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Fire Retardant Composites for Current Collection Equipment on 3rd Rail Rolling Stock


Fire Retardant Composites for Current Collection Equipment on 3rd Rail Rolling Stock

Following the fire disaster at King’s Cross St Pancras tube station in 1987, stringent new fire safety regulations were issued for the governance of materials used on London Underground.  To this day these fire safety regulations, formerly BS6853, and now incorporated in the European railway standard for fire safety EN45545, include some of the most demanding requirements in the world for composite materials in terms of flammability, smoke and toxic fume emissions.

Above: The aftermath of the King’s Cross fire, 1987 [credit: London Fire Brigade]


Following the disaster, Permali’s material scientists worked closely with the technical authorities of London Underground to develop a unique glass reinforced epoxy laminate, Permaglass MER35, that complied fully with the new RSE/STD/014 for fire and arc protection.  Since 1990, when Permaglass MER35 and Permaglass MER20 were developed, approved and entered service, they have been used extensively on all new and refurbished rolling stock operating on London Underground, and are used frequently on other third rail networks throughout the world.

This programme of development work, with contributions from industry experts, contributed greatly to Permali’s credibility as a world leading technical authority on the performance and behaviour of fibre reinforced composites when burning.

Above: London Underground today


Arc Protection

Modern trains collecting 750 V DC of electricity from a third rail require insulating materials that offer the best possible protection from electrical arcing that occurs at the current collection point.  The potential damage and destruction that can be caused by electrical arcing to critical components on the under carriage of modern rolling stock can be catastrophic. Permaglass MER35 has been developed to quench the arcing and limit the electrical tracking that can follow, offering the best protection possible for passengers and expensive equipment.

Fire, Smoke & Toxic Fume Emission Protection

Permaglass MER35 incorporates a high-performance fire retardancy system into its epoxy resin. The complex nature of these fire-resistant additives requires a combined construction of woven and non-woven glass reinforcements to offer outstanding protection in a fire situation – self extinguishing with low smoke and toxic fume emissions when burning.

High Strength

Extreme track forces transmitted through the bogie into current collection gear can put high stress loadings on critical safety components.  Permaglass MER35 is designed to offer high strength and excellent resistance to fatigue to ensure train operators have components made from materials with a strong track record of reliable performance.  Permali’s expertise in design supports our customers in ensuring all load carrying features are optimised through design to ensure fitness for purpose.

Above: Permali’s MER35


Precision Components

Permali compliments it’s material manufacturing capabilities with precision machining, assembly, and inspection capabilities – ensuring your shoebeam and arc barrier components are not only compliant with current standards but manufactured and assembled to exacting standards. We operate on a 10,500m2 site in Gloucester, UK.

Put Permali to the test, email us at

Aircraft Cockpit Door Protection Upgrade

aerospace composites

Aircraft Cockpit Door Protection Upgrade

Above: Armoured cockpit door

The terrible September 11 attacks on the US in 2001 permanently changed the nature of air travel for everyone, and the world is now familiar with the increased security measures at airports and on-board aircraft.  These measures include making aircraft cockpit doors both intrusion resistant and bulletproof, with Permali playing a major part in the worldwide programme to upgrade existing doors in accordance with new regulations from 2002 onwards.

Permali had already anticipated such a requirement as a result of an incident in December 2000 when a passenger stormed the cockpit of BA Flight 2069 from Gatwick to Nairobi and forced the aircraft into a dive before the crew were able to overcome the intruder and regain control of the aircraft.

British Airways were a Permali customer for cargo bay liners, and in discussions with BA engineers it became apparent that aircraft cockpits were extremely vulnerable to forcible intrusion.  Permali was able to combine their extensive knowledge of both composite ballistic protection and aircraft interior flammability standards to rapidly develop a material suitable for reinforcing cockpit doors.

Whilst nobody had predicted a determined and coordinated attack on the scale of 9/11, Permali had already developed and tested a suitable material when the attacks happened, and immediately began working with aircraft manufacturers and airlines on solutions for preventing cockpit intrusion.  Permali’s material, branded Permaglass XFS2, provided a lightweight composite armour solution capable of stopping handgun threats, whilst also meeting all aircraft interior flammability standards per FAR25, including vertical burn, heat release, and smoke & toxic fume emissions.



Above: Boeing 737

The first airline to respond was Virgin Atlantic Airways who contracted Permali to supply retrofit cockpit door reinforcement for their aircraft in advance of the new regulations being published.  This retrofit solution was supplied in October 2001, less than 6 weeks after the September 11 attacks took place.

Permali went on to work closely with Airbus and various aircraft interior manufacturers to supply solutions for Airbus, Boeing, McDonnell Douglas, Embraer and other aircraft, helping to protect thousands of aircraft and millions of passengers worldwide.

Permali continues to work on solutions to protect cockpit doors and bulkheads, developing lighter and thinner materials to meet the stringent requirements of modern civil aircraft.

For more information on Aerospace solutions, contact

Panther Command & Liaison Vehicle Roof Solution

Panther Command & Liaison Vehicle Roof Solution

Our customer approached Permali to help solve an issue with the Panther vehicle roof (weighing 7-tonnes, the Panther is a command and liaison vehicle which is air transportable and can be underslung beneath a Chinook helicopter). Greater stiffness was needed within the roof plate and this could have been achieved through the increase of the sectional thickness of the roof’s metalwork or with inclusion of stiffeners. The former would have incurred a significant mass penalty, whilst the latter would have compromised the available internal space. A mass neutral solution was sought.

Panther Vehicle
Above: Panther Vehicle


Working with the customer Permali undertook the challenge of designing and manufacturing an innovative, moulded composite roof capable of providing the desired stiffness and delivering enhanced levels of survivability. Product development and validation activities were run in parallel with the design phase to provide an in-theatre solution within 18 months of conceptualization.

Permali's machined Panther roof
Above: Permali’s machined Panther roof


As the project and working relationships developed, Permali were tasked with the machining of the roof panel and subsequent fitting and installation of the, ground plane, hatch rings, and seals.

Permali panther roof fitted
Above: End result


In total, 440 units were provided and delivered lineside, fully painted and kitted out to the vehicle OEM.

For more information, get in touch at

Merlin Helicopter Mk3 Ballistic Protection

Merlin Helicopter Mk3 Ballistic Protection

By 2009, Permali had developed a reputation for providing high performance composite ballistic protection, and rapid responses to Urgent Operational Requirements (UORs). A significant number of British platforms deployed to Iraq and Afghanistan were in-service with ballistic armour solutions supplied by Permali, including various land vehicles and the RAF Chinook HC2 helicopters.

Merlin Mk3 Helicopter


Facing a need to increase helicopter lift capacity in Afghanistan to reduce vulnerable troop and supply movements on the ground, the MOD took the decision to deploy Merlin Mk3 aircraft to Afghanistan. In support of that deployment, ballistic protection for the aircraft cockpit and passenger cabin was required. Permali had already demonstrated lightweight, advanced composite armour technology to the MOD, and was engaged by AgustaWestland (now Leonardo Helicopters) to work with them on developing a solution. Permali provided material and protection expertise while AgustaWestland took responsibility for integration onto the airframe, with both parties cooperating closely to ensure that an optimised solution was quickly developed, tested and manufactured.

As with all aircraft applications, weight was critical, so Permali developed a lightweight Ultra High Molecular Weight Polyethylene composite material solution. The composite panels were pressed at very high pressure in Permali’s platen presses, and then waterjet cut and assembled in-house.  The result was a ballistic protection suite supplied in record time, and delivered to the end user to accompany the initial deployment of the Merlin to the Afghan theatre.

Permali went on to build on the close and effective working relationship that had been developed with AgustaWestland to develop and supply ballistic protection for the naval Merlin Mk2 variant, and later also the Mk4.

For more information, please contact

British Army Heavy Equipment Transporter Cab Armour Upgrade

British Army Heavy Equipment Transporter Cab Armour Upgrade

During British Army operations in Afghanistan, ground vehicles were very vulnerable to attack, whether from roadside bombs, mines and IEDs or from ambush. Increased helicopter lift capacity was provided to allow personnel and supplies to be transported by air whenever possible, however there remained regular significant movements of equipment too heavy to be transported by helicopter.

In particular, the Oshkosh Heavy Equipment Transporter (HET) vehicle was tasked with transporting other vehicles and heavy loads by road, and was encountering attacks of various kinds.

By that stage, Permali had developed a reputation for providing high performance and effective armour solutions with very short lead-times to satisfy Urgent Operational Requirements (UORs). Permali was contracted by the MOD to develop and supply an armour upgrade for the HET vehicle to give protection to the crew from small arms fire and IEDs. The requirement initially provided rear hemisphere, side and floor protection, and Permali was challenged with a very short programme to deliver kits for installation in theatre, including manuals and installation instructions.

The short timescales required very close cooperation between Permali, the Army, MOD and subcontractors, with mock-up and prototype work being conducted on a HET vehicle delivered to Permali’s Gloucester facility by the British Army.

Further enhancements to the protection, including the addition of armoured glass side window and windscreen panels were later added.

For more information, contact

Chinook Cargo Handling System (CCHS®)

Chinook Cargo Handling System (CCHS®)

Permali was contracted to develop and supply a comprehensive ballistic protection solution for RAF CH-47 Chinook helicopters as an Urgent Operational Requirement (UOR), adding protection panels in the cockpit and cabin of the aircraft.

During later discussions it became apparent that the RAF also had a need for a cargo handling system for the Chinook to allow the rapid despatch of wooden cargo pallets when re-supplying forward operating bases in Iraq and Afghanistan, to minimise the time the aircraft spent stationary and vulnerable on the ground. The RAF already had a cargo handling system, but it was rarely used due to being heavy and time consuming to install and was also not compatible with the ballistic protection installed on the aircraft.

Permali worked to offer a solution to the RAF, meeting the requirements of:

  • Easy to install and maintain in theatre
  • Lightweight
  • Provide low friction cargo rollers to allow easy and rapid despatch of cargo pallets
  • Be installable with or without ballistic protection fitted

The resulting product became known as CCHS® and was purchased by the Ministry of Defence under another UOR. CCHS® proved to be very successful and popular with the operators in theatre. It can be installed or removed by 2 people in only a few minutes, is much lighter than the system used previously, and proved highly reliable and easy to maintain. RAF Chinook crews became adept at despatching pallets at forward bases while rolling the aircraft forward, or in some cases even without touching the ground, so that the aircraft was never stationary and vulnerable to enemy fire.

CCHS® was subsequently purchased by the US Army and Canadian Air Force for their Chinook aircraft as it provides an unrivalled capability on the battlefield and has also proved its worth during disaster-relief operations.

For more information, please contact

Vehicle Underbelly Mine Protection

Vehicle Underbelly Mine Protection

Permali have provided a range of technologies to help enhance a vehicle’s survivability when faced with underbelly attack from mines and IEDs.

At lower threat levels this typically involves protection against fragments penetrating the vehicle floor originating from threats such as grenades and antipersonnel mines. Solutions typically take the form of an internal liner fastened to the floor. Dependent upon the severity of the threat faced, solutions can range from relatively thin and flexible liners to bespoke moulded composite components that conform to the profile of the vehicle’s floor.

Materials used for internal protection are similar in nature to those formulations used for spall liners. So as well-as offering fragmentation protection the internal liners will, with the correct material selection and configuration, provide cone angle reduction against EFP’s and shaped charge IEDS too.

Solutions manufactured from the more structural composite protective materials provide enhancements to a vehicle’s graceful degradation, protecting welds and other structurally weak areas. They can also improve a vehicle’s structural response under blast loading, reinforcing areas of weakness and enhancing global stiffness. Components take the form of laminated, foam cored sandwich panels or moulded composite structures. These structural mouldings can also be mounted to the outside of the vehicle as a first line of defence in areas such as wheel arches, flitch plates and belly pans.

For more information, contact



Warthog AOA Spall Liner

Warthog AOA Spall Liner case study

Permali successfully completed the design, development and production of spall and appliqué armour ballistic protection for Singapore Technology Kinetics Warthog for UK MoD.

The Challenge

UK MoD placed an order with STK for the supply of over 100 Warthog vehicles. The Warthog is an enhanced version of STK’s proven Bronco ATC. The UOR nature of the programme meant that the timescale from concept to In Service date were less than eighteen months. Permali has a proven track record of supplying appliqué ballistic protection to UK MoD and it for this reason that they were selected by STK to provide protection systems for the Warthog programme.

The Solution

In order to achieve the critical timescales of the programme Permali undertook parallel design development and production readiness programmes.


First stage of design was an initial visit to STK premises in Singapore where a cardboard template of the armour and spall liner was produced using an existing Bronco base vehicle.

These templates were taken back to the UK where detailed 3D models of the parts were produced. These CAD models were sent to STK for inclusion in the overall vehicle model. Following further exchange of models and refinement of the panel designs a mock-up set of panels were manufactured in Plexiglas. These templates were shipped to Singapore for mock-up fit on vehicle.

Following this visit further refinement of models was made and a final mock-up was manufactured from Plywood. Again, these were shipped to Singapore where the UK design team fitted the panels and then made final adjustments to ensure perfect fit. The changes to these panels were again transferred into the 3D CAD models before design freeze and transfer of designs to manufacturing.

During the design stage Permali liaised closely with STK, the UK based armour supplier and the vehicle integrator to ensure all interface requirements were met and there were fitted with no clashes with other equipment. The designs were also approved by Dstl and MoD to ensure maximum ballistic coverage was achieved.

Development and Qualification

In parallel to the design of the physical shape of the panels, a ballistic development programme was undertaken to design the optimum armour material solution to meet the ballistic requirements criteria and weight budget of the vehicle.

Ballistic testing of the armour system was undertaken as an array consisting of hull armour and spall constructs. Testing was conducted against KE round and fragment. Multi hit was also demonstrated. Following selection of the ceramic construct, qualification ballistic testing was undertaken at both upper and lower operating temperatures.

Shock and vibration environmental testing of the appliqué ballistic armour was also undertaken to ensure the robustness of the armour design.

All testing was presented to Dstl and UK MoD IPT to ensure performance met the requirements of the end user.


Permali worked closely with material suppliers to ensure just-in-time deliveries of all critical raw materials to negate the need to hold large stocks of expensive materials.

New ceramic armour production line was installed in Permali’s Gloucester facility consisting of 10 vacuum tables which allowed a production rate of 12 sets of armour to be produced per month.

All the spall liner sets were dispatched to Singapore for integration into the vehicle whilst the armour was dispatched to STK’s subcontract vehicle assembly facility in South Wales.

The initial sets of both armour and spall liner fitted perfectly demonstrating the success of the prototyping operations.

Management of design changes

Late in the prototyping phase significant design changes were made to the rear cab necessitating a redesign of the rear cab spall liners and armour.

Following customer feedback of the first vehicle design, changes had to be made to front armour and spall liners to allow for the fitting of additional equipment. These design changes were incorporated in Permali’s production build standard and Permali worked closely with STK and UK Vehicle Integrator to rework existing sets that had already been delivered.

For more information, please contact

Composite Naval Safety Systems

Composite Naval Safety Systems – Examples of our work

Permali are market leaders in the supply of lightweight Glass Reinforced Plastic (GRP) safety systems for naval vessels. Permali’s Safety Nets, Stanchions, Guardrails and Ladder systems offer the following key benefits over conventional metallic systems:

  • Lightweight, easy to use and vibration free
  • High strength and durability
  • Fixed, foldable and removable quick release options
  • Rigid guardrail, rope, chain and safety net systems
  • Can be deck or hull mounted
  • Foldable systems with variable angle position
  • Positive lock ‘camlock’ fittings specified
  • Flight deck approach lighting can be incorporated
  • Low maintenance, corrosion resistant components
  • Non-conductive, with reduced radar signature

Flight Deck Safety Nets

Permali safety nets are designed to protect personnel working on flight decks. Permali have provided Flight Deck Safety Net systems for several vessels of the Royal Navy and our allies, including the Visby Class Corvette (above), Type 45 Destroyers, Type 23 Frigates and Queen Elizabeth Class Aircraft Carriers. Fully modular net assemblies can be hull or deck mounted. Permali systems can be customised to suit the required net height / width / seated angle. Net assemblies are modular and can have removeable sections or fixed/removeable guardrail or parafil sections incorporated. Automated systems, and high temperature resistant systems are also available.

Weather deck Stanchions & Guardrails

Permali Guardrail & Stanchion assemblies are designed to protect personnel on weather decks and walkways. Permali systems are in-service on the Type 45 Destroyers and RFA Bay Class vessels (above), among others. The modular Permali system allows any combination of fixed guardrails, removeable parafil and lift off gates as required by the vessel architecture. Systems are approved to stringent fire safety standards and are designed to withstand severe naval impact tests.

Permali also design & manufacture GRP ladders, hatches, light beam assemblies & infill nets.

For more information, contact

Fuel Tank Protection System – Permali tests with Small Arms Fire & Grenades

Fuel tank Protection System – Permali tests with Small Arms Fire & Grenades

BattleJacket® is a passive, self-sealing system that prevents leakage of fuel when a fuel tank is penetrated by projectiles from IED’s, mines, and small arms fire. The multi-layered elastomeric system is designed to allow projectiles to penetrate and pass through the polyurethane coating and into the fuel tank providing an instantaneous seal behind it. The coating sustains only minor perforation damage and maintains form and function through an excellent multi-hit capability.

Before becoming a licenced solution provider for HIT (High Impact Technologies), we decided that we’d put this advanced technology through a series of rigorous tests to ensure we understood the system’s capabilities before entering into a partnership.

The threats chosen for evaluation were selected to be representative of those most likely to be seen in an attack i.e 7.62 calibre rifle rounds and fragments representative of those generated by small IED threats. The specification was reviewed by the MoD (Dstl) to sense check our methodology prior to embarking on the evaluation trials.

Four large heavy goods vehicle fuel (saddle) tanks, 2 metallic and 2 plastic, were shipped to HIT for coating with the Battlejacket system. Once returned, these were taken to Radnor Ranges for ballistic testing and evaluation. The tanks were filled to ¾ capacity with standard diesel and aim points were marked on the fuel tanks.

To help determine the system’s environmental performance, the fuel tanks were conditioned by subjecting it to either an ambient, cold- 15 or elevated temperature +70. Trials were conducted over a one-week period and witnessed by representatives from Permali, HIT and Dstl.

The system performed well for main arear tests, multi-hit and edge performance. The Battlejacket system provided near instantaneous damp seals with dry seals being formed typically within 4 minutes.

Repair patches were also tested to evaluate their capability of stemming a fuel leakage from an exit hole caused during an overmatch event. The patches were simple to apply and were able to provide a near instantaneous seal.

To complete the trials one metallic and one polymer tank were each subjected to a grenade test. DM31 hand grenades were placed under the centre of the tank at a 300mm standoff. No leaks were observed post detonation with the tank remaining in-tact.

To summarise, Permali found the HIT Battlejacket system to provide excellent sealing and fuel stopping capability both at ambient and extreme conditions. With exceptional performance demonstrated on the grenade test too.

Permali are proud to provide this complimentary technology as part of our protection portfolio and have supplied fuel tank protection to our customers for military vehicle fuel tanks and auxiliary helicopter fuel tanks.

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