🔬 Dissolved acetylene — classification, requirements and determination of impurities, PN-C-84905
In short
A national standard for acetylene dissolved in acetone: it gives the classification and requirements, describes methods for determining the impurities it contains, and provides information about the porous fillers used in acetylene cylinders. The test is performed according to PN-C-84905:1998 (wersja polska); Presence in accreditation scopes (own measurement): ZERO entries and zero laboratories (measurement 23 September 2026: every form of the number, in four fields). The standard describes a product — dissolved acetylene — but also contains methods for determining impurities (see the description). Why no laboratory enters it in its scope, we have not established. The procedure comprises 5 steps; it is used for: Assessment of the quality of industrial acetylene supplied in cylinders, Control of acetylene used as the fuel gas in flame atomic absorption spectrometry (FAAS), Acetylene for welding and cutting metals.
At a glance
- Standard: PN-C-84905:1998 (wersja polska)
- Category: Physicochemistry
- Procedure steps: 5
- Presence in accreditation scopes (own measurement): ZERO entries and zero laboratories (measurement 23 September 2026: every form of the number, in four fields). The standard describes a product — dissolved acetylene — but also contains methods for determining impurities (see the description). Why no laboratory enters it in its scope, we have not established
- Subject of the standard: Acetylene DISSOLVED IN ACETONE — not compressed acetylene, which is not stored in that form
- Three layers of the document: Classification and requirements (product standard); methods for determining impurities (methodology); information about porous fillers (packaging)
Overview
THE SCOPE FROM THE PKN CATALOGUE CARD, IN FULL: "The classification and requirements for acetylene dissolved in acetone are given. Methods for the determination of the impurities it contains are described. Information is also given about the porous fillers used in acetylene cylinders".
THREE THINGS IN ONE DOCUMENT — A RARE COMBINATION. The standard is at once a product standard (classification and requirements), a collection of test methods (determination of impurities) and a document about the packaging (porous fillers in cylinders). Such a combination is met with in older national standards; newer European documents usually separate these layers into distinct items. For a laboratory it means that one standard here answers questions that elsewhere would require three.
WHY THE ACETYLENE IS "DISSOLVED" AND WHY THIS IS NOT A COMMERCIAL DETAIL. Compressed acetylene is unstable — under pressure it can decompose explosively even without oxygen. It is therefore not stored like other industrial gases: the cylinder is filled with a porous mass saturated with acetone, in which the acetylene dissolves. Hence the name of the product and hence the presence in the standard of information about porous fillers — here the packaging is part of the safety conditions of the product and not merely a container.
ACETONE AS A SOLVENT — AND AS AN IMPURITY. The very substance that makes the safe storage of acetylene possible passes in part into the gas phase on withdrawal. The acetone content of the gas drawn off is therefore one of the parameters that matter in assessing quality — particularly where the acetylene serves as a fuel for burners in analytical work.
USE IN THE LABORATORY. Acetylene is the fuel gas in flame atomic absorption spectrometry (FAAS) — a technique present in many entries of this knowledge base, among others in the determination of metals in workplace air and in water. The purity of the acetylene there affects the background and the stability of the flame directly, and hence the limit of determination.
THE AGE OF THE STANDARD. The edition dates from 1998 and superseded the edition of 1971. The card retrieved on 16 September 2026 contains neither the heading "Withdrawn" nor a "Date of withdrawal" row — the standard is in force. It is a purely national standard: the card has no "Implements" field, so it implements no European or international document.
WHAT WE DO NOT GIVE. We do not have the text of the standard — PKN supplies it for a fee (7 pages, KT 223 — the PKN technical committee for Industrial Gases). We therefore GIVE NEITHER the purity classes, NOR the permissible contents of impurities, NOR the details of the methods of determining them.
Method principle
Industrial acetylene is stored dissolved in acetone held in the porous mass filling the cylinder, which prevents its explosive decomposition under pressure. Assessment of the product covers the classification, verification of the requirements and the determination of impurities by methods given in the same standard; the information about the porous filler is part of it — the card speaks of "information", not of requirements — because the packaging conditions the safety of the product.
Applications
- Assessment of the quality of industrial acetylene supplied in cylinders
- Control of acetylene used as the fuel gas in flame atomic absorption spectrometry (FAAS)
- Acetylene for welding and cutting metals
- Assessment of the porous fillers used in acetylene cylinders
Key parameters
| Parameter | Value |
|---|---|
| Presence in accreditation scopes (own measurement) | ZERO entries and zero laboratories (measurement 23 September 2026: every form of the number, in four fields). The standard describes a product — dissolved acetylene — but also contains methods for determining impurities (see the description). Why no laboratory enters it in its scope, we have not established |
| Subject of the standard | Acetylene DISSOLVED IN ACETONE — not compressed acetylene, which is not stored in that form |
| Three layers of the document | Classification and requirements (product standard); methods for determining impurities (methodology); information about porous fillers (packaging) |
| Why dissolved | Compressed acetylene can decompose explosively without oxygen — dissolving it in acetone within a porous mass is a condition of safe storage |
| Character of the standard | NATIONAL — the card has no "Implements" field, so it implements no European or international document |
| Use in the laboratory | The fuel gas in FAAS — its purity affects the background and the stability of the flame, and hence the limit of determination |
| Classes and values of impurities | WE DO NOT GIVE the full list — we do not have the text of the standard (7 pages). In laboratory practice one meets dissolved acetylene of CLASS A, cited as such in other entries of this knowledge base |
| Status | In force — the PKN card carries neither the heading "Withdrawn" nor a "Date of withdrawal" row (checked 16 September 2026); supersedes the 1971 edition |
Standard
- Standard number
- PN-C-84905:1998 (wersja polska)
- Title (PL)
- Gazy techniczne -- Acetylen rozpuszczony
- Title (EN)
- Technical gases — Dissolved acetylene
Step-by-step procedure
-
Establish the class of the product
The standard gives a classification; we do not quote the full list of classes, as we do not have the text. Other entries in this knowledge base cite dissolved acetylene of CLASS A to PN-C-84905 — it is therefore one of the classes met with in laboratory practice.
-
Take a sample of the gas
From the cylinder, observing the precautions proper to a flammable gas under pressure.
-
Determine the impurities
By the methods described in the same standard.
-
Check the porous filler
Information about fillers is part of the standard — relevant in assessing the cylinder, not the gas itself.
-
Record in the report
Give the class of the product and the full designation of the standard with its year.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Apparatus for determining impurities | The methods are described in the standard itself — we do not hold its text, so we do not list the apparatus | — |
| Acetylene pressure regulator | Acetylene fittings must contain no copper or alloys high in copper — acetylene forms explosive acetylides with it | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Acetone | 67-64-1 | The solvent in which the acetylene is stored; it passes in part into the gas phase on withdrawal |
Health and safety (OHS)
- Acetylene is an extremely flammable gas, forming explosive mixtures with air over a very wide range of concentrations
- Compressed acetylene can decompose explosively WITHOUT OXYGEN — cylinders are protected against shocks and heating and stored upright only
- Acetylene forms explosive acetylides with copper and silver — fittings must contain no copper or alloys high in it
- The acetone released on withdrawal is flammable and an irritant — work with ventilation
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-C-84905:1998 (wersja polska) — “Technical gases — Dissolved acetylene”.
How does this method work?
Industrial acetylene is stored dissolved in acetone held in the porous mass filling the cylinder, which prevents its explosive decomposition under pressure. Assessment of the product covers the classification, verification of the requirements and the determination of impurities by methods given in the same standard; the information about the porous filler is part of it — the card speaks of "information", not of requirements — because the packaging conditions the safety of the product.
What is the measuring range and accuracy?
Presence in accreditation scopes (own measurement): ZERO entries and zero laboratories (measurement 23 September 2026: every form of the number, in four fields). The standard describes a product — dissolved acetylene — but also contains methods for determining impurities (see the description). Why no laboratory enters it in its scope, we have not established; Subject of the standard: Acetylene DISSOLVED IN ACETONE — not compressed acetylene, which is not stored in that form; Three layers of the document: Classification and requirements (product standard); methods for determining impurities (methodology); information about porous fillers (packaging); Why dissolved: Compressed acetylene can decompose explosively without oxygen — dissolving it in acetone within a porous mass is a condition of safe storage.
How long does the test take?
The procedure comprises 5 steps. The standard does not give a duration for every stage — the laboratory's own procedure decides.
What equipment is required?
Apparatus for determining impurities, Acetylene pressure regulator.
Where is this test used?
Assessment of the quality of industrial acetylene supplied in cylinders; Control of acetylene used as the fuel gas in flame atomic absorption spectrometry (FAAS); Acetylene for welding and cutting metals; Assessment of the porous fillers used in acetylene cylinders.
What safety precautions apply?
Acetylene is an extremely flammable gas, forming explosive mixtures with air over a very wide range of concentrations; Compressed acetylene can decompose explosively WITHOUT OXYGEN — cylinders are protected against shocks and heating and stored upright only; Acetylene forms explosive acetylides with copper and silver — fittings must contain no copper or alloys high in it; The acetone released on withdrawal is flammable and an irritant — work with ventilation.
Which laboratory can perform this test?
The test is performed by laboratories accredited to ISO/IEC 17025. On LabCoda you can find them by the standard number PN-C-84905.