Working Outdoors In Cold Climates
When working outdoors the effects of the weather in the UK environment can potentially have a serious impact on an employee's health if the risks have not been considered or properly managed. This impact may be immediate or it may occur over a long time period.
When working outdoors the weather can have influenced an individual's effectiveness and this is not readily managed using just engineering controls. In these circumstances some of the most effective ways of managing these environments are to introduce some simple administrative controls for example:
Cold environments
• ensure the personal protective equipment issued is appropriate
• provide mobile facilities for warming up, and encourage the drinking of warm fluids such as soup or hot drinks
• introduce more frequent rest breaks
• consider delaying the work – can it be undertaken at warmer times of the year without compromising on safety?
• educate workers about recognising the early symptoms of cold stress
• HSE resource
Cold stress
Hypothermia means "low heat" and is a potentially serious health condition. It occurs when body heat is lost from being in a cold environment faster than it can be replaced. Symptoms begin with shivering. As the body temperature continues to fall, slurred speech, lack of coordination and memory loss develop and shivering ceases. Once the body temperature falls to around 29° C the person may become unconscious, and at 25c the person could die.
Risk Factors
Anyone working in a cold environment may be at risk for hypothermia. However, older people may be at more risk than younger adults, since older people are not able to generate heat or regulate body temperature as quickly.
Certain medications may prevent the body from generating heat normally. These include anti-depressants, sedatives, tranquilizers and some heart medications.
Signs and symptoms
Mild hypothermia (32c - 36°C )
• shivering
• lack of coordination, stumbling, fumbling hands
• slurred speech
• pale, cold skin Moderate hypothermia (30c- 32c)
• shivering stops
• mental confusion or impairment
• reduced breathing and/or heartrate
• unable to walk or stand
• confused and irrational Severe hypothermia (25-30°C)
• severe muscle stiffness
• very sleepy or unconscious
• extremely cold skin
• irregular or difficult to find pulse
First Aid
Proper treatment depends on the severity of the hypothermia.
Mild hypothermia:
• move to warm area
• stay active
• remove wet clothes and replace with dry clothes or blankets, cover the head
• drink warm (not hot) sugary drinks such as sports drinks. Avoid caffeinated beverages and alcohol.
Moderate
Telephone emergency services.
• Cover all extremities completely
• Place warm objects, such as hot packs or water bottles on the victim's head, neck, chest and groin Severe hypothermia
• Call Emergency services
• Handle the victim carefully. Sudden movement or rough handling can upset heart rhythms
• Do not attempt to re-warm -- the victim should receive treatment in a hospital
Frostbite
Frostbite occurs when layers of skin tissue freeze. In severe cases, amputation of the frostbitten area may be required. Frostbite can be caused by exposure to severe cold or by contact with extremely cold objects. In fact, frostbite occurs more readily from touching cold metal objects because heat is rapidly transferred from skin to metal.
Frostbite typically affects the extremities, particularly the face, ears, fingers and toes. Initial symptoms vary, but typically include skin that looks waxy and feels numb. Once damaged, tissues will always be more susceptible to frostbite in the future.
Signs and symptoms:
• Cold, tingling, stinging or aching feeling in the frostbitten area, followed by numbness
• Skin color turns red, then purple, then white or very pale skin, cold to the touch
• Hard or blistering skin in severe cases First Aid
• DO NOT rub the area
• Wrap in soft cloth
• If help is delayed, immerse in warm, not hot, water. Don’t pour water directly on the affected area because it will warm the tissue too fast. Warming should take about 25-40 minutes
• Do not warm the skin if there is a chance of refreezing. Severe tissue damage can occur.
Trench foot
Trench foot or immersion foot is caused by having feet immersed in cold water for long periods of time.
It is similar to frostbite but considered less severe.
Signs and symptoms:
• Tingling, itching or burning sensation
• Blisters
What to do:
• Soak feet in warm water, then wrap with dry cloth bandages
• Drink a warm, sugary drink
Preventing Cold Stress
Planning for work in cold weather is the most important defense. Wearing appropriate clothing and being aware of how your body is reacting to the cold are important to preventing cold stress. Avoiding alcohol, certain medications and smoking can also help to minimize the risk.
Protective Clothing
Wearing the right clothing is the most important way to avoid cold stress. The type of fabric also makes a difference. Cotton loses its insulation value when it becomes wet. Wool, on the other hand, retains its insulative qualities even when wet. The following are recommendations for working in cold environments:
Wear at least three layers of clothing:
• An outer layer to break the wind and allow some ventilation (like Gortex® or nylon)
• A middle layer of down or wool to absorb sweat and provide insulation even when wet
• An inner layer of synthetic weave to allow ventilation
• Wear a hat. Up to 40% of body heat can be lost when the head is left exposed
• Wear insulated boots or other footwear sized appropriately. Tight-fitting footwear restricts blood flow, as can wearing too many socks
• Wear insulated gloves sized appropriately, especially when contacting metallic surfaces and tool handles
• If you get hot while working, open your jacket, but keep hats and gloves on
• Keep a change of dry clothing available in case work clothes become wet.
• Do not wear tight clothing which can restrict blood flow. Loose clothing allows for better ventilation.
Work Practices
• Drinking: Drink plenty of liquids, avoiding caffeine and alcohol. It is easy to become dehydrated in cold weather.
• Work Schedule: If possible, heavy work should be scheduled during the warmer parts of the day. Take breaks out of the cold.
• Buddy System: Try to work in pairs to keep an eye on each other and watch for signs of cold stress. Victims of hypothermia may not recognize symptoms.
Engineering Controls
Some engineering controls are available to reduce the risk of cold stress:
• Radiant heaters may be used to warm workers
• Shield work areas from drafts or wind
• Use insulating material on equipment handles when temperatures drop below -1 C
Training
Employees and supervisors need to be trained to be able to detect early signs of cold stress. Supervisors should watch for signs of cold stress and allow workers to interrupt their work if they are extremely uncomfortable. Supervisors should also ensure that work schedules allow appropriate rest periods and ensure liquids are available. They should use appropriate engineering controls, personal protective equipment and work practices to reduce the risk of cold stress.
HSE and NIOSH resource. 2018
Cold stress
HSE does not have specific guidance for working in temperatures below 13°C.
You will likely be complying with the law if you work in accordance with British/European Standards but you can demonstrate compliance by alternative means.
As the first point of reference, you are advised to refer to the British Standards listed below.
The standards listed are not an exhaustive list but provide a framework around which you can develop your risk assessment and start managing the problem. You may need to refer to other standards listed elsewhere, dependant on your operational circumstances.
British standards for assessing cold stress in the workplace
• BS EN 511: Protective gloves against cold
• BS EN ISO 13732-3: Ergonomics of the thermal environment. Methods for the assessment of human responses to contact with surfaces
• BS 7915: Ergonomics of the thermal environment. Guide to design and evaluation of working practices in cold indoor environments
• DD ENV SO 11079: Evaluation of cold environments. Determination of required clothing insulation (IREQ)
• BS EN SO 15743: Ergonomics of the thermal environment. Cold workplaces.
