FAQ: Frequently Asked Questions – SFS

voestalpine Metsec Steel Framing System (SFS) is a fast-track metal (galvanised steel) stud panel framing system providing a carrier for insulation, exterior cladding and interior boarding. Cold-rolled galvanized steel sections are typically supplied to site as individual components which are assembled in-situ using screwed connections. Components can be supplied pre-cut to required lengths or cut as needed on site.

Steel framing systems are used in a wide range of applications including:

• Infill walling.
• Continuous walling.
• Load-bearing structures.
• High-bay walling.
• Modular and offsite construction

These applications can be applied to different sectors across the construction industry, including:

• Student accommodation
• Residential developments
• Hotels
• Healthcare facilities
• Education buildings

The suitability of each solution depends on project-specific structural, fire, acoustic and thermal requirements.

Non-load bearing SFS, often referred to as infill, is primarily designed to support façade systems and transfer wind loads back to the primary structure.

Load bearing SFS is a complete frame system consisting of roof, floors and walls, without the need for a primary hot-rolled or reinforced concrete frame.

Infill SFS is constructed from the floor to soffit of the primary structural frame to ‘infill’ the external wall zone. Primary frame deflection is accommodated with a suitable deflection head detail, such as voestalpine Metsec’s patented slotted head track. Infill is generally the more economical framing solution.

Continuous SFS is typically constructed on the outside of the building so the walling oversails the edge of the primary structure, with the SFS studs fixed via cleat, such as the voestalpine Metsec Universal Cleat. Continuous walling maximises the available floor area of a structure.

High bay walls are a high performance SFS system single span internal walling system used to provide high separating walls for factory units or atriums. As they are often constructed within hot rolled steel portal frames, the amount of primary frame deflection that needs to be accommodated can be much greater than required for infill panels. The voestalpine Metsec SFS high bay walling system offers lightweight separating walls up to 20m high.

SFS sections are C profile studs which range from 90mm to 350mm deep, and are formed from steel 1.2mm-3.0mm gauge (thickness). Full details of the section range are available in the voestalpine Metsec SFS Specification Manual

Metsec SFS sections are manufactured from pre-hot dipped galvanised steel with Z275 coating. Z275 coating means 275 grams of zinc per square metre summed over both faces of the steel strip, this corresponds to approximately 0.02mm overall thickness of zinc per face. A reduced range of sections are also available with a thicker Z600 coating.

Metsec SFS sections are primarily manufactured from pre-hot dipped galvanised steel with a minimum yield strength of 450N/mm².

Load bearing capacity tables for compressive resistance and buckling resistance are available in the voestalpine Metsec SFS Specification Manual.

Span/Load tables for wind loads between 0.5kN/m² and 2.0kN/m² are available in the voestalpine Metsec SFS Specification Manual.

When used in a “warm frame” environment, SFS sections achieve a design life in excess of 60 years. For further guidance for steel with different exposure conditions, consult the Steel Construction Institute publication ED022 – Durability of Light Steel Construction

The galvanised zinc coating protects the steel in two ways. First, it acts as a physical barrier, limiting contact between the steel, moisture and oxygen. Secondly, zinc is sacrificial to steel, so at small scratches, cut edges or fixing penetrations the surrounding zinc corrodes preferentially, helping to protect the exposed steel. Durability remains dependent on the coating thickness, exposure conditions and effective control of moisture ingress or condensation.

Damaged areas of corrosion protection must be reinstated with an appropriate zinc-rich paint. Local areas with exposed edges of steel (ie. cut ends, bolt holes, tek screw penetrations) are protected by sacrificial loss of the zinc coating and require no further attention.

All voestalpine Metsec sections are manufactured with a hot dip galvanised coating to ensure the durability of the frame for internal applications not directly exposed to moisture. Control of moisture ingress and condensation is essential and should be accounted for in design and construction.

Steel is classified as Euroclass A1 and is therefore non-combustible. However, the relevant consideration is the fire resistance of the complete SFS wall assembly, assessed using tests such as BS EN 1364-1, rather than the reaction-to-fire classification of individual components under BS EN 13501-1.

Duty holders are increasingly expected to demonstrate not only product performance but also how performance claims can be verified.

Traceability enables stakeholders to understand:

• What system was specified
• Which components were used
• What evidence supports performance claims
• Whether substitutions have occurred
• What maintenance or future modifications may affect performance

Traceable information supports compliance, accountability and effective building management.

The Golden Thread requires accurate, accessible and up-to-date information to be maintained throughout the building lifecycle.

For SFS this may include:

• Design calculations
• Structural models
• BIM information
• Fire test references
• Junction details
• Installation guidance
• Declarations of Performance
• Change control records
• Product traceability

The objective is that future designers, building owners, accountable persons and regulators can understand exactly what was specified, installed and evidenced.

As part of the Golden Thread, accurate digital information is becoming increasingly important. BIM allows design teams to coordinate structural, architectural and services information whilst improving information management throughout the project lifecycle.

voestalpine Metsec is the first tier two organisation globally to be awarded the BSI Kitemark for its BIM capabilities and tier 2 designer and manufacturer complying with BIM Level 2 for Design and Construction in the UK accredited by the BSI.

Questions worth asking include:

• Is the system supported by UKAS-accredited testing?
• Can performance claims be traced to supporting evidence?
• Does the manufacturer provide in-house engineering?
• Is BIM information available?
• Has the product information been verified through CCPI?
• Are junction details supported by evidence?
• Is there a clear Golden Thread approach to documentation?
• What warranties are available?

These questions help assess the strength of the technical offering rather than simply comparing product specifications.

Every building presents unique design challenges. The performance of a steel framing solution is influenced by:

• Building geometry
• Wind loading
• Cladding type
• Structural movement
• Fire strategy
• Buildability considerations

An in-house engineering team can coordinate these requirements into a complete system rather than treating each design challenge independently.

Metsec’s design service includes chartered structural engineering expertise, BIM support and project-specific detailing.

The Code for Construction Product Information (CCPI) was developed to improve the quality and transparency of construction product information.

CCPI focuses on ensuring information is:

• Clear
• Accurate
• Accessible
• Up to date
• Unambiguous

For specifiers and duty holders, this provides greater confidence that published information can be relied upon throughout the design and construction process.

Metsec’s SFS framing systems have achieved CCPI verification, demonstrating a commitment to transparent and evidence-based product information.

A building is made up of interfaces, not isolated products.

Traditional fire testing often focuses on the performance of individual wall constructions. However, real buildings include numerous junctions between external walls, compartment walls, floors, roofs, windows and structural elements.

These interfaces can represent critical points within the fire strategy. Even where individual components have been tested, the performance of the junction between them may not be fully understood without additional evidence. That is why Metsec continues to invest in testing representative junction details, helping specifiers and contractors understand how complete assemblies perform rather than relying solely on assumptions about individual elements.

Not all wall constructions are symmetrical, and where wall constructions are asymmetrical, performance from one side may not be the same as performance from the opposite side.

If an external wall is at a boundary to an adjacent structure, it is a requirement of Approved Document B and performance from both faces is critical to demonstrating compliance.

For load bearing walls, it is a requirement of Approved Document B that external walls are tested from both directions, regardless of whether it occurs on a boundary.

Ask for:

• Fire test references
• Classification information
• Assessment documents
• System build-up details
• Component schedules
• Installation requirements

Evidence should be clearly traceable to the actual system being specified and installed.

Where supporting evidence cannot be identified or linked to the claimed system, further investigation may be required before relying on the performance claim.

The Building Safety Act places significant emphasis on accountability and information management.

Duty holders increasingly need to demonstrate:

• What was specified
• What was installed
• What evidence supports it

Traceable systems, documented test evidence, BIM information and controlled documentation all support this process and help maintain the Golden Thread of information throughout the building lifecycle.

You should ask:

• Is the system CCPI verified?
• Can I see the fire test references?
• Are junction details supported by evidence?
• What information supports Building Safety Act compliance?
• Is BIM information available?
• Does the manufacturer provide in-house engineering design?
• Is there a through-wall warranty available?
• How are product changes controlled and communicated?
• How can system performance be traced back to test evidence?

The answers to these questions will often tell you more about the robustness of a manufacturer’s technical offering than a product datasheet ever will.

Not all evidence carries the same weight. When assessing the suitability of a steel framing system, consideration should be given to the quality, applicability and traceability of the evidence supporting a performance claim.

A typical hierarchy of evidence may include:

• UKAS-accredited fire testing
• Classification reports
• Extended Application (EXAP) reports
• Third-party assessments
• Engineering judgement
• Manufacturer declarations

The closer the evidence is to the proposed installation, the greater confidence can generally be placed in the claim. A clear hierarchy of evidence also supports Building Safety Act obligations and helps maintain the Golden Thread of information throughout the lifecycle of a building.

Yes. SFS sections are UKCA marked in accordance with BS EN 1090, where applicable to the structural components being supplied.

Metsec operates a certified Factory Production Control process for the manufacture of structural cold-formed steel components. This supports UKCA marking and provides traceability of material, manufacturing control and compliance with the relevant execution requirements.

The Declaration of Performance for Purlins and Framing sections is available from the Metsec downloads area.  

100% of the steel sections can be recycled at the end of use or life.

Add figures

Add figures

Quality, Health, Safety and the Environment are considered to be of utmost importance and voestalpine Metsec shall actively promote and administer a strong Quality, Health, Safety, Environmental and Ethical culture amongst staff, visitors and sub-contractors.

To assure these objectives are realised, voestalpine Metsec plc have established an Integrated Management System in accordance with PAS 99: 2012, which incorporates the requirements of BS EN ISO 9001 for Quality Management, BS EN ISO 14001 for Environmental Management, and ISO 45001 for Health & Safety Management.

Metsec Decarb incorporates steel produced using manufacturing processes designed to significantly reduce embodied carbon compared with conventional alternatives. Decarb solutions are available across Metsec product ranges, helping support project sustainability targets without compromising performance.

Yes. Steel framing systems can support embodied carbon reduction strategies through efficient structural design, optimisation of material use and the availability of lower embodied carbon steel alternatives such as Metsec Decarb.

Steel Construction Institute (SCI) publication SCI P448, Embodied Carbon of Light Steel Frame Infill Walls summarises how SFS can contribute to lower embodied carbon buildings where it replaces heavier masonry infill wall solutions within a suitable structural frame. In the SCI study, light steel frame infill walls had a gross weight of 96 kg/m² GFA, compared with 274 kg/m² GFA for blockwork, a reduction of approximately 65%. This reduced wall weight can also offer secondary savings in the primary frame and foundations, although those savings were not included in the study’s foundation design comparison.

The embodied carbon benefit is also material. The assessed light steel infill wall build-up was 58 kgCO₂e/m² GFA, compared with 80 kgCO₂e/m² GFA for blockwork, meaning the blockwork wall option was around 38% higher in embodied carbon. At whole building structure level, including the reinforced concrete frame, floors, roof, stairs and core, the scheme using light steel infill walls was approximately 10% lower in embodied carbon than the comparable blockwork scheme.

These reductions are achieved primarily through efficient structural form, low self-weight and material optimisation. The Module D credit for light steel infill walls was reported as -10 kgCO₂e/m², compared with only -1 kgCO₂e/m² for blockwork, reflecting the future recycling potential of steel. Metsec Decarb steel may provide a further opportunity to reduce embodied carbon, subject to project-specific specification, EPD data and the adopted whole-life carbon assessment scope.

Yes. Metsec provides Environmental Product Declarations for its purlins and framing products, including a third-party verified EPD for standard steel purlins and framing, and a separate EPD for Metsec Decarb purlins and framing. These declarations provide independently verified environmental impact data in accordance with recognised EPD standards and can be used to support embodied carbon assessments, specification decisions and project sustainability submissions.

The current Metsec EPD’s is available from the Metsec downloads area. Project teams should always use the latest published EPD applicable to the specified product range.

voestalpine Metsec can offer product warranty for our components, collateral design warranty for our engineering services and our MetWALL Perform performance warranty for our specified systems.

MetWALL Perform is the industry leading 30-year performance warranty covering fire, thermal, acoustic and structural performance. Our Warranty is based on the wide-ranging performance testing and assessment, and sits in addition to our collateral design warranty; Metsec’s own product warranty and PI insurance.

A product warranty typically relates to an individual component.

A through-wall warranty is a performance warranty that considers the complete wall construction and how the various components work together as a system.

For designers and developers, this provides greater confidence that performance has been considered at a system level rather than on a component-by-component basis.

MetWALL Perform provides this system-based approach to performance assurance

Yes. voestalpine Metsec carries professional indemnity insurance for its design-related activities. A copy of our £5m professional indemnity insurance certificate is available from the Metsec download area. Project teams should refer to the current published certificate for policy details, scope of cover and any applicable limitations.

Design responsibility carries risk. Professional indemnity insurance can provide assurance that design services are supported by appropriate cover should issues arise relating to professional design activities.

Metsec SFS designs are supported by professional indemnity insurance and collateral warranty options, providing additional confidence for clients and project teams.

Buildings are constructed from systems, not individual products.

A single component may perform perfectly whilst the overall wall assembly fails to meet expectations if interfaces, compatibility or installation requirements have not been fully considered.

System warranties and tested wall solutions provide greater confidence that the complete assembly has been considered rather than individual products being assessed in isolation.

The performance of a building may need to be supported for decades after construction.

When selecting a supplier, designers and developers may wish to consider:

• Long-term business stability
• Professional indemnity cover
• Warranty support
• Technical resource
• Product continuity
• Ongoing compliance support

A financially stable organisation is often better positioned to continue supporting projects, warranties and technical enquiries throughout the life of the building.

Metsec forms part of voestalpine, an international steel and technology group, providing customers with confidence in long-term support and technical capability.

Steel framing is not an off-the-shelf product. Every project presents different requirements relating to:

• Wind loading
• Building geometry
• Structural frame movements
• Façade loads
• Fire strategy
• Buildability

Manufacturers with dedicated in-house design teams can provide a coordinated solution that considers both product capability and project-specific requirements.

Metsec’s design team includes chartered structural engineers and specialist SFS designers, enabling design, detailing and technical support to be delivered from a single source.