🔥 Gross calorific value and net calorific value of solid fuels — PN-G-04513:1981 (standard WITHDRAWN, still listed in a regulation)

Petrochemistry PN-81/G-04513

Overview

SCOPE FROM THE PKN CATALOGUE CARD, IN FULL (our translation): "The principle of the method, safety regulations, the type of apparatus, instruments and materials, and of reagents and solutions, the method of preparing the sample for testing and carrying out the determination, the calculation of results are given. The permissible differences between the results of determinations and the method of converting the net calorific value are specified".

THE STANDARD IS WITHDRAWN — YET THE REGULATION STILL LISTS IT. The PKN card (read on 23.09.2026) has the heading "Withdrawn" and the line "Withdrawal date: 17-12-2012"; there is no "Replaced by" line. Meanwhile, the Regulation of the Minister of Energy of 27 September 2018 on methods for testing the quality of solid fuels (consolidated text: Journal of Laws 2021 item 1366) states in point 5.3 of the annex that the method of determining the net calorific value "is specified by the standard PN-ISO 1928:2002 or PN-G-04513:1981" (our translation). The amending regulation of 7 December 2023 (Journal of Laws 2023 item 2661) replaced these words with "PN-ISO 1928:2002, PN-G-04513:1981 or PN-ISO 1928:2020-05" — it added the new edition of PN-ISO 1928 but did not delete the withdrawn national standard. For the purposes of this regulation, the 1981 standard is therefore still one of the three listed routes.

WHAT THE REGULATION ITSELF SAYS ABOUT THE METHOD. Point 5.1 of the annex: the net calorific value "is determined by the calorimetric method consisting in determining the gross calorific value of the analysis sample at constant volume in a calorimetric bomb calibrated on the basis of combustion tests of reference benzoic acid" (our translation). Point 5.2: the net calorific value "is calculated on the basis of the determined gross calorific value reduced by the heat of vaporisation of the water released during the combustion of the fuel and formed from the hydrogen contained in the fuel". These are sentences of the regulation, not of the standard — we do not have the text of PN-G-04513.

HOW THE SCOPES RECORD THIS STANDARD. All 56 records use the old scheme "PN-81/G-04513", while the PKN card lists the standard as "PN-G-04513:1981". In 27 of 56 entries (at 18 of 36 laboratories), PN-ISO 1928:2020-05 also stands in the same row of the scope — in 7 in the same record, in 20 as a separate record; laboratories keep both routes that the regulation lists. The international edition ISO 1928:2025 appears in 4 entries at 3 laboratories: AB 313 ("ISO 1928:2025", two entries), AB 883 and AB 103 ("ISO 1928:2025-08"). The test is called "Gross calorific value" (Ciepło spalania) (measured quantity) and "Net calorific value (calculated)" (Wartość opałowa (z obliczeń)); in one record also "Approximate hydrogen content (calculated)" (Przybliżona zawartość wodoru (z obliczeń)). Technique — "Calorimetric method" (Metoda kalorymetryczna). Subject: mainly hard coal, also lignite and coke; one record concerns solid biomass, and one concerns wastes with the codes given, including ashes and slags (AB 688).

RELATED ENTRIES IN THIS DATABASE: PN-ISO 1928 (the same quantity for solid mineral fuels), PN-EN ISO 18125 (solid biofuels) and PN-EN ISO 21654 (solid recovered fuels); from the same family of national standards — PN-80/G-04511 (moisture) and PN-G-04516 (volatile matter).

WHAT WE DO NOT GIVE. We do not have the text of the standard — PKN sells it (11 pages, KT 220 Natural Solid Fuels). That is why WE DO NOT GIVE the sample mass, the parameters of the bomb, corrections, conversion formulae or the permissible differences between results — the card only says that the standard contains them.

SCALE OF CITATIONS (measurement of 23.09.2026). The key "PN-81/G-04513" matches by the beginning of the notation and covers all citations: 36 laboratories / 56 entries — the same as across all forms of notation.

Method principle

According to the regulation on methods for testing the quality of solid fuels (annex, points 5.1–5.2): the gross calorific value of the analysis sample is determined at constant volume in a calorimetric bomb calibrated by burning reference benzoic acid, and the net calorific value is calculated from the gross calorific value reduced by the heat of vaporisation of the water released during combustion and formed from the hydrogen contained in the fuel. WE DO NOT GIVE the details of execution according to PN-G-04513 — we do not have the text of the standard.

Applications

• Testing the quality of solid fuels for the purposes of the regulation on methods for testing the quality of solid fuels (annex, point 5.3)
• Gross calorific value and net calorific value of hard coal, lignite and coke (subjects from accreditation scopes)

Key parameters

Standard

Standard number

PN-G-04513:1981 (wersja polska)

Title (PL)

Paliwa stałe — Oznaczanie ciepła spalania i obliczanie wartości opałowej

Title (EN)

Solid fuels — Determination of gross calorific value and calculation of net calorific value

Step-by-step procedure

1. Choosing the route

   The regulation lists PN-ISO 1928:2002, PN-G-04513:1981 or PN-ISO 1928:2020-05 — record in the report which one was used.

2. Determining the gross calorific value

   In a calorimetric bomb at constant volume, on the analysis sample (point 5.1 of the regulation). WE DO NOT GIVE the sample mass and the parameters.

3. Calculating the net calorific value

   The heat of vaporisation of the water released during combustion and formed from the hydrogen contained in the fuel is subtracted from the gross calorific value (point 5.2 of the regulation). WE DO NOT GIVE the formulae of the standard.

4. Entry in the report

   The standard is withdrawn — when citing it, give the full designation PN-G-04513:1981 (in the scopes: PN-81/G-04513).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The card lists safety regulations in the standard — WE DO NOT GIVE their content
• The calorimetric bomb is a pressure vessel — operation only according to the instructions of the instrument manufacturer

Frequently asked questions