Get a humidity meter and temp guage - there is a legal threshold beyond which you can't work - you add the percentage humidity and temp in C numbers together or some such - and if it's over the threshold then it's unsafe, and a violation of some health and safety provisions - from memory the threshold is 110 - but don't quote me on that. edit - I googled this a bit - found a regulation doc - not sure if it's the latest. “time-weighted average” means the average of a number of representative measurements that are taken over a period of time and that are calculated as follows: Time-Weighted average = x1t1 + x2t2 + x3t3 + …. + xn.tn t1, + t2 + t3 + …. + tn where x1, x2, etc., are the observed measurements during the corresponding periods t1, t2, etc., minutes, and t1, + t2 + t3 + …. + tn is the total time in minutes over which the measurements are taken; “WBGT index” means a number which characterises the thermal conditions in the environment to which that number applies; it is calculated by adding seven tenths of the reading in degrees Celsius obtained with a naturally ventilated wet-bulb thermometer to one fifth of the reading in degrees Celsius obtained with a globe thermometer and adding that sum to one tenth of the reading in degrees Celsius obtained with a dry-bulb thermometer; the index may also be obtained by using an electronically integrating direct-reading instrument which has been designed, built and calibrated for that particular purpose; (4) Where the time-weighted average WBGT index, determined over a period of one hour, exceeds 30 in the environment in which an employee works, the employer of such employee shall - (a) if practicable, take steps to reduce the said index to below 30; or (b) where it is not practicable to reduce the said index to below 30 and where hard manual labour is performed- (i) have every such employee beforehand and thereafter, at intervals not exceeding one year, certified fit to work in such environment by a registered medical practitioner or a registered nurse according to a protocol prescribed by such practitioner, and every such employee shall, if found fit to work in such environment, be issued with a certificate to that effect by such practitioner or nurse; (ii) ensure that every such employee is acclimatised to such working environment before he is required or permitted to work in such environment; (iii) inform every such employee of the need to partake of at least 600 millilitres of water every hour; (iv) train every such employee in the precautions to be taken to avoid heatstroke; and (v) provide the means whereby every such employee can receive prompt first-aid treatment in the event of heatstroke: Provided that, where the question arises as to whether any particular type of work does in fact constitute hard manual labour, the decision of an inspector shall be decisive. Source - https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=0ahUKEwjkz9SFh5jYAhWjK8AKHRK8B5kQFghKMAU&url=http%3A%2F%2Fwww.labour.gov.za%2FDOL%2Fdownloads%2Flegislation%2Fregulations%2Foccupational-health-and-safety%2FRegulation%2520-%25202281%2520-%2520Environmental%2520regulation%2520for%2520workplaces.doc&usg=AOvVaw2EnYpYOHQ2QgRNd1YWtZD3
