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Intex™ Fire Protect – All Your Questions, Answered!


Since the launch of Intex™ Fire Protect, we have had an overwhelmingly positive response from our customers. However, there are a number of questions regards the product that come up time and TIME again. Therefore, we have put together a list of some of the frequently asked questions:


Question: When is the system available?

Answer: The product can be specified on projects now and in fact has already been integrated into several project specifications.

Question: What is the accommodation of tolerances front to back?

Answer: The system allows for varying levels of tolerance to cover typical construction tolerances, as well as additional testing completed at higher tolerance values. The system has been tested to a maximum front closure of 20mm and a maximum rear closure of 39.5mm.

Question: BBA for the system? NHBC Accepts?

Answer: We are currently in the process of attaining a 3rd party Agrément Certificate for both the 4-in-1 and 3-in-1 product. NHBC Accepts is not a service offered on products anymore, it is designed for full system offerings to specific MMC categories.

Question: What fills the gap at the top of the tray? There is an open gap at the bracket clip on location plus you are reliant on a flat concrete slab edge as no seal.

Answer: ACS have held conversations with leading membrane manufacturers to ensure that a solution can be achieved which ensures compliance to building regulations as well as guaranteeing a watertight system.

Question: What are the maximum / minimum cavity widths the system can be used?

Answer: The maximum cavity size is 350mm, the minimum cavity size is 150mm.

Question: How do you deal with corners, both 90 degree and non 90 degree?

Answer: For the bottom section consisting of the masonry support angle, a fully welded detail is provided at corners ensuring a watertight seal. For the top section, a corner tray is provided which covers the full corner area. This then overlaps the next trays by a minimum of 50mm following the constraints from the ACS cavity tray range of products. This applies to all angles of corner, not just 90°.

Question: How does the clip tray work with a large drop bracket system?

Answer: For very large drops, an additional 0.5mm tray is required to ensure full waterproofing. The minimum height where this is required will be specified within the product Agrément Certificate.

Question: What happens at floors with no MSA?

Answer: If masonry support is to be utilised at every other floor, traditional methods of cavity tray and cavity barrier are to be utilised at alternative floors.

Question: Is there a minimum slab thickness requirement.

Answer: This is dependent on a number of factors such as cavity size, masonry load, and the relationship between fixing position and support level. The absolute minimum thickness would be 150mm, however this would be project specific based upon the factors listed.

Question: Do you have psi values for this system?

Answer: The intention for the short term is for a number of typical scenarios to be provided with their psi values. The long term intention is to be able to provide this for every system.

Question: What is the maximum drop from the slab to the brick support?

Answer: In a similar manner to the minimum slab thickness, this is dependent on a large number of factors. The best method is for us to run sample calculations for specific scenarios.

Question: How is the fire barrier secured in place?

Answer: The barrier is mechanically fixed into the tray utilising waterproof rivets.

Question: Is there a plan to provide an A1 weep vent shorter than 65mm to accommodate the thickness of the angle in relation to the cavity tray / brick height?

Answer: ACS offer two A1 non-combustible weep vents. The first is a 65mm product designed for traditional methods of construction. The second is a 55mm tall product for use with pistol bricks and the Intex system.

Question: Are the brackets fixed in terms of geometry or are they bespoke to site requirements?

Answer: Each system is bespoke to both the site, as well the specific section detail. Near enough every eventuality can be catered for within the bracket design.

Question: How is the system sealed from the masonry just below the angle to allow for movements?

Answer: The system is utilised in the same manner as traditional masonry support with a soft joint and mastic seal to allow for brickwork expansion and construction, as well as system deflection.

Question: Since the mineral wool insulation is required to complete the cavity barrier for fire performance – are there constraints on density/product for the mineral wool insulation?

Answer: Data for this will be provided within the product third party assessment of the fire testing when available.

Question: Is there a system to overcome different cavity widths either side of a corner?

Answer: Yes, as the system is bespoke to the area in question, the corner will be provided to suit the specific geometry.

Question: Is it tested as a hybrid system with traditional method e.g. where one a part of the building is below 150mm or above 350mm cavity?

Answer: This will need project specific sign off from the project fire engineer. All relevant test certification can be provided to the fire engineer to assist with this decision.

Question: Does the intumescent seal to the cavity insulation?

Answer: Yes, the system has been tested as a full assembly allowing for the intumescent to expand in the rear closure back to the cavity insulation. As a side point, the intumescent expands to the brickwork on the front closure.

Question: What are the benefits of the open state design you have utilised?

Answer: The first advantage is that traditional closed state barriers rely on a specific compression value to ensure they perform as tested. In reality on site, to achieve this can be problematic when dealing with typical construction tolerances. With an open state design, the intumescent element of the barrier allows for these tolerances and ensures the product still performs as per its design. The second advantage is around the installation of barriers during the construction phase. When utilising closed state barriers, there is the requirement to let your mortar joints sufficiently set before installing the barrier. If you do not wait, the mortar is effectively ‘green’ and the barrier pushes the brickwork outwards. This in turn results in the barrier having insufficient compression.

Question: Will a copy of the webinar be accessible for us to listen to again?

Answer: Please contact ACS for the link to be provided.

Question: Does the system work with your Azure soffit offering?

Answer: Yes, the system can be used with our brick slip soffit systems. Due to the requirement for slots to install the soffits, a bespoke combined system is utilised to suit each specific scenario. Indicative site specific details can be provided if we are in receipt of DWGs.


Do you want to learn how to specify Intex™ on your next construction project?

Let’s have a chat: 0844 850 0860


Article originally published on 27th July 2023