Welcome to the summary of the most frequently asked questions about the DuPont protective clothing and service offering.
|Are garments made of NOMEX® more expensive than FR cotton garments ?
Both initial cost and durability need to be considered when determining cost-effectiveness.
Although the initial price of garments made of NOMEX® is higher than FR cotton garments, they are still more cost-effective. This is because they are 3 to 5 times more durable.
The NOMEX® fibre is a high-tech product with inherent heat and flame protection properties.
The heat and flame resistant properties are permanent and cannot be destroyed over time by wear or washing.
The flame retardant treatment of FR cotton can be affected over time by wear and washing.
|Can DuPont give certification for EN469 or EN531 ?
The European Technical Centre is accredited for some tests described in the above norms. However,
because it is located outside the EU, it can not deliver certificates.
|Do racing drivers wear similar garments made of NOMEX® fibre to firefighter/industrial ?
The garments for racing drivers and firefighters / industrial firefighters are made of the same fibre.
However, the activities of driving a car and fighting a fire are completely different.
Fighting a fire requires movement and activity of the body, which generates heat from within the garment.
The garment thus needs to be looser fitting and have a very durable outer shell.
A racing driver needs a non-bulky garment, which is not waterproof and breathes well,
and at the same time looks good. In a flash fire a driver needs to be protected in a sitting position ;
a one-piece garment does this best.
|Does DuPont have a product that meets EN 1149 for antistatic protection ?
Yes, DuPont has a product that meets EN 1149:1.
It has been used in the market for more than 10 years and is considered a standard product.
This is NOMEX® III with 1% stainless steel fibre.
NOMEX® Antistatic and NOMEX® Comfort are the most recent solutions to offer permanent antistatic properties.
Both products contain 2% P140, a carbon-core antistatic fibre. These meet the requirements of EN1149-3:2001.
|Does NOMEX® exist in high visibility colours ?
NOMEX® in high visibility colours according to EN471 (orange, yellow) is available in fabric form and can be used for example as outershell material in multilayer systems.
|NOMEX® is expensive – why should I choose it ?
Flame resistant fabrics are more expensive than everyday non-FR fabrics (such as cotton or polyester-cotton).
However flame resistant fabrics provide protection from heat and flame and in the case of an accident will reduce costs (e.g. hospital, rehabilitation, insurance, work loss). Initial price and durability should both be considered when evaluating the cost effectiveness of a protective garment.
|What does DuPont recommend as a solution against electric arc hazards ?
DuPont would always recommend that a thorough risk assessment be made by a qualified party before going through the analysis of what protection is required.
The level of thermal protection must match the worst expected arc hazard level. DuPont can offer advice on suitable protective clothing systems made from NOMEX®. In addition, DuPont has developed an unique test facility, ARC-MAN®, which allows end-users to test and evaluate the performance of different garment systems.
In general, two (or more) lightweight layers offer greater protection than one heavy layer.
|What does DuPont recommend for the design of garments ?
DuPont recommends that a garment manufacturer works with the end-user to determine his specific design needs.
Various elements of the NOMEX® Quality Programme help to show the impact of design on thermal protection –
e.g. covering of zippers and buttons, use of NOMEX® sewing thread and velcro, not skin tight fitting, elasticised cuffs and ankles. Experience has shown that for a fireman, the normal size should usually be increased by 1 unit.
THERMO-MAN® and ARC-MAN® can give comparative guidance on garment design.
|What fabric weight do you recommend for petrochemical workers ?
There is no simple overall answer to this. Risk assessment is the first step toward finding an appropriate solution.
The typical range of fabric weights is from 170g/m² up to 265g/m². NOMEX® Comfort is often selected because of its light weight and comfort.
|What is the difference between NOMEX® Antistatic and NOMEX® Comfort ?
The difference between NOMEX® Antistatic and NOMEX® Comfort is that the denier or decitex of the NOMEX® Comfort fibre is finer than that of NOMEX® Antistatic.
This enables a finer yarn to be made, which in turn allows a lighter, more comfortable fabric to be made in NOMEX® Comfort, a feature which is particularly appreciated in clothing designed to be worn next-to-skin.
Both products contain 2% P140 for permanent antistatic properties.
|What is the difference between NOMEX® Quality Programme (NQP) and non-NQP garments ?
An NQP garment meets the requirements of the DuPont™ NOMEX® Quality Programme. It has been tested by DuPont, using tests which go far beyond accepted national and European norms. It is made exclusively of reliable materials and according to a reliable and proven design. An NQP garment can be recognised by its special label from DuPont.
A non-NQP garment has not been tested for its reliability and quality by DuPont.
|What is the difference between piece dyed and pigmented fabrics ?
For pigmented fabrics, colour (in the form of pigments) is injected into the polymer before the fibre is made.
For piece-dyed fabrics, colour (in the form of dyestuffs) is added to an ecru or greige fabric during dyeing.
With the exception of white and other very light pastel shades, a very wide range of pigmented fabric is available.
Piece-dyed fabrics can be made in virtually any shade. The main performance difference is light/colour fastness,
where pigmented fabrics are generally better than piece dyed fabrics.
|What is the difference in protection between NOMEX® and FR cotton ?
NOMEX® fibre is permanent flame resistant. NOMEX® will not support burning in a normal atmosphere.
It is inherently non-flammable. FR cotton is topically treated with chemicals after the fabric is made.
These treatments are not permanent and can vary in their durability to laundry conditions, which can reduce the
non-flammable characteristics of the fabrics.
All flame-retardant chemicals have a relatively low decomposition temperature (190 to 200 degrees Celsius).
In a flash fire (temperatures reaching 600 to 1000 degrees Celsius) this FR agent can flash off.
The remaining cotton, without the treatment, will burn. This is known as afterburn and can cause severe skin injuries. When FR agents evaporate, they can leave a tar-like deposit, which can cause additional burns, because of its high temperature.
Nearly all FR Cotton fabrics are heavier than NOMEX® fabrics.
They contain a minimum of 30% by weight of flame retardant chemicals.
For example a 300g/m² FR cotton fabric has nearly 100g/m² of chemical agent or resin which when flashed off leaves only approximately 200 g/m² of untreated cotton.
|What kind of tests can DuPont carry out ?
Most of the norm testing can be carried out by DuPont. DuPont further specialises in obtaining and interpreting test data beyond the norm requirements. These tests involve unique, sophisticated hi-tech equipment.
They are based on full-sized finished products, such as garments. The two key testing facilities are the DuPont™ THERMO-MAN® and ARC-MAN®. Special attention is given to testing where a specific need cannot be measured by standard testing equipment. DuPont also has access to the latest techniques in comfort testing.
|What should I consider when starting a protective clothing programme ?
First and foremost a risk assessment must be carried out.
As any end-user, you must contribute to this risk assessment which should be carried out by an expert in this field.
Once this has been done, DuPont can then assist in advice on thermal protection and basic design.
|Which are the available colours of NOMEX® ?
NOMEX® can be dyed in fabric form, or coloured by pigment. These pigments are injected into the polymer before the fibre is made. With the exception of white and other very light pastel shades, a very wide range of colours is thus available. Pigments have much higher light stability than the piece dyed fabrics. The colour flexibility of NOMEX® is undoubtedly the greatest and widest available in the segment of protective clothing made of aramid fibre.
|Why should I go to DuPont for advice on heat and flame protective clothing ?
DuPont is acknowledged as the leader and expert in the field of protecting people from heat and flames.
DuPont invented aramid fibres more than 30 years ago. Since then, DuPont has invested in developing thermal testing equipment (such as THERMO-MAN® and ARC-MAN®) and gathered vital experience from continuous contact with end-users.