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11 11 Bell and Spigot MWUsing the heating blanket joining System The heating blanket is an electrical (120V AC) heater made of thin, flexible and (continued) lightweight silicon rubber. It provides an efficient method for the rapid cure of adhesive -bonded joints. Heating blankets are available in two sizes: Heating Blanket Size Nominal Heating Blanket Pipe Size Size (in) (mm) 2 50 I 3 80 4 100 6 150 The heating blanket will reach a maximum temperature of 250°F (121 °C), providing adhesive cures in approximately 30-40 minutes. Place the thermostat end of the heating blanket against the assembled joint with the thermostat side facing out from the joint. Wrap the remainder of the blanket around the joint so that any overlap will cover the thermostat. Tie the blanket in place with any nonconducting tie. Standard wrap for pipe and fitting joints Warning: Before connecting to a power source, inspect the blanket and its cord for loose wire connections and bare wires. Do not plug the cord into a live power source when standing in water or on wet surfaces. Use alternating current (AC) at the voltage marked on the heating blanket. Do not use a direct current (DC) power supply. Mark the start-up and disconnect time on the pipe with a white grease pencil so that you will have a record of cure for each joint in the system. Be sure all electrical connections are good and that the blanket actually heats up each time. Insulating the joint It is always a good idea to insulate around the heating blanket and to close the pipe ends. This is especially important when it is windy or when the air temperature is below 50°F (10°C). Fiberglass insulation backed with aluminum foil has been found to work well. Overlap the edges of the blanket about 4 inches (100 mm) on each side and tie down the ends of the insulation to trap the heat. Caution: Do not move, vibrate or otherwise disturb the joint while the adhesive is curing.