Not all personal protective equipment (PPE) are created equal. Choosing the right kind of PPE for the job is just as important for work safety as wearing a PPE. Knowing the different types of PPE materials, their features and limitations can help you make an informed decision about PPE selection.
Whether you’re in a medical operating room or an industrial welding environment, personal protective equipment (PPE) is essential in keeping employees safe. As diverse as the applications requiring PPE are, the variety of options available for eye and face protection and level of protection each product provides are equally as distinct.
To ensure employees at your organization are equipped with the most applicable eye and face PPE for their environment, it is critical to identify the characteristics of faceshields and eyewear that are most important to the situation — from overall optical clarity to impact and heat resistance.
Understanding the PPE needs of your industry is the first step, although becoming educated on the materials that provide these required traits is essential in helping select the proper protective equipment. All materials — including cellulosics, polycarbonate (PC), polyethylene terephthalate glycol (PETG) and new-generation tetramethyl cyclobutanediol (TMCD) based copolyesters — provide benefits for eye and face PPE. Sorting through the characteristics that make each material applicable for certain environments can ensure employees are safe in the workplace.
Face protection factors to consider
PPE that fails to perform its duties of providing unobstructed vision and complete protection to its user often is considered a failure, regardless of the retention of other properties.
For example, a faceshield that has been hit and cracked by flying material fragments may be completely compromised due to its lack of toughness, despite the remaining potential for chemical resistance. Similarly, marring in the surface of a protective faceshield caused by chemical contact can impair vision, sacrificing the overall value of the product to its user even if its toughness remains intact.
Considering this, it is important to equally evaluate all demands your industry has for PPE — specifically in terms of impact resistance, chemical exposure and optical quality, in order to make the proper eye and face protection purchasing decision.
High chemical resistance and optical quality
Environments such as pharmaceutical manufacturing require faceshields and eyewear that provide superior chemical resistance and optical clarity. In these situations, cellulosics have great advantages. PPE made with cellulosics offers exceptional chemical resistance because the material is able to release stress caused by chemical exposure. Because of how the material is processed, eye and face protection applications made with cellulosics exhibit unmatched optical clarity. PPE made with cellulosic materials also has great inherent scratch resistance.
For situations requiring PPE with special antifog and antiscratch properties, cellulosics provide added benefits by providing clear, pristine optical clarity. PPE made with cellulosics, however, will not endure environments requiring extreme impact strength or heat resistance.
High impact, fair chemical resistance
For situations requiring high-impact resistance, such as those in industrial or construction settings involving cutting or grinding, PC has long been the industry standard. For faceshield and eyewear for ballistic and military environments, PPE made with PC provides the toughness needed to comply with American National Standards Institute (ANSI) regulations at speeds up to 300 feet per second.
PPE made with PC is also suitable for applications involving exposure to moderate temperatures, such as in welding environments, as the material has good heat resistance, and is commonly selected for use in situations requiring average scratch resistance and clarity. In addition, faceshields and eyewear made with PC can be coated with antifog and antiscratch coatings.
Despite the inherent impact resistance of products made with PC, faceshields and eyewear made with the material offer only fair chemical resistance. When exposed to the common cleanser additive ammonium hydroxide, PPE made with PC exhibits catastrophic change including whitening of the lens or shield and loss of visibility. Likewise, manufacturing processes involved in the development of PPE made with PC can result in aberrations, sacrificing optical clarity and visibility provided by the protective device.
Good chemical and impact resistance
Faceshields and eyewear made with PETG provide a solid option for a variety of safety applications requiring middle-of-the-road protection. For environments with little chance of high impact, such as in most medical fields, PETG is commonly selected for PPE applications because it has good chemical and impact resistance. Eye and face protection made with PETG provide good optical clarity, offering an affordable overall option for many settings. However, face and eye protection made with PETG can only handle minimal impact because the material does not consistently pass ANSI regulations at thinner gauges.
High impact and chemical resistance
To help consolidate protective requirements in one universal product, including high-impact and superior chemical resistance, new generation TMCD-based copolyesters are utilized for eye and face protection. PPE made with new-generation TMCD-based copolyester material is used in a wide variety of environments, from refineries to laboratories, where users may frequently transition from situations with a possibility of interacting with flying debris and chemicals or cleansers.
Eyewear and faceshields made with TMCD-based copolyester have greater durability, meeting ANSI 300-feet-per-second, high-impact resistance parameters, similar to PC. PPE applications made with these copolyesters also provide greater protection against chemicals, and, unlike PC, will not stress-whiten and inhibit visibility when exposed to chemical agents. Another benefit of PPE made with TMCD-based copolyesters is the reduction of vision- and durability-impairing fractures and cracks where the faceshield attaches to the headgear frame due to the material’s lower flex modulus that gives it the ability to bend. PPE made with TMCD-based copolyester, however, is not resistant to high temperatures.
Making the final decision
Whether your focus is solely on high-impact protection, or your occupation requires an integration of impact and chemical resistance, making the final PPE decision doesn’t have to be complicated. Consider the intended function of your eye and face protective equipment and select the material that possesses the inherent strengths that best match these requirements — a simple solution to maximize the eye and face safety of all employees.
[em]Ann McGlone is market development manager, specialty plastics, at Eastman Chemical Company. Eastman, a global company committed to providing chemicals, fibers and plastics, is located in Kingsport, Tenn., 423-229-2000. You may contact McGlone at email@example.com