⚗️ Free carbon dioxide in water — titrimetric method with phenolphthalein or using a potentiometer and indirect method using a nomogram; in accreditation scopes the titrimetric method, also for wastewater; PN-C-04547-01:1974 (withdrawn standard)

Physicochemistry PN-74/C-04547/01

Overview

WHAT THE STANDARD COVERS. The "Scope" field of the PKN card, in full: "The subject of the standard are the following methods for determining the content of free carbon dioxide in water: a) titrimetric method with phenolphthalein or using a potentiometer, b) indirect method using a nomogram." (our translation). We did not have the text of the standard (3 pages).

STATUS (cards as of 13.10.2026). The card of PN-C-04547-01:1974 (Polish version) bears the heading "Withdrawn": publication 25-10-1974, "Withdrawal date: 07-12-2016", 3 pages, price group B, Health, Environment and Medicine Sector, KT 121 Water Quality — Chemical Tests — Inorganic Substances, "Replaces: PN-C-04547:1956 - Polish version", ICS 13.060.50; there is no "Replaced by" field. The PKN search under "PN-C-04547" (13.10.2026) returns 5 items, all withdrawn: PN-C-04547:1956 (drinking water, water for domestic and industrial purposes — free carbon dioxide; "Withdrawn and replaced by PN-C-04547-01:1974"), sheet 00 "General provisions and scope of the standard" (withdrawn on 16-01-2006), this sheet, sheet 03 "Determination of aggressive carbon dioxide in water" (withdrawn on 07-12-2016) and sheet 05:1979 on total carbon dioxide in industrial water. We do not name a standard that would replace this sheet.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database from the production server, refreshed on 12.10.2026). Number 04547/01 appears in 8 records at 7 laboratories; in the current PCA documents (read on 12–13.10.2026; issues from 18.12.2025 — AB 005 — to 08.09.2026 — AB 300) — in 8 rows at the same laboratories (AB 005 repeats the notation in the English version of the entry; at AB 313 the same documents cell also covers aggressive carbon dioxide); a search of all downloaded PCA documents found no laboratories outside the database copy, no row with the number is set in bold italics, and no pages are repeated in any document. Notations: "PN-74/C-04547/01" — 5 laboratories (AB 213, AB 300 with "pkt. 2.1", AB 313 next to PN-74/C-04547/03, AB 418, AB 1095 with "pkt 2.1" and the location code "M" — Mysłowice); "PN-74/C-04547.01" — AB 005 (with "pkt 2.1") and AB 1488. The "Laboratories" tab looks for notations BEGINNING with the search term: "PN-74/C-04547/01" — 5 laboratories, "PN-74/C-04547.01" — 2 — checked with the tab query on the labcoda.pl production server on 13.10.2026; this page searches with "PN-74/C-04547/01", so the tab shows 5 of the 7 laboratories.

WHAT THE LABORATORIES TEST (database copy and PCA documents). Test object: water — AB 005, AB 213, AB 418; water, water intended for human consumption — AB 1488; water, wastewater — AB 300, AB 313; water, water intended for human consumption, wastewater — AB 1095. Characteristic: concentration of free carbon dioxide. Technique: titrimetric method — 6 laboratories; potentiometric titration method — AB 1095. Ranges: 2.2–220 mg/l — AB 313, AB 1488; 2.2–1000 mg/l — AB 300, AB 418; 2.2–2000 mg/l — AB 005; 4.4–2200 mg/l — AB 213; 8.8–4400 mg/l CO2 — AB 1095.

ALONGSIDE THIS STANDARD. In the entries with this standard: PN-74/C-04547/03 (aggressive carbon dioxide) — AB 313; the same set of documents stands there for aggressive carbon dioxide (calculated). Free carbon dioxide in water and wastewater is determined by 7 laboratories in the database copy (entries with free carbon dioxide in the test description or parameters and with water or wastewater as the test object) — all according to this standard. Aggressive carbon dioxide is determined by 8 laboratories: according to sheet 03 — 4 (AB 300, AB 313, AB 1095, AB 1488), according to PN-EN 13577:2008 — 4 (AB 005, AB 213, AB 418, AB 894). The card of sheet 03 gives three methods: with marble, indirect using the tables according to Lehmann and Reuss, and indirect using nomograms. The determination of aggressive carbon dioxide according to PN-EN 13577 is described in a separate Knowledge Base entry.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — method variant: the standard has a titrimetric method (with phenolphthalein or using a potentiometer) and an indirect one using a nomogram; the accreditation scopes give the titrimetric method, AB 1095 — potentiometric titration, and AB 005, AB 300 and AB 1095 narrow the citation to point 2.1 of the standard — check in the report which variant was used to obtain the result. Second — free and aggressive carbon dioxide are different quantities from different sheets (01 and 03) or from PN-EN 13577; the result of one cannot be reported as the other. Third — test object: "Water and wastewater" is the title of the series, while the "Scope" field of the sheet speaks of water; AB 300, AB 313 and AB 1095 also apply the standard to wastewater. Fourth — status: the sheet has been withdrawn since 07.12.2016 without a successor, the whole PN-C-04547 series is withdrawn. Fifth — tab: because of the two notations of the number, the "Laboratories" tab of this page shows 5 of the 7 laboratories.

WHAT WE DO NOT GIVE. We did not have the text of the standard — we do not give the titrant and its concentration, the sample volume, the way of taking and preserving the sample, the end point of the potentiometric titration, the nomogram, the calculation formula or the content of point 2.1. We do not give limit values for free carbon dioxide in water — we did not check the regulations.

Method principle

Free carbon dioxide in water is determined titrimetrically — with phenolphthalein or using a potentiometer — or indirectly, using a nomogram (PKN card); in accreditation scopes the laboratories give the titrimetric method. WE DO NOT GIVE the titrant, conditions or formula — we did not have the text of the standard.

Applications

• Water, including water intended for human consumption — concentration of free carbon dioxide (withdrawn sheet in the current accreditation scopes of 7 laboratories)
• Wastewater — in the accreditation scopes of AB 300, AB 313 and AB 1095 (the "Scope" field of the sheet speaks of water)

Key parameters

Standard

Standard number

PN-C-04547-01:1974

Title (PL)

Woda i ścieki — Badania zawartości dwutlenku węgla — Oznaczanie wolnego dwutlenku węgla w wodzie

Title (EN)

Water and wastewater — Tests for carbon dioxide content — Determination of free carbon dioxide in water

Step-by-step procedure

1. Sample

   Water (in accreditation scopes also wastewater); WE DO NOT GIVE the sampling or volume. PN-C-04547-01:1974 withdrawn on 07-12-2016 (card as of 13.10.2026).

2. Titration

   With phenolphthalein or using a potentiometer (PKN card); WE DO NOT GIVE the titrant.

3. Indirect method

   Or using a nomogram (PKN card); not indicated in the accreditation scopes.

4. Result

   Concentration of free carbon dioxide in mg/l (accreditation scopes); in the report the method variant.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Safety rules of a chemical laboratory and the safety data sheets of the reagents used
• SUBJECT-MATTER NOTE: free and aggressive carbon dioxide are different quantities — sheets 01 and 03 of the PN-C-04547 series or PN-EN 13577

Frequently asked questions