Flammability testing horizontal burn test

Air Products, a manufacture of latex binders, has completed a comprehensive study of flame retardants for latex binder systems. This study evaluates the inherent flammability of the major polymer types used as nonwovens binders. In addition, 18 of the most common flame retardants from several classes of materials were evaluated on polyester and rayon substrates. Two of the most widely recognized and stringent small scale tests, the NFPA 701 vertical burn test and the MVSS-302 horizontal burn test, are employed to measure flame retardancy of a latex binder-flame retardant system. Quantitative results of the study indicate clear-cut choices of latex binders for flame retardant nonwoven substrates, as well as the most effective binder-flame retardant combinations available. 

The UL 94 standard specihes bench-scale test methods to determine the acceptability of plastic materials for use in appliances or other devices with respect to flammability under controlled laboratory conditions. The test method that is used depends on the intended end-use of the material and its orientation in the device. The standard outlines two horizontal burning tests, three vertical burning tests, and a radiant panel flame spread test. The most commonly used test method described in the UL 94 standard is the 20-mm Vertical Burning Test V-0, V-l, or V-2. The method is also described in ASTM D 3801. A schematic of the test setup is shown in Figure 14.3. 

In contrast to the considerable number of fire tests for plastics, there are relatively few fire tests specifically for rubbers as such. There are a number of tests for rubber products including cable insulation, hoses of various types, and cellular products. In some cases, e.g.. cellular products, the test relates to both cellular plastics and rubbers, e.g.. BS 4735 and ISO 3582. Horizontal burning characteristics when subjected to a small flame or BS 5111. Determination of smoke generation. For convenience, these have been described in the section dealing with plastics tests, Other tests for rubber products include ISO 8030 [51], Flammability of rubber hoses for underground mining, ISO 3401 [52], Conveyor belts Flame retardation specification and test method, and BS 5173, Part 103 [53], Fire rc.sistance of plastics and rubber hoses and hose assemblies, and linings of hoses, etc. 

Figure 30 shows typical dripping behavior of unfilled LDPE and a LDPE/LDH composition (PE-LDH5) at comparable time after the first 10 s flame application. The UL94 horizontal burn test showed better flammability performance of the LDPE/LDH nanocomposites as compared to the pure polyethylene. 

Flammability The flammability of a plastic is most commonly characterised by the Underwriters Laboratory (UL 94) horizontal burning test. The test sample, a rectangular bar 127 mm long, is held horizontally, or at 45°, and clamped at one end. The burning speed of the bar is measured when exposed to a pilot flame. The bar is held 305 mm above the surface of a layer of surgical cotton. The thickness of the bar can be varied, but is quoted as part of the result, e.g. VO, 1.57. The commonly quoted ratings given to a material are ... 

The ASTM fire test procedure describes a small-scale laboratory determination of the relative linear rate of burning of plastics and plastic-based composites. Specimens can be in the form of bars, molded or cut from sheets, plates, or panels and tested in the horizontal position. The results of the test are intended to serve as a preliminary indication to their flammability. 

Two kinds of test method are laid down by BS 2848 1973 for the flammability of flexible insulating sleevings. In the rate of burning test, a 100 mm long tube is marked at 25 and 50 mm from one end and the marked end of the horizontally mounted tube is ignited by a gas flame. The tube is then turned to the vertical position and, under... 

This test is very similar to Method A for determining the flammability of non-rigid solid plastics except for the specimen support. Unlike the previous test, the specimen is supported horizontally at one end. The free end is exposed to a specified gas flame for 30 sec. The time and extent and relative rate of burning are measured and reported along with visual observations. 

The cathode of the lamp which is filled with Ar or Ne at low pressure, sputters when a H.V. is applied to the electrodes. Collision of the noble gas and metal atoms excite the latter then they emit radiation in the visible/u.v. region of the spectrum. The metal compound in the sample to be analysed, dissolved in a suitable solvent, has to be transformed to a mist of gaseous atoms. This is generally achieved by aspirating the solution into a nebuliser where a mist is sprayed in a flame of a flammable gas widi an oxidising gas. The gas mixture may pass through the nebuliser first or it may burn directly. Alternatively, furnace atomisers are used, when smaller volumes of test solutions can be handled. The solution is placed in a horizontal graphite tube or a carbon rod which are heated in an electric furnace. 

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