Monday, July 22, 2019

Safety Tidbit 4.36 - Sunburn


Safety Tidbit 4.36 – Sunburn

Reference:        OSHA Webpage - https://www.osha.gov/Publications/OSHA3166/osha3166.html

I hope everyone made it through the heat wave okay. In the last Safety Tidbits, we talked about the temperature and how to protect yourself. How many of you enjoy the warm summer sunshine and like a good tan?

Note: There are no safe UV rays or safe suntans. Sunlight contains ultraviolet (UV) radiation, which causes premature aging of the skin, wrinkles, cataracts, and skin cancer. The amount of damage from UV exposure depends on the strength of the light, the length of exposure, and whether the skin is protected.

Skin Cancer


Sun exposure at any age can cause skin cancer. Be especially careful in the sun if you burn easily, spend a lot of time outdoors, or have any of the following physical features:
  • Numerous, irregular, or large moles.
  • Freckles.
  • Fair skin.
  • Blond, red, or light brown hair.

If you find such unusual skin changes, see a health care professional immediately.
Controlling Exposure

Engineering controls:
            Shelters - Stay under a room, Use portable shelter, tarps or umbrellas to keep the sunlight out.
Administrative Controls:
            Limit your duration of exposure. UV rays are most intense between 10 a.m. and 4 p.m. If you're unsure about the sun's intensity, take the shadow test: If your shadow is shorter than you, the sun's rays are the day's strongest.
Personal Protective Equipment:
Skin - Cover up. Wear tightly-woven clothing that blocks out light. Try this test: Place your hand between a single layer of the clothing and a light source. If you can see your hand through the fabric, the garment offers little protection.
Head - Wear a hat. A wide brim hat (not a baseball cap) is ideal because it protects the neck, ears, eyes, forehead, nose, and scalp.
Eyes - Wear UV-absorbent shades. Sunglasses don't have to be expensive, but they should block 99 to 100 percent of ultraviolet radiation.
Last resort - Use sunscreen. A sun protection factor (SPF) of at least 15 blocks 93 percent of UV rays. You want to block both UVA and UVB rays to guard against skin cancer. Be sure to follow application directions on the bottle. Remember: Swimming or sweating reduces sunscreen protection.
Hope this was helpful and thank you for reading my Safety Tidbits! Comments and questions are always welcome. ~ Bryan

P.S. If you have a new safety or health question, please let me know.

Friday, July 19, 2019

Safety Tidbit 4.35 - Wet-Bulb Globe Temperature



Safety Tidbit 4.35 – Wet-Bulb Globe Temperature

Reference:        ACGIH -Threshold Limit Values (TLV) 2018
                        National Weather Service (https://www.weather.gov/tsa/wbgt)

Last Summer I and two of close friends rode our motorcycles from San Francisco back to Pennsylvania. One our stops along the way was Death Valley. But we couldn’t just visit “Death Valley” we had to visit in the middle of Summer and the middle of the afternoon. The temperature was 118 degrees F. Everyone told us it wouldn’t feel as bad as the heat back East because it was a “dry heat.” Let me tell you, when riding a motorcycle, 118 degrees is hot wet or dry! Since the forecast is for extreme heat over the next few days. I thought I would spend a little time discussing measuring heat stress. See Safety Tidbit 2.41 for more on the Heat Index.

The Wet-Bulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight, accounting for: temperature, humidity, wind speed, sun angle and cloud cover (solar radiation). This differs from the heat index, which takes into consideration temperature and humidity and is calculated for shady areas. If you work or exercise in direct sunlight, this is a good element to monitor. Military agencies, OSHA, and many nations use the WBGT as a guide to manage workload in direct sunlight.

The WBGT can be calculated using the formula
            WBGT = 0.7GB + 0.2WB + 0.1DB

Where GB is globe temperature, WB is the web-bulb temperature and DB is the dry bulb temperature. The globe temperature is the heat loading from radiant sources. Outside in the summer the largest source of radiant heat being the sun. This temperature is found by using a copper globe painted in black matte paint with a thermometer inserted so that the bulb is in the center of the globe. As you can see this portion is 70% of the over WBGT. The wet bulb temperature describes humidity and is 20% of the calculation. Lastly, at only ten percent of the calculation is the common household dry bulb temperature.

Once the WBGT is calculated precautionary actions can be taken when working outdoors. A WBGT of 80 degrees is usually the starting point where fifteen minutes breaks out of every hour of work outdoors are necessary. The most severe is when the WBGT exceeds 90 degrees when the ratio is reversed, and 45 minutes of rest are necessary for fifteen minutes of work outdoors.

  Take breaks in the shade. Strenuous outdoor activities should be reduced, especially in direct sunlight where there is little ventilation.
  Drink plenty of water or other non-alcohol fluids. Your body needs water to keep cool. Drink plenty of fluids even if you don’t feel thirsty.
  Don’t get too much sun. Sunburn makes the job of heat dissipation that much more difficult

Hope this was helpful and thank you for reading my Safety Tidbits! Comments and questions are always welcome. ~ Bryan

P.S. If you have a new safety or health question, please let me know.