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PPE: PROTECTIVE APPAREL Material matters — and there are many materials available to address high-heat hazards in common industrial applications. on a hot stove burner is heated through conduction. ■ Radiation is heat transfer through electromagnetic waves. Radiant heat is heat that you feel when you are near a heat source, like when you’re sitting near a campfire. When selecting PPE to address thermal hazards, it’s important to classify the kind of heat transfer involved as a preliminary step — especially when there are multiple types of heat in play. A foundry worker might spend part of their day next to a furnace bringing metals to the melting point and later pouring that molten material into molds, with the risk of molten splash. A welder might be working outside in cold weather, but still need protection from sparks and slag. Hazards Uncovered Common hazards identified within the risk assessment for high- heat industries include: ■ Thermal burns from splashing hot liquids or contact with hot surfaces ■ Chemical burns from exposure to acids, caustics, flamma- ble, and toxic substances ■ Back strains and musculoskeletal disorders from awkward positioning, improper or heavy-weight lifting, repetitive motion ■ Heat stress from the high-heat, high-humidity environ- ment, enhanced with wearing PPE ■ Impact, crushing, or amputating injuries from manual lift- ing or moving of heavy materials These types of hazards lead to first-, second- and third-degree skin and eye burns, short-term and long-term back pain, and al- tered quality-of-life from significant injuries or heat-related ill- nesses that forever impact an injured person, his/her family, and his/her ability to work (livelihood). The hazards present on site and the serious consequences of inadequate protection should motivate any responsible manager to ensure adequate protection for workers. But how can you tell if your PPE is sufficient? A Material Difference Identifying thermal transfer type helps in selecting the right PPE. Material matters — and there are many materials available to ad- dress high-heat hazards in common industrial applications. ■ A para-aramid fifiber such as Kevlar provides high heat re- sistance and makes for a very strong, flflexible yarn. ■ A meta-aramid fifiber such as Nomex also provides high heat resistance, but Nomex yarns have lower tensile strength than Kevlar1 and tear more easily. ■ Why would you ever choose Nomex over Kevlar then? Be- cause Nomex yarns have a soft hand that tends to make softer fabrics and therefore more comfortable clothing. More comfort- able means an increased likelihood of wear which means better compliance. ■ And then there are fibers like OPAN, the core fiber in Car- bonX2 fiber blends, that carbonize and expand when exposed to intense heat or flame, starving the yarns of oxygen and therefore eliminating the fabric’s ability to combust. That Limiting Oxygen Index (LOI) yields a fabric that is truly non-flammable. Key Questions to Ask Before Buying So, how can you discover the best information to make a deter- mination on which protective apparel to use in a given high-heat situation? The following questions will elicit enough information to narrow in on good options — and then you may well have to test samples in the specific environment. A good PPE manufac- turer or distribution partner will work collaboratively to get to the safest, most cost-effective solution. 1. What is the average working temperature during the task? 2. What is the maximum temperature that might be reached? How often does that happen? How long does exposure at the high temperature last? 3. Does the wearer touch the hot item (conductive heat) or just work near the heat (radiant heat)? 4. How long is usual exposure time? 5. If the wearer is picking something up or holding something, how heavy is that object, and how long do they hold it? (The heavi- er the object, the more it compresses the fibers in the PPE fabric, leading to quicker heat transfer and a shorter time to pain.) 6. Is there moisture or splash involved? If so, how often and how much? What substance is the splash? (Will the wearer need chemical protection as well?) 7. Are there abrasion or cut hazards? (If so, need to choose a fabric that is more abrasion-resistant.) 8. What are the ambient air conditions in the facility — is nor- mal heat stress an issue in addition to the high-heat hazard? 9. And the simplest but best question of all: What are you us- ing now? What do you like about it, and what would you like to improve? You Can Ask for Help You don’t have to make this decision alone. Many vendors and suppliers have in-house safety experts on staff who can offer additional information and perspective. Some also perform on-site assessments in order to properly gauge the hazards your employees will be facing and determine the appropriate PPE. 24 Occupational Health & Safety | FEBRUARY/MARCH 2024 www.ohsonline.com Mary Ann Merikoski the Director of Product-Apparel at Chicago Protective Apparel, a division of Mechanix Wear. REFERENCES 1. tinyurl.com/28hypfap 2. tinyurl.com/4cv95uvd