🏗️ Fly ash — fineness determined as the residue on a sieve with 0.045 mm apertures by wet sieving, reference method, PN-EN 451-2

Construction PN-EN 451-2

Overview

WHAT THE STANDARD COVERS. Scope from the PKN card, in full (our translation): "This European Standard describes a method for determining the fineness of fly ash as the residue on a sieve with an aperture size of 0.045 mm by wet sieving (ISO 565). The European Standard specifies a reference method. If other methods are used, it shall be demonstrated that they give results equivalent to those obtained with the reference method. In cases of dispute only the reference method may be used." We did not have the text of the standard. From the preview of BS EN 451-2:2017 (BSI) we know the EN title page and the table of contents: EN 451-2:2017 of May 2017, approved by CEN on 27 February 2017, superseded EN 451-2:1994; clauses: scope, normative references, terms and definitions, reagents (including 4.2 distilled water), apparatus — sieve (5.1), spray nozzle (5.2), pressure gauge (5.3), weighing bottle (5.4), oven (5.5), desiccator (5.6), balance (5.7) — checking the test sieve (6), preparation of the sample (7), procedure (8), calculation (9), results (10), repeatability and reproducibility (11). From the preview of the tracked-changes version (BSI) we know the European foreword: the standard was prepared by CEN/TC 104 "Concrete and related products" (secretariat DIN), and the EN 451 series "Method of testing fly ash" has two parts — 1: determination of free calcium oxide content, 2: determination of fineness by wet sieving.

WHAT WE KNOW ABOUT THE 1994 EDITION. The BSI national foreword to BS EN 451-2:1995 (removed in the 2017 edition) describes EN 451-2:1994 as the reference method for determining the fineness of fly ash by wet sieving on a calibrated 0.045 mm (45 µm) sieve and compares it with Annex D of BS 3892-1:1993: water pressure in EN 451-2 — (80 ± 5) kPa, sample mass — about 1.0 g, calibration of each test sieve after 100 tests, EN 451-2 requiring only that the reference material consist of rounded sand particles. Whether the 2017 edition kept these values we do not know from the previews.

STATUS (state of the cards on 30 September 2026). The card of PN-EN 451-2:2017-06 (English version) has no "Withdrawn" header — the standard is CURRENT: published 13-06-2017, 11 pages, price group F, Construction and Building Structures Sector, KT 274 for Concrete, ICS 91.100.30, "Introduces: EN 451-2:2017 [IDT]", "Replaces: PN-EN 451-2:1998 - Polish version". The PKN search for "PN-EN 451-2" (30 September 2026) shows this standard and PN-EN 451-2:1998 (Polish version) with the label "Withdrawn and replaced by PN-EN 451-2:2017-06 - English version", and next to them standards with other numbers containing this string (e.g. PN-ENV 1451-2, PN-EN 13451-2).

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation-scope database, data loaded up to 17 September 2026, read on 30 September 2026). All notations of number 451-2: 13 records at 10 laboratories — the same number of cells in the PCA documents. The notation "PN-EN 451-2:2017-06" — 9 laboratories (at AB 054 in one of three entries), "PN-EN 451-2:2017" — AB 874, without a year — AB 054 in the other two entries. The "Laboratories" tab looks for notations that BEGIN with "PN-EN 451-2" and will show all 10 laboratories — checked with the tab's query on the production server labcoda.pl on 30 September 2026: 10. Current scopes on the PCA website (read on 30 September 2026, issues from 20.11.2025 to 22.09.2026): the entries with this standard are not suspended (AB 054 has another part of its scope suspended), but AB 1393 — the PCA page has no link to the scope, and the scope in the PCA archive (issue No. 16 of 20.11.2025) carries the annotation "Accreditation voluntarily withdrawn at the request of the body in the full scope from: 31.08.2026". So today 9 laboratories are accredited for this test.

ITEMS, RANGE AND TECHNIQUE. Fly ash — under various names: fly ash (AB 550, AB 687, AB 713), siliceous fly ash (AB 054), fly ash for concrete and building materials (AB 688, AB 786, AB 927), wastes with codes 10 01 01, 10 01 02, 10 01 03, 10 01 15, 10 01 17, 10 01 24, 10 01 80, 10 01 82 (AB 672, AB 688, AB 713, AB 874, AB 927), wastes 19 01 12 and 19 01 14 as well as wastes of group 10 01 (AB 054), ash-slag mixture and ash with desulphurisation products (AB 688), chemical products (AB 1393). Ranges (residue on the sieve): from 0.1 % to 70.0 % (AB 687), from 0.6 % to 90.0 % (AB 054), from 1.0 % to 50.0 % (AB 874) or to 60.0 % (AB 713), from 8.0 % to 70.0 % (AB 786), from 10.0 % to 40.0 % (AB 672), to 50.0 % (AB 688, AB 927) or to 65.0 % (AB 550), from 20.0 % to 50.0 % (AB 1393). Technique: gravimetric method — 7 laboratories, sieve method or sieving — AB 054, AB 550, AB 687; AB 786 names the quantity directly "fineness as the residue on a 45 µm sieve", AB 054 — "fraction above 0.045 mm".

ALONGSIDE THIS STANDARD. In two entries of AB 054 (wastes 19 01 12 and 19 01 14, and wastes 10 01) PN-EN 14227-4 stands next to this standard (at AB 054 in the form "PN-EN 14227-4:2013-10" or without a year). The only entry for the fineness of fly ash without this standard is AB 054 for calcareous fly ash — "fraction above 0.04 mm" according to PN-EN 197-1. A different quantity — the particle size distribution of fly ash — is determined by AB 550 by laser diffraction according to ISO 13320:2020 (from 0.1 µm to 600 µm) and by dynamic image analysis according to ISO 13322-2:2021 (from 30 µm to 30 mm); the result of such a method is not fineness according to this standard — the card allows other methods only after equivalence has been demonstrated and never in cases of dispute. The same scopes contain tests of fly ash for concrete according to PN-EN 450-1 (e.g. at AB 054 water requirement according to Annex B, setting time and soundness).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — reference method: the result of another method may be given instead of the result of this standard only after equivalence has been demonstrated, and in a dispute only the reference method counts. Second — sieve: fineness is the residue on the 0.045 mm sieve (ISO 565); the standard has a separate clause on checking the test sieve (6) — a worn or unchecked sieve shifts the result. Third — quantity: the result is the residue on the sieve in percent by mass (a larger number — a coarser ash); the ranges in the accreditation scopes, from 0.1 % to 90 %, are the laboratories' measuring ranges, not requirements for the ash. Fourth — 1994 versus 2017 edition: we know the values of water pressure, sample mass and sieve calibration frequency only from the description of the 1994 edition. Fifth — accreditation: AB 1393 has this test in the last issue of its scope, but has had no accreditation since 31.08.2026.

WHAT WE DO NOT GIVE. We did not have the text of the standard — neither the content of Clauses 4–11 (reagents, requirements for the sieve, nozzle and pressure gauge, the method of checking the sieve, sample preparation, the course of sieving, drying, the formula, precision), nor the requirements for the fineness of the ash, which are set by product standards.

Method principle

A weighed sample of fly ash is wet-sieved with a water jet from a spray nozzle on a sieve with 0.045 mm apertures, and the residue on the sieve is weighed after drying (the apparatus list of the standard includes a drying oven, a desiccator and a balance); the fineness is expressed as the residue on the sieve in percent by mass, taking into account the check of the test sieve (Clause 6). Details of the procedure and the formula are NOT GIVEN — we did not have the text of the standard.

Applications

• Fly ash, including for concrete, and ash as a building material — fineness as the residue on a 0.045 mm sieve — in the scopes of 10 laboratories
• Power-plant wastes (codes 10 01) and wastes from thermal treatment (19 01 12, 19 01 14) — AB 054 and power-plant laboratories

Key parameters

Standard

Standard number

PN-EN 451-2:2017-06 (wersja angielska; EN 451-2:2017 IDT)

Title (PL)

Metoda badania popiołu lotnego — Część 2: Oznaczanie miałkości przez przesiewanie na mokro

Title (EN)

Method of testing fly ash — Part 2: Determination of fineness by wet sieving

Step-by-step procedure

1. Status and sieve

   PN-EN 451-2:2017-06 current (state of the card on 30 September 2026); 0.045 mm test sieve checked according to Clause 6.

2. Sample

   Preparation of the sample according to Clause 7 — details NOT GIVEN.

3. Wet sieving

   Sieving with a water jet from the nozzle at a pressure controlled by the pressure gauge (Clause 8); values of the 2017 edition NOT GIVEN.

4. Result

   Residue on the sieve after drying, in percent by mass, taking into account the check of the sieve (Clauses 9–10); precision according to Clause 11.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Fly ash is a dust — respiratory protection when weighing and pouring the dry sample
• SUBSTANTIVE NOTE: the result of another method replaces the result of this standard only after equivalence has been demonstrated, never in a dispute; AB 1393 has had no accreditation since 31.08.2026

Frequently asked questions