This article is about Noise Attenuation System and Soundproof a Metal Building. And here you will find materials and procedures for Noise Attenuation System.
NOISE ATTENUATION SYSTEMS
1. General Company might require the installation of noise attenuation systems within certain buildings and enclosures. Following are materials and procedures for Noise Attenuation System and Soundproof a Metal Building. Alternate designs and verified test data for noise attenuation assemblies using the building supplier’s standard components may be submitted.
The metal building assembly shall meet the following minimum criteria generally:
- Sound Transmission Loss Decibel (dB) 28 at 1000 Hz
- Sound Transmission Class (STC) 27
- Assembly may be either shop- or field-assembled
2. Procedures to Soundproof a Metal Building
Roof Assembly Procedure for Metal Buildings
Figure 1
- Blanket insulation with a 2-mil vapor barrier shall be supported by one layer of flexible steel netting. The insulation, vapor barrier, and netting shall be placed between the roof panel and the roof purlin. Tape all seams and tears in the vapor barrier with an approved tape.
Roof Assembly Procedure for Metal Buildings
Figure 2
- Where removable roof sections are required, the assembly shall be constructed with one layer of 1 inch rigid insulation board covered with a 2-mil vapor barrier and secured to the underside of the roof sheet with spindle-type, stick clip fasteners with self-locking washers at 24 inches on center each way. The vapor barrier shall extend at least 6 inches beyond the ends of the board and wrapped under. Vapor barrier seams and stick clip penetrations shall be covered with an approved tape. The entire assembly shall be further supported with a galvanized, corrugated, perforated liner panel. The ends of the panels shall be supported by the purlins and/or other subframing and by the perimeter frame and shall be secured in place by a continuous support angle. The side laps shall be at least one corrugation.
Roof Assembly Procedures for Enclosures
Figure 3
- Where an enclosure requires a shed roof to enclose a cooler or similar equipment, and the roof panel does not require the support from a purlin system (because of clear span, panel configuration, or other considerations), then the following method to attach the noise attenuation shall be used:
- One layer of 1-inch rigid insulation board covered with a 2-mil vapor barrier shall be secured to the underside of the roof sheet with spindle-type stick clip fasteners with self- locking washers at 24 inches on center each way. The vapor barrier shall be extended at least 6 inches beyond the ends of the board and wrapped under. Vapor barrier seams and stick clip penetrations shall be covered with an approved tape. The entire assembly shall be further supported with one layer of flexible steel netting and 16 gauge galvanized tension wires at 48 inches on center stretched taut. Secure the tension wires with #14 galvanized sheet metal screws and fender washers.
Roof Assembly Procedures for Enclosures
Wall Assembly Procedure for Buildings
Figure 4
- Blanket insulation with a 2-mil vapor barrier shall be supported by one layer of flexible steel netting. The insulation, vapor barrier, and netting shall be placed between the wall panel and the girt. Tape all seams and tears in the vapor barrier with an approved tape.
- A metal stud partition comprising of stud tracks and nonload bearing curtain wall studs shall be constructed inside of and adjacent to the wall girts. The studs shall be attached to the girts to ensure stability and reduce lateral deflection.
- The 1-inch rigid insulation board shall be secured to the face of the stud with contact cement to maintain its position until the liner panel is installed.
- The galvanized steel, corrugated, perforated liner panel shall be installed over the insulation board with the corrugations horizontal. Secure the panel to each stud (at 16 or 24 inches on center) with #14 galvanized sheet metal screws in every sixth corrugation. Ends of sheets shall be butt-tight, and side laps shall be at least one corrugation.
Wall Assembly Procedure for Buildings
Wall Assembly Procedure for Enclosures
Figure 5
- A structure having only walls and no roof shall be considered an enclosure. Walls are exposed to the weather on both sides. For example, the walls around the upper level of an elevated compressor or the lower level that encloses the coolers is an enclosure.
- The wall panels shall be load-carrying wall panels. Panels shall be attached to the supporting structure at the top and bottom only and shall be free of intermediate support.
- Insulation without vapor barrier shall be manufactured and cut to a 16-inch width to fit snugly within the wall panel. Stick clip fasteners shall be secured to the inside of the wall panels at 48 inches on center vertically and 10 inches horizontally to hold the insulation in place. Stick clips shall be placed a minimum of 3 inches from the edge of the insulation.
- The 1-inch rigid insulation board shall be installed over the blanket insulation and secured to the inside of the wall panel ribs with contact cement to maintain its position until the vapor barrier and liner panel are installed.
- Before the liner panel is attached, a 2-mil polyethylene vapor barrier shall be installed over the entire interior surface of the rigid insulation board.
- The vapor barrier shall be extended at least 6 inches beyond the top, bottom, and at each end and wrapped under. Tape all seams and tears in the vapor barrier with approved tape. The vapor barrier, in conjunction with flashings, shall prevent the infiltration of rainwater into the cavity and prevent the saturation of the blanket and rigid insulation.
- The aluminum, corrugated, perforated liner panel shall be installed over the vapor barrier with the corrugations horizontal. Secure the panel to each panel rib (at 16 inches on center) with #14 stainless steel sheet metal screws in every sixth corrugation. Ends of sheets shall be butt-tight, and side laps shall be at least one corrugation.
Wall Assembly Procedure for Enclosures
Materials for Noise Attenuation System
Blanket Insulation
Insulation shall be 3 inches thick glass fiber blanket (unfaced) with a density of 0.60 pound per cubic foot, as manufactured by Owens Corning Fiberglas Corp., or approved equal. The glass fiber blanket shall be flexible, resilient, odorless, and incombustible and shall not contribute to corrosion of steel or aluminum nor breed or promote fungi or bacterial growth. The insulation (unfaced) shall qualify for a UL flame spread rating of 25 or less.
Rigid Board Insulation
Rigid board insulation shall be manufactured of inorganic glass fibers preformed into rigid boards with a density of 3.00 pounds per cubic foot and a thickness of 1 inch. Board shall be Type #703 (unfaced) as manufactured by the Owens Corning Fiberglas Corp., or approved equal. The board shall be odorless and incombustible and shall not contribute to corrosion of steel or aluminum nor breed or promote fungi or bacterial growth. The insulation shall qualify for UL flame spread rating of 25 or less.
Vapor Barrier
- Vapor barrier for use with noise attenuation systems shall be clear polyethylene, 2 mil in thickness, and shall comply with the following:
- Impact Resistance – ASTM D1709.
- Tensile Strength – ASTM D882.
- Water Vapor Transmission – ASTM E96.
- Thickness – ASTM D374M.
- Tape all seams and tears in the vapor barrier with a manufacturer approved tape.
Flexible Steel Netting
Flexible steel netting shall be 20 gauge galvanized steel fabric (poultry netting) with a 2-inch mesh and reinforcing line wires at 12 inches on center. Fasteners to attach netting shall be #8 galvanized sheet metal screws with fender washers placed at 16 inches on center.
Galvanized Corrugated Perforated Liner Panels
- Galvanized steel liner panels shall be minimum 24 gauge (.0276 inch thick) manufactured according to ASTM A924 and having 1.25 ounces per square foot commercial coating. Corrugations shall be 2 2/3 inches crest-to-crest and 1/2 inch deep.
- All panels shall be perforated with 0.125-inch diameter holes at 3/16 inch staggered centers (33 holes per square inch, 40% open area).
Aluminum Corrugated Perforated Liner Panels
- Aluminum liner panels shall be 20 B&S Gauge (.032 inch thick), corrugated with a 2.67-inch pitch and 7/8 inch deep. Color shall be natural aluminum, mill finish as manufactured by Alcoa or equal.
- All panels shall be perforated with 0.125-inch diameter holes at 3/16 inch staggered centers, (33 holes per square inch, 40% open area).
Insulation Fasteners
- Fasteners shall be installed in accordance with the manufacturer’s recommendations. Before applying the fastener and adhesive to the metal panel, spot-clean the area with solvent (naphtha or mineral spirits) to remove all waxes, residual oils, or forming lubricants from the surface.
- The length of the fastener shall be kept as short as possible; all projecting ends shall be clipped off or bent flush.
Metal Curtainwall Studs
- Nonload-bearing curtain wall studs and stud tracks shall be 20 gauge, fabricated from galvanized, Type 1 aluminized or Galvalume steel. Studs are available in 2 1/2, 3 5/8, 4, and 6- inch depths. Spacing shall be 16 or 24 inches; studs and tracks shall conform to ASTM C645.
- Height limitations based on allowable deflection of L/120:
| Stud Depths
(Inches) |
Stud Spacing
(Inches) |
Maximum Height
(Ft)(In) |
| 2 1/2 | 16 | 16-2 |
| 2 1/2 | 24 | 14-8 |
| 3 5/8 | 16 | 20-10 |
| 3 5/8 | 24 | 18-11 |
| 4 | 16 | 21-5 |
| 4 | 24 | 19-5 |
| 6 | 16 | 27-4 |
| 6 | 24 | 24-10 |
-
- Each stud shall be attached to the second horizontal wall girt above the floor (approximately 12 ft 4 in above the floor), thereafter attached to the wall girt at 10 ft 0 in o.c. vertically and at the top to the eave purlin or rake beam.
Sound Control Curtain
- Noise control curtains for interior use shall be lead powder-loaded, vinyl-coated on both sides of a beta-glass fabric. The curtain shall have a nominal weight of one pound per square foot, a breaking strength (warp and fill) in excess of 320 pounds per inch, a tear strength (warp and fill) in excess of 35 pounds, and shall be self-extinguishing and fire- resistant.
- Each curtain panel shall be furnished with Velcro self-adhering nylon closures along the entire length of each edge, pipe access slits, and pipe openings. Support points at the top of each panel shall be reinforced at grommet locations, 12 inches apart.
- The channel support system for the curtain shall be a 1 5/8 x 1 5/8 inches, 12 gauge formed channel with associated hardware, including two-wheel trolley assemblies for each curtain support point.
- Curtains shall be product type KNC-100B (light green in color) with sound transmission loss (dB) of 28 at 1000 Hz and a sound transmission class (STC) of 27. The curtain and track system shall be as manufactured by Peabody Noise Control Inc., 6300 Irelan Place, Dublin, OH, or approved equal.
Service Doors and Roll-up Doors
- Service doors and roll-up doors shall comply with the requirements of Air Products 309750D, sheet 2 of 2, Standard Door and Hardware Schedule, Special Buildings.
- Insulated core roll-up doors may be substituted for removable wall sections in specific cases approved by Air Products.
Duct Silencers
- Duct silencers shall be the rectangular module type for inlets and the tubular conitube type for mounting in conjunction with exhaust fans as manufactured by the Industrial Acoustics Company, Bronx, NY or same company.
- The model number and nominal size and length shall be as indicated on the drawing.
- The unit shall be rated for a sound transmission loss (dB) of 28 at 1000 Hz.
Load-Carrying Wall Panels
Sculptured, trapezoidal-faced, interlocking wall panels shall be 24 minimum gauge and shall be 16 inches wide x 3 inches deep. All panels shall be continuous from sill to top of structure except where the panel length exceeds 40 ft or otherwise becomes prohibitive for handling purposes. All fasteners shall be concealed.
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