Paul Burling obtained an HNC in Production Engineering with Merits and Advanced Mathematics from Cambridge College of Art and Technology. He has extensive experience in project management of large commercial projects worldwide, which include in depth knowledge of composite materials for military and commercial applications. This required comprehensive customer support throughout the life cycle of the projects. His technical expertise includes design, fabrication, joining and costing composite materials; using novel production techniques in producing carbon laminate for manufacturing industry.
The demand for good quality cost-effective housing is greater today than it has ever been. With an estimated four million new dwellings required in the UK over the next 25 years today's technology and manufacturing supply mechanism will not be able to satisfy that demand. As Paul Burling reports there is an urgent need for an alternative to bricks, timber and concrete. That alternative could very readily involve a TWI invention known as Barrikade ®, a fireproof composite which lends itself well to modular building construction.
There is a need for a fixing system that both uses composite sandwich structures and accommodates last minute changes in design and functionality. TWI developed Barrikade in the late 1990s, and since then it has been embraced in heat related products such as exhaust silencers and fireproof doors.
It is a low cost, fire resistant and easily machineable material without the disadvantages of traditional core products. Polymer foams, ceramic foams, aluminium honeycomb cores, and timber all have a number of disadvantages when used as a core product. None fulfils the criteria that many architects and engineers require related to density, cost, insulation, flame spreading, and non-toxicity.
Among other quick-build construction systems on the market the Endegill building system, with which TWI has been working, addresses the needs of designers and architects for the future.
A new approach ....
Endegill cladding and curtain walling varies from the traditional. It comprises a patented top and bottom chassis member manufactured by pultruding advanced composites.
Pultrusion is a manufacturing process for producing continuous lengths of structural shapes from fibre reinforced plastic. The raw materials include:
- Liquid resin mixture (containing resin, fillers and specialised additives)
- Reinforcing fibres - glass, carbon or Aramid
The process involves pulling these raw materials (rather than pushing as in extrusions) through a heated forming die using a continuous pulling device. The reinforcing materials are added in continuous form.
These finished sections are manufactured to suit three sizes of wall panel thickness and are then cut to two lengths of 3.0m and 6.0m.
Panels are progressively assembled side by side by interlocking along the panel's edge. This provides a watertight and fireproof seal. In addition there is a device for fixing the panels to the superstructure from the inside of the building. This idea allows damaged panels to be replaced, or added as an afterthought in the case of a window or door aperture. Assembled panels are interlocked top and bottom to the main structure adding strength and a consistently good appearance.
Walls and interior partitions
The Barrikade sandwich structure may well be the material of choice, depending upon the precise demands of architects and engineers.
In such applications structures are required to conform to mandatory fire regulations. For example
- EN 1364-1 Non load bearing elements. Walls
- EN 1364-2 Non load bearing elements. Ceilings
- EN 1365-1 Load bearing elements. Walls
- EN 1365-2 Load bearing elements Floors and roofs
- EN 1634-1 Door and shutter assemblies
The sandwich panel is a composite construction consisting of layered material; an outer facing of thin ridged sheet material and an adhesively bonded lightweight core material. The flexural strength is achieved by the combined structural action of the ridged facing and the core material.
It is the core materials that are of particular concern because many materials that are used in sandwich structures are combustible. They can be classified into three main groups:
- Thermoplastic
- Thermosetting
- Inorganic materials
In many applications, materials are required to have fire resistance, and reduction of heat transfer for protection of people, equipment and increasingly the surrounding environment. Sandwich structures comprise a variety of materials and configurations, and therefore can provide a cost-effective solution for many engineering problems including that of fire protection, and insulation for exterior and interior panelling. So far trials on Barrikade have revealed some impressive performance figures. Building regulations, technical standards and their supporting guidance define periods of fire resistance for structural elements within buildings. The periods of fire resistance depend upon such aspects as:
- the use of buildings
- the height of the building
- the distance from the boundaries
- the position of the element within the building
- the role of the element in providing fire compartmentation or means of escape
There are various ways of demonstrating compliance with the requirements, but for products the most significant method is by undertaking a recognised fire test.
Barrikade has shown that it can perform up to four hours without losing its integrity and has the ability to insulate at elevated temperatures. However it is the system that incorporates the Barrikade material that is tested and not the materials on their own.
Barrikade has been tested under the new European fire regulations and performed well, maintaining its integrity and insulation using composite skin materials. A fireproof door assembly provided a fire barrier for commercial use. Particular attention is needed at the joint design stage and where Barrikade is joined to the adjacent materials or the sandwich structure itself. If this attention is not given the total cladding envelope will be compromised and the building will not perform as designed. Barrikade is very versatile, it can be included in many ways to prevent the spread of fire, and can also be used with structural elements to provide a monocoque structure. This approach will enable the building to be modified or upgraded, and also enable disassembly at the end of the building's life.
To learn more about Barrikade and its eminent suitability for the construction business contact Paul Burling at TWI.
