Firestop putty K-flex K-Fire Putty O15mm 5×20 cm — intumescent seal for pipe and cable penetrations

K-Fire Putty O15mm is an intumescent firestop putty sheet manufactured by K-flex, supplied in 5×20 cm dimensions with a nominal thickness of 15 mm. The material is formulated to seal small penetrations, service openings and gaps around pipes and cables in walls and floors, restoring the integrity of fire-resistance barriers. Its compressible, flexible structure allows simple on-site fitting into irregular openings and around round or flat services without the need for special tools.

Advantages

The putty expands when exposed to heat, forming an insulating char that helps prevent the passage of fire, smoke and hot gases through openings. Its compressible nature ensures good contact with uneven surfaces and different service profiles, improving the seal in busy installation areas. The sheet format and moderate thickness make it convenient for fast installation and retrofitting in existing constructions.

Suitable for

• Sealing pipe penetrations in masonry and lightweight partitions
• Sealing cable entries and cable trays where small gaps remain
• Restoring fire resistance around small service openings in floors and walls
• On-site retrofitting and maintenance of fire seals in electrical and mechanical installations

Key specifications

• Form: intumescent putty sheet
• Dimensions: 5 × 20 cm
• Nominal thickness: 15 mm
• Material property: compressible and flexible for tight fitting
• Function: passive firestop for sealing small openings around services

How to use

Measure the penetration or gap and cut the putty sheet to the required size with a knife or scissors. Press the cut piece firmly into the opening ensuring continuous contact with the substrate and services; the material should form a tight fit without gaps. For irregular shapes, compress and shape the putty by hand to achieve full coverage. No special primers or adhesives are typically required, but follow project-specific firestop system instructions and compatibility checks with surrounding materials.

Usage recommendations

Inspect installed seals after fitting to confirm complete contact around services and make sure the putty is not left exposed to conditions outside its intended use without appropriate protection. Use this product as part of an approved firestop solution and consult project firestop specifications or a fire-safety professional for complex penetrations or where system listings are required.