ISO 5658-4:2001

Overview

ISO 5658-4:2001 - Reaction to fire tests - Spread of flame - Part 4 specifies an intermediate-scale test method for measuring the vertical spread (upward and downward) of flame over a vertically oriented specimen. The method exposes a conditioned specimen to a defined field of radiant heat flux with non‑impinging pilot flames to measure ignition time and flame‑front progression. The test also permits measurement of lateral spread, observation of flaming drips/debris, and can be modified for some profiled surfaces to represent end‑use conditions. This procedure is intended for comparative performance data for materials, composites or assemblies used as exposed wall surfaces and other vertical construction products.

Key topics and technical requirements

• Test principle: vertical specimen adjacent to a gas‑fired radiant panel; pilot burner ignites volatiles; record ignition time and flame front travel vs time.
• Orientations: upward and downward vertical flame spread; recognizes enhanced upward spread on surfaces >20° from horizontal (e.g., sloping surfaces, stairs).
• Specimens: conditioned representative pieces; may include substrates, backing boards or air gaps to represent end use.
• Measured outputs: ignition time, vertical spread distances/times, optional lateral spread, flaming drips, damaged/burned area. Mass loss, heat release and smoke can be measured with appropriate hood/duct (e.g., ISO 9705).
• Apparatus and calibration: defined radiant heat field, calibrated heat flux meters, pilot‑flame adjustment and verification, test enclosure requirements.
• Safety and limitations: annexed safety precautions for toxic combustion products. The standard explicitly warns it should not be used alone to appraise overall fire hazard under real fire conditions.

Applications and practical value

• Provides comparative performance data for wall linings, claddings, coatings, laminates, sandwich panels and other vertical construction products.
• Useful in product development, quality control, regulatory compliance evaluation, and material selection where vertical flame spread behavior matters (e.g., escape routes, stairways, internal linings).
• Helps fire safety engineers and manufacturers assess early‑stage fire behaviour representative of a single burning item (e.g., wastepaper bin, upholstered chair) in an enclosure.

Who uses this standard

• Fire testing laboratories and conformity assessment bodies
• Product manufacturers (building materials, wall coverings, composites)
• Fire safety engineers, specifiers, architects and building code authorities
• R&D teams performing comparative flame‑spread evaluations

Related standards

• ISO 5658 series (see Parts 1 and 2)
• ISO/TR 11696‑1 and ISO/TR 11696‑2 (application of reaction‑to‑fire results)
• ISO 13943 (fire safety vocabulary), ISO/TR 14697 (substrate guidance)
• ISO 9705 referenced for heat release/smoke measurement

Keywords: ISO 5658-4:2001, reaction to fire tests, vertical flame spread, intermediate-scale test, radiant heat, pilot flame, construction products, wall linings, ignitability, flame front.