Fire protection of structures

Some authors provide an overview of the state of knowledge of the engineering methods for fire protection of structural elements that be incorporated in the regulations [5]. These methods affect all materials concrete, masonry, steel, and wood. The engineering analysis of the response of structures exposed to the fire involves considering the following aspects ... 

Law, M., A basis for the design of fire protection of building structures, The Structural Engineer, January 1983, 61A(5). 

Fire protection for structural steelwork can be provided by water spray that cools and wets fire exposed surfaces. This active form of fire protection can be used on vertical structural steel columns, horizontal supports and other steelwork. 

A generalized comparison of equivalent fire protection for structural steel using water spray rates recommended in NFPA 15 and fire-resistive insulation used alone or in combination is provided in Table 8-9 (NFPA 15). 

NFPA 914 of Worship Code for Fire Protection of Historic Structures... 

There are two codes addressing buildings of particular interest NFPA 909 Code for the Protection of Cultural Resource Properties—Museums, Libraries, and Places of Worship126 and NFPA 914 (Code for Fire Protection of Historic Structures).127 NFPA 909 and NFPA 914 include definitions for various terms, which are important to understand what the codes intend ... 

A munber of nitrogen derivatives of phosphoric and polyphosphoric acid (ammonium polyphosphate, melamine pyrophosphate) are used for improving the flame retardance of polyurethanes and other polymers. In thermal decomposition these compounds produce ammonia and the corresponding phosphoric acids which catalyze dehydration and other reactions, causing polymer dehydration during combustion. The coke produced in this process is more or less foamed. Ammonium polyphosphate and melamine pyrophosphate are added to compositions of intumes-cent coatings used for fire protection of various structural elements in construction... 

An extremely fire-resistant coating material designed for spray applications to onshore and offshore oil and gas facilities has been introduced by Hempel s Marine Paints. The product, called ContraFlam 3810, is easy to apply and is particularly well-suited to the protection of structural steel work, walls, and floors. Another coating of a surface hardener/weather barrier material, such as Contraflam Topclad 3811, can then be applied followed by a color coat. 

Full scale experiments on FRP structural members subjected to realistic fire exposure are also necessary. Not only does this supply valuable results and provide confidence for the fire performance of FRP structural members to be used in civil engineering, it also validates the above modeling concepts on the structural level. Similarly, as performed in the fire design of structures made by traditional materials such as steel and reinforced concrete, active and passive fire protection techniques may be necessary for prolonging resistance time of composite materials in fire. Such techniques are reviewed and compared, particularly with regard to their applications for composite materials. 

NFPA 328 Recommended Practice for the Control of Flammable and Combustible Liquids and Gases in Manholes, Sewers, and Similar Underground Structures, 1992 edition. National Fire Protection Association, Quincy, MA. 

The architect continues to look for products that can he multifunctional. As an example in roofing, the product could perform a part or all of the functions. The roof has to provide structural integrity, temperature and sound insulation, vapor and moisture control, weather resistance, elastic qualities for change in weather, fire protection, aesthetic appeal, and so on. 

Engineering Guide to Fire Exposures to Structural Elements, Society of Fire Protection Engineers, Bethesda, Maryland, May 2004. 

American Society of Civil Engineers (ASCE), ASCE 78-92. Structural Fire Protection. ASCE, New York, NY, 1992. 

Underwriters Laboratories Inc. (UL), UL 1709, Safety Rapid Rise Fire Tests of Protective Materials for Structural Steel. First Edition, UL, Northbrook, IL, 1991. 

Rapid Rise Fire Tests of Protection Materials for Structural Steel, 1989. 

Steel, aluminum, concrete, and other materials that form part of a process or building frame are subject to structural failure when exposed to fire. Bare metal elements are particularly susceptible to damage. A structural member undergoes any combination of three basic types of stress compression, tension, and shear. The time to failure of the structural member will depend on the amount and type of heat flux (i.e., radiation, convection, or conduction), and the nature of the exposure (one-sided flame impingement, flame immersion, etc.). Cooling effects from suppression systems and effects of passive fire protection will reduce the impact. 

ASTM E 1529 Standard Test Methods for Determining Effects of Large Eiydrocarbon Pool Fires on Structural Members and Assemblies and Underwriters Laboratories Inc. 1709 Standard for Rapid Rise Fire Tests of Protection Materials for Structural Steel are two tests which are used to evaluate the performance of structures, equipment, and protective materials to hydrocarbon fires (see Figure 5-17). 

Passive protection can be used to increase the time to structural failure. For example, intumescent mastic coatings of less than 1 inch thickness have been shown to provide up to 4 hours of fire resistance when applied to steel columns. Cementitious materials have been shown to provide 1-4 hours fire resistance for thicknesses of 2.5-6.3 cm (1-2.5 in). For additional information on passive fire protection, see Chapter 7. 

Fire protection systems achieve exposure protection by absorption of heat through application of extinguishing agents to structures or equipment exposed to a fire. The application of some extinguishing agents removes or reduces the heat transferred to the structures or equipment from the exposing fire, as well as limits the surface temperature of exposed structures and equipment to a level that will minimize damage and prevent failure. 

The water demand for enclosed process structures may depend on the degree of compaitmentalization by solid floors and the number of separate systems used to protect the structure. At a minimum, ground floor systems should be assumed to operate in a spill fire scenario. But, if water spray systems are used, it should be assumed that all systems will operate in order to estimate maximum water demand. 

Solid floors in multilevel process structures can provide a passive means of containing any spilled liquids or solids and preventing materials from falling onto lower levels. To maximize the effectiveness of solid floors, the floor design should include appropriately located drainage for spills and fire water runoff. Fire protection systems can be designed to effectively manage liquid pool fires. 

Local containment systems are designed to retain the spilled or released material within the process structure or area. Hence, the structure, equipment, vessels, and piping in that area will be exposed to any fire resulting from the contained material. Usually the exposed portion of the structure will require appropriate fire protection, unless it is considered of low value and expendable. 

The decision to provide or not to provide fixed fire protection systems within process structures, areas, or on specific vessels or equipment is usually based on a qualitative assessment of the following factors such as ... 

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