Fire resistance measurement

Locations Requiring Consideration of Fire Resistant Measures... 

LOCATIONS REQUIRING CONSIDERATION OF FIRE RESISTANT MEASURES... 

Fire Resista.nce. Many fillers, particularly inorganic oxides, are noncombustible and provide a measure of passive fire resistance to filled plastics by reducing the volume of combustible matter in the filled composition. Depending on their density, they may also serve as insulation. 

The physical properties important for the projected use of hydraulic fluids are viscosity, density, foaming behavior, and fire resistance. There is no generally recognized test method for measuring flammability of hydraulic fluids, although various test methods maybe utilized (Moller 1989). 

Mitigation measures can also be passive safeguards, meaning that they require no human intervention and no engineered sensing and actuation system to work. Examples of passive mitigation measures are secondary containment systems, blast-resistant and fire-resistant structures, insulated or low-heat-capacity spill surfaces to reduce the rate of evaporation, and an increased distance between the hazardous materials and energies and the sensitive receptors. 

Fig. 5.2 Variation of conductivity with mol% Ru02 in the coating. The measurement technique and the final firing temperatures are noted below. The symbols are = 350-600°C/ direct resistance measurement (Ref. [3]) O = 450°C/a.c. impedance (Ref. [4]) A = 400°C/ direct resistivity measurement (Ref. [5]).

Measures to reduce the impact of fire include active and passive systems. Active systems include automatic sprinkler, water deluge, water mist, gaseous agent, dry chemical, foam, and standpipe handle systems. Passive protection is provided by fire resistive construction, including spray-applied or cementitious fireproofing of steel, concrete/masonry construction, and water-filled steel columns. Chapter 7 provides details on the design of fire protection systems. 

The material and its installation should be designed to protect for a specific time period. For hydrocarbon fire exposure materials and their installation are generally tested to either UL 1 709 or ASTM El 529 to determine time-to-failure of different thicknesses and installation methods. It should be noted that the fire resistance rating is a measure of the ability of the installed material to withstand a specific "standard" fire. While these conditions closely match those in any given hydrocarbon fire, during actual fires the material may be exposed to conditions that may be more or less thermal intense, thus it can be expected to retain its integrity for a greater or lesser time. 

The term thermal properties is open to more than one interpretation. Specific heat, thermal conductivity and diffusivity clearly come under this heading but the term can be taken to also include heat ageing, low temperature tests and fire resistance. However, these are more properly dealt with, as in this volume, under Effect of Temperature. Thermal analysis is a group of techniques in which a property of a sample is monitored against temperature, or time at a temperature, and, therefore, is also generally concerned with measuring the effect of temperature. Nevertheless, for convenience, a brief overview of thermal analysis is given here. 

When one considers the millions of non-fire-resistive substandard buildings in use today, it appears obvious that the field of opportuniyt is unlimited for marketing a good, reliable fire-retardant paint. A paint that would retard the ignition and spread of fire to a measurable degree would render many of these substandard buildings reasonably safe, and a paint or mastic that would increase the fire-resistance of an ordinary wood-studded, wood lath and plaster partition to 1-hour resistance, would find an immediate demand. 

It could become a major factor in developing our national and civil defense programs. Its greatest asset would be the fact that the safety factor in existing non-fire-resistive structures could be increased measurably. 

The property of a wood material or assembly to resist the penetration of fire or to continue to perform a given structural function, or both, is commonly termed fire resistance. The measure of elapsed time that a material or assembly will exhibit fire resistance under the specified conditions of test and performance is called fire endurance. Large furnaces are used to measure fire endurance of walls, floors, roofs, doors, columns, and beams under the standard ASTM E119 (30) time-temperature exposure conditions. 

We have shown in this chapter that microscale measurements can provide a good screening method for the design of fire-resistant materials modified by nanoparticles (and fire retardants) and also, they can be used to quantitatively model and predict the behavior in mesoscale experiments even though an additional parameter is needed to predict the reduced MLR in the mesoscale experiments. The major breakthroughs and challenges are the following ... 

ASTM E 1822 Standard Test Method for Fire Testing of Stacked Chairs ASTM E 1966 Standard Test Method for Fire-Resistive Joint Systems ASTM E 1995 Standard Test Method for Measurement of Smoke Obscuration Using a Conical Radiant Source in a Single Closed Chamber, With the Test Specimen Oriented Horizontally... 

The fire resistance of a composite board when tested to BS 476 Parts 20 to 238 is a measure of the ability of the panel to prevent the passage of flame and heat for a certain period of time (such as a half hour, 1 hour, etc.). It is a function of the substrate used, the face laminate having little or no bearing on the outcome of the test. 

To be fire resistant, a material should have a low Qz value and a low A value another possibility is that the material contains elements which, on decomposition, form combustion inhibitors (Cl- and Br-containing polymers). Qz will be low if only small amounts of combustible gases develop in the pyrolysis, for instance, because the material chars considerably and mainly splits off carbon dioxide and water. The residue of pyrolysis or the sum of the residue and the weight of carbon dioxide and water formed by pyrolysis may be used as a rough measure of non-flammability. 

Sheets of paper, two fire-resistant siipport.s, measuring beaker, safety glasses, protective gloves. 

The philosophy of fire protection is based fundamentally on the prevention of fire by choice of materials and by minimization of inventory of incendiary material. Once a fire occurs (going on in the scenario), the second measure is to prevent the spread of fire by the design of fire sectors and the use of fire-resistant barriers. Thirdly, one has to detect the fire, usually by means of a fire alarm system. Finally, no doubt, one needs organization, staff, and equipment for fire extinguishing by installed and mobile means. 

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