Question 1:
(5 marks)
Herbicide spraying is taking place with a hand-held spray. The sprayers carry a container of weedkiller on their backs and the spraying covers a large area which they are covering on foot.
The sprayers have just come back from annual leave, this being their first week back.
To protect themselves against the herbicide, they are wearing cotton coveralls and gloves.
On the day when spraying is to take place, the temperatures are measured at 11am.
They are: Globe temperature 43.50C Air temperature 32.00C Natural wet bulb temperature 20.00C * Calculate the WBGT * What work-rest program would you recommend? * …show more content…
The adverse effects of heat stress faced by the workers are the combined effect of industrial heat exposure and the climatic one. The Wet Globe Bulb Temperature for indoors is calculated as WGBT= (0.7XNWB) + (0.3XGT) According to the above mentioned values, where the WGBT for workers in operator position is very high, the work-rest cycle provided by the organisation is perfect i.e a 50% work to rest ratio. The thirty minutes during which the workers are on standby, they should seek rest in a cool area. The workers in this unit are required to wear protective gloves and apron, which hinder evaporation of sweat from the skin thereby, increasing body’s core temperature. Under such circumstances, it is necessary to reduce the WGBT levels of exposure to below those appropriate for workers wearing light clothes (cotton). A number of steps can be followed to minimise heat stress levels in the aluminium refinery: * Fluid Replacement: * Drinking non-alcoholic beverages like energy drinks preceding work. * During work, water should be taken in small quantities at regular intervals to avoid dehydration. * Electrolyte balance in the blood should be maintained by having drinks containing 0.5-0.7g/l of sodium. Low electrolytes in blood result in muscle cramps (a side effect of heat stress). * Organisation of work: Under the occupational health and