperatures climbing above 30 degrees again later this week, do construction companies have an obligation to stop work when temperatures become too hot? Amanda Stubbs and Tola Balogun explain how contractors should protect their workers during heatwaves.

The Health and Safety at Work Act 1974 (HSWA) requires employers to provide their employees with a safe and healthy working environment, which, in particularly hot and dry weather conditions, will require them to assess and control risks arising from working in hot temperatures, possibly with increased exposure to the sun.

While there is no set maximum temperature for working outdoors in the UK, the Workplace (Health, Safety and Welfare) Regulations 1992 require employers to provide a “reasonable” temperature in the workplace.

‘Suitable assessment’

This may be easier said than done when ambient temperatures are regularly exceeding 24 degrees centigrade in various parts of the UK, but the Management of Health and Safety at Work Regulations 1999 require employers to make a "suitable assessment" of the risks to the health and safety of their employees arising out of their work activity, and to take action "where necessary and where reasonably practicable". The temperature of the workplace is one of the noted potential hazards.

Construction companies therefore need to undertake an adequate risk assessment to ensure that employees working in hot temperatures or exposed to the sun do not suffer from dehydration, heatstroke, sun burn, heat rash or similar conditions.

At high temperatures, defined as 24 degrees centigrade and above according to the Trades Union Congress, employees may become drowsy and less aware of dangers. There is also an increased risk of accidents due to slips, trips, falls, poor manual handling, and injury from hand tools. Thermal discomfort gives rise to reduced efficiency that can lead to poor decision-making with resultant errors.  It is also generally recognised that too much sunlight is harmful to the skin and may cause skin cancer, although covering up and/or wearing appropriate Personal Protective Equipment may increase thermal discomfort.

So what can you do?

For employees working in hot conditions, the Health & Safety Executive recommends that employers should:

  • include sun protection advice in routine health and safety training;
  • encourage workers to keep covered up with long-sleeved shirt and a hat with a brim or flap that protects the ears and neck;
  • encourage workers to use sunscreen with a sun protection factor (SPF) of at least 15 on any exposed skin;
  • site water points and rest areas in the shade to encourage hydration;
  • schedule work to minimise exposure to heat and sun, so far as reasonably practicable; and
  • encourage workers to check regularly for any unusual skin spots, moles or discolouration that may require medical attention.

While an employer’s failure to provide a safe and healthy working environment will be a breach of the HSWA leading to possible prosecution with a risk of criminal fines or even imprisonment, the HSWA also imposes a duty of care on employees to take reasonable care of themselves, which means heeding advice given to them about keeping cool and hydrated, and being aware of the performance and health risks arising out of thermal discomfort.

Amanda Stubbs is health, safety and environmental law partner and Tola Balogun is a solicitor at Trowers & Hamlins.

Story for CM? Get in touch via email: [email protected]


  1. Pity that advice wasn’t given in regards to those who work in the office. I know from experience what it is to work in high temperatures. However, we just get on with it. That’s the nature of the construction industry. I suppose the saying that “the show must go on” applies.

  2. Yet more UK mollycoddling of workers. What do you think happens in countries where +30C is the norm?
    People simply need to use common sense. Don’t make it the employers responsibility.

  3. No stop-work order must be issued on any construction site during hot-weather conditions to obviate the danger of construction delay. If the site is well risk managed; in construction industry, weather conditions are expected to vary during the field work. Wind and moisture, as well as areas lacking in shade at the site may combine with low or high temperatures to create unfavorable working conditions. Sudden changes in the weather, extreme weather conditions, and natural disasters can create a number of subsequent hazards such as poor working conditions and slip, trip, and fall hazards.
    Natural disasters can create many secondary hazards such as, the release of hazardous materials to the environment, structural failures, and fires. Operations that involve worker exposure to elevated air temperatures, radiant heat sources, high humidity, and direct contact with hot objects or strenuous activities have a high potential for heat stress. With the use of personal protective equipment [PPE], the potential for inducing heat stress is exacerbated further.
    Depending on the planned work activities and the protective clothing anticipated, the heat stress potential must be considered at ambient temperatures at or above 70 degrees Fahrenheit. When impermeable PPE is being worn, physiological monitoring is the preferred and recommended method to track heat stress susceptibility in workers.
    By employing a Site Safety and Health Officer to [SSHO] monitor the site conditions, make periodic ambient temperature measurements and implement the appropriate control measures to provide for the comfort and safety of project personnel.

  4. Why not check what members in other countries do that have plus 24 degrees as the norm.

    In Victoria Australia, we have the rhyme – “35 Stay alive” which means that over 35 degrees stop work. We do ensure suitable PPE is worn such as long sleeves etc.

    I am afraid the UK only looks naive when such articles are published… rather like leaves on the line in Autumn and snow in February.

    I am a Brit living abroad and it is common for people to think the British do not ask how things are things are done but rather tell them how things are done in Britain.

    I am afraid the article has raised a few chuckles over here!

    Phil 4th August 2018

  5. Oh dear, does Mr. Adesanya actually want to get anything built in this country?

  6. My honorable member Richard Moore, my response does not focused on one particular country since our industry is universally diverse. Though, my comment were based on the general site conditions, regardless of the country. However, I work also in a nation that experience high heat-waves year round. We never stop-work on-site due to heat-waves but make critical daily construction scheduling with risk management plan in-place. I categorically stretched on the use of “Personal Protective Equipment” designed to protect workers from injury, infection, or adverse weather conditions. The hazards addressed on my response for the use of protective equipment include physical, heat, biohazards and airborne particulates. Safety and Health of workers should be the utmost priority to employers who wants to stay in construction business because our industry dependent on human resources – Health is Wealth!

  7. Good morning
    I’m working on the M4 monkey island for Balfour Beatty,
    I’d just like to ask why these big companies don’t have enough information or when to stop work due to it being to hot !
    There’s men stood in one position all day with PPE on with a long walk to any shade or water station ,
    Don’t you think that there should be a law telling construction sites that they should close sites down due to the heat

Comments are closed.

Latest articles in Legal