🧵 Ease of ignition of vertically oriented textile specimens — burner flame applied to the surface or bottom edge of a 200 × 80 mm specimen, iterative method (at least 10 specimens per direction), mean ignition time from a weighted mean; PN-EN ISO 6940

Materials and NDT PN-EN ISO 6940

Overview

WHAT THE STANDARD COVERS. ISO 6940:2004 (clause 1) specifies a method for measuring the ease of ignition of vertically oriented textile fabrics and industrial products — simple or composite (coated, quilted, multilayered, sandwich and similar) — subjected to a small, defined flame. The method assesses the properties of the product on flame contact under controlled conditions; the results are not transferable to situations with reduced air supply or exposure to large sources of intense heat. The influence of seams can be determined by placing the seam in the specimen so that it is subjected to the flame; trimmings are tested, whenever practicable, as part of the assembly with which they are or will be used. According to the introduction, it is one of two very closely related methods of test for the flammability of textile fabrics: this one determines the "ease of ignition" (vocabulary according to ISO 4880), the other measures the "flame spread time" (ISO 6941; a separate entry in this database). We read the text of the standard in the iTeh sample of ISO 6940:2004 (French text) from the title page through the foreword, introduction and clauses 1–7 up to and including 8.1, and in the iTeh sample of ISO 6940:2026 (English and French text) from the title page through the table of contents, foreword, introduction and clauses 1–3 up to the first sentence of clause 4.

DEFINITIONS AND PRINCIPLE (clauses 3–4). Flame application time — the time for which the igniting flame is applied to the specimen. The afterflame time (after removal of the ignition source) is measured to the nearest second, and times shorter than 1,0 s are recorded as zero. Ignition — initiation of combustion. Sustained combustion — burning of the specimen lasting 5 s or more after removal of the ignition source, or in which the flame reaches the top or a vertical edge in less than 5 s. The 2004 edition also defines the minimum ignition time — the shortest time of exposure to the ignition source that produces sustained combustion under specified conditions (3.5). Principle (2004 edition): a defined flame from a specified burner is applied to the surface or the bottom edge of vertically oriented specimens; the mean ignition time is determined from the weighted mean of the times from flame application to ignition of the specimens. The table of contents of the 2026 edition names both variants: procedure A — surface ignition, procedure B — bottom edge ignition.

APPARATUS (clause 5, 2004 edition). The mounting frame holds the burner and the specimen holder in the relative position of Figure 3. The burner (Annex A) is moved from a standby position — tip at least 75 mm from the specimen — to a horizontal or inclined operating position. Specimen holder: a rectangular metal frame 190 mm × 70 mm with a pin at each corner; pins of at most 2 mm diameter and at least 26 mm length (longer ones may be needed for thick or multilayer specimens); next to each of the four pins a spacer of 2 mm diameter and at least 20 mm length — the specimen lies at least 20 mm from the frame. Template: flat, rigid, with the specimen dimensions 200 mm × 80 mm, with holes of about 4 mm diameter at the corners, at the pin spacing. Gas: commercial propane or butane or their mixture (commercial propane preferred). Timers: one to control and measure the flame application time, settable at 1 s in 1 s steps, with an accuracy of 0,2 s or better; three with an accuracy of 0,2 s or better for the afterflame time — started preferably automatically at the end of flame application or on its removal and stopped manually.

PRECAUTIONS AND SPECIMENS (clauses 6–7, 8.1). Combustion products may be corrosive — apparatus made of fume-resistant materials. The volume of air must not affect the test; in an open-fronted cabinet the specimen at least 300 mm from each wall; smoke and toxic gases are removed by ventilation between tests. With the template a set of twelve specimens is marked in order to obtain at least five cases of ignition and five cases of non-ignition. Specimens are usually tested vertically in the length direction, face side towards the flame; if the material is not homogeneous and preliminary tests show differences, specimens in the length and width directions are tested separately, and with surface ignition, when the faces differ in appearance and behaviour — each face separately, with a separate result. The method is iterative, so the exact number of specimens cannot be stated: at least 10 specimens per direction are needed, and one additional specimen for setting up the method. Specimen dimensions: (200 ± 2) mm × (80 ± 2) mm; for open-structure fabrics (e.g. canvas, gauze) the pin locations are marked on small pieces of adhesive paper stuck on. Conditioning, unless otherwise specified: (20 ± 2) °C and relative humidity (65 ± 5) % for at least 24 h; specimens not tested immediately are kept in an airtight container, and each is tested within 2 min of removal (it may be mounted in the holder while still in the conditioning atmosphere). Further clauses (titles from the table of contents only): testing atmosphere, setting up the apparatus (procedures A and B), test procedure, calculation of the mean ignition time, precision, test report; Annex A (normative) — construction of the burner, B (informative) — worked example of calculation of the mean ignition time, C (informative) — experimental techniques.

EDITIONS. ISO 6940:2004 (ISO/TC 38/SC 19 "Burning behaviour of textiles and textile products") — second edition, replaced ISO 6940:1984 after technical revision and incorporated amendment ISO 6940:1984/Amd.1:1993; it cites ISO 4880 and ISO 6941. ISO 6940:2026 — third edition, prepared by ISO/TC 38 in collaboration with CEN/TC 248 (Vienna Agreement), replaced ISO 6940:2004 after technical revision; changes according to the foreword: corrected Figure 1 b) (angular dimension line and shape of the gas jet tip), revised Figures 3 a) and b) so that the specimen is clearly shown; the revision aims to clarify without structural changes. iTeh catalogue card of ISO 6940:2026 (read on 06.11.2026): status "Published", publication 13.05.2026, stage "6060 – International Standard published", ICS 13.220.40 and 59.080.30; next to it EN ISO 6940:2026 (corrected version 2026-06).

STATUS (as of 06.11.2026). The card of PN-EN ISO 6940:2005 (Polish version) carries the label "Withdrawn and replaced by PN-EN ISO 6940:2026-10 - English version": withdrawal date 27-10-2026, publication 12-12-2005, 21 pages, KT 27 Floor Coverings and Flammability of Textile Products, "Adopts: EN ISO 6940:2004 [IDT], ISO 6940:2004 [IDT]", "Replaces: PN-EN ISO 6940:2004 - English version", ICS 13.220.40, 59.080.30; in the line "Current in conformity assessment" the card gives "30-11-2026 - See Communication of the President of PKN" (we did not read the communication). "Scope" field of this card (our translation): "A method is specified for measuring the ignitability of vertically oriented textile fabrics intended for clothing, curtains and net curtains, in the form of single- or multi-component products (coated, quilted, multilayered, sandwich constructions and similar combinations)" — the mention of clothing, curtains and net curtains is not in clause 1 of the ISO 6940:2004 text we read, which speaks of textile fabrics and industrial products. The card of the successor PN-EN ISO 6940:2026-10 (English version) has no withdrawal label: publication 27-10-2026, 28 pages, KT 27, "Adopts: EN ISO 6940:2026 [IDT], ISO 6940:2026 [IDT]", "Replaces: PN-EN ISO 6940:2005 - Polish version", the same Polish title; its "Scope" field speaks of textile fabrics and industrial products, without naming clothing and curtains. Three questions about the withdrawal: when — 27.10.2026; replaced by what — PN-EN ISO 6940:2026-10 (English version; the card lists no Polish version); what changed for the result — according to the foreword of ISO 6940:2026, Figures 1 b), 3 a) and 3 b) were corrected, and the revision aims to clarify without structural changes. We did not compare the full texts of the two editions.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database refreshed from the production server on 02.11.2026 and current PCA documents, read on 06.11.2026). Number 6940 appears in the database copy in 7 records at 6 Polish laboratories: AB 023, AB 029 (two), AB 154, AB 225, AB 304, AB 1280. In the current PCA documents of these 6 laboratories the standard occurs 6 times — once each; the difference comes from the copy: at AB 029 both flammability entries have all seven standards of both rows assigned in the copy, while in PCA PN-EN ISO 6940:2005 stands only with ignition time. No entry is suspended; the entries of AB 023, AB 304 and AB 1280 belong to the flexible scope of accreditation (mark "E"). Notations: "PN-EN ISO 6940:2005" (AB 029, AB 154, AB 225) and "PN-EN ISO 6940" without year (AB 023, AB 304, AB 1280). In the database copy the number also appears in 4 records at 4 Czech laboratories (notation "ČSN EN ISO 6940", also as the basis of an in-house procedure); two further Czech records containing the string "6940" are procedure numbers of another laboratory ("PI 69403-…", sampling of air) — we do not count them. The "Laboratories" tab ("PN-EN ISO 6940") shows 10 laboratories: these 6 Polish and 4 Czech (tab query on labcoda.pl, 06.11.2026).

WHAT THE LABORATORIES TEST (database copy and PCA documents, complete entries). Ignition time: textile products, curtains and net curtains (AB 225, together with PN-EN 1101:1999+A1:2006) and flat textiles (AB 1280). Flammability — ignition time, single-flame method: textile products (AB 029, together with PN-EN 1101:1999+A1:2006 and PN-EN 1625:2002). Flammability of vertically oriented specimens: flat textiles (AB 154, together with PN-EN 1625:2002). Combined entries with PN-EN ISO 6941: degree of flammability of flexible products — extent of flame spread and time to ignition: curtains, drapes, theatre curtains, films, tent fabrics, awnings (AB 023); resistance to ignition and vertical flame spread: drapes, curtains, net curtains, large tents, awnings, films and other hanging products (AB 304). No scope indicates procedure A or B.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — the ignition criterion: "ignited" means sustained combustion (at least 5 s of burning after removal of the burner, or flame at the top or a side edge in less than 5 s); a brief flame that goes out at once is not ignition, and burning shorter than 1,0 s is recorded as zero. Second — number of specimens: the method is iterative and needs at least five ignitions and five non-ignitions, at least 10 specimens per direction; a result from a few specimens or from ignitions only does not give the weighted mean according to the standard. Third — direction and face: for a non-homogeneous product or one with different faces, the result is given separately for directions and faces; averaging them together hides the weaker direction. Fourth — conditioning: (20 ± 2) °C, (65 ± 5) %, at least 24 h and testing within 2 min of removal; an over-dried or damp specimen ignites differently. Fifth — mode of ignition: the standard has surface and bottom edge ignition, and the scopes do not state it — the test report must state the procedure. Sixth — range of validity of the result: the method says nothing about the behaviour of the product with restricted air supply or with a large heat source. Seventh — citing the edition: three laboratories (AB 029, AB 154, AB 225) cite PN-EN ISO 6940:2005, which PKN withdrew on 27.10.2026 (successor: PN-EN ISO 6940:2026-10, English version), and three in the flexible scope (AB 023, AB 304, AB 1280) — the number without year; the test report must state which edition was used. According to the foreword of the 2026 edition the changes concern figures and do not change the structure — we did not compare the full texts, so we do not claim that the results of both editions are always equivalent.

WHAT WE DO NOT GIVE. The fragments we read end: ISO 6940:2004 — at 8.1, ISO 6940:2026 — at the first sentence of clause 4. We do not give the testing atmosphere, burner and flame adjustment, the course of the iteration (how successive flame application times are chosen), the formula of the weighted mean, precision, test report content or burner construction (clauses 8.2–13, Annexes A–C). We did not check whether the 2026 edition retained the definition of minimum ignition time — the fragment we read has definitions 3.1–3.4. We did not check the status of the standards cited alongside in the scopes (PN-EN 1101, PN-EN 1625); we did not check references to ISO 6940 in legislation.

Method principle

A 200 × 80 mm specimen mounted vertically on pins is subjected to a defined burner flame applied to the surface or the bottom edge, and it is assessed whether sustained combustion occurs (at least 5 s of burning after the burner is removed, or flame at an edge in less than 5 s). The method is iterative — at least 10 specimens per direction, with at least five ignitions and five non-ignitions — and the mean ignition time is determined from the weighted mean of the times from flame application to ignition; the flame application time is set with a timer in 1 s steps (ISO 6940:2004, clauses 3–5, 7).

Applications

• Textile fabrics and industrial products, simple and composite: coated, quilted, multilayered, sandwich (ISO 6940:2004, clause 1)
• Influence of seams and trimmings on ease of ignition (ISO 6940:2004, clause 1)
• Paired with ISO 6941 (flame spread) — according to the introduction, two very closely related methods of testing the flammability of textile fabrics
• In accreditation scopes: 6 Polish laboratories — textile products, flat textiles, curtains, net curtains, drapes, theatre curtains, large tents, awnings, films and other hanging products

Key parameters

Standard

Standard number

PN-EN ISO 6940:2026-10 (English version; adopts EN ISO 6940:2026 and ISO 6940:2026 [IDT]; replaced PN-EN ISO 6940:2005 — Polish version, withdrawn on 27.10.2026)

Title (PL)

Wyroby włókiennicze — Zachowanie się podczas palenia — Wyznaczanie zapalności pionowo umieszczonych próbek

Title (EN)

Textile fabrics — Burning behaviour — Determination of ease of ignition of vertically oriented specimens

Step-by-step procedure

1. Specimens

   Set of twelve specimens (200 ± 2) × (80 ± 2) mm with pin locations marked with the template; usually length direction, face side towards the flame; if there are differences — directions and faces separately (7.1–7.3).

2. Conditioning

   (20 ± 2) °C and (65 ± 5) % relative humidity for at least 24 h; each specimen tested within 2 min of removal (8.1).

   ⏱ Time: ≥ 24 h

3. Mounting and flame

   Specimen vertical on four pins, at least 20 mm from the frame, at least 300 mm from the walls; burner from the standby position to the surface (procedure A) or the bottom edge (procedure B) (5.2, 5.3, 6.2; flame adjustment — clause 9, not read).

4. Iteration

   Testing successive specimens until at least five ignitions (sustained combustion) and five non-ignitions are obtained, at least 10 specimens per direction (3.4, 7.1); how the flame application time for the next specimen is chosen — clause 10, not read.

5. Result

   Mean ignition time from the weighted mean (clause 4; calculation — clause 11 and example in Annex B, not read), separately for directions and faces, stating the ignition procedure. PN-EN ISO 6940:2005 — withdrawn on 27.10.2026, successor PN-EN ISO 6940:2026-10 (English version; PKN cards, 06.11.2026).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• TECHNICAL NOTE: ignition in the sense of the standard is sustained combustion (≥ 5 s or flame at an edge in < 5 s), not any small flame
• TECHNICAL NOTE: the result does not apply to conditions with restricted air supply or large heat sources (clause 1)
• Smoke and toxic gases from combustion — ventilation of the room between tests; combustion products may be corrosive (6.1, 6.3)
• Mounting the specimen on the pins within 2 minutes — beware of injuries (note to 8.1)

Frequently asked questions