Content of this page

1°) Entering the world of performance
2°) Certifications
3°) Polycondensation & fabrication
4°) Properties
5°) Appearance
6°) Kermel + Viscose
7°) Customers

1°) Entering the world of performance

The Kermel fibre is a Polyamide-imide classified in the Meta-Aramide family. It is naturally non-flammable, which is a permanent characteristic thanks to its chemical structure including a high proportion of aromatic structures and combined double bonds. The fire resistance properties of the Kermel don’t disappear neither over time nor after washings. Kermel is used in protection apparels against heat and flames. The Kermel fibre offers a maximal protection of several seconds against extreme temperatures (1000°C). Since thermostable outfits were first introduced thirty years ago for use by the Army's armoured vehicle teams, Kermel® fibre has had nothing but success. KERMEL is the leading European manufacturer of aramid fibres dedicated to protective clothing against heat and flames. Innovation is a key element within KERMEL.

This aramid fibre has permanent flame resistant properties and is intended for the manufacture of high-protection clothing for people out in the field. In today's world, countless police and armed forces use it on every continent. Kermel fibre, made in France at our ISO 9002-certified Colmar site, guarantees maximum protection without sacrificing anything in the way of comfort. For those at the centre of the action, faced with heat hazards, flames, chemical splashing and other dangers, Kermel is the key element in a world of high performance, protection, and comfort. Kermel® fibre has permanent flame resistant properties and is intended for the manufacture of fire suits along with protective coveralls for fire fighters.

Defining such clothing is not easy because the qualities required can appear contradictory, such as comfort and protection. It is only by a good understanding of the major parameters and by maintaining a good dialogue with users that products can evolve and the best balance can be achieved. All of the studies conducted by KERMEL and the contact with users have allowed us to develop new complexes with our partners in the textile industry that meet not only the EN 469 standard, but also quality criteria that are important for the job of fire fighters. Kermel® is the leading European manufacturer of aramid fibres dedicated to protective clothing against heat and flames. Fire suits for fire fighters, flight suits for fighter pilots together with protective coveralls for public order squads, military and industrial uses are some of the most popular applications. In parallel with these developments, Kermel® is continuing to diversify, especially in the field of hot gas filtration using its’ Kermel® Tech fibre.
BACK TO TOP
Go to photography and pricing page

2°) Certifications

• Kermel® fibres are OEKO-TEX Standard 100 certified in the class of articles in direct contact with skin. The certified articles fulfil the requirements of the existing European legislation regarding the use of azo-dyes.

• Kermel® facilities are also ISO 9001: 2000-certified.

Non-flammable (EN 532)

A calibrated flame is applied for 10 seconds to the surface of the vertically positioned specimen. The behaviour of the material is observed during and after lighting (persistence of flame or incandescence, formation of a hole
or inflamed debris).

Convective heat protection (EN 367)

The source of heat is a gas flame (80 kW/m2). A sensor is placed above and in contact with the sample positioned horizontally. The rise in temperature of the sensor is recorded and the time required to reach an elevation of 24°C is noted (parameter HTI 24).

Radiant heat protection (EN 366)

The source of heat is an electric radiator (40 kW/m2). A sensor is placed behind and in contact with the specimen that is set vertically, opposite the radiator. The rise in temperature of the sensor is recorded and compared with the theoretical tolerance curves of the skin. Parameter t2 represents the theoretical second degree burn time.

Resistance to chemicals (EN 368)

Clothing must provide a durable barrier against these agents and be easily decontaminated. A water-repellent treatment of the outer fabric allows better detachability and prevents the fabric from impregnation. The  resistance of the materials to chemical products means that a screen structure can be maintained. The specimen is placed on a piece of absorbent paper in the hollow of an inclined gutter. A chemical liquid is projected (10 ml in 10 s) on the part of the specimen at the top of the gutter. The rate of liquid recovered at the bottom of the gutter is recorded. The absorbent paper under the specimen is also observed and any traces of penetration are noted.

Surface wetting

The presence of water in a complex can reduce thermal insulation and  represent a risk of scalding by vapour. In addition, if sprays of flammable liquids penetrate into the clothing, they represent a danger. A membrane within the garment and a water-repellent treatment are key-elements
in protective garments. The fabric is stretched over a hoop and a defined quantity of water is poured through a rose. The attachment of the drops is recorded from 5 (no trace) to 1 (complete impregnation).

Hydrostatic pressure

Cleaning cycles alter the proofing quality of the fabric. That is why it is necessary to implement a particular cleaning process, which will reactivate the treatment. The water pressure that has to be reached to see drops appear on the other side of the complex or fabric is recorded.

Mechanical resistance

The fabric must have and retain high tear strength. Since all these attacks will reduce this mechanical resistance, losses of performance must be anticipated. All Kermel® outer shells guarantee a high safety level.

Chemical resistance

A pilot may be subjected to projections of acid or any kind of chemical products. The proofing treatment and the Kermel® inherently resistance to chemical products ensure that there is only a low level of alteration of the outer shell.

Heat resistance

Heat is not only a danger for the wearer; it can also damage clothing. The most exposed layer always ends up being weakened by extreme heat. The thermostability of Kermel® ensures a high residual strength of the outer layer after long heat exposure (according to EN 469, the residual strength of the outer shell is measured after 3 minutes of radiant heat exposure at a flux of 10 kW/m3).

Mobility

The clothing must not hinder the wearer’s movements. Even if the jacket only represents approximately 10% in mass of the pilot's full  equipment, the correct performance/weight ratio of the complex is an important element.

Effects on physiological parameters

To be at its maximum efficiency, the body must be at a temperature of approximately 37°C. Over this, heat stress can result in loss of consciousness or cardiac arrest. Three factors are involved: physical effort, environment (heat, gas, danger...), and clothing that retain body heat.
The body can be cooled in two ways: through diffusion into the air and by sweat, which cools the skin when it vaporises. Therefore, two parameters are measured as far as the clothing is concerned: thermal resistance and evaporative resistance. Limiting this "wearer heat" can be obtained with thin, light complexes, thanks to the selection of intrinsically high performance layers. Permeability to the water vapour that facilitates the work of sweat can be obtained without sacrificing impermeability thanks to waterproof and breathable membranes.
BACK TO TOP
Go to photography and pricing page

3°) Polycondensation & fabrication

+

=

Complex aromatic structure + important resonance of double bonds = intrinsic non flammable properties and important heat stability. Spinning in wet process and solution-dyed.

4°) Properties

Low humidity rate: allows for a quick drying of the clothing

• Density: 1.34 g/cm3
• Moisture Regain: 4%

Resistance to washing

• Shrinkage in boiling water (15 min): 0%
• Shrinkage in dry air (15 min-200°C): 0.2%

Non Flammability

Polyamide-imide based garments are permanently non-flammable. The physical measurment which allows to qualify the non-flammability of the material is the Limited Oxygen Index (LOI). If it is considerably higher than the oxygen content in atmospheric air (approx 21%) the combustion of the product cannot sustain itself in a normal environment.

• Kermel fibre has a LOI of 30-32%

Kermel fibre do not melt when exposed to high temperatures but slowly char without dripping. The point of vitreous transition is 285°C. Kermel fibre does not burn but carbonize slowly when exposed to very high temperatures. Kermel fibre cannot burn in the air. The Fibre doe not melt or drip. Fabrics made out of Kermel® fibres ensure an exceptional level of protection against heat and flames. Kermel® is an aramid fibre, i.e. inherently non-flammable, thus guaranteeing permanent non-flammability.

Thermostability

Polyamide-imide fabrics are stable in flames, and the integrity of the clothing is sufficient to enable the wearer to move away from the hazardous area. Thermostability of a fibre or fabrics concerns the conservation of mecanical characteristics and dimensional stability for a given temperature exposure. For the protective clothing applications, fabric is required to withstand temperatures of over 1,000°C for a few seconds. Kermel is extremely efficient in this field. When subjected to flames, fabrics made from polyamide-imide retain their integrity and their dimensions, which means that in addition to acting as a protective screen, they also maintain the protective layer of air between the skin and the clothing.

Thermal insulation

Polyamide-imide fibre is a very good thermal insulator, which allows good protection against heat with lightweight fabrics.

• Kermel has a thermal conductivity of 0.04 W/m °K

Kermel® has a very low rate of thermal conductivity, combined with a high infrared reflectance, making Kermel® fabrics an excellent primary thermal barrier.The thermostability of the fabric and the constituents of the multi-layer making up the clothing, guarantee that the structure of the clothing is preserved and therefore the protective air layer between the wearer and his clothing maintained.

Good mechanical strength

The mechanical strength of Polyamide-imide fibre is ideally suited for making durable, long-wearing clothing. Kermel's mechanical data shows supple and flexible fibre with good elasticity. The fibre also has a high resistance to abrasion (transversal resistance) thanks to its amorphous structure. This explains the excellent durabiliy of the product. The Kermel fibre offers a high resistance to abrasion thanks to an important transversal resistance. High resistance + smooth surface = no pilling
Tensil strength: 40 cN/tex +/- 4
Elongation at break: 19% +/- 2
Elasticity modulus: 240 to 320 cN/tex

Resistance to chemicals

The chemical properties of Polyamide-imide provide efficient protection against most chemical agents. Kermel fibre gives good resistance to cold acids, even when concentrated, and dilute alkalis at ambient temperature, when immersed for a fairly long period. It also withstands most organic solvents (except highly polar solvents and phenol based solvents), chlorine bleach, detergents and water vapor. For short-period contact (i.e acciental contact), Kermel has very good qualities as it retains its integrity and therefore sustains the protective screen effect.

Comfort

Comfort is not only a question of well being for the pilot, it can be a matter of life and death. Keeping the ability potential of the wearer is also the function of protective garments. The low modulus of the fibre is realized in the extreme softness of Polyamide-imide fabrics and knits.

Gas emissions

For applications where gas emissions are very important, such as the confinement of an aircraft cockpit, Kermel is a particularly appropriate solution as the fibre generates pyrolysis gases with a very low toxic content (HCN and CO), and the opacity is very low when exposed to a flame.

Excellent appearance

Polyamide-imide does not have pilling, i.e fabrics continue to look as good as new for a long time.

Excellent colourfastness

Kermel Polyamide-imide is solution-dyed during the manufacturing process for improved colourfastness.
BACK TO TOP
Go to photography and pricing page

5°) Appearance

Pilots have to perform their job in public. Therefore, uniform aspect and aesthetics should not be neglected.
KERMEL has drafted assembly specifications with its partners in order to guarantee the quality control of the product until its final shaping into clothing.
Durability of clothing made out of Kermel® is ensured thanks to:

• the ease of care

• colour fastness : Kermel® is solution-dyed during the manufacturing process for improved colour fastness

• no pilling: particular to Kermel®, fabrics that continue to look as good as new for a long time

BACK TO TOP
Go to photography and pricing page

6°) Kermel + Viscose

Protection and comfort requirements vary from one situation to the next, so Kermel fibre comes in a complete range of textile products to meet every demand and every standard.

Kermel® V50: Permanent protection with high level of comfort

Fabric for permanent wear clothing, made from 50% Kermel, 49% FR viscose and 1% antistatic. Kermel V50 is specially intended for manufacturing camouflaged outfits. It guarantees minute-by-minute protection against exposure to fire or heat flashes. It's the ideal clothing for hot, humid climates, giving unmatched comfort. Kermel® V50 fabric is intended for average surface densities, e.g. 260 g/m2 twill. This fabric is worn and well appreciated by most fighter pilots worldwide. Station wear garments made out of Kermel® V50 combine durability with high performance.

• Extreme comfort thanks to the drape and the

softness of the blend.

• Moisture absorption capacity very similar to cotton.

• protection against fire

• available as woven fabric but also in knitted form for the manufacture of underwear

Mechanical performance on a cross section of fabrics

• Product: Kermel V50
• Armour: Herringbone
• Surface density 235 g/m2
• Tensile strength (ISO 5081) 1350 x 900 N
• Tear strength (ISO 4674A2) 65 x 55 N
• Abrasion resistance (EN 530) > 40 000 cycles
• Radiant heat protection (20 kW/m2) (EN 366) 16 s
• Pilling at 5 /15 / 30 minutes (NF G 07 121) 5 / 5 / 5 (no pilling)
• Air permeability 80 l/m2/s

Thermal performance

example of performance for a two-layer garment:
Kermel V50 – 235 g/m2 + Kermel V50 interlock – 250 g/m2
Protection against radiant heat (EN 367)
HTI 24 = 11 s
HTI 24 = Theoretical 2nd degree burn time

Kermel® V70: Permanent and still high protection with lighter fabrics for summer

With its increased Kermel content (70%, mixed with 30% FR viscose), Kermel V70 can be used for the same high performance as Kermel V50 but with reduced weight. It is therefore ideal for very hot, dry climates.
Kermel® V70 (70% Kermel, 30% FR viscose) is intended for lighter products, e.g. 205 g/m2 twill. The higher percentage of Kermel® compensates for the lightness of the fabric and maintains the same level of high performance as the Kermel® V50 blend proposed in heavier fabrics. Kermel® V70 particularly suits pilots located in very hot and dry areas. Kermel® V70 also offers more breathability, i.e. increased comfort.

• Quick drying.

• Better balance between comfort and resistance
• High protection against fire

Mechanical performance on a cross section of fabrics

• Surface density 205 g/m2
• Tensile strength (ISO 5081) 1050 x 800 N
• Tear strength (ISO 4674A2) 65 x 55 N
• Abrasion resistance (EN 530) 100 000 cycles
• Radiant heat protection (20 kW/m2) (EN 366) 16 s
• Pilling at 5 /15 / 30 minutes (NF G 07 121) 5 / 5 / 5 (no pilling)
• Air permeability 120 l/m2/s

Infra-red reflectance performance

example based on Kermel V50