Preventing and Responding to Heat Illness
I. Effective Work Practices
2. Shade and Other Cooling Measures
See Shade and Access to shade
To prevent heat illness, there must be a balance between heat load on the body (heat produced internally by the body and gained from external sources) and heat released from the body to allow the body to cool.
You can use shade and/or the alternative measures listed below to provide cooling to your employees during breaks or at lunch. During Heat Waves, in addition to shade you may need to add one or more of the Alternative Cooling Measures listed below to prevent heat illness.
You can also use shade and the other cooling measures listed below to provide cooling during a Preventative Recovery Period should one become necessary. No matter how you choose to provide cooling for your employees remember to ensure that:
- Sufficient supplies of potable drinking water are close by
- Individuals are encouraged to frequently drink sufficient amounts of water
- Employees are able to assume comfortable body postures
Ways To Provide Cooling
Provide Cooling from Shade by Using:
- Structures that are mechanically ventilated or open to air movement (e.g., semi finished garages or other unfinished structures). If two or more stories are available employees can rest in the lowest floor in the shade.
- Tarpaulins tied to 4 posts
- Conex mounted RV canopies
- Full and thick tree canopies that block direct sunlight
- Enclosed areas only if they provide cooling comparable to shade in the open air
More About Shade:
- Set-up in advance portable umbrellas, canopies, and other portable devices used for providing shade
- Provide shade for the head and eyes by wearing wide brimmed hats and sunglasses
- Move portable shade areas close to work areas
Shade is adequate only when it completely blocks the direct sunlight and allows the body to cool. In adequate shade people and objects in the shade do not cast shadows in the area of blocked sunlight. Shade is not adequate when it does not allow the body to cool.
Do not provide shade by using:
- Metal storage sheds and other similar out-buildings unless they provide a cooling environment comparable to shade in the open air
- The interior of vehicles. This is because they keep heating up in the sun and do not provide cooling unless the air-conditioning system is continually running and working effectively
- Areas underneath or near equipment (e.g., tractors) or vehicles as they expose employees to other potential hazards
Provide Cooling Using Alternative Measures
There are also alternative ways to cool the body besides shade. Before using alternative cooling measures make sure they are safe to use for the conditions in your workplace.
Alternative cooling measures include, but are not limited to, cooling employees by:
- Putting them in an air-conditioned environment, if available
- Using misting machines
- Giving a cool shower, bath, or sponge bath if available
- Immersing them in a tub of cool water
- Spraying them with cool water from a garden hose or other sources
- Wrapping them in a cool, wet sheet or towel and fanning vigorously. Use this only if the humidity is low and evaporation is not restricted
- Using wetted clothing (e.g., terry cloth coveralls or wetted whole-body cotton suits). Use this only if the humidity is low and evaporation is not restricted.
- Directing compressed air of less than 10psi (see Cal/OSHA T8 CCR 3301) around the body from a supplied air system. This improves evaporative and convective cooling (i.e., cooling from a moving fluid)
- Using cooling vests (e.g., commercially available ice vests)
- Using water-cooled garments (e.g., hoods, vests and "long johns"). These require a battery-driven circulating pump, liquid-ice coolant, and a container
- Using battery operated, hand held, portable cooling devices or equipment
- Using air cooled garments (e.g., suits or hoods)