What can we learn from Gateway 2 Rejection Notices?
The SFE recognises that one of the biggest questions and challenges faced by façade engineers is what information should be submitted for Gateway 2 (GW2) – the key gateway submission for all Higher Risk Building (HRB) projects that must be passed before construction can commence. The legislation currently leaves the content of the building regulations compliance statement and supplementary design information open to the project teams to determine the level of information that is required to demonstrate the design and compliance of the façade to the Regulator.
Members of the SFE have now seen a number of anonymised rejection notices from the Regulator for GW2 submissions. The authors of this article would note that they have not seen or contributed to the original submission to the Regulator, so are not aware of what was submitted, but these rejection notices provide us with valuable insight into the expectations of the reviewers within the Building Safety Regulator (BSR) and the reasons for the rejections due to the façade.
Reasons for rejections related to the façade from these notices are:
Design Maturity
A number of the submissions were rejected due to incomplete façade design. Generally this was due to the submission only including design intent, and referring to final contractor design that would follow later, presumably assumed to occur within Stage 5 as has been common. Rejections also referenced notes within the submissions referring to the potential for change – such as of design or loading – that may occur during construction, again implying a level of uncertainty in the final design. In one notice the reviewer cited the lack of final product selection for a long list of façade components, including wall ties as being a key reason for rejection.
Part A – Structure, and coordination with Structural Engineers
Parts of the submissions related to façade aspects of Part A of the regulations were rejected due to:
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Lack of coordination or contradictory assumptions between the façade and structural information around support strategies and loading.
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Clarity on how façade loads have been derived. Lack of clarity on how load application locations had been cross-referenced to the façade design.
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Contradiction between written descriptions of structural support strategies of the façade and what is implied by the submitted drawings.
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Wind loading calculations being insufficiently detailed, such as not considering funnelling, or not using the detailed directional method.
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Incomplete design of structural elements that often sit between façade and structural packages, such as balconies and secondary steelwork.
Part B – Fire, and coordination with Fire Engineers
Parts of the submissions related to façade aspects of Part B of the regulations were rejected due to:
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Insufficient information about the fire performance and compliance of façade system components and green roof systems. The reviewers cited the lack of specifications for all materials to demonstrate their compliance, listing a range of façade components.
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Gaps in coordination between fire strategy and façade design – in one report the reviewer identified the fire strategy requiring smoke vent AOVs in the façade, yet no AOVs were shown within the façade information. Fire strategy also showed requirement for fire resistant façades within re-entrant corners of the building at compartment wall interfaces, yet this was not reflected in the architect’s information.
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Non-compliances with Regulation 7 within the façade details. One submission cited combustible roof insulation extending within the façade at a roof interface beyond the limits of Reg.7.
Part K
Parts of the submissions related to façade aspects of Part K of the regulations were rejected due to:
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Insufficient information provided on how Part K was being met. The reviewer expected evidence of how all parts of the regulations were being met, including safe opening of windows, protection against trapping or collision with doors and windows, glazing types proposed, etc.
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Insufficient information provided about how windows would be cleaned safely.
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Design of AOVs not showing how protection would be provided against falling when they are activated.
Other regulations
Other reasons for rejection were:
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A number of the submissions included no explanation of how Part C was being met with the façade systems proposed.
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A submission did not adequately explain how the façade was meeting Part L and showing therefore how the façade design had been coordinated with the Part L energy model and assessments.
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Lack of information of how Part Q was being met with the façade design, such as security devices to opening windows.
What do these rejections teach us?
A key theme of these rejection notices is the need for the design to be complete at Gateway 2 (GW2), and that if this requires the input of contractors to complete the design that this must also be completed before GW2. It is clear that where the submissions cited further design to follow, or that design was performance based only for completion by contractors post GW2 that these were reasons for failure. These notices also show the level of detail the Regulator is expecting in terms of naming of products or materials for all façade components, and evidence of how these products or materials meet the regulation requirements. If the design is incomplete, there is a high risk that the submission will be rejected, or Major Changes occurring in construction.
A common theme across the notices was also the lack of explanation by the submitter of how regulations were met. In many instances it seems that design information or calculations were submitted without explaining how they demonstrate compliance. There may be an expectation here on the part of the submitter that the Regulator will tell them that they comply, but the comments in these notices make clear that the Regulator expects the design team to explain clearly how they deem compliance to be achieved.
The comments also show a general lack of coordination across the submissions – missing cross-referencing, conflicting information (e.g. between façade and structural information), and assumptions of information being produced “by others”. Due to the timing of these reports, it is likely that the submissions were prepared when the role of the BR-PD and the processes to be used by them were in their infancy, and that therefore the lack of an overarching coordinated Regulation Compliance Statement and relevant requirements tracker contributed to the lack of clarity in the submission and the consequent failure.
In summary:
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The façade design must be complete at GW2. If this requires the input of contractors to complete design or specify products, this must also be provided in GW2.
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The design must be compliant with the Regulations.
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Submissions must clearly explain how all functional requirements of the regulations are being met. We should not expect the Regulator to interpret the design themselves to confirm compliance – we must explain our strategy clearly to give them the opportunity to review.
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The submission must show how the building holistically meets the regulations. Façade design information must reference its context within the total building design and be coordinated with other interfacing aspects of the submission to remove contradictions, ambiguities and gaps.
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The Regulator will review submissions in detail – we should be prepared for this scrutiny and prepare information that has a clarity in design, decision making and compliance.
The SFE and CWCT ask members to please share further examples they see of reasons for GW2 submissions being rejected due to aspects of the façade design. this will help us develop more detailed advice on the content we should provide for GW2 submissions. Please share your feedback through the SFE website: https://www.cibse.org/get-involved/societies/society-of-facade-engineering-sfe/building-safety-act/