Cold

Working in cold conditions is a hazard with many thousands of workers exposed to cold in environments such as outdoor work in winter months, freezer plants, meat packinghouses and cold storage facilities.

Action Plan For Health And Safety Representatives

As with all workplace hazards, the hazard should be dealt with in this way:

  1. Identification of the hazard
  2. Assessment of the risk
  3. Elimination or reduction of the risk
  4. Review and evaluation of any control strategies

1 - Identification of hazard

  • Ensure the employer monitors the workplace environment - air movement and temperature in particular. You should also consider the combined effect of wind and low temperature ('wind chill' factor - see information on Canadian website), where cooling or freezing of exposed flesh increases rapidly as wind velocity increases.
  • Talk to members of your work group - ask co-workers whether they are experiencing problems with cold.
  • Investigate any past incidents (see Incident Investigation form - as an example).

2 - Assessment of Risk

  • Keep a check on all workplace monitoring results and reported incidents.

3 - Elimination or reduction of risk

  • Negotiate with the employer to introduce appropriate controls. Always attempt to introduce controls at the source first. Examples of possible risk controls are:
    • Effective, controllable heating of workplaces.
    • Outside work in cold weather to be sheltered, screened and warmed with hot air blowers if possible.
    • If the environment cannot be effectively controlled, implementation of an appropriate work/rest regime: for example, paid rest breaks of ten minutes per hour for temperatures between 9° and 7°C, twenty minutes per hour for temperatures between 7° and 4°C, and thirty minutes per hour for temperatures between 4° and 1°C. (An air temperature of 1°C should be regarded as the minimum acceptable for normal work. When the temperature reaches this point, workers should be stood by on full pay.)
    • Workers needing to do work in intentionally cold environments below 1°C - freezers for example - must be provided with appropriate protective clothing and the time they work in such environments must be kept to a minimum.
    • Heated rest rooms or shelters should be provided so those workers may obtain temporary relief from the cold.
    • Provision of hot drinks.
    • Proper education and close monitoring of new workers or those returning from leave until they are accustomed to the work conditions, requirements for appropriate clothing, and so on.
    • Protection of the extremities through the use of appropriate protective clothing, including gloves, insulated or vapour barrier boots, and face masks as necessary
    • Provision of hot air jets, radiant heaters and appropriate types of gloves and mittens to keep the hands warm and maintain manual dexterity.
    • Insulation or substitution of metal handles and control bars to reduce conductive heat loss
    • Provision of protective clothing which is adequate and appropriate for the degree of cold and physical activity to be encountered.
       

      A recommended method for protective clothing is the ventilating, insulating and protective layering (VIP) method. The ventilating layer consists of cotton, waffle weave, or fishnet type of underwear, not only providing for the trapping of body heat, but also providing the opportunity for moisture to escape. Wool, or some of the newer materials, such as fibrefill, is best used for the insulating layer, since these materials will retain their insulating value even when they become wet. The outer or protective layer can range from nylon to waterproof suits or ponchos. The main purpose of this layer is to protect the other layers from the elements and serve as a windbreak.

Legal Standards

There are no regulations specifying standards for minimum temperatures in the workplace. However, employers have a duty under the Victorian Occupational Health and Safety Act (2004) to provide and maintain for employees, as far as practicable, a working environment that is safe and without risks to health. This includes providing a safe system of work, information, training, supervision, and where appropriate personal protective equipment. The employer also has the duty to monitor conditions at the workplace - this includes temperature. Some workers have been able to negotiate agreements (now in either their award or Enterprise Agreement) on this issue.

In addition, the Victorian Compliance Code for Workplace amenities and work environment includes provisions in relation to temperature: 

  • Workplaces that are buildings need to be capable of maintaining a temperature range that is comfortable and suitable to the work. Workplace temperatures that are too high or too low can contribute to fatigue, heat illness and cold-related medical conditions. (Para 122)
  • Optimum comfort for sedentary work is between 20°C and 26°C, depending on the time of the year and clothing worn.  Employees undertaking work requiring physical exertion usually prefer a lower temperature range. (124)
  • The means of maintaining a comfortable temperature will depend on the working environment and the weather and could include any of the following (125):
    • air conditioning
    • fans
    • electric heating
    • open windows
    • building insulation
    • the layout of workstations
    • direct sunlight control
    • controlling airflow and the source of draughts
    • a work and rest regime 

All heating and cooling facilities need to be serviced regularly and maintained in a safe condition (126)

  • Subject to clauses 104 & 105 dealing with outdoor work, outdoor employees need to have access to shelter for eating meals and taking breaks, and for protection when weather conditions become unsafe.  Employers need to ensure access to shelter such as shelter sheds, caravans, tents, windbreaks or portable shade canopies. In some situations, vehicles or public facilities may provide adequate short-term shelter. 

The UK's OHS regulator, the Health and Safety Executive (HSE), has a section on their website which specifically addresses matters of Temperature, including what the HSE recommends in terms of minimum and maximum temperatures in workplaces.

The Problem

The Body's Response To Cold

The human body produces its own heat from chemical energy (breaking down food and building up molecules in all tissues) and may lose heat to a cool environment.

When the human body is exposed to cold, it tries to minimise heat loss in two ways:

  1. By decreasing heat loss by constricting the blood vessels in the skin and underlying tissues (vascoconstriction) leading to a corresponding reduction in the volume of blood reaching the skin. This significantly reduces the amount of convective heat loss from the body. A reduction in surface area by changes in posture, such as "hunching up the body", also assists in reducing heat loss.
  2. By increasing the metabolic heat production rate, either by voluntary movements, such as exercise and the performance of work, or by shivering.

    Through shivering, it is possible to increase the metabolic rate of heat production 5 to 7 times for short periods of time. Shivering is a relatively inefficient way of increasing heat production when compared with active muscular work.

    An increase in metabolism during cold exposure leads to increased oxygen consumption - up 3 to 5 times the normal resting rate. This is mainly due to shivering, increased voluntary movement caused by discomfort, and non shivering thermogenesis. Non shivering thermogenesis is a defence mechanism that goes into action as a consequence of prolonged continuous exposure to cold environmental conditions.

What are the health effects of exposure to extreme cold?

Exposure to cold environmental conditions can result in a number of disorders. It should also be remembered that when working in clothing that is also damp with rain, body heat is lost even faster. Also the combined effect of wind and low temperature exacerbates conditions.

  1. Increased incidence of arthritis, rheumatism and bronchitis; muscle/tissue damage
    These conditions are commonly associated with the cold. Muscles and soft tissue are susceptible to damage when used in cold conditions.
  2. Decrease in dexterity and sensitivity
    As hands and feet become cold, stiff, numb and painful, a worker cannot perform manual tasks with as much dexterity or skill. Shivering also makes it difficult to perform work skilfully or accurately.
  3. Increase in accident rates
    Factors listed above promote an increased rate of incidents. Research has found that incident rates increase as the temperature falls below 19°C.
  4. Hypothermia
    Hypothermia is one of the most serious hazards of exposure to cold working conditions. It is a decrease in the core body temperature to a level at which normal muscular and cerebral functions are impaired. The warning signs are:
    • Numb hands
    • Shivering not under voluntary control
    • Loss of fine motor co-ordination (particularly in the hands - for example trouble with buttons, laces, zips)
    • Slurred speech
    • Difficulty in thinking clearly
    • Irrational behaviour - sometimes a person even begins to discard clothing

    This may lead to unconsciousness, even death. Most cases of hypothermia occur in air temperatures between 1°C and 10°C, although the body can lose significant heat in air temperatures as high as 18°C or water temperatures as high as 22°C. Body heat is lost much faster when wet, either as a result of weather or perspiration.

    During activity, the body increases its metabolic heat production. This heat production drops by as much as one half when the body becomes inactive. Uncontrollable shivering followed by hypothermia is likely to result. The body's physiological response, designed to minimise heat loss becomes ineffective when the body's core temperature drops below 30°C.

  5. Reproductive disorders
    The brain of an early developing foetus is vulnerable to severe disturbances as a result of its mother suffering hypothermia.
  6. Frostbite
    Frostbite is a freezing of tissue (e.g. of the face, hands or feet) during exposure to temperatures well below freezing. Damage may range from mild, superficial tissue damage to massive tissue damage and gangrene.

See also:

Last amended November 2016

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