Tunnel fire test

Metal deck assembhes are tested by UL for under-deck fire hazard by usiag their steiaer tunnel (ASTM E84). The assembly, exposed to an under-deck gas flame, must not allow rapid propagation of the fire down the length of the tuimel. FM uses a calorimeter fire-test chamber to evaluate the hazard of an under-deck fire. The deck is exposed to a gas flame and the rate of heat release is measured and correlated to the rate of flame propagation. A different FM test assesses the damage to roof iasulations exposed to radiant heat. 

Many tests have been devised to evaluate the fire and flame resistance of surface-treated acoustical fiberboard. The most widely accepted test, recognized by both the building industry and the building code agencies, is the fire-resistance test specified in federal specification (3). Other tests under consideration, but not universally adopted, are the tunnel test of the Underwriters Laboratories, Inc. (11), and the Factory Mutual room burn out test (2). A small scale test that is being employed for plant control and quick finish evaluation is the Class F fire test (12). 

The fire safety of mine conveyor belts is covered by the MSHA. The convoluted history of requirements is described by Verakis.93 The regulation mandates the exclusive use of flame-resistant conveyor belts, without details. The actual test used is a Bunsen burner-type test, based on ASTM D 635 (UF 94HB),94 which has been shown to be inappropriate for the associated fire hazard. Originally, large-scale tunnels were used to classify the flammability of the conveyor belts, but those tunnels have since been destroyed. There have been fire-testing research projects addressing the correlation of the various proposed tests with standard tests, but nothing has been implemented till date. 

Chapter 7 is the chapter dealing with Special Conditions and it addresses most of the cables with highly improved fire performance. Thus, Articles 725 (Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits), 760 (Fire Alarm Systems), and 770 (Optical Fiber Cables and Raceways) all use the same two schemes for fire performance of cables, as shown in Figures 21.4 and 21.5. The figures show that the best is NFPA 262,65 a cable fire test for flame spread and smoke, conducted in a modified Steiner tunnel (86 kW or 294,000 BTU/h), for which the requirements in the NEC are that the maximum peak optical density should not exceed 0.5, the maximum average optical density should not exceed 0.15, and the maximum allowable flame travel distance should not exceed 1.52m (5 ft). The next test, in the order of decreasing severity is UL 1666,64 known... 

Within ASTM, technical committees associated with plastics, electrical materials, textiles, protective clothing, thermal insulation, consumer products, detention and correctional facilities, and ships have developed tests that are often application tests that are of specific interest to the products involved. One fire test has spawned more application standards than any other, primarily because of its vast use in the United States ASTM E 84 (Steiner tunnel). Thus, NFPA 262, UL 1820, UL 1887, ASTM E 2231, ASTM E 2404, ASTM E 2573, ASTM E 2579, and ASTM E 2599 are all test methods and practices based on the Steiner tunnel test. In some cases, the base apparatus is being modified (although usually it is permissible to conduct the ASTM E 84 test in the apparatus of the other test, but it is often not permissible to conduct the other test in any apparatus complying with the ASTM E 84 apparatus). The other test method that has resulted in many application standards is the cone calorimeter the standards are ASTM D 5485, ASTM D 6113, ASTM E 1474, ASTM E 1740, and ASTM F 1550. 

Fire tests in a 25-foot tunnel furnace were carried out according to standard ASTM E84 by the Underwriters Laboratory and the Hardwood Plywood and Veneer Association. Results are given for the flame spread index (FSI) and smoke developed index (SDI). The values obtained from burning the test materials represent a comparison with that of Va inch inorganic reinforced cement board expressed as zero and red oak flooring expressed as 100. 

The fire test chamber (Fig. 3.93) consists of a horizontal duct of 7620 mm in length, 451 mm in width, and 305 mm in height, lined with an effective insulating material and provided with observation windows on one side. The test specimen, 7320 mm long and 514 mm wide, is fastened at the fire end of the tunnel as a lid then ignited by a 1370 mm long two-wing gas flame for 10 min. Forced air ventilation... 

Full-scale fire tests can give more useful information than small-scale tests with tiny specimens. They can simulate the behaviour of plastics articles such as foam-filled furniture and television sets in fires. Examples include the Steiner tunnel test, the ISO 9705 room comer test and the CAL 133 test. Many fire test procedures are specific to a given industry, such as construction or the railways. In the latter case, the standard of flammability required may depend on whether a train is to be operated through long tunnels. 

Typical Examples of Fire Tests. The following two examples are commonly used tests that illustrate two distinct approaches to simulate the thermal exposure conditions in a pre-flashover compartment fire. The steiner tunnel test uses a gas burner to heat the specimen primarily by convection. The radiant flooring panel test relies on a gas-fired panel that exposes a flooring specimen to a radiant heat flux profile. 

The PVC formulations shown in Table 2 represent typical compounds used by the wine and cable industry. PVC compounders have developed new PVC-based formulations with very good fire and smoke properties (can pass the UL 910 Steiner Tunnel test) that compete with the more expensive fluoropolymers. These can be used in fabricating telecommunication cables usable for plenum area appHcations. 

Flame Resistance. Traditionally, small-scale laboratory flammabiUty tests have been used to initially characterize foams (38). However, these do not reflect the performance of such materials in bulk form. Fire characteristics of thermal insulations for building appHcations are generally reported in the form of quaHtative or semiquantitative results from ASTM E84 or similar tunnel tests (39). Similar larger scale tests are used for aircraft and marine appHcations. 

Eureka-Project EU 499 FIRETUN, Fires in transport tunnels, Report of Full Scale Tests. Ed. Studiengesellschaft Strahlanwendung e.V., Diisseldorf, 1995. 

As mentioned earlier, the fire hazard of interior finish materials is primarily due to the potential for rapid wind-aided flame spread over the surface. It is therefore not a surprise that reaction-to-fire requirements for interior finish materials in U.S. building codes are primarily based on performance in a wind-aided flame spread test. The apparatus of this test is often referred to as the Steiner tunnel. The Steiner tunnel test is described in ASTM E 84. Although the test does not measure any material properties that can be used in a model-based hazard assessment, a discussion of the test is included here due to its practical importance for the passive fire protection of buildings in the United States. 

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