Working in hot temperatures

Human beings need to maintain a constant body temperature if they are to stay healthy. Working in high temperatures will induce heat stress when more heat is absorbed into the body than can be dissipated out. Heat illness such as prickly heat, fainting from heat exhaustion or heat cramps are visible signs that people are working in unbearable heat. In the most severe cases, the body's temperature control system breaks down altogether and body temperature rises rapidly. This is heat stroke, which can be fatal.

Warning signs of heat exhaustion are :

clammy skin confusion light-headedness fainting slurred speech nausea

rapid pulse vomiting weakness short temper fatigue loss of concentration

staggering walk mental confusion hot skin temperature rise (yet person may feel chilled) convulsions unconsciousness incoherence deliriousness

Is there an upper temperature limit at which workers should stop work?

Section 8(i) of the NSW Occupational Health and Safety Act 2000 states that an employer has a legal duty to ensure the health, safety and welfare at work of all employees. If workers are suffering from any of the above symptoms, then it is clear that your employer is not complying with the law. But the law does not state any precise temperature at which workers should stop work, or any specific actions which must be taken by the employer at certain temperatures.

What helps to prevent heat stress?

It is obviously more difficult for the employer to control the environment for outdoor work, than for indoor work. However, if work has to be done outdoors then employers must be responsible in taking steps that are available to protect workers. These include:

• Providing canopies or awnings over sections of the site where work is currently being carried out, to shield workers from the ultra-violet rays of the sun, as well as from the direct heat of the sun.



• Providing regular rest breaks. A ten minute break every hour, in a cooler area, helps the body to cool off, especially where the work is hard, physical work. The length of the break should be increased if the temperature is very high. As a practical guideline, the following measures can be followed in most workplaces:
  
  

  Temperature	Rest Period
  30 to 32º	10 minutes
  32 to 35º	15 minutes
  more than 35º	at least 30 minutes




• Providing air-conditioned sheds or vehicles for rest breaks. These must obviously be near each area where work is being done, or break time will be spent walking to and from the shed or vehicle. Also, the nearer the shed or vehicle, the more likely it is to be used.



• Provision of cold (non-alcoholic) drinks. Frequent small drinks of cooled water will help replace the water lost to your body through sweat, before dehydration begins. This is better than infrequent large drinks. Again, the cold water supplies should be near each working position, to encourage frequent drinks.


Alcoholic drinks should not be taken as replacement fluids. Alcohol stimulates the body to eliminate fluids, and will increase your risk of dehydration. For example, if you drink one can of beer, you will lose more than that volume of urine.


• Salt tablets should not be taken - more water will be required by the body to help it get rid of the salt - this will increase the amount of work the kidneys must do and increase the risk of dehydration. Salt tablets also increase the risk of high blood pressure. Drinking water will not give you stomach cramps, as some people believe.

What action should be taken if someone has symptoms of heat illness?

• First take the sufferer to a cooler area (for example, an air-conditioned shed or vehicle).



• Then remove excess clothing (hard hat, boots, shirt).



• Give water to drink, if conscious.



• Allow the person to rest if they are suffering from heat exhaustion



• If the person is suffering from heat stroke they should be cooled with water, cold compresses, and/or rapid fanning. A person suffering from heat stroke should be taken to a medical facility for further cooling and monitoring of body functions.

• Ask workers exposed to high temperatures if they find conditions too hot or have any heat stress symptoms. Write a simple questionnaire based on your own knowledge and the symptoms listed on this factsheet.



• Ask management to measure and record the temperature regularly throughout the year, preferably with an automatic Wet-Bulb Globe Temperature Instrument, or at least with instruments that measure dry temperature and humidity. Safety Reps have a legal right to these results. Put all of your requests to management in writing.



• Persuade workers to put all incidents of high temperatures and symptoms suffered into the Accident Book.



• Compare these results with the results of the membership survey, your own monitoring results and the accident and sick/absence record. Do accidents happen more frequently during high temperature conditions? Is there more sick absence during these conditions?



• Demand that management bring in ventilation and heat control consultants to (re)design and install air conditioning or cool air providers, or insulation of radiant heat sources. Your union or the Workers Health Centre will be able to help you with these arrangements.



• Negotiate exposure reduction by frequent rests away from the source of heat and job rotation.



• Demand that the employer provide suitable clothing and footwear - clothing which increases body heat or prevents sweat evaporating is not suitable (for example, nylon).



• Arrange for regular medical checks of employees particularly of blood pressure.



• Demand information and training for all employees on the need for adequate water, recognition of heat symptoms, acclimatisation to heat, exposure build-up for new workers after holidays and types of work which increase heat hazard. This is a legal entitlement under the NSW Occupational Health and Safety Act 2000.



• Ensure that first aiders are trained in the recognition of heat symptoms and first aid treatment of heat stress.



• If you are getting no response from management, consider calling in the WorkCover Inspector who may encourage your employer to take action. Retain copies of your records and written requests to management to show the inspector.