Local Sections - London & South East Events

Bullets v Textiles ....Who wins?

London & SE Section May 2008 Event.

Paul Fenne, Head of the Physical Protection Group, Operational Technical Support Unit, of the Metropolitan Police Service was the Guest Speaker at an event held at London College of Fashion, Davies Street, London W1 on May 21st 2008.

Paul previously worked at the UK MOD, at MVEE (Military Vehicles & Engineering Establishment) developing many different aspects of combat vehicle design from armour, weapon systems, battlefield survivability and ergonomics. In 1987 Paul joined the Met Police to run a team to develop the engineering aspects of design and procurement of physical protection solutions. This ranged from vehicle protection to body armour.

Weapons using projectiles have been used for centuries, ranging from stones to arrows to bullets. Textiles have been optimised to provide protection from all these sorts of projectiles at various times in history in the development of personal armour schemes. Today the high velocity bullet is a significant problem to design protection against.

Paul’s talk traced the history of the development of personal armour and the success and continuing research into modern personal armour schemes using textiles.

When Paul was recruited to the Met Police in 1987 a need had been identified for development of protected saloon cars, armoured riot buses and personal body armour. A brief was given to potential suppliers to provide a body armour solution that would provide protection from both bullets and knives. The resulting prototypes were totally impratical due to their immense weight and Michelin man like bulky appearance. This was the starting point for Paul’s team to find a practical solution that was light enough to wear all day and yet would give an appropriate level of protection against both bullets and knives.

‘Know your enemy’ would be a good place to start for a military comander, so the team started by identifying the types of bullets / knives being used and the effect of their use on body armour materials. Lead bullets have a high mass, are malleable and expand on impact causing massive damage. The energy is measured in Joules. For example a tennis ball hit by a professional player travelling at about 100mph would equate to approx 36 Joules of kinetic energy. A bullet from a hand gun would produce 500 Joules and from a rifle 5000 Joules. Being hit by a tennis ball at 36 Joules would no doubt be very painfull but the force of 500 Joules or 5000 Joules from a bullet would be lethal.This therefore illustrates the immense energy on impact that the body armour needed to be able to repel. Although knives are not propelled with such high energy, their effect on body armour weaves designed for absorbing ballistic impacts were liable to result in a perforation because a knife has greater piercing properties because of the small surface area of the point. The best body armour therefore had to have elements of protection against both bullets and knives.

In London there is, on average, a knife crime every 50 mins and annually 3350 crimes with guns with, on average, 20 people shot per year.

The original body armour developed was the Metvest (which was originally worn next to the skin). The resistance to bullet perforation, or ballistic protection, is provided by a high performance fabric of para-aramid. This is best known under the trade names of Kevlar or Twaron. This yarn has the following characteristics:

High tensile strength – requiring a small amount of extension to break.
High strain rate resistance

Both Dupont and Teijpn Twaron produce the para-aramid filament. The weave needed to be close but with good flexibility to be made into garments. Polyethylene as used in milk cartons can be produced with the polymer molecules aligned with the length of the filament. This is marketted as Dyneema and offers another alternative to give ballistic protection.

To understand the tensile strength of these materials a theoretical comparison of the maximum length of a number of different materials until they break under their own weight can be calculated.

Dyneema - 400km
Aramid - 235
Carbon Fibre - 195
Glass - 135
Polyester/ Nylon - 85
Steel - 25

When measuring ballistic performance there is a difficulty in that as the bullet velocity increases, instead of there being a clear point at which bullets penetrate, the outcome is very unpredictable. A large number of impacts have to be made and a statistical analysis of the outcome particularly in the range of velocities over which bullets do or do not perforate.

When providing knife resistance, chain mail made out of light weight stainless steel is a good solution. An alternative is to impregnate the aramid fabric with a polymeric resin. However these solutions tend to be less flexible. A body armour panel would typically consist of a sandwich of an outer textile cover, with chain mail immediatley beneath (knife resistance) with an woven aramid fibre below this (bullet resistance). The garment is usually sleeve less and needs to be flexible for movement and shaping to the body. Each body armour would cost about £300 / £400

Research is continuing to provide body armour with better protection / flexibility / coverage / shaping properties / lighter weight / better edge feel / thermal insulation / breathability / etc, but with both knife and gun crime on the rise it is likely to be needed by the police force for a long time to come. Even the bird life at the Met test range has felt the need to upgrade their nesting materials to incorporate Twaron para-aramid fibres and titanium swarf, see photos below.

Uncovering Lingerie 17th April 2008

Underwear, foundation garments, lingerie, smalls, call it what you will, we all wear it and apparently are buying more of it than ever. Planning for this seminar raised all sorts of discussions such as the growing retail market, the trend for underwear as outerwear and the specific technical challenges in manufacturing small garments composed of many parts. They not only have to fit well, but the diverse range of raw materials needed has to be colour matched and compatible for washing, besides which the size range offers can be vast. M&S have some forty-six bra sizes on offer, which need pattern grading and component variation. Lace and elastic may need to be made in varying widths, and some sizes may require extra components or construction methods. And then two or even three different garments may be needed for a set, such as matching bra, knickers and cami or pyjamas etc. For small garments they can pack in a huge amount of specification requirements!

The American InterContinental University in London agreed to host this years joint TI and SDC lingerie seminar and so for the first time we found themselves in a converted Church just off Marylebone High Street, London W1 now used as a studio for the AIU fashion students. Gill Stark, Fashion Dean of the AIU welcomed approximately 100 delegates and seven speakers and said that she looked forward to more collaborations with industry associations.

Julie King, Dean of Fashion and Textiles at De Montfort University, kindly agreed to chair our event as well as deliver two short talks. Her opening presentation discussed the growing retail market for underwear, the changing shape of women, and the increased demand for larger cup size bras, topics perhaps not so unrelated as might seem at first glance. One reason for the global rise in sales of underwear is related to evidence that societies who traditionally did not wear our type of underclothes are now adopting western forms of underwear. Another is that underwear has become much more than unseen foundation garments and are worn in a new way, almost blurring the distinction between outer and underwear. Contributing factors for the demand for larger bra cup sizes include diet and obesity, exercise, or lack of it and an increase in breast enhancement surgery. Where once a style was offered in cup sizes A to D, now DD and above are much more readily available.

Shelley Tweed and Lisa Joughin, Fabric Technologists at Marks and Spencer, jointly presented the key stages used by the company in the sealing and manufacture of their lingerie. Beginning with the viability of a product in terms of aesthetics, technical elements and cost, they outlined the entire process through fit and grade seals, pre-production garments for wearer trials and wash testing and finally production. As a single garment can have over 20 component parts made from a wide range of materials, such as lace, elastics, hooks and eyes, strap adjusters, under wires, foam cups etc, close contact with the raw material suppliers is vital in ensuring that all the approved parts are ready for garment manufacture at the same time. Shelley and Lisa also spoke about their innovative projects, which have included 'Magic Knickers' and more recently products developed specifically for people with eczema and sensitive skin.

Frank Rankin, Fabric Manager at the Stirling Group, began by rhetorically asking how he could distil a lifetimes experience into 20 minutes, but went on to deliver a talk packed with technical know-how and advice on problem solving. He began, to my immense delight, by asserting that the design process was both creative and technical and in fact, the two went hand in hand. (Without expressly saying it, Shelley and Lisa had actually demonstrated the same thing.) To Frank beauty was the satisfactory engineering and resolving of technical difficulties to produce an aesthetically pleasing, and functional product. Building on the M&S talk he went into the detail of managing the raw materials and ensuring that all were compatible and fit for purpose. A single garment can be composed of nylon, elastane, stainless steel, polyesters and plastics. On colour matching he advised relating all fabric colours to the finished garment and in the way any particular item was to be used. For example, lace as a single layer against the skin will look different when placed over another layer of something different. A stretch fabric will appear one shade when relaxed and another in its extended state. Embroidery formed of one fibre type stitched onto a different fibre base will require a dye method different to that of a matching fibre type and so the examples went on. Frank spoke of the diversity of fibres contained, for example, in one lace fabric and its associated problems in dying, how moulding processes affect colour and the perennial phenomenon of yellowing. Finishing with a 'best practice' list of many do's and don'ts, Frank left us with much to think over over and digest.

Sandra Ball from Avlanon Stands brought and displayed the most recent type of mannequins featuring soft sections well suited to fitting underwear. A power point presentation showed the development and possibilities for mannequin customisation to company requirements by the use of 3D scanning of a fit model. During the coffee break all of the exhibits, the mannequins and samples brought by all of the speakers were examined with interest.

Liz Lawes from Courtaulds is a print designer for lingerie and shared with us her different approaches to designing for children, for a broad mass-market appeal or more sophisticated labels. She showed a selection of mood boards and many fabric examples of print designs. Colour again played an important part as well as print techniques and the use of modern fabrics developed particularly for items to be worn against the skin. Designing lingerie, Liz explained, included the importance of being fully aware of the end use of her garments. A girls' first bra, probably worn under a school uniform has quite specific requirements, very different to that of an impulse buy or the luxury demanded by the high-end label.

Nichole DeCarle graduated from De Montfort University with a first class degree, did an internship with Alexander McQueen and then set up her own designer label aimed at the luxury niche market. Via her website she now has a worldwide clientele for her designs and explained that while it is exciting having many international contacts and invitations, it comes with its own set of problems. A company in Montreal had placed a large order, which, due to manufacturing capacity she was unable to fulfil. Unfortunately it came too soon, but shows the potential of her business. Nichole spoke of the difficulties in manufacturing in the UK, and her reluctance to go to the Far East. Her ideal is for ethically sourced raw materials and sustainable ways of manufacture, and to this end she has set up her own manufacturing base. Her first year in business hasn't been easy but from her talk showed that she has the determination, energy and passion to succeed.

Julie closed the seminar by thanking all of the speakers, and expressing the immense value in this kind of event as another means for educational links with industry. De Montfort University have specialist contour garment courses and try to ensure that all students have work experience in the industry before graduation. The course syllabus includes industry linked projects and competitions to help identify their high-flying students. It is only by an ongoing relationship with industry that the colleges can know and understand what the industry needs, and it is the work placements which help to bridge this gap.

In writing this review I asked myself 'what were the key messages from our speakers?' and in different ways they had all said the same thing. Standards and procedures are borne from sound education and good working practices, something we al know but it was good to hear it repeated. Add to this the importance of good relationships with suppliers and manufacturers and combine with a passion for a job well done. On a personal level, I felt privileged to have been at a morning where industry and education experts had generously shared their knowledge to the benefit of us all.