MAXIMISING EFFICIENCY IN FACADE PROJECT DELIVERY

Jon Knaggs, Technical Manager for Industrial Lightweight Construction at EJOT UK, explains why the ETA is crucial for compliance and key to faster, lower-risk project delivery.

Higher performing and better quality building façades rely heavily on the right fastening and framing systems. But how do you establish which products and systems will meet the brief with confidence, as well as minimising non-compliance risks and delays when the façade design is reviewed by building control or – in the case of higher risk buildings (HRBs) – the Building Safety Regulator?

Most certification and approval schemes used by manufacturers to demonstrate that individual products meet the declared performance have, at their core, minimum standards. These are determined and strictly governed by statutory frameworks, building laws and collaborative technical committees.

However, façades are bespoke and often complex, and there is no single stamp of approval available to independently declare that a design that combines multiple BS or EN certified products will work with any degree of certainty. This is why the design of multi-layered rainscreen – or rear-ventilated façade –systems requires not only a thorough review of these individual components, but also assessment or testing under a scheme that considers the complete system’s performance.

WHY THE ETA CARRIES WEIGHT

A European Technical Assessment (ETA) is an independent, documented evaluation of the performance

characteristics of a construction product or system. Fundamentally, the ETA serves as a voluntary route for manufacturers to obtain CE marking for products where no harmonised European standard (hEN) fully applies.

Each ETA is underpinned by a Declaration of Performance (DoP) and a European Assessment Document (EAD), the latter acting as a custom rulebook that defines exactly how the manufacturer must assess the system within set application parameters. The result is a vetted, independently verified engineering baseline rather than a blanket approval for use on any specific building.

ETAs vary widely in depth, so the level of detail included is significantly important. CROSSFIX is a complete stainless steel façade substructure system supported by an ETA (ETA-21/0756) which assesses the kit as a whole, not just the individual parts. Crucially, its performance is assessed at system level.

WIND LOADING

Under EAD 090034-00-0404 the system’s wind resistance is calculated from the independently tested resistances of every component, then validated by a load test on the fully assembled kit rather than on isolated parts. For that validation, the complete assembly is mounted on a rig exactly as installed, then subjected to uniformly distributed wind suction and pressure applied in defined steps until significant irreversible deformation occurs. The weakest configuration is chosen deliberately, so the figure reflects a worst case scenario rather than a best one.

FIRE DESIGN

The CROSSFIX system is classified Euroclass A1 to EN 13501-1, the highest non-combustible rating, with no contribution to fire from wall through bracket to rail. For a building reviewed against the Building Safety Act, a non combustible substructure removes one more fire-safety variable.

AUDITABLE SCRUTINY

Behind the figures sits a conformity system called Assessment and Verification of Constancy of Performance (AVCP) System 2+, under which a notified third-party body carries out continuing surveillance of factory production control. As a result, it is a clear way to answer a question that the Gateway process implicitly asks: how do you know the product delivered to site matches the one that was tested?

MATERIAL CHARACTERISTICS

The ETA also confirms that the CROSSFIX brackets are stainless steel A2 or A4 with 6063-T66 aluminium profiles, assessed for a working life of at least 25 years under the stated installation conditions, with the real service life of the stainless system in normal use expected to be considerably longer.

DESIGNING OUT RISK

BEFORE GATEWAY 2

For project teams to leverage the maximum benefit from CROSSFIX’s robust ETA, EJOT provides support to ensure it can be correctly applied. For example, to get ahead of the evidence demands of Gateway 2, EJOT’s engineering team produces a preliminary dimensioning on a representative reference area of a project.

This generates a traceable calculation package that evidences material requirements and gives designers early, defensible confirmation of bracket type, spacing and feasibility. It supports the project structural engineer’s analysis rather than replacing it, which keeps responsibilities clear under the Building Safety Act.

That same engineering depth extends to the substructure anchoring fixing, which must be verified separately. Drawing on more than 60 ETA assessments across its fastening range, EJOT can specify and prove the anchor’s performance in concrete, masonry, steel, timber or otherwise, closing a gap that teams often leave open. An assumed anchor is exactly the kind of missing evidence that triggers a Gateway 2 query. CROSSFIX’S ETA also supports compliance with NHBC Standards for warranty-backed residential work, where the same discipline around documented performance applies.

EFFICIENCY BY DESIGN

CROSSFIX’s contribution to improving efficiency in compliance is not the only way the system aligns well with a changing construction sector. The system can also streamline the design and installation processes due to its innovative design.

The system’s core ‘Konsole’ bracket works with both vertical and horizontal profiles, so one bracket family spanning 40mm to 400mm of protrusion covers different elevations. Fewer component types means simpler design with reduced risk of the wrong bracket reaching site. The optional ‘Powerkey’, fitted to fixed point brackets, more than doubles fixed-point resistance in the assessed vertical system while also providing tolerance compensation, twisting up to two revolutions to take up anchor inaccuracies.

Thermal performance of a façade is enhanced when using CROSSFIX because of the system’s stainless steel composition. This material conducts up to 15 times less heat than aluminium, meaning each console introduces a significantly smaller point thermal bridge into the façade. In addition, as the system’s high strength results in fewer brackets across the elevation versus other systems, its cumulative contribution to the wall’s thermal transmittance falls further still.

This enhanced thermal performance is reflected in CROSSFIX holding Passive House Institute certification with point thermal bridge coefficients (χ-values) as low as 0.0095W/K per bracket, verified across all five evaluated cladding load classes from lightweight aluminium panels through to heavy ceramics.

In practice, a lower bracket-induced thermal penalty can allow a reduction in insulation thickness within the wall build up, either increasing net internal area or reducing the overall façade zone depth on constrained urban sites where the building envelope must remain within the boundary line.

CROSSFIX is also backed by a third party verified Environmental Product Declaration (EPD) reporting embodied carbon of 16.2kg CO2-eq per m² at cradle-to-gate (modules A1–A3 for the 240mm single-layer system), with a further 11.6kg CO2-eq credited back through material recovery at end-of-life.

Over 90% of the system by mass is recyclable and it incorporates 37% post consumer recycled content, contributing to LEED v4 Materials and Resources credits. The overall result for design teams is a single system that answers structural, fire, thermal and sustainability questions from one manufacturer.