Before 2018 the GIB Fire Rated Systems manual included ‘fire rated sealant’ as a generic product reference. At the time GIB supplied GIB Soundseal, which did not have fire-resistant properties, as an acoustic sealant. Customers frequently asked why GIB Soundseal was not fire-rated, and what suitable alternative sealant to use in fire-rated and noise control applications.

This urged GIB to develop a sealant with dual capabilities for use in GIB fire and noise control systems.

GIB Fire Soundseal is for use with GIB plasterboard systems and has been tested in accordance with AS1530.4, the industry standard for fire-resistance test for elements of construction. Although the sealant is capable of more than what is published in GIB's literature, applications must remain within the verified scope, which means there are some restrictions on its use. On the GIB Helpline the team get asked some fiddly questions which they clarify as bullet points:

GIB Fire Soundseal

• Can be painted over. It is acrylic based and needs to dry properly. Drying can take longer depending on applied thickness. 
• Still has acoustic properties, that’s why “sound” remains in its name.
• Can be applied in layers, even after the first application has dried.
• Cannot be used as a ‘fire-rated glue’. It is a gap filler, not a structural adhesive for sticking and holding things together.
• Can adhere to concrete, metal, wood, masonry and AAC block.
• Can adhere to a ‘rough edge’ of plasterboard, but remove any loose bits and dust, this can be done by giving it a rasp and sand.
• Is not recommended for use outside published GIB system applications.
• MUST have backing to be applied against. You cannot ‘float’ the sealant in a gap or joint. Install backing material or a backing rod as appropriate. 
• Cannot be simply ‘smeared’ in a thin layer over sheet joints to replace taping and plaster stopping.

The most frequent question the GIB team get relates to linear gap-filling. The GIB Fire Soundseal User Guide specifically states the following:

Unless applied as a continuous perimeter bead between GIB plasterboard layers in GIB Noise Control Systems, GIB Fire Soundseal is applied to a minimum depth of 6mm and maximum width of 40mm at a ratio between 1:1 and 1:2.

Note that the sealant thickness and width-to-depth ratio apply to a designed linear gap between construction materials or elements, and the seal is intended to prevent the spread of fire.

This does not include the use of GIB Fire Soundseal as an acoustic perimeter seal between layers of plasterboard.

The GIB Noise Control Systems manual states the following, which is intended to seal the element perimeter against unwanted sound leaks:

A bead of GIB Soundseal acoustic sealant is required around the perimeter of the inner lining. The outer lining is then bedded onto the bead.

This is not a ‘linear gap seal’, and neither is the use of GIB Fire Soundseal to fill any minor gaps or cracks in general fire-rated or noise control applications. The stated 1:2 ratio applies to intended linear gaps and this does not mean cutting away plasterboard to make room for sealant in all cases. Unfortunately, the GIB team have come across situations where installers have been instructed to do just that. Not good advice!

Note that ‘GIB Noise Control Systems, 2017’ still refers to GIB Soundseal and pre-dates the addition of fire-rated properties. GIB Fire Soundseal can now be used and retains all the acoustic properties of its predecessor. Now is also a good time to point out that the requirement for a perimeter seal does not mean every sheet in that wall or ceiling needs to have sealant applied.