UL 2846 2021 pdf download – Fire Test of Plastic Water Distribution Plumbing Pipe for Visible Flame and Smoke Characteristics.
3.1.5 The ladder-type tray used to support the test specimens is shown in Figure 3.2 and Figure 3.3. The tray is to be fabricated from cold-rolled steel, 50,000 psi minimum (350 MPa) tensile strength. The solid- bar-stock side rails are to be as shown in Figure 3.3. The C-shaped channel rungs are to be as shown in Figure 3.3. Each rung is to be 11-1/4 inches (286 mm) long. The rungs are to be welded to the side rails 9 inches (229 mm) on centers along the tray length. The tray is capable of consisting of several sections having a total assembled length of 23.9 feet (7.28 m) and is to be supported with 16 supports equally spaced along the length of the tray. The supports (see Figure 3.3) are to be fabricated from bar steel. 3.1.6 One end of the test chamber, designated as the “fire end” in Figure 3.1, is to be provided with two gas burners delivering flames upward that engulf the test specimens. As shown in Figure 3.2, the burners are to be positioned transversely to each side of the centerline of the furnace so that the flame is evenly distributed over the width of the specimens. 3.1.7 The controls used to maintain a constant flow of gas to the burners are to consist of a pressure regulator; a gas meter calibrated to read in increments of not more than 0.1 cubic foot (2.88 mm 3 ); a gauge to indicate gas pressure in inches of water (Pa); a quick-acting gas-shutoff valve; a gas-metering valve; and an orifice plate in combination with a manometer to assist in maintaining uniform gas-flow conditions. An air intake fitted with a vertically-sliding shutter extending the entire width of the test chamber is to be provided at the fire end. The shutter is to be positioned to provide an air-inlet port as shown in Figure 3.1. 3.1.8 The other end of the test chamber, designated as the “vent end” in Figure 3.1, is to be fitted with a rectangular-to-round transition piece which, in turn, is to be fitted to a round flue pipe. The movement of air is to be by induced draft. The draft-inducing system is to have a total draft capac