The high stakes of PPE
Published: 01 October, 2005
Finding the best protective clothing solution for workers can be daunting. Get it right, and workers will be comfortable, productive, and most importantly, safe. Getting it wrong could lead – at best – to a demotivated workforce, or at worst, to the law courts – or loss of life.
One of the problems with high performance protective clothing such as this, is that due to its high value many suppliers are unwilling to stock it as an off-the shelf product. It is a problem well understood by Pioner Fristads, part of Swedish group Fristads, a company which specialises in designing high-performance workwear for the oil and gas, chemical refineries and utilities sectors.
The company made its name supplying the offshore oil industry in the early days of North Sea exploration. Colin Clark explains how the pyrovatex-treated coverall developed for this market has now become a commodity product selling under the brand FireMaster – there is also an insulated version designed for use in the winter called the Arctic Firemaster.
Pioner Fristads has been a DuPont quality partner for over 15 years, using Nomex in many of its FR garments. Technical Director Colin Clark says that it is an excellent product for anyone working in a heat/flame environment. “The big advantage that Nomex has is that the fabric is FR inherent so, unlike treated FR fabrics the FR properties remain throughout the wear-life of the garment. Treated fabrics can’t make that claim.”
Another major reason why some people choose Nomex is that it can be produced in lighter weights and still provide excellent levels of protection, he says. The 350gsm FR-treated cotton fabric used in the Firemaster product is preferred by the North Sea oil and gas sector due to the more extreme weather conditions – but workers on the mainland prefer a lighter weight ranging from 220gsm to 260gsm fabrics.
Colin agrees that one of the biggest problems facing users is the difficulty of sourcing stock-supported Nomex and FR garments which meet the users’ specific needs. “It is an expensive fabric and suppliers are reluctant to stock support such high-cost garments,” he says.
Pioner Fristads’ approach is to work closely with customers in key industry sectors to develop a bespoke garment range and then to roll out the products to other related industries. This entails consultation with health and safety advisors to identify the hazards, working up initial design, wearer trials, feedback and then finally testing the garments to ensure that they meet appropriate levels of protection.
Pioner Fristads has built its reputation on providing this service, for instance a recently developed product was an FR high-visibility jacket with a detachable FR-quilted waistcoat. The product was designed for the utilities sector and is fully compliant to EN531 and EN471 Class 3.
“We selected the fabrics and built the product to fit the specific needs of the end user, and had the product tested to achieve a high-performance rating. We plan to introduce a waterproof version of this jacket later this year. Similarly, we recently developed an FR wind-resistant fleece with a Nomex inner liner.”
All the elements in the fleece product, explains Colin, are inherently FR. “We could see that people like wearing fleeces so we set about designing a product which combined performance, comfort, style and durability complete with all the FR requirements that high-risk industries demand. We stock-support these products and many other FR products.”
BP workers have been using Nomex garments for protection within the petrochemical industry for around 20 years. BP International’s Group Fire Advisor at the company’s UK Sunbury Centre, Richard Coates, explains: “Many processes and production activities associated with refining gas and oil exploration carry a risk. Although incidents are extremely rare in these environments, the accidental release of hydrocarbons in liquid or vapour form can lead to flash fire.”
To minimise this risk, in many locations BP employees and contractors wear flame-resistant garments made from Nomex, including coveralls, two-piece workwear, shirts, trousers, firefighter bunker coats and overtrousers. Nomex was chosen, according to Richard, because its protection is inherent. Nomex does not melt or drip if exposed to flash fire, and will also self-extinguish when removed from the source of the heat.
“Before the introduction of these garments, some employees were wearing non-inherently flame retardant garments,” says Richard. “However, our own live-fire testing and research in Europe and the USA over many years has found this type of garment provides limited protection.
“Of particular concern, noted during the BP-sponsored tests, was the amount of chemical and noxious fumes given off by the flame retardant treated material into the face of the wearer, and the fact that some materials can increase burn injury by melting onto the skin.”
Current national standards do not cover the aspect of decomposition of the chemical treatment of materials during full-scale, live fire mannikin testing, which is of some concern when the amount of fumes given off is observed.
Since there is also no consensus between national standards on the exact time period for live fire mannikin tests, and an increase of just one second makes a substantial difference in the amount of chemical products released, this is an area where further work needs to be done by standard committees.
“Analysis of accidents involving flash fire suggests that by wearing inherently flame resistant garments, burn injuries can be reduced or avoided altogether.”
At Sullom Voe Terminal in Shetland, operated by BP, where crude oil and gas is stabilised for export, the Emergency Response Team wears PBI, a fabric made by PBI Performance Products. “The ERT have to respond to all emergencies within the terminal, from gases release, fires and pollution incidents,” explains ERT team leader Tommy Clark.
“They carry out maintenance and the operation of ER equipment, crew the pollution response vessels and perform all cargo operations, and they need protective clothing for all these situations.”
When it came to choosing the fire kit, says Tommy, he picked PBI Gold. “Oil and gas fires give off extreme heat. When we conduct fire hazard assessments we identify the 6.3kw contour, this is the level identified that a fully protected firefighter can stand for 30 seconds. We endeavour to give our firefighters the best protection we can. This is one of the reasons we chose PBI Gold. It is not the cheapest kit around, in fact it might be one of the most expensive, but it is comfortable and has proven to give protection from heat and cold. There is documented proof of a firefighter being caught in a fully developed fire and surviving because he was wearing PBI.”
Cosalt:Ballyclare supplies Sullom Voe’s fire kit. “PBI gives excellent protection from direct flame because it doesn’t break open in the heat,” explains Cosalt’s Ian Callahan. “This is because it has a high Kevlar content in the weave.”
PBI is resistant to high temperatures and is an anti-static fibre which protects the wearer from darting heat and flame. It does not melt, is non-flammable, and resistant to abrasions, acids, caustic solutions, combustible materials and solvents. It is designed to retain its protective properties even after direct contact with flames. PBI fabric is also lightweight and absorbent, alleviating the risk of heat stress.
As the garments are supplied by Cosalt:Ballyclare, they also come with a Petroguard finish that protects against certain chemicals, especially designed for the petrochemical industry. It provides protection against fuels including diesel and aviation fuel, because the finish prevents them from being absorbed into the fabric.
On the other side of the world, in Tasmania, SpotNet Distribution, a specialist supplier of Australian-designed fire resistant garments to high risk industries in the petrochemical, airport and utilities sectors, has chosen to work closely with Kermel, a technical fibre which is widely used in FR fabrics.
Kermel was developed from research carried out by Rhone Poulenc in the 1960s and is produced in France. The Paris Fire Brigade has just chosen Kermel uniforms; Italian firemen are dressed in Kermel summer and winter, and it is used in industrial applications all over the world.
Chris Bishop of SpotNet says that the company puts a lot of effort into selecting the right blends of fibres to suit the end user’s needs. One of those key needs is comfort. “Our main aim is to address the problem that plagues all FR clothing, heat stress. There are other fibres which offer a similar degree of FR protection to Kermel, but end users find them too hot.”
Kermel is a smooth-surfaced fibre with an almost circular cross section. Its shape, combined with its chemistry, makes it as soft and comfortable as cotton. Blended with FR Viscose, says Chris, it is the most comfortable, permanently FR fabric available.
One hundred percent Kermel is not as user friendly as the blends, and it is mainly used for applications such as fire turnout gear and outer garment shells where more frontline protection is required. But for routine day-to-day use in the high risk industries supplied by SpotNet, Kermel fibre is most commonly blended with an FR Viscose fibre, a cellulose-based fibre produced from wood, mainly beech. It is a highly flame resistant adaptation of viscose that offers high wearer comfort as well as optimum protection.
For the petrochemical industry, the preferred blends are known as Kermel V70 (70/30, Kermel/FR viscose) and Kermel A90 (90/9/1, Kermel/FR viscose/anti-static-fibre). SpotNet also provides many garments in Kermel V50, a blend which has become very popular for use in electric-arc applications.
However, Chris says that in the petrochemical industry Kermel V70 is the preferred blend because of its excellent wearer-comfort and resistance to intense heat, abrasion and chemicals. As Chris puts it, these are ‘premium materials and they offer premium performance’.
SpotNet can supply from stock the Edge range of FR garments but specialises in working with customers to meet their specific requirements. “We collaborate with our textile manufacturers to ensure that our end-user customers can fine-tune their personal protection clothing by determining the most suitable textile, design and construction.”
FR cotton layers
Another Australian-based company Flamesafe recommends Proban-treated cotton T-shirts or polos for the comfort and protection of all workers in the petrochemical industry, regardless of their role. Flamesafe, which has just opened a European office, is a manufacturer of flame retardant knitted cotton fabrics, and European sales director Ross Kordakis believes that for those working in hot climates, treated cotton T-shirts are the ideal choice.
“Fabric needs to be natural to reduce heat stress,” he explains, “and although many synthetic fabrics offer moisture-wicking properties, cotton does this naturally and it is more comfortable against the skin.”
Proban has been around for over 60 years, and it is a durable polymer trapped into the core of every cotton fibre. “Imagine the cotton fibre is a straw filled with cement,” says Ross. “The Proban FR polymer is embedded in the fibre and it can’t be washed out. Tests have been conducted in which garments have been washed 200 times and the Proban is still there and working.”
Proban is used worldwide in the petrochemical industry because of its performance in flash fire situations. For this reason it is also used extensively in industries with a risk of electric arc, and for wildland firefighting. “When flame comes into contact with the fabric, unlike with synthetic fabrics, the Proban-treated cotton forms an insulating char,” Ross explains.
“Basically the fabric starts to blacken and the carbon becomes an insulating protective layer between the wearer and the environment. Again, unlike synthetics, the treated garment will not shrink, so there is no tightening around the body that could lead to difficulty in breathing, and no parts of the body become exposed because of shrinkage.”
Flamesafe recommends that everyone working in the petrochemical industry should wear a Proban-treated T-shirt or polo as a base layer, on the basis that building up the number of layers provides greater protection.
“Even if workers are wearing FR coveralls we still suggest a treated under layer,” says Ross. “It is impossible to predict how hot any fire will get, and where the coverall alone might provide a few seconds protection, if it is combined with another FR layer that is a few more seconds the wearer has to get to safety.”
The natural solution
A natural fibre that provides both comfort and protection is Lenzing FR, a viscose fibre derived from wood. A flame retardant substance is incorporated throughout the cross-section of the fibre that cannot be washed out, therefore offering permanent protection. It is a fibre that is often used as a blend with aramid fibres to improve performance and comfort as fabrics made from Lenzing FR are moisture-absorbing, breathable and good at managing heat stress.
Sometimes referred to as the ‘silent’ blending partner, Lenzing FR is used in various blends with aramid fibres such as Nomex and Kermel. For example, a 65/35 Lenzing/aramid blend provides the same level of flame resistance as 100% aramid fabrics.
There is no flame spread, afterglow, holing or after-flame when the fabric comes into contact with flame. This is combined with improved insulation against different kinds of heat – convective, conductive, and radiant – while the heat generated by the wearer moves easily through the fabric to help reduce fatigue and heat stress. The blend also offers improved wearer comfort because of its moisture management characteristics and soft feel, and provides better resistance to pilling and abrasion. The newcomer,
A less well-known competitor of these major brands is CarbonX, manufactured in the US by Chapman Thermal Products, is distributed in Europe by UK-based IQ Textiles. This fabric is not yet widely-used by firefighters, but it has the performance characteristics to make it an strong contender for this industry and so far it has been used extensively in motor sports and by foundry workers.
CarbonX is made from thermally-stabilised oxidised pan fibres that have been blended with para-aramids for strength, but most importantly it has a high LOI, or Oxygen Limiting Index.
The LOI is a crucial test for determining flame resistance, and calculates the amount of oxygen needed in the environment to support combustion. According to European distributors IQ Textiles, the LOI of CarbonX is between 33 and 50% higher than inter-nationally-known brands.
During laboratory mannikin testing employing 4-second flash fire for percentage body burns, only 12.4% of the surface area of the mannikin suffered the equivalent of 2nd and 3rd degree burns, compared to 40-60% with the known brands.
As European sales director Neil Davey explains: “CarbonX fibres carbonise and then expand when exposed to intense heat or flame, dramatically reducing the oxygen content within the fabric. It won’t char, shrink or burn when exposed to heat and flame unlike many of the most widely used FR fabrics.”
In fact, lab tests show that it won’t char or crack when exposed to temperatures exceeding 1,650°C for over two minutes.
Neil is convinced that the inherent properties of the fibre, which during production is ‘cooked’ at temperatures exceeding 700°C, make it a good choice for applications against direct flame.
“Our Achilles heel is that we are not proven in the market. We can do as many laboratory tests as possible but this doesn’t make any difference until CarbonX is used in garment assemblies,” he says.
There are other factors too, however. One is colour limitations. CarbonX is a carbon fibre and therefore is inherently black. “But we can do a mid shade, greys and recently a dark olive.”
As a high-performance, technical fibre, CarbonX has a corresponding price. “But you pay for performance. CarbonX is probably around 20% more expensive than Nomex.”
And so the battle goes on to supply the most effective quality garments for end users in fire brigades and throughout the industrial sectors. Research remains focused on the issue of heat stress experienced by wearers of fire protective clothing – and new solutions appear to be emerging all the time.