FR Garment Comfort: Explaining the Mystery

It is extremely important to consider the three pillars of comfort—heat and moisture management; fabric hand; and garment fit/design—when evaluating your options.

• By Joel DeNardis
• Aug 01, 2014

When it comes to selecting flame-resistant (FR) garments, there are many variables to consider, including protection, comfort, durability, appearance, style, cost, and quality. Although each of these criteria will influence your purchasing decision to some extent, there is no question that protection should be your primary concern. Key industry standards, such as National Fire Protection Association (NFPA) 2112, serve only as a minimum; therefore, it is critical that a hazard assessment be conducted, because not all FR garments perform the same in an exposure.

Likewise, not all FR garments provide the same performance when it comes to comfort attributes. Due to advancements and innovations in FR technology, a wearer no longer has to make a trade-off or sacrifice their protection to be comfortable. As a result, FR garment comfort has rapidly become a key factor in a wearer's purchasing decision.

Why Comfort Is Important
Being uncomfortable can put workers at risk. When FR garments are not comfortable, workers are more likely to take shortcuts with wearing their personal protective equipment (PPE) and job task. In fact, according to a recent National Safety Council Study,¹ 89 percent of workers have observed other workers failing to wear PPE. The top reasons given for failure to wear FR PPE are that the garments are uncomfortable and too hot.

In a third-party market research study,² FR garment wearers said that light weight and breathability were the two most important garment comfort features, followed by garment fit, softness, and moisture management.

By selecting FR garments that provide protection and comfort, your workers will be more likely to wear them—and wear them appropriately. This will not only increase compliance to FR safety regulations, it also can increase productivity, reduce heat-related illnesses, and improve worker morale.

Comfort Is a Complex Issue
Simply stated, comfort is the combination of the garment properties and each individual's perception or preference, with the region and work environment having significant influence on this comfort perception. However, the issue of comfort can seem very confusing because there are many variables involved.

For FR garments, comfort can be influenced at every manufacturing step—from the type of fiber (natural or synthetic) to the fabric weaving construction/finish and final garment design. Comfort also can be influenced by the effects of laundering, including shrinkage and the touch and feel. It is important to not make judgments on comfort based solely on one attribute, but to consider the garment and the work environment in which it will be worn.

Perhaps the most challenging issue is the fact that comfort is subjective. That's why the best test is a personalized wear trial. Wear trials can be time intensive, so it is important to use data as directional indicators of comfort. But what are the key attributes to look for in a garment before wear testing?

The key attributes can be divided into three pillars of comfort: heat and moisture management; fabric hand; and garment fit/design.

Heat and Moisture Management
The body regulates heat in four primary ways: radiation, convection, conduction, and evaporation. In hot and humid environments, evaporative cooling (wet heat transfer) is the primary heat loss method. In cooler environments, the other three methods (dry heat transfer) are more prominent. To manage heat effectively, each of these mechanisms must be considered for FR fabric and garment design.

Managing sweat/moisture is one of the most important aspects of heat management. Moisture travels in both vapor and liquid forms away from the body. While moisture vapor can pass between fibers and through openings in the fabric, liquid/sweat is transmitted from the skin to the fiber's surface before evaporating into the air. Poor moisture management can make a garment feel clammy,³ clingy,³ sticky, and heavy.

Fiber type can be a differentiator in moisture management
Hydrophilic fibers, such as cotton, wool, silk, and cellulosic, have an increased ability to absorb moisture and sweat. However, when saturated, these fibers swell, decreasing the fabrics' ability to breathe, so garments can take longer to dry and can feel wet and heavy. Hydrophobic fibers, such as polyester, modacrylic, and aramid, absorb less moisture than hydrophilic fibers, but they dry faster due to lower moisture content.

Engineered fabric blends incorporate both fiber types to optimize moisture management. The key is balance.

Wicking is a critical indicator of heat and moisture management
Wicking, defined as the movement and dispersion of liquid through fabric, is a critical indicator of heat and moisture management. High wicking can lead to feeling dry, increasing evaporative cooling. According to results from third-party research, wicking is the most effective process to maintain a comfort feel.⁴

In addition to wicking, a fabric's ability to dry quickly can be considered to be almost equally important. Thicker and heavier fabrics are more prone to holding onto the moisture and not releasing it as quickly. A fabric should have a balance in its ability to absorb, wick, and dry to effectively manage moisture.

Fabric weight and air permeability have significant influence on heat and moisture management
Lighter-weight fabrics and more open fabric weaves increase air permeability, leading to garment breathability. Greater air permeability increases moisture movement through the fabric, leading to a wearer's feeling dry and cool. Higher air permeability enables higher sustainable work rates and reduced likelihood of heat stress.⁵

When comparing different fiber/fabric types, it is important to remember that higher weight does not always equal greater protection. In fact, lower weight fabrics can not only meet, but exceed NFPA standards. Be sure to avoid compromising what is at the core of why you wear FR clothing, and that is protection so you can go home safe at the end of the day.

Measuring heat and moisture management multi-dimensionally
The innovative sweating manikin, which contains 34 temperature-controlled sensors, simulates sweat and heat production, taking into consideration garment design, fit, and construction. Although most comfort tests measure a fabric in only one dimension, the sweating manikin uniquely considers several fabric attributes all at once. This includes measuring both wet and dry heat transfer through two key tests: thermal resistance (ASTM F1291) and evaporative resistance (ASTM F2370).

Technology advancements continue to evolve the science of comfort as evidenced by the sweating manikin test and its ability to look more comprehensively at comfort and the impact an FR garment has on regulating body heat.

FR Garment Fit/Design
FR garment fit will vary slightly between manufacturers, so ensuring personalized sizing and conducting a wear trial are important factors in FR garment comfort.

An improper FR garment fit can negatively affect comfort by: increasing contact points between the garment and skin; creating unnecessary compression on the body; and feeling more clingy, clammy, and sticky. In addition, improper FR garment fit may lead to incorrect wearing and limited movement ability, potentially increasing a wearer's risk on the job.

Another consideration, often overlooked, is to monitor FR garment fit on an ongoing basis. This is important because laundry shrinkage can have a major impact on FR garment fit and workers' physiques can change over time.

Laundry shrinkage can vary depending on fabric type. FR garments with higher levels of shrinkage may lead to increased levels of discomfort for workers and higher overall costs due to the need for frequent FR garment re-purchasing.

Fabric Hand—The Touch and Feel of a Garment
Fabric hand is the feeling of a garment on your skin. Significant differences may be noticeable visually, whereas more subtle differences may be determined only through a more extensive analysis including wear trials. However, individual preferences can vary. A common and simplistic approach is to rub the fabric between your fingers, though this does not consider all aspects. Using international standards (ISO), an industry-leading French textile institute classifies fabric hand across 13 different attributes (e.g., smoothness, softness, suppleness, drape, warmth, and recovery), all of which can have an impact on a wearer's perception if they are not in balance.

Laundering also can greatly affect the hand of an FR fabric, and not always for the better. After as few as just five launderings, third-party testing has shown drastic changes in an FR fabric's touch and feel, with some significantly worse. This further underscores the importance of conducting a wear trial and laundering testing as part of the FR garment evaluation process.

The Sure Bet Is a Wear Trial
With an increased focus on providing your workers with comfortable FR garments, it is extremely important to consider the three pillars of comfort—heat and moisture management; fabric hand; and garment fit/design—when evaluating your options.

Data from third-party studies, such as those cited in this article, can provide valuable guidance about the comfort attributes of an FR garment. Poor performance in any one comfort attribute can make a garment undesirable. This information can help you determine which FR garment to put to the ultimate comfort test—a personalized wear trial. After all, a wear trial is the only sure way to determine the most comfortable FR garment for your workers.

References
1. "Survey Finds High Rate of PPE Non-Compliance," OH&S, Nov. 17, 2008.
2. "FR Market Research Study," Bainbridge Strategy Consulting, June 2014.
3. "Comfort Properties of Heat Resistant Workwear in Varying Conditions of Physical Activity and Environment," Yoo, S., Barker, R.L., Textile Research Journal 2005 75:531.
4. "Moisture transmission through textiles," AUTEX Research Journal, Vol. 7, No. 2, June 2007.
5. "Handbook of Fire Resistant Textiles," Kilinic, F.S., May 2013.

This article originally appeared in the August 2014 issue of Occupational Health & Safety.