Overview
ISO 13785-1:2002 - Reaction-to-fire tests for façades (Intermediate-scale test) specifies a screening test method to assess the reaction-to-fire behaviour of façade and cladding materials when exposed to an external fire scenario with flames impinging directly on the façade. Intended primarily as a screening method for producers, the intermediate-scale test helps eliminate systems that would fail the larger end-use test (ISO 13785-2:2002). The standard covers test principle, apparatus, specimen construction, instrumentation, procedures, and reporting - with a focus on vertical, non-free‑standing façades added to existing external walls.
Key topics and technical requirements
- Scope & purpose: Screening reaction-to-fire performance of façade/cladding systems (not for structural strength assessment).
- Test principle: Flames from a propane burner impinge on a 90° re-entrant corner façade specimen to simulate a severe venting fire scenario.
- Test facility: Three-wall specimen support frame, sample holder, and draught screens in a ventilated laboratory.
- Fire source: Propane gas burner (specified burner geometry and even gas flow) delivering a heat output of (100 ± 5) kW; safety controls and leak detection required.
- Specimen construction: Representative assembly including panels, joints, fixings, battens and insulation; sample areas defined (1.2 m × 2.4 m and 0.6 m × 2.4 m) and typical joint locations.
- Instrumentation: Surface and cavity thermocouples at specified positions; heat flux meters (Gardon or Schmidt‑Boelter types) with specified target characteristics.
- Procedure & results: Observation of flame spread, mechanical behaviour, internal temperatures and heat flux; results used for screening and comparative evaluation.
- Safety note: Tests can produce smoke and toxic gases; adequate extraction, extinguishing means and safety systems are mandatory.
Applications
- Manufacturers / producers: Pre‑screen façade systems to reduce the number of full-scale tests required.
- Test laboratories: Conduct intermediate‑scale reaction-to-fire trials as part of product development or certification workflows.
- Fire safety engineers & consultants: Use test data for comparative assessment of façade fire risk and system selection.
- Regulators / specifiers: Reference as part of compliance strategies where intermediate screening is appropriate.
Related standards
- ISO 13785-2:2002 - Large-scale test for full end‑use evaluation.
- ISO 13943:2000 - Fire safety vocabulary (terms and definitions used).
- IEC 60584-2 - Thermocouple tolerances (instrumentation accuracy).
- ISO/TR 3814 - Background on reaction-to-fire testing theory.
Keywords: ISO 13785-1:2002, reaction-to-fire tests, façades, intermediate-scale test, façade cladding, fire safety, screening method, propane burner, thermocouples, heat flux.