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3. All membrane to be welded shall be clean and dry. <br /> B. Hand-Welding <br /> 1. Hand-welded seams shall be completed in two stages. Hot-air welding equipment <br /> shall be allowed to warm up for at least one minute prior to welding. <br /> 2. The back edge of the seam shall be welded with a narrow but continuous weld to <br /> prevent loss of hot air during the final welding. <br /> 3. The nozzle shall be inserted into the seam at a 45 degree angle to the edge of the <br /> membrane. Once the proper welding temperature has been reached and the <br /> membrane begins to "flow," the hand roller is positioned perpendicular to the <br /> nozzle and pressed lightly. For straight seams,the 1'h inch(40 mm)wide nozzle <br /> is recommended for use. For corners and compound connections,the 3/4 inch(20 <br /> mm)wide nozzle shall be used. <br /> C. Machine Welding <br /> 1. <br /> Machine welded seams are achieved by the use of automatic welding equipment. <br /> When using this equipment, instructions from the manufacturer shall be followed <br /> and local codes for electric supply, grounding and over current protection <br /> observed. Dedicated circuit house power or a dedicated portable generator is <br /> recommended. No other equipment shall be operated off the generator. <br /> 2. Metal tracks may be used over the deck membrane and under the machine welder <br /> to minimize or eliminate wrinkles. <br /> D. Quality Control of Welded Seams <br /> 1. The Applicator shall check all welded seams for continuity using a rounded <br /> screwdriver. Visible evidence that welding is proceeding correctly is smoke <br /> during the welding operation,shiny membrane surfaces,and an uninterrupted flow <br /> of dark grey material from the underside of the top membrane. On-site evaluation <br /> of welded seams shall be made daily by the Applicator to locations as directed by <br /> the Engineer or membrane manufacturer's representative. One inch(25 mm)wide <br /> cross-section samples of welded seams shall be taken at least three times a day. <br /> Correct welds display failure from shearing of the membrane prior to separation of <br /> the weld. Each test cut shall be patched by the Applicator at no extra cost to the <br /> Owner. <br /> 3.06 TEMPORARY CUT-OFF <br /> A. All flashings shall be installed concurrently, with the membrane in order to maintain a <br /> watertight condition as the work progresses. <br /> B. When a break in the day's work occurs in the central area of the project install a temporary <br /> watertight seal. An 8" strip of flashing membrane shall be welded 4" to the new field <br /> membrane. The remaining 4"of flashing membrane shall be sealed to the deck and/or the <br /> substrate so that water will not be allowed to travel under the new or existing membrane. <br /> The edge of the membrane shall be sealed in a continuous heavy application of pourable <br /> sealer of 6 inch width. When work resumes,the contaminated membrane shall be removed <br /> and disposed of. None of these materials shall be reused in the new work. <br /> C. If inclement weather occurs while a temporary water stop is in place,the Contractor shall.. <br /> provide the labor necessary to monitor the situation to maintain a watertight condition. <br /> D. If any water is allowed to enter under the newly-completed system,the affected area shall <br /> Sebastian Corners Roof Replacement 07 54 00-9 Thermoplastic Single Ply Roofing <br />