Brick slip systems combine the timeless appearance of traditional brickwork and the efficiency of modern façade construction. However, design variations unique to individual systems means standard cavity fire barriers may not always be enough, making application-specific barriers an important consideration.

Commonly used on refurbishment projects where full depth bricks are impractical, brick slip cladding systems are rapidly being adopted for mid- to high-rise new build projects as a way to achieve traditional aesthetics that are compatible with both modern methods of construction, such as drained and back ventilated (DBV) rainscreens and non-masonry substructures, and current fire safety and energy requirements. 

However, mechanical-fix brick slip systems can differ widely in design, making it difficult for a standardised approach to passive fire protection. For example, some systems use a ‘clip in’ rail fix and others a ‘dovetail’ fix, which present interfacing complexities.  There can also be the added challenge of the irregular cavity sizes within the void created by the profile of the brick tiles, if not using a flat backed system. The cross section of the tile can include a profile or ‘frog’, these small, indented areas between each tile can be difficult to seal effectively using conventional vertical and horizontal cavity barriers. Even with flat-backed systems, there can be hidden voids behind carrier rails. In the past, the solution has been to extensively notch and scribe full fill cavity fire barriers onsite to match the system’s inner profile. However, this approach is time-consuming, inconsistent, and often lacks supporting fire test evidence.

Bespoke-for-brick-slip cavity barrier solutions

Due to the nuances and variations within brick slip systems, there can be insufficient evidence that standard cavity barrier solutions will provide the right performance and protection for the full façade system. Therefore, the onus is on the industry to provide architects and façade designers with dedicated passive fire protection that has been appropriately designed, developed and independently tested for use with the intended system.

Passive fire protection for brick slip systems typically comprises horizontal partial fill ‘open state’ cavity barriers (OSCBs) and vertical full fill barriers fixed to the inner construction. In fire, the integral intumescent strip on the open state barrier’s leading edge activates at a critical temperature (typically around 130°C) and ‘exfoliates’ (expands) to meet and mould to the face of the external leaf whilst the vertical barriers prevent lateral fire spread.

Some passive fire manufacturers have already developed effective bespoke barrier solutions for common brick slip system types in the UK, which are not only supported by primary test data and third-party certification required for demonstrating compliance but also bespoke technical advice and an array of supplementary test data that takes into consideration different factors such as rail types, substrates and pipe penetrations. This means that architects and specifiers can better understand risk factors for more informed decision-making and gather sufficient evidence to demonstrate compliance with the applicable regulations whilst engaging with their technical services to ensure the cavity barrier solutions chosen is suited to brick slip system and application conditions. 

Additionally, where test data may be lacking, some passive fire manufacturers with UKAS accredited in-house test facilities can work collaboratively with project teams to engineer their cavity barriers to overcome the fire safety, moisture egress and ventilation challenges presented by the individual characteristics of a specific system. This not only provides assurance that the OSCBs will achieve a robust seal between the inner construction and outer brick slip, with no small gaps left for flames and smoke to migrate through but also provides important test data critical for demonstrating compliance for that specific system.

It is also worth noting that passive fire protection solutions tailored for brick slip façades can also carry practical benefits too. For example, projects teams have found that vertical cavity barriers with a lamella core can be installed under increased compression and detailed accurately around interfaces using only basic tools. This means that there is no need to install intermittent intumescent strips that run vertically between each rail. This not only reduces the amount of material that needs to be specified and costed but also speeds up installation—enhancing the project efficiency benefits of brick slip systems.

Give standard solutions the slip

Ensuring the passive fire protection of façades is crucial for regulatory compliance and the long-term safety and endurance of any building project. Choosing cavity barrier solutions that have not only be developed to meet the demands of this application and also tested in conjunction with specific brick slip systems created by various façade manufacturers can help to provide clear and data-backed assurance that the façade as a whole can withstand the spread of fire.

Learn more about Siderise’s solutions for brick slip façades.

For enquiries specifically relating to Ash & Lacy NaturAL X and Mechslip systems, please contact Siderise technical services at technical.services(Replace this parenthesis with the @ sign)siderise.com