🔥 Gross heat of combustion of products (PCS) in a bomb calorimeter — reaction to fire test, homogeneous and non-homogeneous products, net heat (PCI) by calculation; PN-EN ISO 1716:2018-08

Construction PN-EN ISO 1716

Overview

WHAT THE STANDARD COVERS. Scope from the PKN card of PN-EN ISO 1716:2018-08, in full (our translation): "This International Standard describes a method for determining the gross heat of combustion (QPCS) of products at constant volume, in a bomb calorimeter. The test method is intended for use with solid products. NOTE Liquid products may be tested using similar apparatus and applying the conditions described in ASTM D240[1] and using apparatus according to ISO 1928[3] under the conditions described in IEC 61039[2]. Annex A describes a method for calculating the net heat of combustion (QPCI), when required. Information on the precision of the test method is given in Annex B" (no full stop on the card). We read the content of the method in the sample extract of ISO 1716:2018 from the cover to the beginning of clause 7.1, with the table of contents; we do not have clauses 7.2–11 or the annexes.

ACCORDING TO THE TEXT OF ISO 1716:2018 (foreword, clauses 1–7.1). The standard was prepared by ISO/TC 92 "Fire safety", subcommittee SC 1 "Fire initiation and growth"; the fourth edition (2018-05) replaced the third (ISO 1716:2010). References (2): ISO 554 (standard atmospheres for conditioning and testing) and EN 13238 (conditioning and selection of substrates in reaction to fire tests of construction products). Definitions (3): homogeneous product — consisting of one material of uniform density and composition; non-homogeneous product — consisting of more than one component, substantial or non-substantial; non-substantial component — a layer with a mass per unit area below 1.0 kg/m² and a thickness below 1.0 mm, substantial component — at least 1.0 kg/m² or at least 1.0 mm (adjacent non-substantial layers are assessed together); an internal non-substantial component is covered on both sides by a substantial component, an external one is not; the heat of combustion Q is expressed in MJ/kg, and the standard marks the term "calorific value" as deprecated; QPCS — heat at complete combustion and complete condensation of the water formed; QPCI — with the water in the form of vapour, it may be calculated from QPCS; surface density — mass per unit area, in kg/m². Principle (4): a specimen of specified mass is burned under standardized conditions, at constant volume, in an oxygen atmosphere, in a bomb calorimeter calibrated by burning certified benzoic acid; the heat of combustion is calculated from the observed temperature rise taking into account heat losses and the latent heat of vaporization of water; the method gives an absolute value for the product and does not take its variability into account. Apparatus (5): a bomb with a volume of (300 ± 50) ml, a mass of at most 3.25 kg and a wall thickness of at least 1/10 of the internal diameter, with a lid (with seals) withstanding an internal pressure of 21 MPa, with an interior resistant to corrosion by the combustion products also with sulfur-rich specimens; a calorimeter with an insulated water jacket, at least 10 mm of free space around the calorimeter vessel, in an adiabatic or isothermal system (the isothermal one requires the corrections of 9.2), a vessel of polished metal, a stirrer at constant speed; temperature measurement with a resolution of 0.005 K; a crucible of metal — e.g. platinum, nickel or stainless steel — or of quartz, flat-bottomed, 25 mm in diameter and 14–19 mm high (recommended wall 1.0 mm for metal, 1.5 mm for quartz); a timer accurate to 1 s per hour; an ignition circuit of at most 20 V; a pressure gauge and a needle valve on the oxygen supply, resolution 0.1 MPa; two balances — an analytical one with a resolution of 0.1 mg and another of 0.1 g; a device for forming the "cigarette" (a metal mould and mandrel, not of aluminium) and a pellet press. The apparatus of 5.1–5.4 may be in an automatic or semi-automatic version — deviations from these clauses are assessed by the user. Reagents (6): distilled or demineralized water; oxygen free from combustible impurities, with a purity of at least 99.5 % (oxygen from electrolysis may contain hydrogen and is then not suitable); benzoic acid with a guaranteed heat of combustion as a calorimetric standard; a combustion aid of known heat of combustion, e.g. paraffin oil; gummed cigarette paper of at least 55 mm × 50 mm and known heat of combustion; ignition wire of pure iron 0.1 mm in diameter (other metals, if they burn through by themselves when the circuit is closed and their heat of combustion is known), which with a metal crucible must not touch the crucible — hence the wrapping with a thread of white cellulose cotton. Specimens (7.1): each component of the product is assessed separately, with rules for non-substantial components; if a non-homogeneous product cannot easily be separated, the components are supplied separately by the sponsor of the test.

STATUS (as of 08.10.2026). The PKN card of PN-EN ISO 1716:2018-08 (English version) has no withdrawal label: title "Reaction to fire tests for products -- Determination of the gross heat of combustion (calorific value)" (our translation), publication 28-08-2018, 42 pages, price group S, Construction and Building Structures Sector, KT 180 Fire Safety of Buildings, "Introduces: EN ISO 1716:2018 [IDT], ISO 1716:2018 [IDT]", "Replaces: PN-EN ISO 1716:2010 - English version, PN-EN ISO 1716:2010 - Polish version, PN-EN ISO 1716:2010/Ap1:2013-07 - English version", ICS 13.220.50 and 91.100.01. The last Polish version, PN-EN ISO 1716:2010 (publication 22-01-2013, 31 pages), has the label "Withdrawn and replaced by PN-EN ISO 1716:2018-08 - English version" and the withdrawal date 28-08-2018; the earlier PN-EN ISO 1716:2004 ("Reaction to fire tests for building products -- Determination of the heat of combustion", ISO 1716:2002) has been withdrawn since 01-01-2011. PKN search, term "ISO 1716" (08.10.2026): 8 items, including five editions of this standard, of which only the English version of the 2018 edition is current, and PN-EN 1716:2002 — another standard with this number ("Plastics piping systems -- Polyethylene (PE) tapping tees -- Test method for impact resistance of an assembled tapping tee", our translation). evs.ee catalogue: ISO 1716:2018 in force since 04.05.2018, in the history ISO 1716:2010.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database and current PCA documents, read on 08.10.2026). As a test method the standard appears in 11 entries at 9 laboratories, the same in the database copy and in the current PCA documents (issues from 16.07.2025 to 13.07.2026); none of these entries is suspended (the suspensions of parts of the scope of AB 054 do not cover it). Notation: "PN-EN ISO 1716" without a year — 9 entries (AB 008, AB 011 two, AB 023 two, AB 054, AB 304, AB 1280, AB 1501); "PN-EN ISO 1716:2018-08" alongside "EN ISO 1716:2018" — AB 1777; at AB 014 in one cell "PN-EN ISO 1716:2010" and "PN-EN ISO 1716:2018" together with the International Code for Application of Fire Test Procedures (resolution MSC.307(88), part 5). At eight laboratories the entry has the mark "N" — a method used in activities relevant to notification under Regulation (EU) No 305/2011; without this mark are the entries of AB 304 and one entry each of AB 011 (masonry units) and AB 023 (cables and wires). Separately, in the part of the scopes listing the essential characteristics of construction products against technical specifications, "EN ISO 1716" stands at the characteristic "Reaction to fire" at eight of these laboratories (AB 008, AB 011, AB 014, AB 023, AB 054 — in the notation "EN 1716", AB 1280, AB 1501, AB 1777); in the database copy, together with such entries, there are 15 records (14 with the notation "ISO 1716" and the record of AB 054 with "EN 1716"). The record of AB 041 with the notation "PN-EN 1716" for impact resistance concerns the standard on polyethylene tapping tees, not this one. The "Laboratories" tab (term "PN-EN ISO 1716") shows 9 laboratories and 11 entries of the method; the term does not pick up standards with other numbers.

WHAT THE LABORATORIES TEST (PCA documents). Quantity: gross heat of combustion (PCS); AB 1280 also net heat of combustion, AB 023 with the addition "temperature rise", AB 014 in MJ/m². Subject: construction products — bituminous shingles, bituminous corrugated sheets, fibre-cement products (AB 008); masonry units and thermal insulation products (AB 011); electric cables and wires as well as construction, structural and finishing products (AB 023); construction materials (AB 054); furnishing and decorative materials in land and marine construction (AB 304); construction products (AB 1280); insulating, structural, furnishing and decorative construction materials and products and chemical products in the solid and liquid state (AB 1501, alongside PN-C-04375-1); construction materials and products (AB 1777); finishing materials of bulkheads, ceilings and decks and primary deck coverings (AB 014). The calorimetric technique is named explicitly by AB 054, AB 1501 and AB 1777.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — liquids: the method is intended for solid products; for liquids the note to the scope indicates the conditions of ASTM D240 and IEC 61039 with apparatus according to ISO 1928. At AB 1501 the subject covers chemical products in the liquid state, and alongside ISO 1716 there is PN-C-04375-1 — the scope does not show according to which document liquids are tested. Second — non-homogeneous product: each component is assessed separately, with rules for non-substantial components; the heat of combustion of one component is not the heat of combustion of the product. Third — absolute value: the standard notes that the result does not take into account the variability of the product. Fourth — gross and net: QPCS (water condensed) and QPCI (water as vapour, calculated according to Annex A) are different numbers, and "calorific value" in the title is a term that the standard itself marks as deprecated. Fifth — the unit: the standard expresses the heat of combustion in MJ/kg and defines surface density in kg/m² (with a separate clause 7.3 on its determination); AB 014 gives the result in MJ/m², together with the FTP Code — how this value is calculated does not follow from the extract read. Sixth — the edition: most laboratories write the number without a year, AB 014 cites the 2010 and 2018 editions in one cell, and a Polish version exists only for the withdrawn 2010 edition. Seventh — oxygen: oxygen from electrolysis may contain hydrogen and according to the standard is not suitable for the test.

WHAT WE DO NOT GIVE. We do not have clauses 7.2–11: sampling (loose-fill materials, products applied in liquid form, thin-layer products), determination of surface density, grinding, type of specimen, conditioning, number of specimens, determination of mass, the crucible method and the "cigarette" method, calibration (water equivalent, conditions for recalibration), the test procedure, corrections, the formulae for the specimen and for the homogeneous and non-homogeneous product, the report or the conditions of validity of the results; nor do we have Annexes A–D (net heat of combustion, precision, graphical determination of the correction for the cooling of the calorimeter, example of a non-homogeneous product).

Method principle

A specimen of specified mass is burned at constant volume, in an oxygen atmosphere, in a bomb calorimeter calibrated by burning certified benzoic acid; the gross heat of combustion (QPCS, in MJ/kg, with complete condensation of water) is calculated from the temperature rise taking into account heat losses and the latent heat of vaporization of water (ISO 1716:2018, clause 4). Each component of a non-homogeneous product is assessed separately; the net heat of combustion (QPCI, water as vapour) is calculated from the gross value according to Annex A. The method is intended for solid products and gives an absolute value, without taking into account the variability of the product.

Applications

• Construction products in reaction to fire tests — gross heat of combustion; in the current accreditation scopes 9 laboratories, at eight in notified activities (mark "N")
• Electric cables and wires (AB 023), furnishing and decorative materials (AB 304)
• Finishing materials and deck coverings of ships — together with the International Code for Application of Fire Test Procedures, part 5 (AB 014)
• Net heat of combustion by calculation according to Annex A, when required

Key parameters

Standard

Standard number

PN-EN ISO 1716:2018-08 (wersja angielska; wprowadza EN ISO 1716:2018 [IDT] i ISO 1716:2018 [IDT])

Title (PL)

Badania reakcji na ogień wyrobów — Określanie ciepła spalania brutto (wartości kalorycznej)

Title (EN)

Reaction to fire tests for products — Determination of the gross heat of combustion (calorific value)

Step-by-step procedure

1. Assessment of components

   Establish whether the product is homogeneous; in a non-homogeneous product assess each component separately according to the rules for non-substantial components (below 1.0 kg/m² and 1.0 mm); components that cannot easily be separated are supplied separately by the sponsor (3.3–3.8, 7.1).

2. Preparation of specimens

   Sampling, surface density, grinding, conditioning, number and mass of specimens and the crucible or "cigarette" method — clauses 7.2–7.10, which we do not have; WE DO NOT GIVE their content.

3. Calibration

   The bomb is calibrated by burning certified benzoic acid (clause 4); WE DO NOT GIVE the determination of the water equivalent and the conditions for recalibration (8.2).

4. Combustion

   Burn the specimen at constant volume in an oxygen atmosphere and record the temperature rise (clause 4); WE DO NOT GIVE the oxygen pressure and the course of the test (8.3).

5. Calculations

   Gross heat of combustion from the temperature rise taking into account heat losses and the latent heat of vaporization of water; with an isothermal calorimeter the corrections of 9.2; net heat according to Annex A. WE DO NOT GIVE the formulae.

6. Report

   State the edition of the standard; WE DO NOT GIVE the content of the report and the conditions of validity of the results (clauses 10–11).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Fire tests can be hazardous: toxic or harmful gases may be released, an explosion is possible, and the disposal of residues also carries hazards — the standard requires a risk assessment, written instructions and training of personnel (ISO 1716:2018, warnings)
• The bomb operates in oxygen under pressure — the lid with seals must withstand 21 MPa (5.1)
• TECHNICAL NOTE: a method for solid products; a non-homogeneous product is assessed component by component; QPCS and QPCI are different quantities; a Polish version exists only for the withdrawn 2010 edition

Frequently asked questions