UL 94-2021 pdf download – Tests for Flammability of Plastic Materials for Parts in Devices and Appliances.
5.18 Support-Gauze – A wire cloth of plain weave, low carbon, plain steel or stainless steel, approximately 215 mm long by 75 mm wide . It is to consist of 6.4 mm mesh gauze constructed of 0.88 ±0.05 mm diameter steel wire. The cloth-mesh and wire diameter are to be determined as described in the Standard Specification for Industrial Woven Wire Cloth, ASTM E2016. (Used for the test procedure in Horizontal Burning Foamed Material Test; HBF, HF-1, or HF-2… Section 12 only.) 5.19 Foam Support Fixture – A metal support fixture capable of holding the support gauze in 5.18 including height adjustment to allow for burner height variations. See Figure 12.1. (Used for the test procedure in Horizontal Burning Foamed Material Test; HBF, HF-1, or HF-2… Section 12 only.) 5.20 Manometer/Pressure Gage – A gage capable of measuring to 200 mm of water, with increments of 5 mm. 5.21 Flow Meter – A rotameter calibrated in accordance with the Practice of Rotameter Calibration, D 3195, with correlation curves appropriate for the gas, or a mass flow meter with ±2 percent accuracy. 6 Conditioning 6.1 Specimens are to be preconditioned in accordance with ASTM D 618 (ISO 291) at 23 ±2°C and 50 ±10 percent relative humidity for a minimum of 48 hours. 6.2 Specimens for certain tests are to be preconditioned in an air-circulating oven for 168 ±2 hours at 70 ±2°C and then cooled in the desiccator for at least 4 hours at room temperature, prior to testing. 6.3 Once removed from the pre-conditioning environment, specimens shall be tested within 30 minutes. 6.4 All specimens are to be tested in a laboratory atmosphere of 15 – 35°C and ≤ 75 percent relative humidity. 6.5 Cotton shall be conditioned in the desiccator for at least 24 hours prior to use. 6.6 Once removed from the desiccator, the cotton shall be used within 30 minutes.
7.3 Test specimens 7.3.1 All specimens shall be cut from sheet material, or shall be cast or injection, compression transfer or pultrusion molded to the necessary form. After any cutting operation, care is to be taken to remove all dust and any particles from the surface; cut edges are to have a smooth finish. Fabrication of test specimens shall be in accordance with current ASTM Practices. 7.3.2 Standard bar specimens are to be 125 ±5 mm long by 13.0 ±0.5 mm wide, and provided in the minimum thickness and 3.0 (-0.0 +0.2) mm thick. The 3.0 mm thick specimens are not necessary if the minimum thickness is greater than 3.0 mm, or the maximum thickness is less than 3.0 mm. The maximum thickness is not to exceed 13 mm. The edges are to be smooth, and the radius on the corners is not to exceed 1.3 mm. 7.3.3 Material Ranges – If a material is to be considered in a range of colors, densities, melt flows, or reinforcement, specimens representing these ranges are also to be provided. 7.3.4 Specimens in the natural and in the most heavily pigmented light color (often white) and dark color (often black/including carbon black) are to be provided and considered representative of the color range, if the test results are essentially the same. In addition, a set of specimens is to be provided in the heaviest organic pigment loading (not carbon black), unless the most heavily pigmented light and dark colors include the highest organic pigment level. When certain color pigments (for example, red, yellow, or the like) are known to affect flammability characteristics, they are also to be provided.