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Treatment Strategy

  • Source Airborne

Application Use

  • Industrial In-plant
  • Industrial New Con.
  • OEM
  • Environmental
  • HVAC


Removable Sound Insulation

Removable/Reusable Blanket Insulation For Sound Attenuation At The Source

Ball Mill Wrap with exposed liner bolts at a cement plant. HUSH COVER™ model HC-500S-1.5" blankets for air cooled screw chiller compressors.


  • Completely removable and reusable
  • Easy to install
  • Can be reused after maintenance
  • Custom-fit to existing conditions
  • Guaranteed fit
  • Predictable performance based on laboratory tests
  • Suitable for harsh environments where solvents, acids, oils and other contaminants are present
  • Outdoor weather-resistance construction
  • High temperature capability
  • Self-contained insulation system
  • Asbestos free
  • Good combination of acoustic and thermal performance


  • Fans and blowers
  • Compressor housings
  • Gear boxes
  • Valves
  • Ejectors
  • Steam and gas turbine casings
  • Pumps
  • Pipes and ducts
  • Expansion joints
  • Any hard to treat, irregular surface where removability is important
  • Chillers and refrigeration equipment
  • Engine exhaust systems
  • Personnel protection (high temperature) for surfaces above 140°F
  • Ball mills



About BRD HUSH COVER™ Acoustic Insulation:   Design Components
For HC-500S:
BRD HUSH COVER™ acoustic blanket insulation is an extremely versatile and efficient solution to common industrial noise problems.  It combines high density fiberglass mat with a mass-loaded vinyl sandwiched inside a weather-proof jacketing.  The purpose of the fiberglass is to reduce reflected noise and to absorb noise energy, while the mass-loaded vinyl blocks transmitted noise.  The fiberglass also has excellent thermal insulation qualities.  Combining both an absorber material and a barrier material that are well matched yields a highly efficient and cost effective means for solving industrial noise control problems.  

OUTER JACKET:  16 oz.yd.2 PTFE silicone
                                   impregnated fiberglass 

ACOUSTIC BARRIER:  Barium sulfate loaded 
                                      vinyl (1 lb. to 2 lb. density)

INSULATION:  Fiberglass needle mat (11 
                            lbs./ft.3 density)

INNER JACKET:  16 oz./yd.2 PTFE silicone
                                   impregnated fiberglass 

Pressure blower housing treated with two-piece velcro system.    


The standard design (HC-450) can be used on equipment not exceeding 450°F (232°C).  Other designs are available for equipment with temperatures exceeding 450°F.



HC-800 is suitable for up to 800°F.  HC-1200 is suitable for up to 1200°F.  Design components for these and other custom HUSH COVERS™ are available upon request.


Test Frequency (in Hz) Noise Reduction (in dBA)

The above data is representative of ASTM test procedure E-1222-87 for the laboratory measurement of the insertion loss of pipe lagging systems.  BRD will not be warranted for performance results of HUSH COVER™ blanket insulation expressed or implied.  Additional test data is available for a variety of blanket constructions.

315 1
400 6
500 10
630 12
800 12
1000 21
1250 23
1600 25
2000 26
2500 26
3150 26
4000 26
5000 28


Liquid cooled screw chiller noise is tamed
using HUSH COVER™ model HC-500S-1.5"
  Ball mill HUSH COVER™ using HC-500-1"
with banding attachment.
Acoustic Field Test Results    
Based on previously tested installations, actual dBA reductions range between 3-5 for HC-500-1" and 6-8 for HC-500-2".       True performance estimates must include field verification of dBA levels and frequency concentrations on an application basis.

 General Installation Instructions

  1. Many of the blankets will have 2" flaps on the edges.  These flaps are to be installed so that the flap on the upper blanket will cover over the edge of the lower blanket, creating a shingle effect.


Boiler feedwater pump at fit-up prior to lacing.



BRD Installation
Services Available

  1. Blanket installation should follow the recommended order of installation provided on the assembly drawings.  Most blankets will either seam at the horizontal or vertical centerlines.  All panels are tagged for easy identification.
  1. "D" Ring assemblies have been provided to ease installation.  To use, simply lace the strap through the adjoining blankets "D" Ring assembly and secure.  Velcro flaps are provided to permanently secure closing seams and to lock material in place.
  1. Occasionally, certain blankets may be difficult to install due to space limitations or obstructions.  If this occurs, it may be necessary to modify the blanket's shape or size.  Stainless steel staples are the recommended closure method for any modifications.
  1. Generally, all tags should read from left to right and will be oriented horizontally.  This will show the correct orientation of the acoustic blanket.
  Before and after views showing velcro installation of HUSH COVER™ multi-piece design for a steam ejector.


Valve Cover Take-Off Sheet

Typical Design and Fabrication Parameters

  • HUSH COVER™ blankets can be quoted based on field sketches, equipment cut-sheets or templates created in the field.
  • Standard items such as valves, elbows, fittings, pumps, etc. can be quoted based on standardized take-off sheets such as the one shown above.
  • Field measurements by a qualified BRD Representative may be required prior to fabrication.
  • Fabrication techniques include computer aided design (CAD) capabilities to assure proper fit.
  •  HUSH COVER™ designs are complete and require no additional tools or materials.
  • When requesting a quotation, please supply the make and model of the equipment if known.
  • For OEM applications, private labeling can be provided to meet customer specifications.

HUSH COVER™ on air cooled screw chiller suction lines, compressor, discharge line and oil separator.

Typical "D" ring and strap attachment feature.