The most important solutions to heat stress are frequent rest and water breaks in the shade. If laborers work in the sun they absolutely must have tents or shade sails available with cool water and seating.
- By Dave Shank
- Mar 01, 2014
The Occupational Safety and Health Administration can trace its history back to President Nixon's signature in 1970. Driven by calls from labor unions and the increasing reality of deaths and disabilities in many industries, both OSHA and its sidekick NIOSH were born. Interestingly, OSHA became a division of the Department of Labor while NIOSH reported into the CDC, part of Health and Human Services. Clearly, the former deals with enforcement and the latter with research.
Since its inception, OSHA has done much to improve industrial safety, often in response to tragic episodes. Many efforts and compliance directives have focused on chemicals and pollutants, such as asbestos, vinyl chloride, arsenic, lead, benzene, and carcinogens. Unsafe working conditions have been eliminated or diminished in many industries, including shipbuilding, meatpacking, petroleum refining, sugar production, grain, construction, textile, and process industries.
While such regulations have dealt appropriately with obvious industrial issues, it was not until 1987 that minimal initial standards were issued for the more subtle, seasonal, and variable issue of heat stress. This originated in the fields where low-wage braceros roamed from crop to crop to harvest our nation’s agricultural bounty. These invisible and defenseless Mexican workers would perform the "Stoop Labor" that was somehow a better living standard than in their own country. The basic regulations demanding potable drinking water, toilet type facilities, and clean water for washing hands was an initial step, and those instructions are still posted in most restaurant bathrooms to this day for kitchen help.
Now, let's fast forward to the heat stress issues of today:
1) Many companies still look at resolving heat stress as a business cost and not an opportunity.
2) Heat stress is addressed by "Definitions, Symptoms, and Guidelines."
3) Manufacturing operations and distribution budgets are always under intense scrutiny, often by management in air-conditioned offices and not even on job locations.
4) Much of the OSHA standards, by necessity, deals with modifying work schedules where possible, emergency planning, supervisor training, and promoting adequate water and rest breaks.
Comfort and Productivity in Context
In an effort to illuminate some issues regarding heat stress, consider looking at this issue in the light of significant benefits of cooling and the hidden cost of not cooling. The negative impact of having a significant incident can be quite costly. Of course, there is the exposure to increased OSHA oversight, paperwork, and possible fines. The 911 call, if necessary, can prove expensive if an ambulance is required. Disruption or a slowdown of the workforce for a length of time is natural.
In many industries, finding and training new employees is a significant challenge. Take an auto shop that competes with a new car dealer with a new, air-conditioned service area. If it is 100 degrees in the summer, the risk of your best employee being enticed to a better work environment is something to think about. And consider the one-time cost of investing in your workers' comfort, as opposed to the annual issue's always being salary.
Now, consider productivity. Do workers work as efficiently when their glasses are fogging up or when the sweat is dripping off their noses? How many water and rest breaks might be avoided if it were 10-12 degrees cooler? How many errors are made that need to be reworked or retooled? How many shortcuts are taken that lead to customer complaints?
However, possibly the greatest reason for reducing the heat is the feeling a workforce gets when the employees believe that management cares a little about them and wants to make them more comfortable. That can be a more valuable inducement than a pay raise.
Using the Heat Index Table
What is seat stress and how is it measured? The Heat Index Table is considered the bible for heat stress measurement and is simply a combination of the temperature and the relative humidity (%).
The combined impact of heat and humidity greatly increases as each one increases:
- At 40% humidity and 88 degrees, the index is only 88.
- At 40% humidity and 94 degrees, the index is up to 97.
- At 40% humidity and 100 degrees, the index is now 109.
- At 60% humidity and 88 degrees, the index is up to 95.
- At 60% humidity and 94 degrees, the index is up to 110.
- At 60% humidity and 100 degrees, the index is now 129.
Clearly, higher-humidity climates are particularly risky as the temperature becomes more intense.
The various types of heat stress symptoms correlate closely to the heat index. Difficulties can vary from a heat rash or cramps to fainting, exhaustion, and stroke. Most, if not all, OSHA professionals are well in tune with these relationship issues, and I won't labor to repeat the obvious here.
The most important solutions to heat stress are frequent rest and water breaks in the shade. If laborers work in the sun they absolutely must have tents or shade sails available with cool water and seating. In California, for example, it is a state OSHA regulation that there must be shade to accommodate at least 25 percent of the workers at any given time.
To further cool workers, a mist line can be attached to the perimeter which will reduce the temperature by as much as 20degrees. Even if no faucet is available as a supply line, portable units are available with 12-volt batteries and booster pumps (200 psi) that do an excellent job for five hours without a water refill.
Personal Gear and Fans
Many industries have major issues with sugar or grain dust or petroleum processing vapors that can explode with a spark. For those intense problems, Class 1, Div 2 explosion-proof pumps are available, albeit at about triple the price of a regular pump. Just the same, those industries are some of the most demanding on workers, and the price seems insignificant compared to the human relief.
For intense heat, personal gear is available as vests with freezable ice packs that can last two to three hours or as air vests, which are inflated by a compressed air tube. Yes, they are somewhat cumbersome, but also effective.
In the factory, warehouse, or shop floor, circulating fans to move air and exhaust fans to remove hot air from above have been a traditional method to make the air more bearable. Large areas have found some relief by installing 8- to 24-foot-diameter ceiling fans that are marketed under several brand names.
In the past decade a new and remarkable workplace cooling capability has emerged through the use of high-pressure misting fans. Most likely, you have seen fogging fans on the sidelines at college and professional football games to chill players during the intense heat of the summer and fall games. These are similar to what some fire department use for emergency "blast" chilling of burn trauma victims. When a boiler needs repair or maintenance work is required by an individual or a small team, high-pressure portable misting fans can be filled with water, moved to locations, and run for five to six hours without a refill. This can reduce the temperature by up to 30 degrees, not including the increased wind chill factor.
Misting fans have the advantage that many fans can be outfitted with nozzles and run off a single pump. They can be wall mounted, hung from support beams, or attached to pedestals. Many people suspect that mist will wet equipment, product, and floors, but that is simply not true if the smallest orifice nozzle is utilized with 1000 psi pumps.
In less-humid areas (40 percent humidity or less), a simple 180 psi booster pump can suffice with a significant cost savings if no more than 25 nozzles are required for cooling four to five workers in auto shops and related venues.
In summary, because the impact of heat stress varies with the worker exertion level, humidity, and shade factors, it is clearly up to management to determine the best path to reduce the chance of incidents and consider the improved performance of workers by providing a cooler atmosphere.
This article originally appeared in the March 2014 issue of Occupational Health & Safety.