ST. PAUL, Minn. — Workers who are required to wear protective apparel such as coveralls often state that comfort and ‘moveability’ are paramount. Moreover, they express that their number one complaint is heat buildup since wearing protective suits over their clothes can result in hot conditions.
The challenge lies with having a breathable coverall that is also highly protective. Balancing the need for comfort while maintaining an acceptable level of protection in coveralls do not have to be opposing goals.
The Science of Sweat and Designing Breathability in Coveralls
First, the breathability of fabrics depends on the type of fabric used. SMS, or Spunbound Meltblown Spunbound, fabrics generally have more breathability than laminates. The breathability of laminates can vary as well depending on the size of the micropores in the fabric. Generally, the larger the micropores the less protective the fabric may be.
So, how do you know if a coverall is breathable or not? There are a number of tests designed to quantify the breathability of fabrics. One test is to measure the water vapor resistance of a fabric under steady-state conditions. This is often referred to as the “sweating guarded hotplate test” or “skin model” because, in many ways, it tries to replicate the way the human body sweats in order to cool down and maintain a steady temperature.
The result of the test is what is called the RET value. Using the resulting RET, it is possible to suggest a comparison between fabrics with different RET values. The lower the RET value suggests more breathability in the fabric.
Completing the Job Safely While Working in Comfortable Coveralls
These tests should be used when developing coveralls and designing protective apparel that allows for breathability, which can be accomplished without sacrificing protection. To achieve breathability in protective apparel, such as coveralls, the key is the ability of the fabric to enable the wearer to maintain a comfortable body temperature. The human body, particularly when it is being worked hard, generates heat. If this heat is trapped inside the garments, then the wearer is likely to get hotter faster and experience more and more discomfort.
For instance, look at the needs of the workers at The Hinckley Company, where they handmake custom yachts in Maine. These workers need to maintain a constant temperature and humidity in the facility so products can be the best they can be and adhere correctly to the boat paneling.
Debbie Henry, a Safety and Compliance Specialist at Hinckley, states “They were looking for something that would afford them some breathability and not be so hot and humid on top of the environment they are working in. They tried the [3M] coveralls and they haven’t looked back. They love them. I can get them on them, but I can’t get them off them!”
Understanding the dynamics of breathability and protection levels in coveralls can help you to choose the right coverall for the application.
You can also find the specifications on the User Instructions supplied with each product, or by contacting your local 3M representative. We also invite you to try our coveralls today by requesting a complimentary sample.
Read more about the dangers of heat-stress and download this thorough report by NIOSH.