Mason Industries (Hong Kong) Limited

Silencer / Acoustic Louvre / Acoustic Panel & Enclosure / Acoustic Lining

HVAC Silencer and Acoustic Louvres
Rectangular Silencers:	Rectangular silencers effectively eliminate noise generated by air conditioning ducting while preventing as much pressure drop and energy loss as possible. They are factory built to fit the duct, made in sections to fit under or through beams, with or without various types of acoustic media that control noise breakout and incorporate different degrees of silencing to suit each individual application.
Elbow Silencers:	Elbow silencers are basically the same as rectangular models but only used when space is a major constraint for the installation of silencers.
Circular Silencers:	The circular straight through silencers with thick acoustic media over the entire circumference provide the same airflow passage as connecting duct but excellent noise suppression properties. An aerodynamic acoustic centrebody incorporates in the circular centrebody silencers for even greater acoustic performance, particularly in the high frequency range.
Acoustic Louvres:	Acoustic louvre is a short design for wall openings. The louvre vane is filled with acoustic media and protected from the weather by position and perforated metal blades. The standard size is 3050 x 1220 mm while the standard thickness is either 300 or 600 mm.

Acoustic panels are constructed by a roll formed inner and outer skins of stainless steel with internal stiffening. The outer skin can be perforated in some models. Thermal / Acoustical material is sandwiched between skins for outstanding acoustic performance. The sound absorptive layer can be made of fiberglass, mineral wool or foam. The panels are self-aligning and can be installed in minimum of time with excellent moisture, air and noise resistance properties.

Thickness: 50 or 100 mm
Width: 950 to 1125 mm
Length: as required

Acoustic enclosures are constructed by acoustic panels with access doors. Special sealant is installed along outside seams between acoustic panels. Two rows of caulking tape are installed between concrete wall and acoustic panels if necessary. Access door is constructed by galvanized steel frame, galvanized or stainless steel face sheet and solid inside sheet with internal stiffening. Thermal/ Acoustical material is sandwiched between skins for outstanding acoustic performance. Other features include double pane Plexiglas window, premium quality of 2 Ventolok 310 handles, 2 plated butt hinges and neoprene bulb gasket door perimeter seal.

Standard door size: 1500 x 600 mm
Standard window size: 300 x 300 mm

Exhaust muffler has much greater outside body dimensions than duct or pipe connection for low frequency attenuation. It is made from cold rolled steel sheet with fully welded construction. Braces and stiffener are provided to minimize “drumming”. High temperature heat resistance aluminium paint which withstands an operating temperature of 600˚C is coated on the muffler for extra protection and durability. It can be installed in vertical, horizontal or inclined position as long as the direction of gas flow is correct. Apart from standard models, tailor made solutions are also available for your choice.

Standard outer diameter: 150 to 1950 mm
Standard length: 760 to 8250 mm

Acoustic wall lining is particularly used at plant room for reducing noise from reverberant sound field. Basic design is identical with the use of sound absorptive material, e.g. glassfibre or mineral, which held in place by fixing channels onto wall or ceiling soffit. To protect the sound absorptive materials from mechanical abrasion, it is surface covered with galvanized steel perforated sheet.

Thickness of lining: 50 or 100 mm depending on sound absorption requirement.

WILHAMS Noise Control Products

Wilhams CFC Free PUNF Foam is a polyurethane foam designed to meet the fire resistance and high performance specifications with outstanding acoustic absorption characteristics. The absorption coefficient is 0.97 with 50 mm thick foam at frequency of 1000 and 2000 Hz. The fire test result is class “0” according to BS 476: Part 6 & 7 standard and UL94 classification V-0. It also complies with the ATS 1000.001 standard on smoke toxicity. It eliminates the long unsolved “Fiber Flying” problem with fibrous sound absorptive material which makes it suitable for use in clean environment such as hospital.

Density: 108 kg/m³
Indentation Hardness: 156 N
Tensile Strength: 88 kPa
Operating Temperature: -30 to +110˚C
Maximum Width: 2.05 m
Thickness: from 6 to 50 mm

WB Mineral Load PVC Barrier is a mineral loaded PVC sound barrier mat with wear resistant skin. It is designed to improve the sound insulation performance of existing panels of metal, wood, plastic, etc. The barrier is fixed in intimate contact with the original panel and particularly effective in overcoming coincidence dip resonance found in stiff lightweight composites such as plywood sheets and hollow core panels. The installation of this barrier is simple. It is suitable for general purpose acoustic absorption.

Thickness: 2 to 4.5 mm
Weight: 5 to 10 kg/m²
Mean Sound Reduction Index: 22 to 28 dB
Flammability: FMVSS302 self extinguishing

Wilhams Acoustic Pipe Lag

Acoustic Pipe Lag is a laminate made by foam, fiberglass or mineral wool with a heavy mass layer with an outer facing of Class 0 reinforced foil. The installation is simple and it can be used for internal and external duct linings to effectively reduce noise breakout.

Thickness: 25 mm
Size: 1000 x 2000 mm
Sound Absorption Coefficient (foam): 0.65 (at 2000 Hz)
Sound Absorption Coefficient (fiberglass): 1.00 (at 2000 Hz)

Wilhams ASTEX Fabric Covered Wall Panel System

ASTEX is a highly absorbent, fabric covered, composite panel. It is not only decorative but also adds acoustic absorption whilst improving transmission loss and thermal characteristics. It is constructed from high density fiberglass and enclosed by fire retardant fabric. ASTEX is easy to install, is virtually maintenance free and may be hoovered or lightly sponged. It can be used as lining for studio, office, auditoria where high acoustic absorption combined with level of aesthetically pleasing appearance is required.

Thickness: 25 and 50 mm
Standard Size: 2.5 x 1.2 m
Weight: 3.25 kg/m² and 5.00kg/m²
Panel Fire Class: BS476, Part 6 & 7 – Class 0

Sound Absorption Coefficient:

0.92 (25 mm thick panel with 25 mm air gap)
1.04 (50 mm thick panel suspended)