The ALARA principle is used in industrial radiography to protect workers during the testing of weld seams in a tank or pipeline.
(ALARA) or “as low as reasonably achievable” is a phrase used in the United States to denote minimization of exposure to radiation. Workers exposed to radiation can maintain their radiation doses ALARA by reducing the time spent near sources of radiation, increasing their distance from radiation sources and establishing a shielding mechanism between them and radiation sources.
A great way of achieving ALARA is to half the exposure time to radiation as this would reduce the radiation intake by 50%. Increasing the distance between a person and source of radiation can also help in drastically reducing the radiation dose rates. There is an inverse relationship between distance and dose rates; an increase in distance leads to a decrease in the dose rate, according to the Inverse Square Law. Radiation shields are also effective in reaching ALARA levels. Radioactive materials or machines that emit energetic negatively charged electrons and those that emit photons are two common external radiation sources. Certain materials are effective as radiation shields depending upon the levels of interactions that take place within them. It is simpler to shield electrons compared to photons as electrons of a particular energy have a fixed range. On the other hand, energetic photons do not have a set range for a material category.
Other measures that can minimize exposure to radiation include the use of adequate protective equipment such as gloves, glasses and lab coats; and the use of fume hoods for volatile substances, among others.
A program to prevent heat stress
Heat stress refers to the combination of environmental, work and clothing factors that lead to a rise in body temperature, heart rate and sweating. As a site safety officer at a hazardous waste site, I have been asked to design a program to deal with heat stress and would take consequently take the following steps.
I would focus on making basic changes in the work environment such as reducing physical work, simplifying clothing rules, lowering the exposure time to hot surfaces and controlling the air temperature and air speed. Other practical steps would consist in shortening the duration of each exposure as a larger number of infrequent short exposures are better than fewer long exposures and scheduling hot jobs in the cooler part of the day to the extent feasible. I would also ensure proper acclimatization of new workers to the prevailing heat conditions, wherever unavoidable, and emphasize frequent intake of water in order to conserve energy levels and prevent hypo-hydration.
References
Barbara A. Plog and Patricia J.Quinlan. Fundamentals of Industrial Hygiene (6th Ed)
