【Personal Protection】Comparison of Technical Standards of Fire Protection Suits in the United States and Europe

Abstract: This paper wear chemical suits and anti-permeability, the test environment temperature and flame resistance performance in four areas, compared with NFPA standards NFPA1991 and the European Union, represented by standard EN934, fire chemical suits involving two The main international standards ; and introduced the characteristics of disposable ( simple ) chemical protective clothing , as well as the special working environment such as enclosed space, introduced the requirements of fire protection clothing.

1 The emergence and application of fire protection clothing

Fire Chemical protective clothing (the CPVC, i.e. ChemicalProtectiveVaporClothing) from military nuclear, chemical and biological protective suit (NBC, i.e. NuclearBiologicalClothing), can be effectively prevented include chemicals and toxic industrial chemicals, vapors, gases, liquids and small particles penetrate the human body against. At present , fire protection clothing has been used more and more widely in civil fields such as firefighting and emergency rescue . It has become a necessary protective equipment for fire fighting departments to carry out firefighting and rescue operations in the environment of chemical dangerous goods. The United States as the representative of the advanced countries emphasize more variety in the process of development of fire chemical suits, a dedicated and used with other protective equipment, chemical suits and continuously adjust the technical specifications, targeted to the development of new products.

Fire Chemical protective clothing design original intention is to prevent direct contact with the wearer's skin various forms of dangerous goods. Today , there are 8 million kinds of chemical dangerous goods that people use or may come into contact with in production, life, or in contact with them . Contrary to the complicated reality , scientists are currently in direct contact with most dangerous goods and human skin. Little is known about the side effects. Therefore, the more the need for effective passive protection measures, to improve the ability of fire protection chemical suits, to ensure safety in fire fighting and rescue work in a dangerous environment for firefighters.

"A class" air-tight (gas-tight) fire chemical suits can withstand the threat of all hazardous chemicals or other hazardous substances on the human body, no matter what state they appear, gaseous, liquid or solid. Therefore , " Class A " air-seamed chemical protective clothing is generally regarded as the most protective chemical protective clothing internationally.

Currently, the International Fire Chemical protective clothing design and material selection trends were varied to accommodate different working environment. Experts generally use the "Protection Parameters" (PF, that is ProtectiveFactor) represents the fire protection effect of chemical warfare suits; however, due to lack of professional guidance from health and the health sector, in many cases, the fire department chose to chemical warfare suits based on the traditional concept of .

2 Development of Fire Protection Chemicals Standards

As the use time is not long , the standards for fire protection suits and related accessory products and the detection methods used for type approval ( type approval ) are still not perfect , and it is urgent to strengthen relevant international cooperation. Before the 1990s, German and British standard BS vfdb standard is the only national standard fire involving chemical warfare suits.

Over the past decade , in the face of increasingly serious threats of terrorist attacks , industrial and industrial associations in various countries have gradually strengthened the formulation and preparation of product standards and testing methods . In particular, the United States Fire Protection Association (NFPA) has developed a series of For fire protective clothing, in particular technical standards and specifications biochemical protective clothing, such as NFPA1991 "dangerous emergency disposal vapor standard on protective clothing", NFPA1992 "hazardous emergency disposal splashed standard on protective clothing with liquid proof", NFPA1994 " Biochemical Terrorist Attack Protective Clothing Standard [2] . At the same time , the European Union has also formulated related standards ( such as EN934), thus forming two international standards for fire protection chemical clothing products represented by NFPA standards and European Union standards.

3 　 NFPA1991 and compare the EN934

Through the comprehensive comparison of NFPA1991 and EN934, two of the most representative " Class A " airtight chemical protective clothing standard performance indicators , most professionals believe that the NFPA standard is better than the EU standard , and the former is easier to understand and master. The referenced data is more explicit and the definition of the scope of application of the standard is also more clearly defined ; however , the structure of EN934 is too complex . Although the standard addresses different hazardous environments , a series of alternatives are proposed combining the minimum protection capabilities of various chemical protective clothing. program, but because of the content of EN934 too complex, only a very professional people to master, execution. Experts believe that this situation arises, probably because EU standards in the drafting process, to go through the 15-member discussion, negotiation and mutual concessions between, compromise may finally reach an agreement.

3.1 Wear resistance

According to NFPA 1991, before fire-resistant chemical protective clothing is tested for penetration resistance of dangerous goods , it is first necessary to pass wear-resistance tests designed to simulate everyday wear . EN934 has no similar provisions. Because NFPA1991 emphasizes that fire protection suits are not only used to deal with dangerous goods accidents . During the entire firefighter’s duty , it is inevitable that they often wear and remove chemical protective clothing , and chemical protection clothing will inevitably be subject to certain wear and tear. And folding. The researchers thus draw the first conclusion : NFPA1991 is closer to real life and more comprehensive.

Currently, NFPA fire chemical suits being modified test, testing methods, in order to highlight the practicality and adaptability, to create conditions for the emergence of new protective clothing. NFPA also realized that if the standards are too harsh , it will not only directly increase the cost of R&D and production of protective clothing , but also affect its promotion. For example , when sandpaper is used to detect the wear resistance of the seam , it cannot be said that there is a qualitative difference between the 100 damaged products and the 92 damaged products ; if the standards are too harsh , protective clothing will only become more and more. Heavy , increase the labor intensity of firefighter training and work , and reduce work efficiency.

3.2 anti-permeability

"Penetration test" (ThePermeationTest) is the primary means test fire chemical suits against chemical hazards - erosion. Both NFPA1991 and EN934 have made clear and clear requirements in this regard , and the NFPA1991 regulations are particularly harsh : in the test period of 60 minutes , the maximum permeation amount of chemical tested chemical protective clothing cannot exceed 0.1mg/cm2 • min; the requirements of EN934 is much lower: the maximum amount of penetration as long as the test chemical suits chemicals within 10 minutes of not more than 1.0mg / cm2 • min deemed qualified - even chemical warfare designed for emergency rescue workers used clothes, but also the longest test time extended to 30 minutes.

NFPA1991 of chemical suits "anti-penetration test" minimum time requirement is 60 minutes, and as long as chemical warfare suits the problem does not appear in the test, testing will be carried out continuously until the chemical suits appear damaged or other problems, test possible time reached three hours, or longer. In contrast , EN934 only requires a 10- minute "impermeability test" time , and as long as the tested chemical protective clothing passes the 10- minute test , the test is stopped , and people cannot understand whether chemical protective clothing can be used in chemical dangerous goods. How long work in the environment.

Experts believe that although the current understanding of the mechanism of various dangerous goods through skin contact against the human body is not very thorough and comprehensive , it is clear that NFPA1991 places a greater emphasis on the potential hazards of chemical hazards than EN934 —this is the number one expert obtained through comparison. Two conclusions.

Of course , some experts believe that Vapor-Protectivesuit , which complies with NFPA 1991 , is effective in preventing the infiltration of chemical gases and vapors , but also completely separates the discharge of sweat and human heat ; and , because of the air supply to the air respirator cylinders, time is generally only an hour, firefighters wearing protective clothing vapor of effective working time is only 20-25 minutes each time, there is no need to extend the test time to 60 minutes.

3.3 Test environment temperature

A direct impact on an important factor in the above-mentioned "penetration test" the conclusion is NFPA1991 and EN934 are on the ambient temperature when the test proposed limit requirements: NFPA1991 required temperature test environment should not exceed 27 ℃, EN934 is not more than 20 ℃.

Obviously, the higher the temperature, the stronger the activity of the molecule of various hazardous chemicals, the stronger its penetration ability. Because NFPA1991 specified test ambient temperature is higher than EN934, experts believe that by testing the performance NFPA1991 "vapor protective clothing" is higher than similar products only through EN934 test - This is the third conclusion.

3.4 Fire Test

Compared with EN934, NFPA1991 set more stringent fire-resistant and flame resistant test of time shall be longer for the fire chemical suits; and EN934 has put forward different options for different flame test requirements. Experts believe that although EN934 is theoretically more scientific and targeted , in actual work , if chemical protection suits are selected in accordance with EN934 , various alternatives are likely to cause user confusion and confusion - this is the fourth Conclusions.

4 Preliminary conclusions

In summary , although EN934 was developed after NFPA1991 , its many indicators are generally lower than NFPA1991 . Although the EN934 has its unique features , for example, it proposes a gas leak test for chemical protective clothing , and NFPA1991 does not have a corresponding requirement , but in general , any chemical protective clothing that passes NFPA 1991 testing and product type certification , its overall performance is superior by EN934 detection products. Moreover, NFPA1991 emphasizes that the type certification of fire protection chemical protective clothing products is not once and for all . Chemical protective clothing must also pass the annual review conducted by the relevant authorities , and the annual review is not only a random inspection of key technical indicators of the product , but also includes The verification of the production process and the manufacturer's quality assurance system.

5 disposable ( simple ) protective clothing

With the advancement of materials science , disposable chemical suits (disposablesuits) and limited-use chemical suits ( limited-use suits ) have been used in recent years . The above products are made of very thin thickness of sealing film or metal lining foil material , and are compounded in a certain order and stacked on the surface of a substrate with low ductility and porosity , and have the characteristics of low cost and convenient use.

Disposable chemical protective clothing and simple chemical protective clothing can be worn directly on the outside of ordinary work clothes , or they can be worn at the same time inside and outside of ordinary work clothes. However, the sealing film can easily disposable (Simple) suits and gloves because of an external force (such as impact, friction) damage, sensitive to high temperatures and flames; and, without the aid of specialized tools, once the user is difficult to visually find of the (simple) chemical suits common scratch, scuff marks and small cracks could cause problems during use.

In general , the testing methods of NFPA1991 and EN934 regarding the wear resistance of chemical protective clothing and the penetration of chemical dangerous goods are also applicable to disposable ( simple ) chemical protective clothing. Meanwhile, the particularity of such products, NFPA1991 firefighters must requirements (simple) chemical suits in a disposable wear out "flashover protective clothing" (flashcoverprotectivesuit), in order to withstand the impact, damage of the friction force; while so also can better protect the wearer from flames and high temperature thermal radiation hazards. According to NFPA 1991, "flashing protective clothing" is also a necessary supporting measure to ensure that the protective clothing meets the standards when performing abrasion resistance test and penetration resistance test.

6 new challenges

Although the current product standards and product type certification procedures for fire protection suits lay the foundation for the development of new personal protective equipment , neither EN934 nor NFPA1991 has limitations , and it restricts fire protection clothing in certain locations and The use of the environment.

A typical example is that the majority of the existing fire-fighting chemical protective clothing is not suitable for work in a confined space, it is very difficult when passing through narrow passages and entrances and exits, dangerous. At present, in line with NFPA1991 "full cover" (totallyencapsulatedtype) is the only chemical warfare suits to a full range of self-contained breathing apparatus (SCBA, ie selfcontainedbreathingapparatus) contained in the inner, fire chemical suits and breathing apparatus to ensure normal work. But such chemical suits are often too large, and there may be pierced by sharp, and even endanger the personal safety of users, and is not suitable for use in confined spaces through narrow entrances.

Although in the international market, “ nonencapsulatedsuit” chemical vapors and vapor protective suits have been used for external self-contained air-ventilators that are suitable for use in confined spaces . However , none of these products have so far passed. NFPA1991 product type certification program. The main reason is that there is no supporting self-contained air breathing apparatus product on the market that meets the requirements of NFPA 1991 while obtaining corresponding special certification .

NFPA1991 different structure and EN934, which specifications are also substantially lower