ISO 6940:2004

Overview

ISO 6940:2004 - "Textile fabrics - Burning behaviour - Determination of ease of ignition of vertically oriented specimens" defines a laboratory method to measure the ease of ignition of vertically oriented textile fabrics and multi-component textile products (coated, quilted, multilayered, sandwich constructions, etc.) when exposed to a small, defined flame. The procedure quantifies how readily a specimen ignites under controlled conditions and reports a mean ignition time as the primary outcome. It is one of two related ISO methods for textile burning behaviour (see Related Standards).

Key topics and technical requirements

• Test purpose: Measure ease of ignition (minimum exposure time to obtain sustained combustion) for vertically oriented specimens.
• Specimen size & mounting: Cut specimens to 200 mm × 80 mm (±2 mm) and mount on a metal specimen holder using corner pins and spacer stubs to position the sample plane correctly.
• Ignition modes: Two procedures - surface ignition (flame applied perpendicular to the face) and bottom-edge ignition (flame applied to the lower edge at a defined incline).
• Burner & fuel: Uses a specified gas burner (Annex A) fueled by commercial-grade propane, butane, or propane/butane mixtures; burner geometry and flame reach/height are adjusted per the standard.
• Timing & measurements: Flame application times and afterflame times are measured with timing devices accurate to 0.2 s; mean ignition time is calculated as a weighted mean of individual ignition times.
• Sampling & repeats: Iterative testing with a minimum number of specimens - the standard describes using a set (e.g., 12 marked specimens) to obtain at least five ignition and five non-ignition outcomes; at least 10 specimens per orientation are normally required.
• Conditioning & atmosphere: Specimens are conditioned (standard specifies temperature and relative humidity) for at least 24 h prior to testing; tests are performed in controlled ambient conditions with low air movement to avoid influence on flame behaviour.
• Safety & construction: Equipment materials must resist corrosive combustion products; proper ventilation and operator safety measures are required.

Applications and users

ISO 6940 is used by:

• Textile and technical-fabric manufacturers for product development and quality control
• Independent testing laboratories performing flammability testing
• Regulatory bodies and safety engineers assessing compliance with fire-safety requirements
• OEMs specifying materials for apparel, furnishings, protective textiles, and industrial products where small-flame ignition performance is relevant

Practical uses include evaluating seam or trimming effects, comparing fabric constructions, and supporting material selection to reduce ignition risk.

Related Standards

• ISO 6941 - Measurement of flame spread properties of vertically oriented specimens
• ISO 4880 - Burning behaviour of textiles and textile products - Vocabulary

Keywords: ISO 6940, textile fabrics, burning behaviour, ease of ignition, flammability testing, vertically oriented specimens, mean ignition time, surface ignition, bottom-edge ignition.