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 (TGD 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.