The Use of Lightweight Materials in Blast and Fire Protection Systems

Abstract

ABSTRACT This paper describes the use of lightweight materials for blast and fire resistant structures. The paper discusses the influence of the properties of brittle and ductile materials on the choice of section shapes for components of blast and fire walls. Glass Fibre Reinforced Plastic (GFRP) is examined as an example of a brittle material and Aluminium is taken as representative of a very ductile material. Both materials offer weight and durability advantages over the equivalent steel structures. Projectile impact on typical blast panels is discussed and the influence of material properties on dynamic response behaviour is examined for a number of typical blast panel configurations. Data on the fire resistance of these materials is also presented. Stainless steel is not in itself a lightweight material. However, thin and light sections may be used since a corrosion allowance is not necessary and, in this context, stainless steel has been treated as a lightweight material. The findings presented in this paper may be used as guidance on the design of blast and fire resistant structures using lightweight materials, particularly in the selection of configurations and methods of construction. INTRODUCTION Reduction of the effect of blast and fire within the topside structure of an offshore platform may be achieved by the following means: effective layout, water deluge, explosion venting or the inclusion of blast and fire walls. Carefully considered layout of equipment and venting arrangements can effectively vent combustion products and reduce the explosion overpressure. Water deluge systems are the most conventional fire fighting method. Specifically designed blast and fire walls can resist the loading exerted by fires, blast waves and secondary projectiles. The proper design and installation of blast and fire walls will segregate hazardous areas and consequently prevent the spread of flames and explosions. Escalation of the event and possible progressive collapse may then be avoided. Conventional blast and fire protection systems are usually made of steel. A recent industry-wide survey of North Sea operators, manufacturers and contractors has revealed that many operators are seriously considering the use of alternative materials such as glass fibre reinforced plastics (GFRPs) and aluminium alloys for this application. Indeed, some leading oil companies have installed many tonnes of composite blast and fire walls and aluminium cladding on their platforms. This paper reviews the concepts of design and the use of lightweight materials in blast and fire resistant and relief structures. It also highlights the offshore industry's experiences and the associated implication on the future use of such materials within topside structures. THE NEED FOR LIGHTWEIGHT MATERIALS On an offshore platform, heavy blast and fire resistant structures not only entail more material and cost in their own construction and installation, but they could also create a problem in terms of the support structure. It is therefore worth considering lightweight materials in the design and construction of new platforms as well as their use in upgrading existing platforms. Lightweight structures are also very easy to handle during fabrication, transportation and installation.