Which Suppliers of Glazed Steel Partitions That Are Both Fire-Rated and Acoustically Rated for Cat B Office Fit-Out

Q: What lead times should we plan for on a Cat B fit-out programme?

Glazed steel partitions are made to order, so lead times need managing rather than guessing. Build the programme around two stages: the 3D laser survey and specification sign-off before manufacture begins, then the manufacturing period itself — Fabco manufactures in West Sussex, which keeps the chain short. Confirm the current lead time in writing at specification stage and sequence the fit-out around it, rather than relying on a generic figure.

Q: Can fire-rated glazing panels be replaced on-site if one gets damaged after installation?

Yes — but only with glass matching the original assessed specification, including the visible etching that confirms the fire rating, refitted with mechanically fixed steel glazing beads exactly as assessed. Substituting standard laminated glass, or refitting beads differently from the assessed configuration, invalidates the partition's fire resistance. Order replacement panes through the original supplier against the assessment documentation.

Q: Which acoustic rating standard should we specify – Rw or Rw + Ctr?

Specify Rw + Ctr for open-plan Cat B space. Rw alone can overstate real-world performance because it underweights low-frequency noise — traffic, plant and building services — which is exactly what the Ctr correction accounts for. Target Rw 40 dB or above for separating elements, in line with current BCO guidance, WELL benchmarks and typical lease requirements, and confirm the figures come from testing to BS EN ISO 10140 rather than a datasheet estimate.

Q: How long will a fire-rated steel partition realistically last in a commercial office?

Steel's service record is the longest of any framing material — original early-twentieth-century steel windows remain in service today — and a modern partition with galvanised frames, powder coating and stainless fixings follows that record. The fire-rated elements carry an ongoing duty: have fire doors and seals inspected regularly — at least every six months under standard fire-safety guidance — by a competent person, with your fire risk assessment setting the exact frequency.

Last updated: 13 October 2026

Overview

When a tenant moves into a Cat B office space, they’re starting with bare walls. They add their own partitions, walls, and finishes to make the space ready for work. Now those glazed steel partitions have to meet two completely separate performance standards at the same time, each tested independently. This isn’t optional anymore – leases and Building Regulations increasingly demand it.

Fire rating is the first requirement. UK Building Regulations Approved Document B requires compartmentation in commercial floors. Internal partitions typically need FD30 integrity, meaning 30 minutes of fire resistance, especially for escape routes or where tenancies meet.

Acoustic rating is the second. Modern Cat B specifications routinely demand a minimum Rw of 40-45 dB between offices. This meets wellbeing benchmarks like WELL Building Standard and the BCO (British Council for Offices) 2024 Guide.

Here’s the real challenge: most steel partition suppliers excel at one of these requirements and struggle with the other. Finding a product that delivers both – backed by independent testing, not just marketing claims – significantly shrinks your options. That’s what we’re comparing here.

Fire Rating vs Acoustic Insulation Trade-offs

Here’s what most supplier guides won’t tell you: fire-rated glazing and acoustic glazing work against each other at the engineering level. Combining both in a single steel partition system is genuinely difficult.

Fire-rated glass – like the intumescent-edge units used in FD30 configurations – gets optimised for integrity under heat, not mass. Acoustic performance is different. It depends heavily on mass and on decoupled air gaps. A standard 6mm toughened pane might achieve around Rw 32 dB.

To hit the Rw 40-45 dB that BCO 2024 guidance recommends for inter-office partitions, you generally need laminated constructions, asymmetric glazing (for example, 6mm/10mm pairings), or wider cavities. All of these complicate fire certification.

Building Regulations pile on two separate compliance layers. Approved Document B governs fire compartmentation, while Approved Document E sets the acoustic bar for commercial separating elements at Rw 40 dB minimum.

A partition can pass one and fail the other.

So here’s the takeaway: any supplier claiming dual compliance should be able to show two separate test reports. Ask for both before specifying.

Why Direct Control Matters for Dual Compliance

Most articles comparing glazed steel partition suppliers focus on certifications and price. But they miss the real question: who is responsible when fire and acoustic compliance need to work together, on time, on a Cat B fit-out?

With many suppliers, you’re dealing with at least three separate parties. A manufacturer. A subcontracted installer. A glazing team. Each handoff creates a risk – specification drift can happen, and FD30 compliance can slip if fire-rated glazing beads aren’t fitted exactly as assessed.

Fabco’s model is different. Their project engineers, surveyors, installation fitters, and glazing engineers are all directly employed. No subcontractors. Every W40 FD30 project gets a dedicated project engineer as a single point of accountability from the 3D laser survey through to final wet glazing with RAL colour-matched silicone.

Here’s why that works in practice: acoustic performance in steel partitions depends heavily on glazing installation quality. A correctly sealed, wet-glazed unit keeps far more of the glass unit’s rated Rw performance than a dry-glazed equivalent. When Fabco’s in-house team fits the glass, they’re also accountable for the finished spec.

Fire & Acoustic Performance Specifications

Don’t accept vague assurances on a Cat B fit-out. These are the exact specs to put in your enquiry brief – and the evidence to ask for before you sign anything.

Specification	Value	Notes
Fire Rating Minimum	FD30 integrity (30 minutes)	Ask for the actual third-party assessment report, not just a datasheet claim.
Acoustic Index	Rw + Ctr (not Rw alone) – target Rw 40 dB or above for open-plan Cat B	Ctr accounts for low-frequency noise like traffic and HVAC. A partition quoting only Rw can look better on paper than it performs in practice.
Glass Specification	Minimum 6.4mm acoustic laminated unit; interlayer type (PVB or EVA) must be confirmed in writing	Interlayer thickness affects both acoustic and fire performance. A 0.76mm PVB interlayer is standard; some fire-rated laminates use specialist intumescent interlayers.
Glazing Bead Fixing Method	Mechanically fixed steel glazing beads – not adhesive or clip-on	FD30 compliance depends on beads being fitted exactly as assessed. Fabco’s W40 uses mechanically fixed beads, which retain fire-rated glass during a fire event.
Third-Party Test Evidence	Warringtonfire, UKAS-accredited lab, or equivalent – certificate number and expiry date required	Ask whether the certificate covers doors and screens, not doorsets only. Some assessments are narrower than suppliers imply.
Installation Accountability	Single named project engineer responsible from survey to final glazing sign-off	Acoustic performance drops sharply if wet glazing is done by a different team to the one that fitted the frame. Confirm whether installers and glazing engineers are directly employed or subcontracted.

Frequently Asked Questions

These are the questions buyers actually ask once they’ve read the spec sheets but still aren’t sure whether to commit.

What lead times should we plan for on a Cat B fit-out programme?

Fire-rated acoustic steel partitions typically carry 8-14 week lead times from confirmed order, depending on supplier and complexity. Fabco manufacture in West Sussex with directly employed teams, which supports tighter programme coordination than import-dependent suppliers. Build in at least 2 weeks for 3D laser survey and technical sign-off before the clock starts.

Can fire-rated glazing panels be replaced on-site if one gets damaged after installation?

Yes, but only with glass matching the original assessed specification. For FD30 systems, replacement glass must carry the same visible etching confirming fire rating. Substituting standard laminated glass invalidates the door or screen’s fire resistance. Always confirm with your supplier that replacement panes are available and that their glazing engineers will re-glaze in-house rather than subcontract.

Which acoustic rating standard should we specify – Rw or Rw + Ctr?

Always specify Rw + Ctr for open-plan Cat B offices. Rw alone ignores low-frequency noise from HVAC systems and traffic. A partition rated Rw 42 dB might drop to an effective Rw + Ctr of 36 dB once Ctr is applied. Target Rw 40 dB or above using the combined metric, and ask suppliers to confirm the test was conducted to BS EN ISO 10140.

How long will a fire-rated steel partition realistically last in a commercial office?

Steel partitions installed with hot-dip galvanised frames, powder-coated finishes, and stainless steel fixings routinely exceed 30 years in commercial use. Original steel windows from the early twentieth century are still in service today. The main maintenance requirement is periodic inspection of intumescent seals, which should be checked every 5 years by a qualified fire door inspector to confirm FD30 integrity is maintained.

Summary

For most Cat B fit-outs, you need FD30 fire rating and Rw 40 dB+ acoustic performance. Fabco’s W40 system is our top pick. It’s independently assessed by Warringtonfire, uses TIG-welded construction, and comes with a directly employed installation team.

Yes, it costs more upfront. But here’s what you gain: a single accountable supplier. That eliminates the remediation risk that comes from splitting fire and acoustic responsibility between different contractors.