ISL - Isolated Systems Limited

Industrial Noise Vibration &
Thermal Management Solutions



Silencers / Attenuators (Circular)

Silencers / Attenuators

Silencers / Attenuators (Circular)


ISL design and manufacture straight through and podded attenuators/silencers from small cross-talk silencers right through to large Industrial Attenuators. We have standard designs and construction methods but in addition to this our design team are always coming up with bespoke designs to facilitate our clients varied needs. Our attenuators are used in a diverse array of industries including HVAC, water & waste treatment, chemical industries, process engineering, off-shore, commercial and general manufacture. ISL works with architects, consultants, contractors, OEM’s & end users.



ISL design and manufacture many types of attenuators/silencers the type of design depends up on a variety of factors including Acoustic performance, size, access, structural reasons and may other factors.

Thin gauge pre-galvanised casings which are generally lock formed or riveted construction are used mainly for HVAC ductwork.

Heavy gauge casings, which are generally a welded construction, are used for Industrial requirements.

The internal side linings are packed with mineral wool which is faced with woven glass scrim or melinex to prevent particles entering the airflow, it is the retained by perforated sheet.

The centre pod is a circular cylinder lined with mineral wool which is faced with woven glass scrim, aerodynamic ends are included to improve airflow and reduce pressure drops.

All Attenuators are available in pre-galvanised mild steel, stainless steel, aluminium, polypropylene and GRP.


Acoustic Performance/selection

All ISL Attenuators/silencers are selected using computer software by trained acoustic engineers, which calculates the attenuation required from the contributing factors such as noise source, distance to listener, reverberation, etc.

When the attenuation is known the acoustic engineer will calculate the configuration and silencer size to achieve the require attenuation, whilst taking into consideration pressure drop restrictions and cost implications.



There are a variety of options available the most common ones are listed below.

Ends – plain, rivnuts, spigoted flange, spigots, etc.

Finish – self, powder coated or wet sprayed to standard RAL/BS no.

Modular – Supplied in sections (split on length) for when Installation access is a consideration.


Ductwork/HVAC Attenuators

ISL design and manufacture a range of ductwork/HVAC attenuators, which are manufactured in accordance with HVAC specification DW/144.


Industrial Silencers

ISL design and manufacture a number of Industrial Silencers that are suitable for all kinds of applications including offshore.


Filter Inlet Silencers

ISL design and manufacture filter inlet silencer c/w access panels for replacing filters, for fan inlets.