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Protecting America's Bravest



nonwovens technology used in bunker gear and personal protection equipment for firefighters



By Michael Ciampo, Lieutenant



Published April 12, 2007
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Firefighting continues to be one of the most dangerous occupations in modern society. Today’s firefighters are facing fewer fires than they were years ago, thanks in part to smoke alarms, early detection systems and suppression systems such as home sprinklers. However, the fires they do face are burning at much higher temperatures, release more toxic and flammable gases and have a more rapid flame spread, thanks in part to the world of technology and the use of plastics in modern-day society.

Firefighters are also seeing an increase in their workload and call volume due to an increase in the services they provide to the public. Many fire departments around the country are now calling themselves fire and rescue services, taking on the tasks of performing emergency medical calls and technical rescues such as confined space, hazardous materials, trench rescue and high-angle rescues. Performing all of these services requires that firefighters be properly protected from the many types of hazards they encounter while performing their job.

 

 

Bunker Gear
Bunker gear is a two-piece ensemble made up of a coat and pants. It is the most recognizable piece of safety equipment in a firefighter’s array of personal protective equipment (PPE). The gear is a three-layer garment, which often includes a nonwoven liner. The layers consist of an outer shell, a thermal liner/heat barrier and a moisture/liquid barrier. Although all three layers work in unison to protect a firefighter, individual manufacturers may use different percentages of fabrics and fibers to make up the individual layers.

Outer Shell


The outer layer, known as the outer shell, is made up of materials such as: Kevlar, Nomex, PBI, PBI Matrix, Millenia, Basofil or blends of the materials. Most manufacturers of these products include some portion of Dupont’s Nomex or Kevlar as part of their outer shell while adding their own products. The combination of Nomex and Kevlar is the reason that bunker gear is flame- and heat- resistant, strong, lightweight and durable. These materials also protect the user from sharp objects and abrasive surfaces while performing firefighting tasks.

If we look at some of the products that fire departments have to choose from, we see options such as:
•PBI—an engineered blend of 60% Kevlar and 40% PBI, offered in a rip stop or twill weave. This product is a natural bronze color but if it is dyed black, it dramatically reduces UV degradation problems and improves durability.
•Nomex III—an engineered blend of 93% Nomex, 5% Kevlar and 2% carbon antistat. The product is available in three weights: 6 ounce, 7 ounce and 7.5 ounce. It is available in three different weave patterns: rip stop, twill and duck.
•Millenia XT—an engineered blend of 60% Kevlar, 20% Nomex and 20% PBO, which is available in a rip stop weave and 7.5 opsy weight.
•Basofil—as used in the fire service, it is an engineered blend of 40% Basofil and 60% Kevlar.
•Advance—an engineered blend of 60% Kevlar and 40% Nomex offered by Southern Mills.
•PBO—perhaps the newest of the materials, this engineered blend was introduced in 2000 and is made up of 40% zylon and 60% Technora Millenia.

To the firefighter, this outer layer is the most important—it has to stand up to the rigors of high temperatures from direct flame and heat, while also being resistant to cuts and abrasions from broken glass and sharp objects. When individual fire departments are looking into purchasing bunker gear, they are looking for an outer shell that is strong and durable and will resist water absorption. In the specification process, departments can choose between an outer shell that offers better thermal resistance to flame and heat or a material that offers more resistance to cuts, tears and abrasion. They can also request that the outer shell materials be protected with the most advanced technology in outer shell water repellency (Super Shelltite with DuPont’s Teflon), which keeps gear dryer, cleaner and resists abrasions.

The outer shell of the bunker gear normally has two or three different types of closure systems (snaps, buckles, zipper and Velcro) to prevent heat, smoke, water and chemicals from penetrating into the coat and onto the firefighter. Elastic material is often sewn into the wrist area to prevent penetration into the arm area. As per the NFPA (National Fire Protection Association) standards, bunker gear is required to have a certain percentage of reflective stripping. This stripping is usually a 3M Scotchlite or Reflexite, which makes firefighters more visible in smoke or in the dark when light is cast upon them. This material is sewn onto the outer shell and some manufacturers are now using a unique Kevlar fiber chord that is abrasion-resistant, known as TrimTraxx. Using this material in an eight- to 10-stitches-per-inch pattern in different areas of the outer shell (reflective stripes, cuffs and seams) is said to increase the overall service life and reduce maintenance cost.

Bunker gear has been a great asset to firefighting in the last 20 years; it has significantly reduced the amount of burn and physical injuries to firefighters in many major fire departments. However, due to the rigors bunker gear faces on the fire ground, it can easily be ruined or required to undergo repairs even after just one fire or incident. Specific areas of the gear are more prone to receiving damage than other areas. These areas are the knees, wrist and pocket areas of the gear.

Firefighters are normally crawling on their knees, crawling with one knee up and one down or “duck-walking” under the heat and smoke, attempting to penetrate to the seat of the fire. Many times this requires advancing over materials that are still hot, which causes damage to the knee areas of the outer shell. Firefighters are taught to “sweep” the floor with the hose stream of water to push hot materials out of the way while advancing. Unfortunately, due to the poor visibility, if any, during the fire and extinguishment tactics, coming into contact with a hot object is a known hazard.

In order to try to reduce knee burns and injuries, some manufacturers have enhanced the area on the outer shell. This is done by adding a knee pad (made of Kevlar, Nomex, PBI or Arafil), which is attached to the knee areas with snaps and Velcro on the outside of the gear. The City of New York Fire Department (FDNY) currently allows its firefighters to choose between a Level 2 and Level 3 knee pads for their personal bunker pants. The Level 3 pad is thicker than the Level 2 and is normally used by firefighters assigned to engine companies that operate the hose lines and have to crawl through hot water and debris. Originally, FDNY had a Level 1 knee pad but noticed a small increase in burn injuries when firefighters chose this pad. Seeing a trend developing, the safety unit issued a directive to have all firefighters remove the Level 1 pad and replace them with the Level 2 or Level 3 pads. At present, FDNY is looking into other options to increase the effectiveness of the knee pads. Unfortunately, the thick knee pads can absorb a lot of water and can cause steam and thermal burns to the firefighter’s knee under certain conditions.

One refinement used to increase an outer shell’s longevity is a newly formulated fabric called Dragonhide, which weighs 9.7 opsy and is made up of 34% para-aramid, 63% aramid and 3% carbon filament. This is used in high abrasion areas such as the knee and elbow area. Due to the fact that firefighters carry some hand tools in their pockets that have sharp ends (screwdrivers and cutting pliers), there are often problems with holes working their way through the material. Currently some outer shells are being made with double layers of material on the outer shell with reinforced stitching.
 
At the wrist area of the bunker coat, one manufacturer, Morning Pride, has patented a shingle cuff that overlaps the glove to protect the wearer from liquid entry while moving an arm or hand during firefighting tactics. This shingle cuff can be stitched into the arm of the coat or held in place by Velcro and adjusted by the wearer. This cuff is another way of increasing the overall safety of the firefighter.

Upgrades And Options


Many manufacturers offer options that can be added to the outer shell of the bunker coat and pants. Some of these options may include: a radio pocket and microphone strap, loops of material that are sewn into and around the waist of the pants that secure a rescue harness by Velcro and/or snaps, a flashlight holder, rope pockets on either the pants or coat and long leg pockets down the side of the pants. These are a few of the most common items a fire department could specify in their bunker gear.

Unfortunately, the field of firefighting is inherently dangerous and tragedies do sometimes occur, despite the fact that more options, upgrades and technological advances are becoming available. Some coats can be equipped with an “emergency evacuation device” or “bail out” rope or chord that is incorporated into the coat. These rope and chords can be specified with Kevlar and Nomex properties. They are meant to be used as one of a firefighters’ last options in self-rescue, in case of becoming trapped in an untenable area. Many manufacturers offer fire departments a choice in pocket location for these ropes if they aren’t incorporated into the inner workings of the coat.

Another new option that has received much fanfare from today’s firefighters is called a Drag Rescue Device and is incorporated into the coat. This device is made up of Kevlar straps that are located between the outer and inner shells. The straps are looped around the wearer’s shoulder, and then one end of one loop comes out of a pocket in the middle of the shoulder. The pocket has a fabric tab connected to the outer shell by Velcro, which keeps the device in place until needed. The other loop is free-ended and has to be clipped together when the wearer is donning the bunker coat. The device is designed to assist a firefighter in pulling an injured or unconscious firefighter to safety.

Thermal Liner and Moisture Barrier


The next two layers, which may be manufactured through various processes, including stitchbonding, needlepunching, highloft or quilting, are equally important but don’t face the same rigorous conditions as the outer shell. The thermal liner and moisture barrier are commonly sewn together and attached to the outer shell by Velcro and snaps. These two components account for up to 70%-75% of the protective gear’s thermal protection performance.

Today there are four basic but different types of batting used in the manufacture of firefighting garments. The selections are often based on the amount of TPP (thermal protective performance) the gear is designed to deliver while also attempting to maximize THL (total heat loss) performance. It is extremely important that a good balance between the materials is achieved to enhance the product in both performance levels. The four basic battings are:

1. Spunlace fabrics—pure virgin fiber fabrics such as E-89 from DuPont. These products have excellent cohesion and durability. They are often configured in multiple layers that trap air and act as an excellent insulator.

2. Pure virgin fiber needlepunch battings—pure virgin fibers and previously unprocessed fibers that are needled together.

3. Reprocessed fiber needlepunch battings—reprocessed fibers needled together, resulting in a weaker and less durable textile.

4. Garnetted fabric/fiber battings—ground up waste and reprocessed fibers, which are normally very thick and heavy. Most of these products will not meet the new NFPA standards.

The thermal liner, which can be made up of such products as Caldura, Aralite and Synergy, is the second barrier protecting the firefighter from high heat temperatures. Caldura is a leader in thermal barrier fabrics. Because the premier face cloth is needled together with an aramid batt, it provides a slick surface that allows the wearer to don and doff the gear in less time. It also has excellent pilling resistance, which is very important to fire departments that face a high call volume. Aralite is a lightweight thermal barrier that features less bulk and a wickable Nomex face cloth for more comfort and more flexible thermal protection.
 
Thermal liners are a form of insulation and control moisture management. They consist of a nonwoven face cloth attached to a batting of insulation, either one- two- or three-layers thick. Firefighters wear self-contained breathing apparatus on their backs that are attached to shoulder straps to keep the unit in place during operation. Some manufacturers are increasing the amount of padding in the shoulder area of the thermal lining for greater compressive conductive heat resistance.

The thermal liner may be sewn to a number of types of moisture barriers that are resistant to water, chemicals and blood-borne pathogens. These two layers are usually quilted together in a diamond or onion stitch pattern. These barriers may be made up of Crosstech, Stedair and Gore. The combinations of these two layers are engineered to relieve heat stress by allowing air movement (breathability) while also preventing saturation of liquids through the garment.
 
A few technological advances are focusing on the ends of the sleeves. First, the wrist guards continue to be made of Nomex and some manufacturers offer them in a longer version with a cut-out for the wearer’s thumb. This allows the wrist guard to extend into the glove and prevent any liquids from injuring the firefighter. Some firefighters dislike this option because they feel that there is too much bulky material in their glove and they loose dexterity. Other wrist guards just employ a small Nomex or other fabric ring that the thumb enters, which maintains the safety factor.

These wrist guards are also being extended up into the arm to form a sleeve well that works to keep water and a liquid out and adds thermal protection. Again, due to the rigors of firefighting, the knee area continues to be an area that sees a lot of gear failure. In order to circumvent this, many manufacturers are now adding an extra layer of the thermal liner and moisture barrier padding to this area. Not only does this offer added protection from hot and sharp objects, it also adds another level of padding for comfort.

Post 9-11 Bunker Gear


Unfortunately, as we would all learn on the morning of September 11, 2001, America is no longer immune to terrorist attacks on its home soil. In addition, we’ve witnessed other terrorist acts in other parts of the world that involve new and sophisticated weapons that can cause mass destruction. Many of the weapons used in these previous attacks have been explosives that have caused large fires, major structural damage and killed numerous people. However, other terrorist events have concentrated on using chemical gases, biological, radioactive and nuclear weapons (commonly referred to as CBRN).

As we witnessed around the country on 9-11, firefighters are our nation’s first responders. Their protective equipment has to be ready to handle today’s new challenges as well as perform effectively in their daily responses. Since 9-11, many government agencies (fire, police and EMS) received federal grants through the Homeland Security Act. These funds were used to outfit their members with such items as bunker gear, gas masks, hazardous material suits and decontamination suits. Having this equipment on hand in preparation of any kind of attack will enable America’s first responders to perform under any adverse condition they encounter.

On another front, some very prominent agencies in the firefighting field, along with some major universities, recognized the need to come together and look into a new solution in bunker gear to handle these new weapons. With funding from the Department of Homeland Security (DHS), a team was organized to rapidly develop the next generation of structural fire fighting bunker gear. The team’s goal is to produce personal protective equipment with CBRN protective qualities without sacrificing thermal protection, comfort and functionality. The advertised results of the design team findings are:

•Replaces the traditional moisture barrier with a chemical/biological barrier that provides the same level of breathability as current moisture barriers.

•Permits departments to still have a choice of various shell and thermal barrier materials.

•Redesigns the entire ensemble with modifications to the hood, glove and footwear area to ensure complete body protection when worn with a CBRN self-contained breathing apparatus.

•Appears almost indistinguishable from current bunker gear.

• Includes some features that will actually enhance structural firefighting protection.

Although five years have quickly passed since the tragedies that occurred across America, the firefighting community is continuing to work feverishly in developing firefighting equipment to protect firefighters for whatever lies ahead.

Protective Hoods


Many fire service developments have been borrowed from other industries and occupations. One such item is the protective hood that firefighters wear over their heads once they have donned their breathing apparatus facepiece. The hood was originally designed for racecar drivers and is still in use in that sport. Once adopted by fire departments, the hood has contributed significantly to the reduction of burn injuries to the ear, neck and facial area of firefighters.

There are many types of hoods available, which are made up of different percentages of materials (such as 8.5 ounce 100% Nomex, blended PBI (20% PBI/80% Lenzing) or a Basofil blend). Many manufacturers are now offering hoods in variable color options and designs (black, tan, stripes and even tie-dye options are available). Most hoods are constructed in a double- layer fashion with triple stitching around the facial area and reinforced with elastic material. Some have an available longer bib option so that it fits correctly down into the neck area of the bunker coat. This longer bib has reduced burn injuries from hot water running down into the chest area of the firefighter.

The FDNY currently outfits it members with a hood that is made up of a double knit fabric that is a blend of 20% PBI (polybenzimidazole, synthetic rayon fiber) and 80% Lenzing (flame resistant synthetic fiber). The FDNY’S specifications call for an open mesh-type design on top of the hood. The mesh is constructed with a combination of Nomex and other fibers and materials. This design enables the firefighter to release body heat in the hope of reducing heat exhaustion and fatigue levels.

Donning a separate Nomex hood may eventually become a thing of the past. With today’s research into making bunker gear CBRN-certified, the hood is being incorporated into the bunker coat neckline. These new hoods will probably be constructed of the outer shell, moisture barrier and thermal liner. They will be all sealed together at the collar line of the coat. Research is still being conducted on this new technology.

Firefighting Boots


Most firefighters today prefer the new military-grade leather or Nomex and Kevlar firefighting boots over the old rubber style boots. Unfortunately, due to the cost of these boots, many smaller departments operating with small budgets can’t afford to equip all their members. These newer style boots weigh much less and are much more comfortable to wear than heavy rubber boots. Since they weigh less, due to the 60% Nomex and 40% Kevlar or leather construction elements, they help reduce the fatigue levels of firefighters. These products also increase breathability, which can increase the firefighter’s performance levels.

Most of these new boots feature a waterproof and breathable Crosstech fabric bootie system, which offers superior penetration resistance against blood, bodily fluids and NFPA common chemicals. The bootie can also incorporate a Cambrelle lining that is abrasion-resistant and features an effective absorbency rate that will not support the growth of bacteria. These booties are normally quilted and laminated to a 7.5 ounce Kevlar felt thermal barrier.

These boots are always being upgraded and offer various options for fire departments. Some manufacturers offer boots with reinforced Kevlar and Nomex or rubber toe guards. These guards help protect the toe area of the boot as the firefighter is crawling through the fire scene. Some boots also have Kevlar stitched Scotchlite or Reflexite on the side for better visibility and firefighter identification.

Since the firefighting community has been involved in natural disasters such as earthquakes, building collapses from hurricanes and tornados, manufacturers have developed an Urban Search and Rescue boot. These boots normally have the same type of Nomex, Kevlar and military-grade leather construction to stand up to the rigors of working in debris fields. They also have similar breathable linings made of Crosstech and Cambrelle in order to reduce fatigue levels and afford breathability. These boots are somewhat lighter than those designed for firefighting, which enables  these firefighters to work for long periods of time in these disaster areas.

Gloves


There are numerous brands and types of gloves made up of various kinds of leathers available to firefighters today. These gloves also incorporate a layered system similar to the bunker gear. Most of the gloves on the market have some type of Nomex lining with self-extinguishing needlepunched fleece (SEF), which is a modacrylic liner that provides optimal thermal protection. They also incorporate a Crosstech moisture barrier, providing superior protection and breathability. These gloves are normally Kevlar-stitched to endure the rigors of firefighting.

Many of these structural firefighting gloves are not equipped with extended Nomex wristlets. These gloves are often specified by departments whose bunker coats have the built-in wristlets and hole for the thumb, enabling the wristlet to extend into the glove. Most firefighters who have the gloves with the extended Nomex wristlets roll them back over onto themselves to make it easier to don the equipment. Once the hand is inside the glove, the wristlet is rolled back into position. The main problem with these actions is that the firefighter may forget to roll the wristlet back down during the donning process and could face an injury to this area.

Structural firefighting gloves are very bulky and don’t offer the wearer much dexterity when they are worn. Since many departments are responding to emergencies and technical rescues that involve hand coordination, other types of gloves are now becoming a necessity. Two alternative glove types are extrication gloves (used when using tools while extricating victims of a car accident) and rope gloves, which are used for performing rope evolutions in high-angle rescues.

The extrication glove is a better fitting glove than the structural firefighting glove. Wearers have much better control of their actions and are able to grip the controls of the hydraulic and air operated equipment with ease. This is extremely important because the movements in some rescues must be performed very delicately, precisely and slowly. Normally, the outside layer of these gloves is made up of leather, Cordura or a spandex/mesh combination.

Most of these gloves are reinforced with Keprotec, Kevlar, or Armortex-reinforced padding that is abrasion- and puncture-resistant. Most of this padding is found in the knuckle area and finger area of the gloves to prevent any cuts from the jagged metal found at automobile accidents. These gloves are often stitched with Kevlar and sealed with elastic wrist seams and cuffs or by a Velcro closure to prevent any chemical or blood entry into the hand area. Some of these gloves use different types of interior barriers. One manufacturer relies on the Hippora barrier that is waterproof and breathable while also resisting NFPA chemicals and any bloodborne pathogens.

Rope gloves are constructed a little differently than extrication gloves. The outside of the glove is usually constructed of leather with Spandex and an air mesh for breathability. They also can be made of Kevlar bonded to Spandex to offer better cut resistance or just a nylon stretch fabric. Most of these gloves have Velcro closures around the wrist area. These gloves are even more lightweight than extrication gloves as firefighters need more dexterity in their hands to tie knots and work with rigging equipment.

Self-Contained Breathing Apparatus (SCBA)


The Self-Contained Breathing Apparatus, combined with bunker gear, is the reason firefighters are able to perform under the adverse conditions they face daily. The SCBA is the familiar tank of air worn on the firefighter’s back that is pressure-regulated and sent through a hose to the facepiece.


Years ago the large air cylinder used to be made of steel and heavy; later on it was switched to aluminum but still was cumbersome to wear for extended periods of time. Today these cylinders are made of a lightweight carbon fibers. These air cylinders are wrapped with Kevlar-impregnated glass filament. They are fitted into an aluminum or wire frame that sits on the firefighter’s back. It is held in place at two locations, the first is at the neck by a metal hanger bracket and the second by a Kevlar strap that is snapped into place by a locking assembly.

The SCBA is normally equipped with two shoulder straps and one waist strap attached to the harness. Most of these straps are made of heavy braided para-aramid webbing or a blend of Kevlar and Nomex to endure the rigors of firefighting. To enhance comfort and fit while also adding an insulation factor, these straps have additional batt material in pressure-sensitive areas. These straps are adjustable and secure the entire SCBA to the firefighter’s back.

The facepiece of some brands have gone away from a rubber spider net and switched to a hair net assembly. The net or head harness is also made of Kevlar material in a mesh design with flame resistant elastic straps. The facepiece of the SCBA was normally used by firefighters at fires or hazardous material incidents. Since the events of 9-11, firefighters have been issued high efficiency particulate chemical cartridges that attach to the facepiece, in case of CBRN attacks. These cartridges use carbon and nonwoven fiber technologies for liquid and gas filtration and separation. In the event the SCBA runs out of air, or if the firefighter has to operate for extended periods of time (such as at a hazardous material decontamination scene), the cartridge and facepiece could be used instead of the entire SCBA.

Emergency Medical Responses


Most fire departments around the country are performing emergency medical duties due to the drop-in fire call volume. Fire departments can often get to an emergency scene within five minutes of initially contacting a 911 operator. This is due to the locations of firehouses that have been strategically spaced out in pre-plans. Everyone knows the importance of getting medical attention to a patient as quickly as possible; it may be the answer between life and death. Nonwoven technologies play a major part in assisting firefighters in saving lives when they use highly absorbent materials to perform wound management on injured people.

Firefighting continues to be a very dynamic occupation. Each call is different and firefighters are never quite sure what awaits them at the next emergency scene. That is the reason they have trust in their protective equipment and are willing to perform under some harrowing circumstances.