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3M Fire Barrier Block B258 is a pre-formed foam block. It seals larger openings against smoke, toxic gas, and flames. The design enables easy installation and helps reduce sound transmission.
A better way to fill large gaps: Use the 3M Fire Barrier Block B258 for sealing larger cavities. The simple application involves stacking and sealing without special tools. The blocks stay securely in place and eliminate the need for wire mesh reinforcements. Pre-formed blocks allow quick filling of large openings. They can be trimmed on-site to achieve a custom fit. There is no cure time needed for installation, making the process faster. The blocks also accept primer for painting, providing a seamless look.
The blocks are re-enterable and reusable, making them cost-effective and reducing waste. After filling, seal around any penetrating items using 3M Fire Barrier Rated Foam FIP 1-Step or other 3M fire barrier sealants, sold separately.
3M B258 Fire Barrier Blocks have been tested for compliance with firestop criteria such as ASTM E 814/UL 1479. These blocks are part of a trusted line of fire protection products.
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