5 Gallon Buckets of FireShell IB4 Ignition Barrier. White in stock. Other colors lead time Free Shipping on 38 Units (Truckload) Building Code Products \ FIRESHELL® (IB4) IGNITION BARRIER COATING FIRESHELL® (IB4) is a proprietary, water based, 1-part, non-flammable, intumescing coating complying with AC 377 ICC ES for interior use. This coating expands up to 2000% and provides oxygen starvation when in contact with fire. This barrier coating / ignition barrier comes in both insulating and fire extinguishing versions and is a non-toxic, drain safe, no fuming, water based coating. Applications: Walls Foams Attics Lumber Approvals: Approved Ignition Barrier over Foam Complying with AC 377 APPENDIX: X AQMD super compliant