Protective Clothing: You Can Achieve Comfortable Protection

By Beth Hohl, Manager
Marketing and R&D
Kimberly-Clark Safety Division

Choosing the most appropriate protective apparel can be a daunting task. With differing standards and guidelines, changing regulations and a checklist of criteria including design, fit and cost, there’s a lot to consider.

Of course, the primary responsibility of protective clothing is to protect the wearer — the critical factor in selecting proper apparel. However, if the garment is not comfortable and breathable, there is a chance that users may "field-modify" the garment by ripping out airholes or not fastening the garment properly to minimize discomfort. Such modifications can compromise the protection the garment offers.

The breathability and comfort quality of a garment are key to preventing heat stress, improving worker productivity and helping workers comply with apparel wearing guidelines. Fortunately, recent advances in fabric development mean that safety professionals no longer need to trade off between comfort and protection. In fact, there are two widely used fabric technologies (spunbond-meltblown-spunbond multilayer laminates and breathable barrier film laminates) for protective garments that prove you can achieve both comfort and protection.

Advances in SMS Technology
One breathable fabric used in protective apparel is an engineered multilayer laminate known as SMS (spunbond-meltblown-spunbond). In typical SMS constructions for protective apparel (see Figure 1), the outer spunbond layers are made of randomly deposited 15-20 micron diameter continuous polypropylene fibers which provide cloth-like comfort, as well as fabric strength, durability, abrasion resistance, and protection for the meltblown layer. The inner meltblown layer provides barrier and is typically comprised of 1-3 micron diameter polypropylene fibers. The advantage of meltblown as the barrier layer is that it is permeable to both air and moisture vapor, meaning both air and sweat vapor can pass through the garment to keep the skin cool and the wearer more comfortable in hot working environments. At the same time, the meltblown barrier layer provides a great deal of particulate and liquid protection. It must be noted, however, that many polypropylene protective garments currently sold contain only a spunbond layer without the barrier meltblown layer. However, the quality and subsequent performance of these products are inferior. Such garments provide minimal protection.

In the two+ decades since the issue of the first SMS material patent by Kimberly-Clark scientists, the properties that make the SMS structure unique have been significantly honed and refined, although the basic laminate structure remains the same. Today, however, the structure is being engineered to meet a wide range of user needs in a variety of ways — most importantly improving the barrier properties while maintaining the breathability and comfort for which the SMS fabric construction is known.
Recently, Kimberly-Clark looked to improve particulate hold-out properties for its SMS fabric against fine particles like carbon black. The goal of the development effort was to find a way to impart particulate barrier without shutting down the breathability of the garment.

The result of these research efforts is a patented technology used in many different products that Kimberly-Clark offers, including protective apparel. MICROFORCE* Barrier Treatment gives the garments excellent barrier protection (superior to that of competitive SMS fabrics) on submicron particulates, making the garments ideal for protection against many fine dusts and fibers while maintaining the workers’ comfort. (see Figure 2)

Breathable Barrier Film Laminates
Breathable-barrier film laminates also provide a unique combination of comfort and protection. These fabric constructions, which have been in existence for more than 25 years, allow the permeation of moisture vapor but prevent penetration by fluids. Of the two main classes of breathable barrier laminates (monolithic, or hydrophilic film laminates and microporous film laminates), it is the microporous film laminates which have been more successful in gaining acceptance in the protective apparel industry.

The most crucial part of the microporous film laminate is the film layer itself. As the name implies, an interconnected network of micropores is formed in the film which, by tortuous path and size, permit the transfer of moisture vapor (such as perspiration) while inhibiting the transfer of liquids and particulates. The transfer of heat and perspiration away from the skin and through the laminate itself enables the body to cool itself and helps the skin to feel drier. Since the microporous film itself is usually not very durable or cloth-like, it is typically laminated to at least one nonwoven layer or preferably two layers, forming a sandwich with the film in the middle (see Figure 3).

Microporous film laminates are extremely versatile in their range of properties. Structures can be produced with an unusual combination of high breathability (comfort) and high barrier. Kimberly-Clark’s KLEENGUARD® Ultra garment is a good example, as a protective garment that protects from blood-borne pathogens and provides liquid spray hold-out. As microporous film laminate technology advances, expect to see its share of the overall industrial protective apparel marketplace advance along with it.

The Right Fit Equals The Right Protection
How many garments do you toss away due to rip-outs? Garments designed to meet ANSI minimum sizing standards can rip when stress is applied to seams during normal work movements. Seam and zipper failures are other frequent problems. A garment that is ripped out or user-modified (not zipped properly, airholes ripped out, etc.) will not provide the protection it was designed to offer.

To avoid these problems, look for garments with seams in the back of the garment instead of at the splash zone in the front. Also, look for a garment with a generous cut in the shoulders, seat and crotch (key stress areas) and elastic waist, and more fabric in key stress areas for greater range of motion.
Kimberly-Clark incorporates these apparel features in its patented REFLEX® Coverall design, helping to ensure garment comfort and compliance with garment-wearing guidelines.

Hazard Assessment
In choosing the most appropriate protective apparel, safety professionals need to consider both protection and comfort. Begin by identifying the particulates, liquids and other hazardous substances that will be present in the worksite and the hazards associated with those substances. In general, the nature of the hazard will steer you to the appropriate garment material. And with today’s advances in materials and designs, there is no need to sacrifice comfort for safety.

For more information on comfort that protects, contact the Kimberly-Clark Safety Division at 1-800-255-6401.