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).
Product bulletin detailing the methods of installation for Burgess Acousti-Pad sound absorbent lining in ventilation systems.
| Identifier | ExFiles\Box 104\2\ scan0226 | |
| Date | 1st April 1936 | |
| BURGESS ACOUSTI-PAD Methods of Installation Typical section of duct with Burgess Acousti-Pad Lining, with dimensions. The above illustration shows the interior appearance of a duct section. Where the sides of the duct require the piecing together of two or more panels, allow 2 in. extra for each seam in calculating the circumference of the duct. The following table gives sizes of panels which may be made from standard 34 in. x 36 in. Burgess Acousti-Pad without waste in cutting the Burgess Acousti-Plate: Length of Section in Inches | Optional Width of Panels in Inches --- | --- 36 | 68, 50, 41, 34, 23, 16, 7 34 | 70¼, 64, 47, 38¼, 32, 21¼, 15, 6¼ These dimensions allow for the 1 in. flange around the edge of each piece of metal. Thus, a 34 in. x 64 in. panel is made from two 36 in. x 34 in. sheets of Burgess Acousti-Plate. Appearance of "Splitter" Section Round ducts may be made from curved sections of perforated metal with a diameter 2 in. less than the outer jacket of the duct. Allow for a half-inch self-locking lap-seam in the perforated cylinder. Lace the Balsam-Wool blanket to the Burgess Acousti-Plate with wire. Seal the exposed Balsam-Wool ends with sheet metal discs 1 in. wide. Method of Calculating Splitters Splitters are panels of Burgess Acousti-Pad located in the duct core parallel to the wide side, uniformly dividing the least dimension of the duct in two or more channels. Splitters should not occupy more than 25 per cent of the cross section area of the duct core, due to the restriction of air flow. A restriction chart in Bulletin 113, "Uses and Applications of Burgess Acousti-Pad," gives the restriction in inches of water per lineal foot of lining for various percentages of core area restriction. The lineal feet of duct lining designated for a given noise condition in the Burgess Acousti-Pad chart, Bulletin 113, may not fit in the space available between curves in the duct or between the outlet grille and the fan. In these cases splitters, which consist of 1 in. thick Balsam-Wool acoustic absorbent between two sheets of Burgess Acousti-Plate, may be incorporated in the straight sections of the duct. The self-tapping screws, which are used to attach Burgess Acousti-Pad to the perforated buttons in regular duct lining, may be used to "quilt" two sheets of Acousti-Plate forming a splitter. The top and bottom flanges of the splitter section are bent outward to provide for mounting it in the duct with self-tapping screws. Splitters should uniformly divide the least dimension of the duct. The required length of the splitter is determined by the least dimension of the channels formed by the splitter panels. From this dimension and the chart in Bulletin 113, the length of the splitter section equivalent to the normally required length of lining may be determined. As a rule it is advisable not to use more than three or four splitters due to the restriction of the duct and due to the increased circumference of the duct if it is enlarged to accommodate the splitter panels. The splitters should be streamlined with unperforated sheet metal. Layout of "splitter" showing streamlining of the panels. Burgess Acousti-Pad, showing Balsam-Wool blanket and facing of Burgess Acousti-Plate made of perforated terne plate. Burgess Acousti-Pad is easily installed as a sound absorbent lining and thermal insulation in ventilating ducts by any practical sheet metal worker. It consists of a Balsam-Wool blanket 1 in. thick, covered with a perforated metal facing of 26-gauge terne plate. The Balsam-Wool blanket may be cut to size with shears; the perforated metal facing (Burgess Acousti-Plate) is cut, formed, and installed with regular sheet metal tools. Perforated metal buttons and self-threading screws are furnished with Burgess Acousti-Pad linings. The buttons are soldered on the inside of the ventilating duct. Self-threading screws are passed through enlarged holes made in the perforated facing with an awl. These screws thread themselves into the perforated buttons and hold the Burgess Acousti-Pad lining securely. The step-by-step procedure is shown in the illustrations on the next page. It is unnecessary, in most cases, to line the entire duct length unless it is exceedingly short or the desired room noise is extremely low, as in radio or recording studios. In short ducts 'splitters', as described on page 4, may be required to provide the extra sound absorbing surface. The use of splitters is not advisable unless space requirements necessitate their installation. There are very few cases, except between adjacent rooms, where splitters are necessary. Burgess Acousti-Pad is usually installed near the outlet grille although it may be placed anywhere in the ventilating system, but when located near the various outlets it tends to prevent a circulation of inter-room noise and absorbs noise of the air rushing around curves in the duct. In the case of a large auditorium or room supplied from a central ventilating unit, all of the Burgess Acousti-Pad may be located near the fan, provided there is a sufficient straight section of duct, which simplifies the installation. This is satisfactory where the remainder of the duct has but few curves or obstructions. The amount of duct lining required should be calculated in advance by the architect or acoustic engineer, using methods described in Burgess Bulletin 113. While Burgess Acousti-Pad absorbs much of the mechanical noise from the fan, motor, or other ventilating equipment, it is advisable to provide sound absorbent mountings for fans and motors, and it is also advisable to break the metallic connection between the fan and duct system with a flexible joint. When properly installed, Burgess Acousti-Pad will withstand high air velocities that would be destructive to many unprotected acoustic materials sometimes utilized as duct linings. The smooth metallic surface offers the minimum resistance to air flow; Printed in U. S. A.{Mr Adams} — April, 1936, 10M Licensed under C. F.{Mr Friese} Burgess Laboratories, Inc., Patents BURGESS BATTERY COMPANY GENERAL SALES OFFICES, 111 W. MONROE ST.{Capt. P. R. Strong}, CHICAGO Battery Division—FREEPORT, ILL. Engineers and Manufacturers of Acoustic and Electric Products Acoustic Division—MADISON, WIS. Bulletin 154 Bulletin 114 Index BS{A J. Barnes - Assistant Manager}/800A | ||