🏗️ Common equipment and calibration in aggregate testing — PN-EN 932-5

Construction PN-EN 932-5

Overview

THE SCOPE FROM THE PKN CATALOGUE CARD, IN FULL: "General requirements are given for common equipment, calibration and checking procedures, and reagents for testing the properties of aggregates."

THREE THINGS IN ONE DOCUMENT. The scope names them plainly and it is worth keeping them apart, for they carry different weight. First, EQUIPMENT: ovens, balances, sieves, vessels, thermometers — the apparatus recurring in most aggregate tests. Second, CALIBRATION AND CHECKING PROCEDURES: it is not enough to have an oven, one must show that it holds its temperature, and do so in a defined way and at a defined frequency. Third, REAGENTS — an element few expect in aggregate testing, yet one needed in determinations such as density or the content of contaminants.

WHY THIS IS A SEPARATE PART OF THE SERIES. The PN-EN 932 series covers the general properties of aggregates: part 2 is methods for reducing samples (a separate entry in this knowledge base), part 5 is equipment and calibration. If the requirements for a balance and an oven were repeated in every test standard, each change of requirement would force the revision of a dozen or more documents at once, and a laboratory would have to watch whether they all said the same thing. Gathering them in one place solves that problem — and thereby makes this a standard one has to know, although it describes no test.

THE DIFFERENCE BETWEEN CALIBRATION AND CHECKING — TWO WORDS THAT ARE NOT SYNONYMS. The scope names both. Calibration establishes the relation between the indication of an instrument and a reference value and ends in a certificate; checking is a control activity, performed more often, confirming that the instrument still behaves as it did at calibration. A laboratory that calibrates its balance once a year and does not check it in between learns of a fault only at the next calibration — and all the results from the intervening period then become doubtful.

CHANGE OF EDITION AND OF LANGUAGE VERSION. The edition in force, PN-EN 932-5:2012, is in the ENGLISH version and superseded PN-EN 932-5:2001 — the POLISH version. The same pattern recurs with PN-EN ISO 9612, PN-EN 12390-4, PN-EN 482 and PN-EN 933-2 — all of them have separate entries in this knowledge base.

WHAT WE DO NOT GIVE. We do not have the text of the standard — PKN supplies it for a fee (25 pages, TC 108, ICS 91.100.15). We therefore GIVE NO NUMERICAL REQUIREMENTS for any instrument: neither the permissible temperature deviation of an oven, nor the scale interval of balances, nor the frequency of calibration and checking. These are quantities a laboratory must take from the text of the standard, not from commentaries.

Method principle

The result of an aggregate test depends on the instruments used at every stage: on the balance, the oven, the sieves and the vessels. Instead of repeating the requirements for them in every test standard, they were gathered in one document together with the procedures for calibration and checking and with the requirements for reagents. A method standard refers to this part, and the laboratory has one place in which to check what it may test with, and how.

Applications

• Equipping an aggregate testing laboratory — balances, ovens, sieves, vessels, thermometers
• Establishing the scope and frequency of calibration and checking of instruments
• A reference document invoked by the test standards of the EN 932 and EN 933 series
• Preparing for an accreditation assessment in the field of aggregates — demonstrating control over equipment

Key parameters

Standard

Standard number

PN-EN 932-5:2012 (wersja angielska; wprowadza EN 932-5:2012 [IDT])

Title (PL)

Badania podstawowych właściwości kruszyw -- Część 5: Wyposażenie podstawowe i wzorcowanie

Title (EN)

Tests for general properties of aggregates — Part 5: Common equipment and calibration

Step-by-step procedure

1. List the equipment used in the tests

   Write out the instruments that recur in the methods the laboratory performs. It is they that are subject to the requirements of this standard.

2. Check the requirements for each instrument

   WE DO NOT GIVE THE VALUES — they are in the text of the standard. Check them before purchase, not after.

3. Establish a calibration plan

   Calibration ends in a certificate and has a defined frequency.

4. Establish intermediate checks

   Checking is done more often than calibration. Without it a fault comes to light only at the next calibration, invalidating the results of the whole period.

5. Keep records

   Maintain a register of certificates and checks. At an accreditation assessment it is the register that proves control over equipment, not the mere possession of instruments.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Laboratory ovens work at temperatures that cause burns — thermal gloves are required when removing vessels
• Dust is raised when working with fine aggregates; with materials containing crystalline silica, respiratory protection is required
• TECHNICAL NOTE: an instrument with a calibration certificate a year old is no proof that today’s result is correct — that is what intermediate checks are for

Frequently asked questions