As a Health & Safety professional, knowing everything there is to know about safety is often quite a challenge. Questions are unavoidable and you won’t have every answer. To help you, we listed the most frequently asked questions and the answers, bundled in one easily accessible place.
Modern turnout gear has been adapted over the last 50 years from thick single layer fabrics (wool, cotton, leather, or rubber) to a highly engineered three component (layer) system with distinct performance and functional characteristics for each component. The three components combined actually enhance the thermal protection due to the pockets of air between the layers.
The outer shell typically garners the most attention since it is the most visible and the first line of defense. Outer shells range from meta-aramid to multi-blend fabrics utilizing para-aramid and high temperature resistant fibers such as PBI and PBO. Since the outer shell provides the initial protection, it must be extremely durable, abrasion resistant, strong enough to resist rips and tears, water repellent, and of course, resistant to flame and thermal exposures. There are many crucial performance elements that must be provided by the outer shell and many factors to consider when determining which outer shell is right for you.
The moisture barrier component, typically the middle layer, is the most fragile component of the three-layer composite. Nearly all modern-day moisture barriers are a combination of ePTFE (expanded polytetrafluoroethylene) and PU (polyurethane) to provide a “breathable” and durable barrier. We think of the moisture barrier as being there to keep the fire fighter dry, but it does more than that. It also provides protection from bloodborne pathogens and common fire ground chemicals. At the same time, it helps to reduce heat stress by allowing the outflow of heat and moisture vapor from the wearer. The moisture barrier plays a critical role in fire fighter safety and comfort.
When it comes to thermal protection, the thermal barrier provides the majority of protection from the intense heat and has the greatest degree of influence on isolating the body from the heat source. Most thermal barriers consist of a thin woven fabric known as the face cloth that is quilted to a nonwoven fabric called batt. The total comfort and user experience with the protective clothing ensemble can be good or bad based on the thermal barrier.
While there is little to do with protection from the face cloth, the ability to work comfortably and don and doff the garment quickly is affected. Slick face cloths make it easier to move in the garment. The use of filament yarn is one of the factors that determine the slickness; the other is the design of the weave which can be adjusted to increase the slickness effect. Moisture absorbing and quick drying face cloths can also enhance comfort.
The batt can be either needle-punch or spunlace.
Needle-punch batts are typically one fairly thick layer, while spun lace batts are much thinner and usually two layers. Needle-punch batts are less expensive and less breathable but can have higher insulative values from heat. Spunlace batts provide improved flexibility, greater ease of movement, higher Total Heat Loss (breathability), but less thermal protection.
It’s easy to understand why so many fire fighters care about their outer shell. If the outer shell fails, the rest of the system will likely be compromised as well. However, all three components deserve your attention. Each is there for a reason, and each contributes to the performance of the garment. Understand each component and how performance is affected when the combination is changed. Carefully consider all three components and select the ones that best fit your needs when writing your next spec.
Multi-norm garmentsare specifically created for work environments with multiple risks. They are designed to meet numerous standards. This sounds like the ultimate protective clothing, but there are a few downsides.
An ‘over-engineered’ multi-norm garment costs and weighs more. Protecting your workers against dangers they won’t ever face makes clothing unnecessarily less comfortable and more expensive. Therefore, conducta risk assessmentfor each workstation and find out what the true relevant threats are for your workers. Then your protective clothing can be designed specifically for your work field.
No. There are many kinds of FR clothing that need to be carefully weighed before you decide which solution is best for your FR needs. The weight, level of protection, and even the design of garments can and will differ greatly. The comfort, feel, and look of any FR garment depend largely upon the kind of FR fabric from which it is made.
What is perceived as being the "cheapest" or most cost-effective solutions can, in fact, turn out to be more costly in the long run. In the rush to meet the new OSHA requirements, many purchased garments that were NFPA 2112 certified and thought that they had found their FR solution. But just because a garment is NFPA 2112 certified and cheaper to buy initially doesn't guarantee a long wear life. What seemed to be a nominal purchase in the beginning can prove to be a millstone over time.
The requirements for protective clothing depend on your work environment and several elements in that environment need to be considered. The best way to find out what protective workwear is suitable for your particular situation, is to conduct a risk assessment. A risk assessment is an evaluation of the potential risks that are relevant for your company.
The NFPA is the National Fire protection Association. It is the body in the US that sets the standards and certifications for protective apparel at all levels. Particularly as it relates to heat and flame-resistant materials and clothing.
NFPA 2112 relates directly to the effects of a flash fire and is designed to predict the level of protection a fabric or garment will provide in the instance that a flash fireoccurs. Meeting this level of certification means that the fabric or garment that you are wearing will provide a level of protection to make sure that any incident of a thermal exposure is, at a minimum, survivable. There is no way to ensure that no injury will take place, the certification is in place to make sure that there is protection provided.
An electric arc is a discharge of electric current across a gap in a circuit. It is sustained by the presence of a thermally ionized column of gas (called a plasma) through which current flows. In general, atmospheric air is a poor conductor of electric current.
The TPP test measures the thermal insulation of the composite: outer shell, moisture barrier, and thermal barrier. The test, which uses a thermal exposure representative of flashover conditions, measures the amount of time it takes for enough heat to pass through the composite to cause a second degree burn.
TPP is a harsh test. It is intended to ensure that fire fighters who may be caught in such a situation have a few seconds to escape. Fire fighters are not intended to work in these conditions. Protection is measured in seconds, and conditions encountered in the field may be even more severe than the test.
Thermal Protective Performance is primarily a function of the thermal barrier, which provides the majority of the thermal insulation. In general, thicker needle punch batt thermal barriers provide higher TPP, and thinner spunlace batt thermal barriers provide lower TPP. Unfortunately, thermal barriers that provide higher TPP tend to provide lower THL. If you want to adjust your TPP, focus on the thermal barrier.
Total Heat Loss (THL) measures the ability of the composite (outer shell, moisture barrier, and thermal barrier) to allow heat and moisture vapor to escape from the wearer through the garment. This is an important factor in reducing heat stress.
THL is driven primarily by the moisture barrier, but the thermal barrier also has significant impact. Thin spunlace batt thermal barriers typically provide better THL results, while thicker thermal barriers tend to offer lower THL performance. Thermal barriers that provide higher THL usually provide lower TPP.
It is also important to note that it typically takes at least a 20 to 25 point difference in THL to be noticeable by fire fighters in the field, depending on the conditions present and the individual.
TPP and THL test results have some inherent variability. In recognition of this variability, the respective NFPA test methods require that each TPP and THL test consist of three specimens. The TPP and THL ratings are based on the average of the three specimens. In addition, 8 percent variance is allowed between the individual specimen results and the average result in TPP tests, and 10 percent variance is allowed in THL tests.
TPP and THL are important performance factors and certainly should be considered when selecting your components but understand there is variance in test results and consider ratings in ranges.
The wearing comfort of protective clothing is of vital importance to its safety. After all, if the workwear is not comfortable, the chance is bigger that workers won’t wear it properly. Making sure your protective clothing is safe and comfortable at the same time is very important.
There are4 essential characteristicsthat make a fabric comfortable: weight, moisture absorption, breathability and softness. Our experts look forward to helping you implement those characteristics in your workwear.
Wear trials enable you and your employees to look and feel the new protective clothing firsthand in a test round. During this test, emotions are just as important as the features and specs of the clothing. It is important that your professionals on the workfloor gladly wear the new clothing. Therefore, a few focus points are essential while conducting such a trial:
The difference between fire resistant and fire retardant is whether the fire repelling property is inherent or not. Fire resistant clothing is made from fabrics that are inherently resistant to catching fire, while fire retardant fabrics have been chemically treated to give them these properties.
Inherent means “existing as a natural or basic part of something”, which means fabrics that are FR inherent contain at least one fiber with natural FR properties. FR treated fabrics get their FR property from the chemical treatment applied to them.
Aramid fibers are a class of strong synthetic fibers, distinguishing themselves from other synthetic fibers due to an excellent heat and flame resistance, high chemical resistance and low molecular weight. Examples are Kevlar®, Nomex®, Twaron® and Kermel®.
There are truly many avenues of exploration and investigation out there for anyone seeking an FR program solution. The most important aspects to be considered should be based on your own risk assessment. Some basic criteria can be a good starting point:
Make sure that the FR garment/fabric you choose is compliant and/or certified to all of the appropriate standards and OSHA regulations.
Choose the style and weight of FR garment that will best suit your environment and the needs of your workers.
Think about the overall wear life of the garment and what the cost will mean long term.
With so many options available and so many outlets for FR garments and fabrics, choosing the right one for your organization can be a daunting task. Always remember that any FR is better than no FR at all and that your needs are not necessarily the needs of everyone in your industry. FR garments and fabrics are not all the same, so be sure to choose the one that will make you feel the most confident in terms of protection, comfort, and durability. Find the facts and dispel the myths about FR, then weigh the evidence and find the solution that's right for you.
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