From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Installation guide for Burgess Acousti-Pad sound-absorbing duct lining.
| Identifier | ExFiles\Box 104\2\ scan0227 | |
| Date | 1st January 1936 | |
| particles from the Balsam-Wool blanket blow into the air stream. The chemical treatment of the Balsam-Wool makes it odorless and resistant to mold or dry rot. It is fire resistant; the perforated metal facing is a further fire retardment. Standard Package The standard Burgess Acousti-Pad package contains 12 sheets of Burgess Acousti-Plate facing, size 34 in. by 36 in., and 12 scrim covered Balsam-Wool blankets of the same size. The package also includes 98 perforated mounting buttons and 98 self-tapping screws. Assembly Procedure 1 — Cut the perforated Burgess Acousti-Plate to the desired size with a standard sheet metal cutter. Allow for a 1 in. flange on each edge. Often two or three sides of the duct may be bent without cutting individual panels for each side. 2 — With tin shears cut a 1 in. square notch out of each corner of the Burgess Acousti-Plate. 3 — Bend 1 in. flanges in a brake, keeping the smooth surface toward the core of the duct. In the case of splitters, the top and bottom flanges are bent the opposite way to provide for mounting with self-tapping screws through the flanges. 4 — Lining is laid on duct in finished position and button positions marked by forcing a 3/16 in. punch through the holes in the lining. This enlarges the holes to accommodate the screw and marks the position on the duct at which the button is to be attached. One button per square foot of lining is satisfactory. Perforated metal anchor buttons are soldered to the wall of the duct centered at the punch marks. 5 — Cut the Balsam-Wool blanket to fit the Burgess Acousti-Plate panels. Attach these panels containing the Balsam-Wool blanket to the perforated buttons with the self-tapping screws. 6 — Note that the Burgess Acousti-Pad panels are made a trifle smaller than the duct which allows space for a lock seam or Pittsburg joint. 7 — It is not advisable to line curves or bends in a duct system where the air stream would impinge on the Acousti-Pad. Where space is limited use splitters, as described on page 4. Image Captions: 1. Cutting the Burgess Acousti-Plate in a standard sheet metal shears. Allow for the 1 in. flange in measuring size to cut. 2. With a hand snips, cut a 1 in. square out of each corner of the Burgess Acousti-Plate. 3. Make the 1 in. flange on four sides in a brake. 4. Solder one perforated button per square foot of duct. 5. Cut the Balsam-Wool blanket to fit the formed Burgess Acousti-Plate panels, forming Burgess Acousti-Pads. 6. Attach the Burgess Acousti-Pads to the duct with self-tapping screws. The screws engage the buttons. 7. Assembling the duct. Note that duct walls lock into position with the overlapping joints. Right Column: Typical layout of Burgess Acousti-Pad sections in existing duct system. The zigzag lines indicate a greater length of lining than the proportions in the sketch. Where Burgess Acousti-Pad lining is installed in existing ducts, every precaution must be taken to reduce air friction caused by the reduction of the duct core area. The diagram above illustrates typical applications of Burgess Acousti-Pad in existing duct designs. Sloping, unperforated panels are installed at each side of the Acousti-Pad section to reduce air friction. The slope of these guides should be approximately 1 in. in 10 in. Where space is limited, as in the above illustration, curved vanes should be installed at the bends in the duct to keep the air flow straight through the acoustically treated section. Curves should not be lined with Burgess Acousti-Pad. Calculating Duct Sections For any rectangular duct, the amount of Burgess Acousti-Pad required may be calculated from the circumference of the core of the duct plus 12 in. for lap-overs and flanges, and the length of the duct to be lined plus 2 in. for each 32 in. or 34 in. section, according to the manner in which the Burgess Acousti-Pad is cut. For example, for a duct having a 9 in. x 34 in. cross section (7 in. x 32 in. core), and lined for 24 ft. (288 in.), the length in inches divided by the length of a single section (32 in.), gives the number of sections which would comprise the duct (288 ÷ 32 = 9). Each section has two 1 in. flanges, and nine sections require 18 in. additional material, or an over-all length of 306 in. of Burgess Acousti-Pad. The 7 in. x 32 in. core section + 12 in. = 90 in.; 90 in. x 306 in. = 27,540 sq. in., the total amount of Acousti-Pad required. Each sheet of Burgess Acousti-Pad is 1224 sq. in.; therefore, 27,540 ÷ 1224 = 22½ sheets of Burgess Acousti-Pad. For duct dimensions which cannot be cut without waste, determine the number of square inches of waste material per section and add to the total duct requirements that amount per section. Footer: Copyright 1936, by Burgess Battery Co. | ||