Specifications include, but are not limited to: A. THE SKIMMER TRUSS OPPOSITE TOW-BRO HEADER NOTE: Assemble scraper trusses or skimmer support trusses opposite the header at the same time the header is installed so that when all of the necessary components are assembled and tensioned and supports are removed, an equal load is acting on both sides of the unit. It is imperative that the lower chord members of the trusses are parallel to the slope of the tank floor unless the drawings specify otherwise. Shimming should result in the lower chord angles all being in line. If, after shimming, any are cambered downward, start with the section joint nearest the pier, jack up the low end of the truss section and add shims. Once the lower chord angles have been brought into line, they must then be made parallel to the floor. Jack up and support each section directly under the joint until the lower chords are parallel to the slope of the floor. When this is accomplished, then make adjustments at the TIE CHORD "A"-FRAME CLEVIS to maintain the new position. This clevis is not intended to be used as a jack. It is only an adjustable supporting device. If supplied, do not assemble the squeegees to the plow blades at this time. Assemble them after the unit has been balanced, adjusted for true plane of rotation. B. UNITUBE HEADER - TIE BAR SUPPORTED UNITS Scraper trusses or skimmer support trusses shall be assemble opposite the header at the same time so that when all of the necessary components are assembled and tensioned and supports are removed; an equal load is acting on both sides of the unit. 1. Unitube header should always be set parallel to the finished floor. 2. Truss opposite header for skimmer support only should always be installed parallel to the finished floor. 3. Truss opposite header for skimmer and scraper blade support should always be set parallel to the finished floor. 4. The header must be straight and must not be pulled out of line by unequal tension on the bars. The header should be checked for proper height at all points. The header lip should be higher at the outer end to conform to the design slope of the tank floor.