AIM Open State Cavity Barriers

The role of a cavity barrier is to prevent the spread of fire and smoke throughout a buildings unseen voids. AIM’s open state cavity barrier manufactured from Rockwool stone wool is faced with intumescent material allowing for a 25mm and 44mm open airspace cavity. The residual airspace allowing airflow throughout the façade cavity but in the unfortunate event of a fire, the intumescent strip expands producing a vigorous cavity barrier. This product in the correct system will offer up to 120 minutes of integrity and insulation performance.

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Extended cavity fire barrier performance within rainscreen façades Responding to changing market requirements, AIM has developed a range of four OSCBs which provide up to 120 minutes integrity and insulation in the event of a fire.

OSCB’s are a polythene sleeved ROCKWOOL® stone wool and intumescent material designed for use within open state cavities (e.g. Rainscreen systems), allowing ventilation and drainage of the cavity under service conditions while providing up to 120 minutes insulation and integrity performance.

Open State Cavity Barriers offer an effective fire barrier for open state voids up to 425mm in width. Having been tested to the Association for Specialist Fire Protection (ASFP) Technical Guidance Document 19 (TDG 19) & the general principles of BS EN 1363-1, OSCBs offer an extended fire rating of up to 120 minutes insulation and integrity performance in open continuous ventilated air spaces of 25mm & 44mm.


• Provides a 25mm or 44mm airspace.
• Tested in accordance with ASFP Technical Guidance Document 19 (TGD 19) & to the general principles of BS EN 1363-1.
• Provides up to 120 minutes integrity and insulation performance.
• Quick and cost effective installation.
• Galvanised steel fixing bracket supplied as standard.
• Stainless steel metal brackets and spring steel screws available as a tested option.


• Flexible specification: Choice of four OSCBs deliver insulation and integrity performance up to 120 minutes.

• Easy to install: Simple fixing procedure incorporates spring steel screws and steel hanging brackets. No specialist tools required.

Product Information

AIM OSCBs are manufactured from high density ROCKWOOL® stone wool and faced with an intumescent strip and colour coded for ease of identification.

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