FAQ: Frequently Asked Questions – Dry Lining

Recent updates to BS EN 1364-1 – The European standard for fire resistance testing of non-loadbearing walls – have led to reductions in the maximum certified heights for certain dry lining systems. This change reflects a more rigorous approach to fire safety and structural performance.

Key reasons include:

Enhanced Fire Testing Protocols: The revised standard introduces stricter criteria for how partitions must perform under fire conditions, particularly regarding structural integrity and thermal insulation over time.

Realistic Simulation of Fire Exposure: Testing now better replicates real-world scenarios, including how taller partitions behave under thermal stress, which can lead to greater deflection or instability.

System-Specific Limitations: Some previously approved systems may no longer meet updated performance thresholds at their original heights without additional reinforcement or redesign.

Improved Safety Margins: Regulatory bodies have recalibrated safety margins to ensure tested systems perform reliably in worst-case conditions, resulting in more conservative height limits.

These changes are intended to improve safety and reliability across the industry. Designers and specifiers should consult the latest test reports and manufacturer guidance to ensure compliance with current standards.

No. Under BS EN 1364-1, fire resistance performance is specific to the exact configuration tested – including the type of stud used. You cannot claim fire performance for an I stud based on a test conducted with a C stud.

Why Stud Type matters

Different Geometry, Different Behaviour: I studs and C studs differ in shape, mass, and thermal response. These differences affect how the partition performs under fire conditions, especially in terms of structural integrity and insulation.
Configuration-Specific Certification: BS EN 1364-1 requires that all components – including stud type, board type, insulation, and fixings – match the tested setup. Substituting one stud type for another invalidates the test result.

How BRE Assessments can help
In some cases, assessments conducted by accredited bodies such as BRE (Building Research Establishment) may allow for performance claims beyond the original test – but only when supported by robust engineering judgment and comparative datum testing.

These assessments:

• Use datum tests to establish baseline performance for different stud types.
• Apply technical reasoning to justify equivalence or extrapolation between configurations.
• Must be specific, documented, and traceable to valid test data.

Acceptability for Building Control

Assessments must be issued by a recognised authority (e.g., BRE, Warringtonfire, UL) and clearly reference the original test data.
They must address the specific change – such as substituting a C stud with an I stud – and demonstrate that fire performance is maintained or improved.
Building control bodies may accept assessments if they are technically sound, properly referenced, and issued by a competent fire engineer or testing organisation.

Always consult with your building control officer before relying on an assessment. If in doubt, commissioning a new test may be the safest route to compliance.

No, not without proper assessment.

If a dry lining partition was fire tested without any insulation in the cavity, adding glass mineral wool – even for acoustic reasons – may affect its fire performance and invalidate the original test result.

Why this matters

• Fire tests are configuration-specific: BS EN 1364-1 requires that all components – including cavity insulation – match the tested setup. Adding insulation changes the thermal dynamics and could alter the fire resistance rating.
• Mineral wool may improve or impair fire performance: While glass mineral wool is non-combustible and often enhances fire resistance, its presence can also affect heat transfer, charring patterns, and structural behaviour – especially if not accounted for in the original test.

How BRE Assessments using Datum Tests can help
A BRE assessment can provide a technically justified route to compliance by:

• Referencing datum tests: These are baseline fire tests conducted on similar partitions with and without insulation. BRE uses these to understand how insulation affects fire performance.
• Applying engineering judgement: BRE experts assess whether the addition of glass mineral wool maintains or improves fire resistance, based on comparative data and thermal modelling.
• Documenting equivalence: If the assessment concludes that the modified partition performs at least as well as the original, it may be accepted by building control – provided the assessment is specific, traceable, and issued by a recognised authority.

What you should do

• Do not assume compliance: Adding insulation without assessment risks non-compliance with fire safety regulations.
• Request a formal assessment: Contact BRE or another accredited fire testing body to evaluate the modified partition.
• Share the assessment with building control: Ensure it clearly references the original test and justifies the change.

Not automatically. While both products may be classified as A1 (non-combustible) under EN 13501-1, fire resistance testing under BS EN 1364-1 is configuration-specific – meaning the exact product used in the test matters.

Why substitution isn’t always straightforward

• A1 rating ≠ Identical performance: The A1 classification confirms that a product won’t contribute to fire growth, but it doesn’t guarantee identical thermal or structural behaviour during a fire test.
• Variations in density, binder, and fibre structure: Different manufacturers’ APRs may have subtle differences that affect how heat transfers through the partition or how the system behaves under fire stress.
• BS EN 1364-1 requires tested configuration: If the fire test was conducted with a specific brand and type of APR, substituting it with another – even if A1 rated – technically invalidates the test unless supported by an assessment.

How a BRE Assessment using Datum Tests can help
BRE or another accredited body may issue a formal assessment to justify substitution, based on:

• Datum tests comparing multiple APRs
• Engineering judgement
• Traceable documentation

What you should do

• Do not substitute without assessment
• Share the assessment with building control