With most silicone based products, you'd find some sort of acoustic rating being that a good resistance to sound is made by dampening vibrations and also quite simply blocking the air gaps that actually leak the noise. As a useful addition to being a certified fire retardant, 3C Firestop Silicone is tested and certified to have a British Standard acoustic rating of: BS EN ISO 140/3 as well as being tested and certified for air permeability to EN13141-1 which is classed as 'Ventilation for buildings'.

As a neutral cure, elastic, acoustic rated silicone sealant, 3C Firestop Silicone is equally suited for external applications as it is with common internal applications. Quite often an architect's joint configuration in something such as a door frame that opens to the outside, requires a double seal, simply explained, that being a perimeter seal of both the frame to the wall on the outside and the frame to the wall on the inside. This a belt and braces approach and works well. Neutral cure silicones cope well with external extremities such as high UV and consistent rain etc. 

3C Firestop Silicone is a premium quality neutral silicone sealant with fantastic elastic properties and as such adheres extremely well to most common substrates found in design and build construction projects so, in general a primer isn't necessary to prepare the surface and/or promote adhesion between the sealant material and the sides. On the very rare occasion that a primer is required (or at least suggested) in a specification, then the correct, compatible product should be sought and used. Our technical sales team will be able to help with recommendations.