🔥 Determination of the heat release rate and dynamic smoke production rate of horizontally oriented product specimens under controlled irradiance from a conical heater (0–75 kW/m²) — heat from oxygen consumption (about 13,1 × 10³ kJ per kg of oxygen) measured with a paramagnetic analyser and the gas flow in the exhaust duct, smoke from the attenuation of a helium-neon laser beam (Bouguer’s law), time to ignition with spark ignition and mass loss from a load cell, ISO 5660-1

Construction ISO 5660-1

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in the iTeh sample of ISO 5660-1:2015 (French version, corrected version — with Formula 4 corrected): from the title page through the contents and foreword to 7.2 (asymmetrical products) on page 9 inclusive. Outside the sample remain further requirements on product suitability (7.3–7.5, including dimensionally unstable materials), specimen preparation (8), conditioning (9), calibration (10), procedure (11), calculation (12), test report (13) and the annexes (including E — testing in vertical orientation, F — calibration of the heat flux meter, G — calculation with CO and CO2 measurement).

ACCORDING TO THE TEXT OF ISO 5660-1:2015 (foreword, Clauses 1–7.2). The standard was prepared by ISO/TC 92 “Fire safety”, Subcommittee SC 1 “Fire initiation and growth”. The third edition replaces ISO 5660-1:2002 (second edition) and ISO 5660-2:2002 (first edition), which were technically revised and merged; the ISO 5660 series has Part 1 and Part 3 (guidance on measurement, technical specification), and Part 4 (heat release measurement for determining low levels of combustibility) was under preparation. Scope (1): a method for assessing the heat release rate and dynamic smoke production rate of specimens oriented horizontally and exposed to controlled levels of irradiance from an external source; the heat release rate is determined from oxygen consumption (derived from oxygen concentration) and the flow in the exhaust duct of combustion products; time to ignition (sustained flaming) is also measured; the smoke production rate is calculated from the attenuation of a laser beam by the combustion product stream, and smoke obscuration is recorded throughout the test whether or not the specimen ignites. References (2): ISO 554 (conditioning atmospheres), ISO 13943 (fire safety vocabulary), ISO 14697 (substrates for building and transport products). Terms (3): essentially flat surface (irregularities within ± 1 mm); flashing (less than 1 s), transitory (1–10 s) and sustained flaming (more than 10 s); ignition — onset of sustained flaming; irradiance (as convection is negligible for horizontal specimens, the standard uses this term instead of “heat flux”); oxygen consumption principle — proportionality between the mass of oxygen consumed in combustion and the heat released; smoke obscuration — reduction of light intensity passing through smoke; extinction coefficient — natural logarithm of the ratio of incident to transmitted light intensity per unit path length; smoke production rate — product of the volumetric smoke flow and the extinction coefficient; smoke production — its integral over time. Symbols (4, Table 1) include: q̇A — heat release rate per unit area (kW/m²), q̇A,max — its maximum, q̇A,180 and q̇A,300 — averages over 180 s and 300 s from ignition, QA,tot — total heat released per unit area (MJ/m²), tig — time to ignition, ṁA,10-90 — average mass loss rate per unit area between 10 % and 90 % of total mass loss, SA,1 and SA,2 — total smoke production per unit area before and after ignition, σ — specific extinction area. Principle (5): the net heat of combustion is generally proportional to the amount of oxygen required for combustion — about 13,1 × 10³ kJ are released per kilogram of oxygen consumed; specimens are burned in ambient air under a predetermined external irradiance of 0–75 kW/m², measuring oxygen concentration and exhaust gas flow; smoke measurement is based on Bouguer’s law (light transmitted through combustion products decreases exponentially with distance) — the fraction of laser light transmitted through the smoke in the duct is measured, the extinction coefficient calculated, and smoke production rate and smoke production are reported per unit exposed area, because smoke production is proportional to it; the method assesses the contribution of the product to the rate of heat and smoke evolution in a well-ventilated fire, on small representative specimens. Apparatus (6): optionally CO and CO2 measurement for calculating heat release (Annex G) and testing in vertical orientation after minor modifications (Annex E); conical heater of a tightly wound 5000 W element in a double stainless-steel shell with a 13 mm refractory fibre blanket, controlled by the average temperature of three thermocouples (stainless-steel-sheathed type K or Inconel) — capable of up to 75 kW/m² at the specimen surface, uniform within the central 50 × 50 mm area to ± 2 % at 50 kW/m²; removable radiation shield, non-combustible, up to 12 mm thick; control system keeping the average thermocouple temperature within ± 10 °C; load cell with 0,1 g resolution, ± 0,3 g accuracy, at least 500 g capacity, 10–90 % response time up to 4 s and drift up to 1 g in 30 min; specimen holder — a square pan (25 ± 1) mm deep with a (106 ± 1) × (106 ± 1) mm opening of (2,4 ± 0,15) mm stainless steel, lined with at least 13 mm of ceramic fibre (about 65 kg/m³); heater-to-specimen-top distance (25 ± 1) mm, and (60 ± 1) mm for dimensionally unstable materials; retainer frame with a (94,0 ± 0,5) mm opening; exhaust system with a fan, hood (bottom of the hood (210 ± 50) mm above the specimen), flow up to 0,035 m³/s at standard conditions, a (57 ± 3) mm mixing orifice, a ring gas sampling probe with 12 holes of (2,2 ± 0,1) mm facing away from the flow, (685 ± 15) mm from the hood, a thermocouple (100 ± 5) mm upstream of the metering orifice and a thin-plate (57 ± 3) mm orifice for flow measurement; gas sampling with filters, moisture removal and a CO2 trap, oxygen analyser delay time td up to 60 s; ignition by a spark plug powered by a 10 kV transformer or a spark igniter, gap (3,0 ± 0,5) mm, (13 ± 2) mm above the specimen centre, and (48 ± 2) mm for dimensionally unstable materials; ignition timer accurate to 1 s per hour; paramagnetic oxygen analyser 0–25 %, drift and noise up to 50 µl/l in 30 min, with pressure regulation and compensation for atmospheric pressure, in an isothermal environment (± 2 °C of a value between 30 °C and 70 °C), 10–90 % response up to 12 s; Schmidt-Boelter heat flux meter (range (100 ± 10) kW/m², target about 12,5 mm, emissivity 0,95 ± 0,05, water-cooled, repeatability ± 0,5 %), checked against two reference meters, one of which is fully calibrated annually by a metrology laboratory; methane calibration burner (purity at least 99,5 %, (500 ± 100) mm² opening, flow accuracy ± 3 % at 5 kW); data logging every second, at least 720 values per parameter; optional side screens — provided it is shown that they do not affect time to ignition and heat release (with an enclosure there is an explosion risk, especially in oxygen-enriched atmospheres); photometer with a 0,5–2 mW helium-neon laser, (111 ± 1) mm downstream of the gas sampling probe, with a thermocouple 50 mm downstream of the photometer; two optical filters of nominal density 0,3 and 0,8, calibrated at 632,8 nm, k = 2,303·D′/L (white-light systems with demonstrated equivalent accuracy are also permitted). Product suitability (7.1, 7.2): the product shall have an essentially flat surface or evenly distributed irregularities — at least 50 % of a representative 100 mm² area within 10 mm depth of the plane of the highest points, or cracks, fissures and holes up to 8 mm wide and 10 mm deep occupying at most 30 % of such an area; otherwise a modified form as close as possible to the requirements is tested and this is stated in the report; products with different faces are tested on both sides if either may be exposed in use.

STATUS (as of 03.10.2026). In the PKN search the term “5660-1” gives no results (03.10.2026) — accreditation scopes cite the international standard ISO 5660-1. In the iTeh catalogue (read on 03.10.2026) ISO 5660-1:2015 has the status “Published”, stage 90.93 (standard confirmed) since 08.05.2026; the iTeh search also shows amendment ISO 5660-1:2015/Amd 1:2019, which we did not read.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, load up to 17.09.2026, read on 03.10.2026). The number 5660-1 appears in 5 records at 5 laboratories: AB 023, AB 304, AB 369, AB 1280, AB 1501. In the current PCA documents (read on 03.10.2026, issues from 16.07.2025 to 13.07.2026) the number appears in 5 rows — one at each; in each of the five documents the number of page markers equals the number of PDF pages, without repetitions; a search of all 1291 PCA documents downloaded from BIP on 03.10.2026 found no laboratories outside the database copy (17 laboratories on the list have no link to a scope document on BIP). At all of them the form “ISO 5660-1” without year; at AB 1501 in one cell with ISO 5660-2 (the 2002 edition merged into Part 1 in 2015), PN-C-04914 and the IMO FTP Code (Part 10), at AB 369 with PN-EN 45545-2. None of these items is suspended (in the AB 023 document the word “zawieszenia” refers to suspension systems of components, not suspension of accreditation). The “Laboratories” tab (term “ISO 5660-1”) shows 6 results: all 5 Polish laboratories and one Czech laboratory (No. 1709) — checked with a tab query on the production server labcoda.pl on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). Object: building, structural and finishing products (AB 023), furnishing and decorative materials used in marine construction and rolling stock (AB 304), non-metallic materials except glass and ceramics (AB 369), insulating, structural, furnishing and decorative building materials and products (AB 1280, AB 1501) — all in the flexible scope of accreditation. Characteristics: heat and smoke release, time to ignition (AB 023), heat release intensity, mass emission of carbon monoxide and dioxide, specimen mass loss, mass burning rate, smoke optical density, smoke production (AB 304), fire and smoke properties — heat release rate, total heat released, mass loss rate, time to ignition, MARHE, total smoke production SA1 and SA2 (AB 369), intensity of heat and smoke release, mass burning rate (AB 1280, AB 1501 — oxygen depletion method).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. With irradiance: uniformity ± 2 % in the 50 × 50 mm area at 50 kW/m² and constant thermocouple temperature ± 10 °C (6.2, 6.4). With distance: 25 mm from the heater, but 60 mm for dimensionally unstable materials — and then the igniter at 48 mm instead of 13 mm (6.6, 6.10). With oxygen: the paramagnetic analyser is pressure-sensitive — pressure regulation, compensation for atmospheric pressure, constant analyser ambient temperature; allowance for the delay time td (6.9, 6.12). With side screens: only after showing no effect on ignition and heat release (6.16). With the surface: an uneven product is tested in a modified form, noted in the report; an asymmetrical product — on both sides (7.1, 7.2). With the document: ISO 5660-2:2002 was merged into Part 1 in 2015.

WHAT WE DO NOT GIVE. We did not read the specimen dimensions and preparation, conditioning, calibration procedures, test procedure, formulae for heat and smoke release rate or the content of the report (7.3–13, annexes), nor amendment Amd 1:2019. We do not give product classification criteria (e.g. for railway products according to EN 45545-2).

Method principle

A horizontal product specimen is exposed to a set irradiance (0–75 kW/m²) from a conical heater and ignited by a spark; combustion products are drawn by a hood into a duct where flow, oxygen concentration and laser beam attenuation are measured, and a load cell records the specimen mass. The heat release rate is determined from oxygen consumption (about 13,1 MJ per kg O2), the smoke production rate from the extinction coefficient and flow; time to ignition and mass loss are also measured.

Applications

• Products and materials — contribution to the rate of heat and smoke release in a well-ventilated fire, on small specimens (5)
• Building products, ship furnishings and rolling stock, non-metallic materials — items in the accreditation scopes of 5 laboratories in PCA
• Items citing PN-EN 45545-2 (AB 369) and the IMO FTP Code (AB 1501) alongside ISO 5660-1 — according to PCA documents

Key parameters

Standard

Standard number

ISO 5660-1:2015

Title (PL)

Badania reakcji na ogień — Wydzielanie ciepła, wytwarzanie dymu i szybkość ubytku masy — Część 1: Szybkość wydzielania ciepła (metoda kalorymetru stożkowego) i szybkość wytwarzania dymu (pomiar dynamiczny)

Title (EN)

Reaction-to-fire tests — Heat release, smoke production and mass loss rate — Part 1: Heat release rate (cone calorimeter method) and smoke production rate (dynamic measurement)

Step-by-step procedure

1. Product suitability

   Essentially flat surface or irregularities within 7.1; asymmetrical products on both sides (7.1, 7.2). Status of ISO 5660-1:2015 — stage 90.93 (03.10.2026).

2. Setting irradiance

   Calibration of the heater with a heat flux meter; thermocouple temperature ± 10 °C (6.4, 6.13).

3. Test

   Specimen in the holder under the heater, shield removed, spark ignition; recording of oxygen, flow, smoke and mass every second (5, 6.10, 6.15); procedure according to Clause 11 (not read).

4. Results

   Heat release rate (q̇A, q̇A,max, q̇A,180, q̇A,300, QA,tot), time to ignition, mass loss, smoke (SA,1, SA,2); formulae according to Clause 12 (not read).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Burning specimens and hot heater — shields, hand protection, smoke extraction
• With closed side screens risk of explosion, especially in oxygen-enriched atmospheres — explosion flap directed away from the operator (6.16)
• High voltage of the igniter (10 kV) and laser radiation

Frequently asked questions