[Personal protection] The importance of the performance of fire fighting suit fabrics

Because of the constant threat of life-threatening environmental conditions, firefighters have to rely on the good fabric properties of combat suits to protect their safety. Reliable, durable and strong uniforms are extremely important to firefighters and even mean the difference between life and death.

Firefighters need to hazards from fire, smoke and heat three areas for self protection. However, in addition to meeting these three requirements, fire fighting suits also need to ensure the flexibility and proper ventilation of firefighters. If the protective fabric used in the fire fighting suit combines these best comforts with the best safety, it means that the fire fighting suit can guarantee its effectiveness and safety as much as possible.

The fabrics with the best heat resistance and high performance still have great uncertainty in ensuring that the firefighters face the least danger ( such as flashover ) in the face of critical situations . The characteristics of the firefighters' work determine that their physical exertion will be very high, their body temperature will rise and they will be accompanied by a lot of sweat. Under such conditions, the flexibility and convenience of their activities will be guaranteed. Firefighters’ personal protective equipment must ensure comfort and freedom of movement and must be able to absorb moisture.

Now that there is a full set of clothes and equipment that can meet these requirements, the firefighters' work efficiency under high working pressure conditions can be improved, enabling them to concentrate their energy on precision work, and concentrate their efforts on precision work in a life-threatening environment. Must have conditions.

If personal protective equipment fails to meet these requirements, it will increase the user’s sense of fatigue and distract them, which increases the risk of occupational injuries and greatly reduces the quality of work. The failure of fabrics in fire fighting suits can lead to serious situations such as heat stroke, putting individual firefighters in danger and endangering their teams.

Before long, the fire protection industry relied on thick wool to make uniforms. However, in recent years, with the in-depth study of the hazards faced by firefighters, the awareness of the dangers faced by firefighters has increased, and the techniques and designs of fire protection uniforms have also taken place. Revolutionary changes.

Complex fabric technology has undergone tremendous changes to ensure that the firefighters’ full range of clothing and equipment can apply the most advanced technology and have critical performance. After in-depth research, the leading textile companies represented by Hainsworth have developed a wide range of fabrics, so that the quality of the final product of fire fighting uniforms continues to improve, providing firefighters with the best quality and comfortable wearing combat clothing.

1 Kevlar and Nomex

Modern firefighting clothing is the main material Kevlar and Nomex, these two materials are developed by the DuPont company in the 1960s developed, and in 1975 introduced to the market by the partners of protective clothing Hainsworth company. At the time, Hainsworth had been operating fire-fighting apparel fabrics for more than 100 years. It is a professional company in the protective fabric textile industry. This technological innovation further consolidates its dominant position in the UK market.

Kevlar is known for its high strength, while Nomex has good fire resistance and heat resistance. Kevlar is 5 times stronger than steel wire , so the risk of tearing clothes made from it is greatly reduced. The Nomex is characterized by the charring that occurs when exposed to huge heat, and its increased thickness, which creates a barrier between the fire and the wearer’s wearer to protect the wearer from fire and heat.

According to DuPont's estimate, fire fighting suits using these two materials account for approximately 70% . But pay attention to the balanced use of these fabrics to ensure that the wearer provides excellent protective clothing.

2 to achieve the best balance - the role of fabric strength

Clothing made of a fabric with high tensile and tear strength as the outer layer is less prone to mechanical damage, requires less repair work, requires less frequent replacement, has a longer life, and is more valuable. In this case, should we all adopt the highest strength fabric ? The answer is negative.

3 The use of the highest strength fabric is not necessarily the best choice

Of course, what kind of fabric is used depends on the different needs of the end user, and is finally determined by the assessment results made by the personal protective equipment assessment agency according to the 1992 edition of the British PPE Work Regulations . The high strength of the fabric means that the outer layer has a high Kevlar content, which leads to various other problems. Although Kevlar is high in strength, it has a high hardness, so it is easily damaged and can be easily broken during a bending process called fibrillation . This led to the emergence of Nomex Tough (23%) and Pbi Gold (60% Kevlar) .

Kevlar wearing characteristics determine its poor wear resistance, long fiber yarn (yarn fibre) is slightly damaged and without the wearer moves or flexion-extension, material wear and tear occurs. In areas of high stress such as the elbows, knees, and shoulders, it is more likely to wear. Kevlar is also faster than Nomex . Therefore, the content of the low Kevlar fabric (such as Kevlar and Nomex Antistatic content of 5% NomexComfort) compared with a high content of Kevlar fabric to the wearer of the heat transfer speed is faster, especially in the lower operating temperature environment is in this way.

During the wearing period of clothing, the strength of the fabric is not fixed, and external factors such as wear ( daily wear and washing ) and UV degradation will adversely affect the strength of the fabric. The original strength of the fabric will not always maintain high strength, so any advantages of high strength will disappear with the use of time.

This is one of the reasons why Hainsworth TITAN moves most Kevlar from the fabric surface to the back. This will avoid the detrimental effects of UV degradation and wear, while maintaining the strength and integrity of the outer layer of the fabric.

After recognizing the advantages of high strength, we should first determine the strength parameters. EN 469: 2005 the required predetermined tensile strength of the outer fabric 450 N. This means that if you do not rely on the knife and scissors, you can't tear the fabric with pure hands. For a variety of reasons, most of the fabrics sold on the market exceed this standard and reach 1 000 N or even higher. What is the reason for this ?

If the tensile strength is too high, there will be no good thermal performance, nor will it reduce thermal stress or increase comfort, but will have a negative effect.

Excessive pursuit of tensile strength will only lead to more laboratory work and will not have more benefits for actual use, nor will it increase the protective effect on wearers. For the apparel industry, the fabric strength is only a small factor of its concern. After all, increasing the strength of the fabric does not necessarily improve the performance of the fabric.

4 Protection Industry Innovation

The pace of development of fabrics is getting faster and faster. Thermal Protective Performance test and analysis through innovation centers and laboratories, Hainsworth developed in 2000 out of the personal protective equipment (PPE) of TI-technology products, marking the protective clothing industry breakthrough change begins.

TI-technology is a revolutionary new technology product that combines the thermal protection properties of the fabric, Nomex 's elasticity and Kevlar 's strength. It is also innovative because it combines the fibers of the two types of fabrics rather than mixing them in the traditional sense of the textile process.

The use of Nomex on the surface of the fabric , while protected with high-strength Kevlar , protects the fabric from the detrimental effects of UV degradation and abrasion. This allows the production of fabrics that remain clean, beautiful, and durable for long periods of time.

This fabric produces active air entrapment even at extreme high temperatures . The Nomex layer of the fabric is strengthened while the Kevlar layer remains relatively constant. Because these two materials have different heat shrinkage rates, they are sewn together and they move relative to each other and affect each other. When necessary, an open air-permeable structure is used to form an air bag between the two layers to increase the effect of thermal protection.

This fabric system provides better thermal protection than traditional heat-resistant aramid fabrics. At the same time, the strength and durability of the fabric system exceed that of aramid fabrics of the same weight, enabling the user to create clothing that meets the job's needs as much as possible.

Hainsworth also recognizes that there are some work hazards that require special protection, so they developed a series of TI technology products to meet these needs. In addition to HainsworthTITAN , Hainsworth METIS can provide relatively lighter fabrics for low-risk environments, while Hainsworth ATLAS is a thicker, double-layer fabric that offers better thermal protection and can create more comfortable firefighting clothing.

The above-mentioned quality properties can be obtained by “ REPEL + ” technology, which is a unique technology with a lasting protective effect that protects fabrics from water and harmful chemicals, even if repeated washing.

Fabrics manufactured by Hainsworth have been widely used by firefighters all over the world, from Boston to San Francisco, from Copenhagen to Madrid, and from Saudi Arabia to Taiwan.

This data from the "international firefighter" in May 2010, re-edited by the Chinese rescue equipment network.