Usually specified at the design stage of any construction project by an architect or project manager, the fire protection aspect in relation to sealants can be split into 2 x different types, one being Stopping and the other being Intumescing. The latter is a method common for sealing joints, voids and irregular holes in fire walls, partitions, internal perimeter pointing of fire rated door and window frames and any other structures that lead through to another area etc. These types of products also serve to maintain the integrity of pipes and cables that penetrate them. The way they work is by swelling up to greater than 3 x it’s original size when exposed to heat, so creating a char that will resist the passage of fire for up to *5 hours (*providing the joint configuration is correct) This is as opposed to silicones that work as fire retardants.

Due to the testing and certification process of Intumescent Acoustic, the joint configurations that were tested as per the technical data sheet suggest that 50mm in width is the absolute maximum that a joint can be, to be effective for it's use as an intumescent sealant. You can see the test results in full here.  

As previously mentioned above, 3C Intumescent Acoustic is a sealant used for sealing joints, voids and irregular holes in fire walls, partitions, internal perimeter pointing of fire rated door and window frames and any other structures that lead through to another area etc. When considering these types of applications, it's worth remembering that this will also serve to maintain the integrity of pipes and cables that penetrate the voids. Another widespread use of this product is internal soundproofing in areas where sound dampening is desired such as office partitions and recording studios.