Tips: Comparison of Technical Standards of Fire Protection Suits in the United States and Europe

Abstract: This article compares the two aspects of the wear-resistance, anti-permeability performance, test environment temperature and flame resistance performance of chemical protective clothing and compares them with the American Fire Protection Association standard NFPA1991 and European Union standard EN934. 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

CPVC (Chemical Protective Vapor Clothing) originates from military nuclear and biochemical protective clothing (NBC, ie Biological Biological Clothing), and can effectively prevent the invasion of human body including the penetration of chemical agents and toxic industrial chemical vapors, gases, liquids and fine particles. 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 advanced countries represented by the United States emphasize the use of multiple varieties, specialization, and other protective equipment in the development of fire protection chemical protective clothing, and constantly adjust the technical indicators of chemical protective clothing to develop targeted new products.

The original intention of designing a fire protection suit is to prevent the wearer's skin from directly contacting 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, it is more necessary to adopt effective passive protective measures to improve the protection capabilities of fire protection suits and to ensure the safety of firefighters who perform fire fighting and emergency rescue work within the dangerous goods environment.

"Class A" gas-tight fire protection suits can withstand the threat to humans of all dangerous chemicals or other dangerous substances, regardless of their state, whether they are gaseous, liquid or solid. Therefore, “Class A” air-seamed chemical protective clothing is generally regarded as the most protective chemical protective clothing internationally.

At present, the design and material selection of international fire protection and chemical protection suits are diversified in order to adapt to different working environments. Experts usually use “PF” (Protective Factor) to indicate the protective effect of fire protection clothing; however, due to the lack of professional guidance from the health and hygiene departments, in many cases, the fire department chooses chemical protection clothing based on traditional concepts. .

2 Development of Fire Protection Clothing 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, the German vfdb standard and the British BS standard were the only national standards involving fire protection 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 Technical standards and specifications for fire protective clothing, especially biochemical protective clothing, such as NFPA 1991 Standard for Vapor Protective Clothing for Dangerous Goods Emergency Disposal, NFPA 1992 Standard for Liquid Splash Protective Clothing for Emergency Handling of Dangerous Goods, and NFPA 1994 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 Comparison between NFPA1991 and EN934

Through the comprehensive comparison of NFPA1991 and EN934, two of the most representative "A" air-seamed 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 due to the complexity of EN934, only very professional people can master and implement it. Experts believe that the reason for this situation may be that EU standards have to go through discussions, negotiations and mutual concessions and compromises among the 15 member states during the drafting process, and finally they may 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.

At present, NFPA is revamping the testing and testing methods for fire protection suits to highlight practicality and adaptability and create conditions for the emergence of new types of 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

"The Permeation Test" (The Permeation Test) is the main method to test the ability of fire chemical protective clothing to resist the erosion of chemical dangerous goods. Both NFPA1991 and EN934 have made clear and clear requirements in this regard, and the NFPA 1991 regulations are particularly harsh: in the test time of 60 minutes, the maximum amount of chemicals that can be tested for chemical protective clothing cannot exceed 0.1 mg/cm2 • min; The requirements of EN934 are much lower: as long as the maximum penetration of the tested chemical protective clothing within 10 minutes does not exceed 1.0 mg/cm2 • min, it is regarded as qualified – even if it is used exclusively by emergency rescue personnel. The longest test time was extended to 30 minutes.

The minimum time required for NFPA1991's “anti-penetration test” time for chemical protective clothing is 60 minutes, and as long as the chemical protective clothing does not have any problems during the test, the test will continue until the chemical protective clothing is damaged or has other problems. The test time may be Achieve 3 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 penetration of chemical gases and vapors while also completely isolating the emissions of sweat and body heat; and, due to the supply of air respirator cylinders, The time is usually only 1 hour. The effective working time for firefighters wearing vapor protective clothing is only 20-25 minutes at a time. There is no need to extend the testing time to 60 minutes.

3.3 Test environment temperature

An important factor directly affecting the above-mentioned “penetration test” conclusion is that both NFPA1991 and EN934 impose an upper limit on the ambient temperature at the time of testing: NFPA 1991 requires that the temperature of the test environment should not exceed 27°C and EN934 does not exceed 20°C.

Obviously, the higher the ambient temperature, the stronger the molecular activity of various chemical dangerous goods, and the stronger their penetration ability. Because NFPA 1991 specifies a higher test environment temperature than EN934, experts believe that the performance of “vapor protective clothing” tested by NFPA 1991 is higher than that of similar products tested only through EN934 – this is the third conclusion.

3.4 Fire Test

Compared with EN934, NFPA1991 sets a stricter flame resistance test and longer flame-retarding time for fire protection clothing; EN934 proposes different options for different flame testing 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, many of its 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 comprehensive performance is superior to those tested by EN934. 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) Chemical Protective Clothing

With the advancement of material science, disposable chemical suits (disposablesuits) and limited use suits (limited use cases) 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 used in disposable (simple) chemical protective clothing is easily damaged due to external forces (such as impact, friction) and is also very sensitive to flame and high temperature; furthermore, it is difficult for users to find it once with the naked eye without using professional tools. The scratches, scratches, and small cracks that are common in (simple) chemical protective clothing may cause hidden dangers 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. At the same time, for the specificity of this type of product, NFPA 1991 requires firefighters to wear a “flash cover protection suit” outside the disposable (simple) chemical protective clothing to withstand the impact of external forces such as impact and friction; This will also better protect the wearer from the heat and heat of the flame. According to NFPA 1991, "flashing protective clothing" is also a necessary supporting measure to ensure that the protective clothing meets the standards when carrying out wear resistance test and anti-penetration 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 most of the existing fire protection suits are not suitable for working in confined spaces and are difficult and dangerous to pass through narrow passages and entrances and exits. At present, "totally encapsulated type" chemical protective clothing conforming to NFPA 1991 is the only fire-resistant chemical protective clothing that can contain a full set of self-contained breathing apparatus (SCBA), that is, self-contained breathing apparatus. However, such chemical protective clothing is often too large, and may be pierced by a sharp device, and may even endanger the personal safety of users, and is not suitable for use through narrow entrances and exits and in enclosed spaces.

Although on the international market, there are “nonencapsulatedsuit” chemical vapors and vapor protective suits that are equipped with external self-contained air-ventilators for use in enclosed spaces, but so far none of these products have 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.

The structure of EN934 is different from that of NFPA1991, and its technical specifications are basically lower than those of NFPA1991. It does not contain the relevant provisions for “non-enveloping” gas, vapor, and solid hazardous goods protective clothing.

In the selection of the next generation of chemical protective clothing, we must truly understand and comprehend the complexity of different specifications and product standards and product type certification procedures. In fact, with the development of protective clothing, the term “personal protective clothing” can no longer meet the needs of real work. At present, experts are integrating various personal protective equipment into a “life support system”, that is, from the system’s point of view, various protective equipment, such as protective clothing, necessary for firefighters to perform fire fighting and rescue operations in dangerous goods environments. Air respirator, life alarm, etc. are organically integrated.