Andrew Christodoulou discusses the effects low temperatures can have on those working on construction sites.


With the onset of winter, it is important to consider the effects of low temperatures while working on construction sites. Low temperatures can introduce many additional health and safety risks and accentuate others, all of which need to be dealt with.

The starting point for considering the potential problems of the effects of the cold is risk assessment, which will identify those “cold weather” aspects affecting health and safety for a particular project.

There are also legal requirements that need to be considered. These require clients and contractors to consider the health and safety aspects of all projects including the effects of low temperatures on site.

Low temperatures

Low temperatures can affect health and safety in a number of ways. In particular, they can affect the way people behave. It is more difficult to concentrate when feeling cold. Therefore, errors of judgment are more likely to occur and these errors can lead to serious accidents in construction. People may also take shortcuts to avoid the cold, resulting in non-adherence to site procedures and rules.

Low temperatures also affect manual dexterity which is important when operating machinery and other manual tasks. For example, those operating woodworking machinery may start to lose some dexterity at temperatures lower than 13°C and the risk of accidents will increase in such temperatures. In extreme circumstances, frost bite and hypothermia may occur.

Other hazards may also be apparent in cold weather. For example, there may be additional slipping hazards due to ice or snow on working platforms and ladders. Plant and equipment may malfunction due to cold and ice. The safety of mechanised lifting operations may be jeopardised by unstable loads. Manual handling may be more risky due to the effects of a cold environment with slippery loads and surfaces. In view of the frequent wet weather, it is worth considering other weather hazards, in addition to those associated with low temperatures.

Wet weather, for example, may:

  • cause slippery surfaces

  • increase the safety risks associated with plant and equipment

  • make excavations more unstable

  • become an important welfare issue for site operatives.

While there are no specific regulations dealing with wet weather, it should be included in the site risk assessment.

The legal requirements

There are a number of important health and safety statutes to consider when dealing with working at low temperatures.

The general requirements of the Health and Safety at Work, etc Act 1974 apply to all construction projects. While temperature is not specifically dealt with by the Act, it is inherent in the requirement to ensure the health, safety and welfare of all employees and others who might be affected.

The Management of Health and Safety at Work Regulations 1999 (the Management Regulations) require the assessment of work-related risks and this must include a consideration of the effect of low temperatures. Control measures must be implemented to deal with those risks identified by the assessment.

Of particular importance are the Construction (Design and Management) Regulations 2007 (CDM). Clients have the duty to provide pre-construction information and this may include the need to consider the possible effects of cold weather depending on the timing of the project.

Principal contractors have a duty to deal with site hazards including those highlighted by the client. In particular, the principal contractor must:

  • plan, manage and monitor the construction phase in liaison with the contractor

  • prepare, develop and implement a written plan and site rules (the initial plan should be completed before the construction phase begins)

  • give contractors relevant parts of the plan

  • make sure suitable welfare facilities are provided from the start and maintained throughout the construction phase

  • check the competence of all appointees

  • ensure all workers have site inductions and any further information and training needed for the work

  • consult with the workers

  • liaise with the CDM co-ordinator regarding ongoing design

  • secure the site.

Regulation 34 of CDM deals specifically with the issue of temperature.

(1) Suitable and sufficient steps shall be taken to ensure, so far as is reasonably practicable, that during working hours, the temperature at any place of work indoors is reasonable having regard to the purpose for which that place is used.

(2) Every place of work outdoors shall, where necessary to ensure the health and safety of persons at work there, be so arranged that, so far as is reasonably practicable and having regard to the purpose for which that place is used and any protective clothing or work equipment provided for the use of any person at work there, it provides protection from adverse weather.

The principal contractor must take steps right from the start of the project to implement regulation 34. What is a reasonable temperature for outdoor working is not defined and it is up to the principal contractor to consider the circumstances of their particular project and take action to protect the health, safety and welfare of all those involved on site.

The Workplace (Health, Safety and Welfare) Regulations 1992 lay down particular requirements for most aspects of the working environment. Regulation 7 deals specifically with the temperature in indoor workplaces and states that:

“During working hours, the temperature in all workplaces inside buildings shall be reasonable.”

The ACOP to the regulations does not state a minimum temperature, but recommends that the temperature inside workrooms should normally be at least:

  • 16°C, or

  • 13°C if much of the work is physical.

It is important to note that the Workplace (Health, Safety and Welfare) Regulations do not apply to construction sites, but they will apply to off-site manufacturing premises associated with a project, eg woodworking shops.

Dealing with the cold

The risk assessment required by the Management Regulations will identify those particular risks that are caused by low temperatures. There are various international standards that may assist in the evaluation of the effects of the cold, eg ISO 11079 Evaluation of Cold Environments — Determination of Required Clothing Insulation.

It is up to the principal contractor to manage the site from a health and safety perspective, including those issues relating to low temperatures, and the measures needed should be detailed in the principal contractor’s pre-construction phase health and safety plan, and then implemented throughout the construction phase.

Typical measures will include:

  • maintaining a “reasonable” temperature as far as reasonably practicable for indoor workplaces; this may include the provision of additional heating if this is possible

  • ensuring appropriate personal protective equipment (PPE) is issued as necessary; reference to specifications and standards will be necessary, eg BS EN 511 (2006) Protective Gloves Against Cold

  • providing adequate facilities for warming up, and encouraging the drinking of warm fluids such as soup or hot chocolate

  • introducing more frequent rest breaks as necessary

  • considering whether the work can be delayed and undertaken at warmer times of the year or when the weather improves

  • considering re-phasing of the work to reduce or limit working outdoors when cold

  • educating workers about recognising the early health symptoms of the effects of cold stress and other health effects

  • considering health monitoring for staff

  • monitoring access routes and working platforms for slips

  • considering the impact of the cold on the operation of plant and machinery and also in relation to manual handling.


Working in the cold is an inherent risk associated with construction. It can introduce a whole range of new and additional risks into an already high risk environment. It is essential that these risks be dealt with, and clients and principal contractors must take positive action to keep people on site safe during spells of cold weather. It is important that those working on construction sites are not left out in the cold, both figuratively and in practice.

Last reviewed 4 January 2019