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Treatment Strategy

  • PathDirect
  • Receiver

Application Use

  • Industrial In-plant
  • Industrial New Con.
  • Architectural Finishes
  • Architectural Walls/Ceilings
  • OEM
  • Environmental
  • HVAC


Acoustical Panels & Enclosures

Modular, Durable, Easy to Install Acoustical Panels for Maximum Noise Reductions

OEM enclosure for hydraulic pump unit utilizes HUSH GUARD™ type HG-QR-200 quick release design.

Minster punch press enclosure using type HG-400 panels.

 Advantages:  Applications:
  • Modular design to form partial or complete enclosures, partitions, dividers and walls
  • Standard 2', 3' & 4' wide panels can be combined with any size special width panels
  • Turnkey design including doors, windows, silenced ventilation systems, lighting, structural steel and more
  • Removable panels provide easy service access
  • Durable rugged construction for long life
  • Maximum noise reduction STC ratings of 37-48
  • Highly customized designs to meet all customer needs/requirements
  • Standard galvanized steel construction; also available in stainless steel and aluminum
  • Readily assembled, demounted, relocated and/or reassembled without sacrificing structural integrity or acoustic performance
  • Machinery and equipment enclosures
  • Shop offices and control pulpits
  • Test environments
  • Outdoor environmental barriers for HVAC, mass transportation, industrial and highway applications
  • Broadcasting/recording studios
  • Machine tool presses and equipment
  • Music practice/educational study rooms
  • Audiometric/medical test rooms
  • Ovens
  • Transformer stations
  • Gas and electric utility equipment enclsoures and barriers
  • Partial personnel barriers
  • Grinders, shredders and other size reduction equipment
  • Wind tunnels
  • HVAC fan plenums


About BRD HUSH GUARD™ Products:

Exploded view of typical HUSH GUARD™ acoustical panel enclosure.

BRD HUSH GUARD™ acoustical panels are formed using sheet metal perimeter reinforcing channels spot welded or pop riveted to a solid and a perforated sheet filled with high density acoustical insulation for an overall thickness of 2", 4" or 6" as standard.  The perforated sheet acts as a retaining screen for the insulation but is acoustically transparent allowing sound waves from the noise source to be absorbed.  The outside solid sheet acts as a sound barrier reflecting incident sound waves back through the acoustic fill where further absorption takes place.  Standard and custom manufactured panels assemble together using "H" joiners or by tongue and groove and are further secured using sheet metal self-tapping screws.
Panel vs. Enclosure Performance  
The tables below list laboratory test data for an individual one piece panel.  This will not always be indicative of the enclsoure performance because of noise leakage (flanking) over the surface area of the enclosure walls and roof.  Leakage aroudn pipe penetrations, under doors and around windows, through air ventilation openings, etc. can drastically compromise the panel performance as shown on the graph at right.  In the example, an enclosure design that has as little as 1% open area over the entire surface area of the enclosure exhibits an actual transmission loss of about 20 even though the panels are rated for almost 40 dB transmission loss.  The lesson to learn is that design drives the enclosure performance as much or more than the panel ratings.

 Acoustic Performance Data:

Product Sound Transmission Loss (dB) Frequency (Hz) STC
125 250 500 1000 2000 4000
HG-200 17 23 34 47 55 57 37
HG-210 24 25 33 43 50 55 38
HG-400 21 28 39 48 56 58 40
HG-410 23 31 40 49 56 62 42
HG-420 27 34 41 46 53 59 44
HG-500 18 26 35 45 49 52 37


Product Sound Absorption Coefficients Per Frequency (Hz) NRC
125 250 500 1000 2000 4000
HG-200 0.15 0.66 1.07 1.06 0.97 0.86 0.95
HG-210 0.26 0.53 1.00 1.03 0.97 1.02 0.90
HG-400 0.60 1.13 1.12 1.09 1.03 0.91 1.00
HG-410 0.68 1.06 1.12 1.08 1.03 0.98 1.05
HG-420 0.45 0.96 1.15 1.10 1.05 0.97 1.05
HG-500 0.92 1.15 1.22 1.13 1.08 1.04 1.15

 Panel Constructions:  Panel Finishes:
  Thickness Solid1 Skin Perf1 Skin2 Weight per sq. ft.  1.  Galvanized steel (std.)
HG-200 2" 18 ga. 22 ga. 4.0 lbs.  2.  Galvanneal "Paint Ready"
HG-210 2" 16 ga. 22 ga. 4.7 lbs.        steel
HG-400 4" 18 ga. 22 ga. 5.0 lbs.  3.  Air dried shop applied
HG-410 4" 16 ga. 22 ga. 5.7 lbs.  4.  Thermosetting TGIC
HG-420 4" 16 ga. 22 ga. 9.6 lbs.  Polyester Powder Coating in
HG-500 5" 16 ga. 22 ga. 6.0 lbs.  color selected by Architect
           5.  Custom as specified
 1.  Panel skins are all galvanized cold rolled steel.  Steel Finishes:
 2.  Perf. skins have 3/32" holes on 3/16" staggered  1.  Prime Painted (standard)
     centers  2.  Primer with air dried shop
 3.  Optional aluminum and high density polyethylene      applied finish paint
     constructions.  3.  Hot dip galvanized
 4.  All stiffeners and panel channel framing is minimum      (availability dependent on
     18 ga. steel with face sheets spot welded in place.      final steel member sizing)
 5.  Panels are designed to withstand wind loads of 25  4.  Colors available to match
     lbs/sq. ft. both negative and positive.      panels
 6.  Panel fill is non-combustible high density semi-rigid  5.  Sand blasting prep only as
     non-hygroscopic HUSH BATT™ packed under 5%      specified by contractor.
     compression.  6.  Custom as specified


  Installation Guidelines


Foundation with anchor bolts for columns.

Structural steel columns are erected.  



Type HG-400 acoustical panels erected in the structural framework.



Review the CAD erection drawings and bill of materials which will list all panels, trim (flashing) and other accessory items required for the job.


Most HUSH GUARD™ enclosures up to a size that does not exceed a 12' roof span in any one direction or height are completely self-supporting without the use of supplementary structural steel.  When required, the structural steel will be detailed on the drawings and should be installed according to the instructions.


Like all trim and flashing, the base channel is supplied in standard lengths and must be cut to size by the installing contractor.  it is the customer's responsibility to be sure that the foundation or bearing surface is suitable for the support of the enclosure.


Start at a corner and set panels on each side of the corner into the floor channel.  Secure corner panels with outside corner flashing using sheet metal screws.  Tongue and groove panels or supplementary H joiners are used to sequentially connect additional panels in either direction until all perimeter walls have been erected.


Door frames and doors are installed during the natural panel sequence with adjacent panels fitting against the frame on both sides for standard doors.  Depending on the size, some standard and premium doors will be pre-installed in a larger panel.


Install the roof panels according to the erection sequence shown on the drawing.


Install all outside and inside trim and flashing.  It is recommended to fasten inside flashing at all panel joints, and at all internal panel stiffeners.


Lighting, ventilation systems and other accessories shoudl be installed as per the drawings.


Factory and field cutouts must be sealed in accordance with BRD guidelines described in a separate bulletin.

 Typical Installation Details

Typical Tongue and Groove
Panel Connection
Typical Panel To Curb
Typical 90 Degree Panel
Typical Panel To Wall


Grinder enclosure using HUSH GUARD™ HG-400-SC panels.  Scrap feed conveyor requires a separate feed tunnel complete with access doors to meet the 85 dBA requirement. Type HG-400 panels are used to quiet an Amada automatic punch press.  Design features include sliding access doors for material flow and integration of the control panel in the right side of the enclosure.
Minimum Design Goals For All HUSH GUARD™ Enclosures:
  • Noise abatement/reduction
  • Lowest dollar per dB reduction
  • Provide for maintenance/service access
  • Accommodate work flow
  • Occupy minimum floor space
  • Meet ventilation requirements
  • Provide adequate lighting
  • Facilitate necessary visual access
  • Aesthetic design and appearance
  • Maintain maximum productivity
Architectural Applications For HUSH GUARD™ Enclosures:
  • Band practice rooms (see right)
  • Recording/broadcast studios
  • Language labs
  • Medical and life sciences
  • Test chambers
  • Anechoic and hemi-anechoic chambers
  • Rooftop barriers and screens
  • Voice over booths
  • Educational study rooms
  • Music and choral rooms
  • Tape recording rooms
  • Dubbing rooms
  • Interview/examination rooms
  • Audiometic booths
  • Radio rooms

Multiple room installation of HUSH GUARD™ HG-400 band practice rooms.


Plan View Typical Corner Detail
Elevation "B" Typical Column Detail
Typical Outdoor Sound Barrier Applications
  • Utilities and substations
  • Mass transportation
  • Highway barriers
  • Rooftop and HVAC equipment
  • Airports and military bases
  • Race tracks and open recreational areas
  • Industrial, commercial and residential
  • Any outdoor equipment or noise source
  • Construction barriers (portable designs available for purchase or rent)

Rooftop sound barrier wall for HVAC unit.

Metering station sound barrier wall.


Non-Progressive Panel Joining Systems

  • Freestanding roof allows removal of individual components or complete walls without disturbing roof panels
  • Individual panels can be quickly and selectively removed for service access
  • Minimal sheet metal screws to cause erection or reassembly problems
  • No tongue and groove fastening required
  • Panels and components may be removed, reconfigured or relocated to meet future enclosure needs
  • Three fastening systems available
  • Highest degree of design flexibility, service access and ease of installation


Panel joining is done with tension latches and sponge gasketing


Panel joining is done with two-piece removable "H" channels


Panel joining is done with Speed-Erect patented features


Type QR panel joining with tension latches.

HUSH GUARD™ type SE panel joining as shown in above exploded view allows quick and easy access to areas not serviced through doors.  The illustration below shows a model HGNP-401 enclosure with partially removed roof and side wall to access the punch press fly wheel.

HUSH GUARD™ type SE enclosure with side wall panels removed.

Hydraulic pump enclosure using HG-QR-200 panel fastening.


Non-Progressive Panel Constructions

Product STC Rating NRC Rating Thickness Panel Construction
HGNP-201 37 1.0 2" 16 gauge damped solid outer skin and 22 gauge perforated inner skin sandwiched around 2" of high density acoustical insulation.
HGNP-401 40 1.0 4" 16 gauge damped solid outer skin and 22 guage perforated inner skin sandwiched around 4" of high density acoustical insulation.
HGNP-402 42 1.1 4" 14 gauge damped solid outer skin and 22 gauge perforated inner skin sandwiched around 4" of high density acoustical insulation.
HGNP-403 48 .95 4" Same as construction for HGNP-402 with the addition of a septum barrier layer for increased low frequency performance (acoustic performance data is estimated).


Header equipment enclosure with telescoping HGNP-201 access doors.

Custom OEM machinery enclosure with pneumatically operated access door.

HGNP-402 enclosure with lift-out sliding access doors for a pipe forming machine tool.

Non-progressive design allows easy access to areas not serviced through door openings.


Standard And Custom Acoustical Shop Offices


HGSO-1 48" 60" 88" 1,100
HGSO-2 48" 90" 88" 1,400
HGSO-3 78" 90" 88" 1,700
HGSO-4 90" 90" 88" 1,800
HGSO-5 108" 90" 88" 2,000
HGSO-6 126" 90" 88" 2,300
HGSO-7 153" 90" 88" 2,600
Dimensions do not include wall or roof mounted fans. Custom modification of a model HGSO-2 at a cement plant.


Custom Designs: Optional Accessories:
  • Custom dimensions
  • Clam shell split designs
  • Polycarbonate or other window materials
  • Can ship fully assembled or knocked down
  • Can be integrated with control consoles
  • Sloped windows for pulpit applications
  • Platform mounted personnel enclosures
  • Drop ceilings and custom interior finishes
  • Explosion proof electrical wiring
  • Air filters
  • Recessed lighting
  • Integral vibration isolation
  • Heaters and air conditioners
  • Eyebolts for lifting