Protective Clothing: Overcome the Shortcomings
Photo courtesy of Vikings America Inc.
HAZARDOUS MATERIALS
The issue of appropriate protective equipment for personnel responding to hazardous material incidents is an area of great concern, confusion, and controversy. Most of the reasons for the dilemma stem from the complexity and diversity involved with hazardous material incidents.
The primary question revolves around the establishment of an “appropriate” level of personal protection necessary for responders to safely deal with a hazardous material. In most cases, reference sources used by emergency response personnel will state either, “Use full protective equipment” or “Use special protective equipment.” Taken at face value, both statements seem straightforward and to the point. However, when examined more closely, there is a margin of doubt. Even more fundamental, the question that still remains is, does the equipment specified actually provide the appropriate level of protection? Unfortunately, the answer is often “No.”
FULL PROTECTIVE EQUIPMENT
Let’s start by examining “full protective equipment.” The terminology itself can and does lead to confusion. It is imperative to understand that full protective equipment used in a hazardous material incident is not the same as full turnout gear used in structural firefighting. Rather, full protective equipment is a taped system composed of bunker pants and coat, boots, hood, positive pressure selfcontained breathing apparatus (SCBA), gloves, and helmet.
This system is designed to lessen the infusion of vapors, liquids, and dusts by setting up a suit barrier. By no means can this barrier be considered a vaporor liquid-tight form of protection. This last statement tells the entire problem.
Consider this form of protection at an incident where materials produce corrosive vapors as they escape from their containers, such as hydrochloric acid, anhydrous hydrogen chloride, ammonia, chlorine, etc. When these vapors contact moisture, they dissolve and produce an acid or a base. In the case of ammonia, the vapors dissolve on contact with perspiration and produce ammonium hydroxide. Ammonium hydroxide is a strong base that will readily destroy skin tissue. There are plenty of stories about firefighters who receive painful tissue injuries to the groin, arm pits, or lower back from just such exposures.
Furthermore, full protective equipment offers no protection for the SCBA worn in such a corrosive atmosphere. Any part of the SCBA that comes in contact with the vapor is exposed to the same type of corrosive attack as exposed skin. Depending on the specific type of SCBA and its design, parts of the regulator may be potential sights of attack. This type of vapor exposure also has produced severe effects on fire apparatus in the past, including corrosion of chrome and painted surfaces and the failure of diesel engines.
Another consideration is the protection that full equipment offers against powdered solids (such as pesticides or caustics) and liquids (such as gasoline or radioactive iodine serum). Short of immersion, the potential for these materials to infuse through the barrier of the protective system is somewhat less than that of vapors. Rather, contamination results from contact with these materials.
It is important to realize that it is almost impossible to decontaminate structural fire clothing effectively. To prove this, sprinkle flour all over a firefighter clothed in full protective equipment, then assign several physical tasks to be accomplished. After the tasks are completed, try to “decontaminate” the protective clothing (simulated by trying to “scrub” off the powder residue) following your standard procedures. You will be amazed at the difficulty of the task and the results. This is also excellent training in decontamination procedures.
If the protective barrier (turnouts, boots, SCBA, acid suit, encapsulating suit, etc.) cannot be decontaminated due to surface contamination or material impregnation, the only alternative is disposal. This is imperative to eliminate additional chemical exposures to future users. In order to dispose of the contaminated equipment, it must first be overpacked and then handled as the hazardous waste that it is.
SPECIAL PROTECTIVE EQUIPMENT
Acid suits fall into the category of special protective equipment, which is somewhat less subject to vapor infusion than turnouts, but is still not a completely effective barrier. Acid suits are composed of a oneor two-piece suit similar to a rain slicker and are easier to decontaminate than turnouts due to their smooth surfaces. However, they are still subject to impregnation and provide no protection for the SCBA.
Encapsulating suits do provide protection for the SCBA. There is a wide variety of suits available on the market. Some are excellent while others are marginal at best. The failure of these suits during incidents has been of major concern. The entire suit must maintain its integrity in order to provide the protective barrier it is meant to.
COMPATIBILITIES AND FAILURES
A crucial consideration during any hazardous materials operation is product and suit compatibility. Compatibility simply means the ability of a given suit material to withstand contact with a given chemical.
It is important to realize that there is no one suit material that is compatible with all hazardous materials. In fact, there are some rather common, as well as some exotic chemicals that have no compatible suit material. Toluene, xylene, nitrogen tetroxide, and chlorine trifluoride are just a few such chemicals. The effects of incompatibility range from stiffening and cracking to impregnation to complete compromise of the suit.
Impregnation can be the most insidious type of compatibility problem in that it may leave no visible evidence of entry into the suit material. The only sure method of testing suit resistance to impregnation is by destructive testing of suit material samples. However, this does not assure that the suit in totality has not been impregnated, only that the sample area tested was not affected.
Another type of encapsulating suit failure is the result of physical damage. There are three primary areas of a suit that are most susceptible to this type of damage: gloves, boots, and body areas (specifically knees, elbows, shoulders, and zippers). Gloves, the most common site of damage, are susceptible to cuts and abrasions from ruptured containers, tools, and rough surfaces. Similarly, boots and the suit body may be damaged by the same types of hostile surfaces and materials. If damage occurs to gloves or boots that are permanently attached to the suit (glued or sewn in place), or to the body itself, the suit must be returned to the manufacturer for repair or replacement. As one would expect, this type of repair can be expensive and time consuming.
Now, let’s summarize the potential shortcomings associated with the present methods of personal protection:
- Protective barriers that are essential for optimum personal
- safety may, in many instances, provide less than effective protection.
- Physical damage can occur with relative ease and lead to a total compromise in the integrity of the protective barrier.
- Decontamination of “permanent” protective equipment is at best difficult and at worst ineffective.
- Disposal and replacement costs for permanently contaminated or damaged equipment can range from $900 to $2,000 or more per unit.
All four of these shortcomings have one point in common—they all involve some type of contact between the primary, reusable, protective barrier and either a hostile chemical or object. But, how do we protect personnel from these encounters? One suggestion is the establishment of standards for encapsulating suits. Standards are necessary, but they take time to implement, address only some of the problems, and do nothing for existing equipment. Another suggestion is the re-design of standard turnout gear. However, such changes would detract from the protection qualities necessary during firefighting operations and again do nothing for existing equipment.
The advantages of layered protection include:
- Extra personal protection.
- Reduced damage to primary protection barriers.
- Relatively low costmaximum cost effectiveness.
- Improved capabilities with existing equipment.
A LAYERED APPROACH TO PROTECTIVE BARRIERS
In order to develop a solution to this protection dilemma, a rethinking of the present approach to protective barriers is necessary. This new approach revolves around the concept of layered protection, that is, the covering of existing, reusable, primary, protection barriers with an inexpensive, disposable, chemical resistant envelope. Such disposable envelopes are presently available and cost from $45-$75 per suit.
The envelope provides superior vapor, liquid, and dust protection compared to that offered by full protective equipment. Due to its design and the manner in which it is worn, the envelope provides protection for the SCBA, as well as minimizing abrasion and chemical exposure to the primary barrier. Because the envelope is disposable and minimizes chemical contact, it simplifies decontamination. Further, due to the comparatively low cost involved, auxiliary personnel, such as those who perform decontamination, can be better protected by using the envelope.
The envelope is composed of three basic units: a body /SCBA covering, a foot covering, and a hand covering. To more fully understand the envelope system, let’s examine each component individually:
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The first component of the exterior envelope consists of a disposable, one-piece, semi-encapsulating suit. Suits constructed by DuPont Tyvek with either a PE coating or a Dow Saranex laminate are ideal for this type of application. These semi-encapsulating suits are equipped with elastic gathers at the wrists and ankles (if not purchased with integral bootee), a large integral mylar faceshield, a zipper with adhesive flap to provide positive closure, and weigh from 7 to 14 ounces. (It is recommended that suits be purchased in the largest size available to accommodate all personnel.)
The second component of the envelope is a foot protection system. The exact makeup of this system depends on the type of primary barrier to be covered. If the primary barrier is equipped with a substantial boot similar to a turnout boot, a bootee similar to a foul weather rubber at least 12 inches long may be sufficient. To insure a maximum range of compatibility, bootees constructed of butyl rubber, nitrile rubber, polyvinyl chloride, or some other chemical resistant material should be available. The chemical resistant bootees range from $5-$15 each. This disposable bootee would be placed directly over the substantial boot and then taped to the disposable suit. If no substantial boot is present, as is the case with many encapsulating suits, a short turnout boot should be placed on the foot first and then covered by the disposable bootee. The bootee would then be taped to the disposable suit.
The third and final component of the envelope consists of two disposable gloves, an inner chemical resistant glove covered by an outer abrasion resistant glove. The chemical resistant glove should be at least 12 inches long and placed over or under the arm of the disposable suit, depending on preference. (It is my opinion that placing this glove over the disposable suit arm facilitates later removal.) This glove is then taped in place. Again, for maximum compatibility, gloves constructed of various materials are recommended. These chemical resistant gloves are priced from $2.25-$20 each. The outer abrasion resistant glove is then placed over the chemical glove. The outer glove can range from a leather/ canvas work glove to a welder’s gauntlet.
It should be evident that through the use of a layered approach to protective barriers, many of the shortcomings inherent in present protective barriers can be overcome. Some of the advantages are:
- Superior personal protection.
- Reduced damage to expensive primary protection barriers.
- Relatively low cost; maximum cost effectiveness.
- Improved capabilities with the use of existing equipment.
Through the use of this layered approach to protective barriers, response personnel can receive much improved protection efficiently and effectively.
