⛽ Manual sampling of crude oil and liquid fuels from tanks, rail and road tankers, drums and pipelines — spot samples from levels, running and all-level samples; PN-EN ISO 3170

Petrochemistry PN-EN ISO 3170

Overview

WHAT THE STANDARD COVERS. Scope of ISO 3170:2004 (clause 1): manual methods for obtaining samples of liquid and semi-liquid hydrocarbons, tank residues and deposits from fixed tanks, railcars, road vehicles, ships and barges, drums and cans, and from liquids being pumped in pipelines. It applies to petroleum products, crude oils and intermediate products stored in tanks at or near atmospheric pressure or transferred by pipelines and handled as liquids at temperatures from near ambient up to 200 °C. It does not apply to special products with their own standards: electrical insulating oils (IEC 60475), liquefied petroleum gases LPG (ISO 4257), liquefied natural gas (ISO 8943) and gaseous natural gas (ISO 10715). According to the introduction, manual samples from a non-homogeneous liquid (large variations in composition, sediment and water) need not be representative, but make it possible to assess the degree of non-homogeneity; the procedures are intended to minimize losses of light ends during sampling and transfer. If the sampling conditions for determining quality, water and other contaminants conflict, separate samples are taken. The "Scope" field of the PKN card of PN-EN ISO 3170:2025-12, in full (our translation): "This document specifies the procedures used for the manual sampling of liquid or semi-liquid hydrocarbons, residues and deposits from stationary tanks, railcars, road vehicles, ships and barges, drums and containers, and of liquids pumped through pipelines. It applies to the sampling of liquid products, including crude oil and intermediate products, synthetic hydrocarbons and biofuels, stored in tanks at atmospheric or near-atmospheric pressure, or transferred by pipelines and remaining liquid at elevated pressure and temperature. The sampling procedures specified in the standard do not apply to the sampling of special petroleum products that are the subject of other International Standards, such as electrical insulating oils (covered by IEC 60474), liquefied petroleum gases (covered by ISO 4257), liquefied natural gases (covered by ISO 8943) and gaseous natural gases (covered by ISO 10715). This document refers to the sampling methods and sampling equipment in use at the time of writing. This does not exclude the use of new equipment, provided that such equipment allows samples to be taken in accordance with the requirements and procedures of this document." The card of the 2025 edition extends the scope to synthetic hydrocarbons and biofuels and does not repeat the 200 °C limit of the 2004 edition; for electrical insulating oils it gives IEC 60474, whereas the text of ISO 3170:2004 gives IEC 60475 (we have not read the wording of the scope of ISO 3170:2025 itself).

EDITION 2025 — WHAT HAS CHANGED (ISO 3170:2025 = EN ISO 3170:2025, foreword and introduction). The fourth edition (June 2025) replaced the 2004 edition as a technical revision: the title was changed from "Petroleum liquids" to "Hydrocarbon liquids" to cover non-petroleum liquids; closed and restricted sampling devices are described on an equal footing with the traditional open devices; clause 3 and the bibliography were expanded; clause 4 "Safety" was added. EN ISO 3170:2025 supersedes EN ISO 3170:2004; conflicting national standards were to be withdrawn by December 2025 at the latest. Table of contents of 2025: 4 safety, 5 sampling, 6 equipment (spot, zone, flow-through, running, all-level, bottom and sediment samplers; open, restricted and closed devices), 7 containers, 8 procedures (shore tanks and ships, pipeline, rail and road tankers, drums and IBCs, packages, dispensers), 9 product requirements (crude oil, gasolines and volatile liquids, aviation fuels, distillates, residual fuel oils and marine fuels, bitumen, samples for microbiological assay), 10 sample handling (transfer, labelling, transport, homogenizing and verification of its efficiency, composite and retained samples).

PRINCIPLES OF SAMPLING (ISO 3170:2004, clauses 3–5 — text read). Two basic manual methods: tank (static) and pipeline (dynamic) sampling; if both are used, the samples of the two shall not be mixed. Tank sampling begins when the contents are at rest; normally upper, middle and lower samples, or upper, middle and suction-level samples, are taken. The upper sample is a spot sample from 1/6 of the liquid depth below the surface, the middle one — from 1/2, the lower one — from 5/6; the "top" sample — 150 mm below the surface. If tests show that the contents are homogeneous, the samples are combined in proportion to the volume each represents; if non-homogeneous, samples are taken from more than three levels and either a composite sample is prepared or — if blending would impair the sample — each is analysed separately and the composition is calculated. A running sample and an all-level sample give a single sample, so they do not allow homogeneity to be assessed. A representative sample of a batch pumped through a pipeline is taken automatically according to ISO 3171; manual pipeline samples are spot samples and may not be representative. With a pressurized ullage space or a tank with vapour recovery, closed or restricted sampling via a vapour-lock valve is used. Equipment shall be leak-tight, robust and clean before use; synthetic fibre cords shall not be used for lowering the sampler (electrostatic sparks), and chains are not recommended (earth continuity cannot be guaranteed).

STATUS (state of the PKN cards on 10.10.2026). The card of PN-EN ISO 3170:2025-12 (English version) carries no withdrawal label: title "Ciecze węglowodorowe -- Ręczne pobieranie próbek" (Hydrocarbon liquids — Manual sampling; our translation), publication 11-12-2025, 84 pages, Sector of Chemistry, KT 222/PK 1 Liquid Fuels, "Replaces: PN-EN ISO 3170:2006 - Polish version", "Introduces: EN ISO 3170:2025 [IDT], ISO 3170:2025 [IDT]", ICS 75.080. The card of PN-EN ISO 3170:2006 (Polish version, "Ciekłe przetwory naftowe -- Ręczne pobieranie próbek", which introduced EN ISO 3170:2004 and ISO 3170:2004): WITHDRAWN on 11-12-2025 and replaced by PN-EN ISO 3170:2025-12. There is no Polish version of the 2025 edition — the current standard is available in English only.

CLAUSE NUMBERS IN THE SCOPES — TWO EDITIONS AT ONCE. In the 2004 edition the procedures are in clause 7 (7.3 tank sampling, 7.4 pipeline sampling) and 8 (crude oil and non-homogeneous liquids), whereas in the 2025 edition clause 7 is sample containers (7.3 — closures), and the procedures moved to clause 8 (8.3 tanks, 8.4 pipeline, 8.5–8.9 tankers, drums, packages, dispensers). Exclusions in the accreditation scopes are written in both numberings: AB 098 ("PN-EN ISO 3170 z wył. p. 7.3.1.1.4, 7.3.1.1.6, 7.3.1.1.7, 7.3.1.4, 7.3.1.5, 7.3.2, 7.4, 7.5…", without a year) and AB 1668 ("PN-EN ISO 3170:2006 z wyłączeniem pkt 7.3.1.1.4…") — according to the 2004 edition; AB 1278 ("PN-EN ISO 3170 z wyłączeniem pkt. 8.3.1.3…", without a year) and AB 484 ("PN-EN ISO 3170:2025-12 z wyłączeniem 8.3.1.3–8.3.1.6, 8.3.1.8, 8.3.2, 8.7…") — according to the 2025 edition.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database of 10.10.2026 and current PCA documents read on 10.10.2026). The number 3170 appears in 27 records at 8 laboratories: AB 387 (12 records, "PN-EN ISO 3170"), AB 484 (8, "PN-EN ISO 3170:2025-12" with exclusions), AB 391 (2, "PN-EN ISO 3170:2006"), AB 009 ("PN-EN ISO 3170"), AB 098, AB 1278, AB 1668 and AB 474 (1 each). In the current PCA documents the standard is present at seven laboratories, with no suspended entries; on 10.10.2026 the PCA page of laboratory AB 474 (accreditation valid until 16-12-2027) had no scope document attached, so we did not check its entries. The "Laboratories" tab ("PN-EN ISO 3170") shows 8 laboratories — all the same ones.

WHAT THE LABORATORIES DO (copy and PCA documents). At all eight it is an activity, not a measurement: "Sampling from tanks for chemical and physical tests" (variant "spot sampling" and one "from tanks and pipelines"). Subject: liquid fuels (unleaded petrol, diesel fuel, light and heavy fuel oil, marine fuel, kerosene, aviation turbine fuel, liquid biofuels — fatty acid methyl esters, bioethanol, bio-hydrocarbons) and crude oil, and at AB 474 and AB 484 also lubricants (base, engine and industrial oils), at AB 474 — petroleum distillates.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — a clause number without the year of the edition: the exclusion "7.3.1.1.4" with an undated reference read according to the 2025 edition points to the clause on container closures and not to tank sampling; clause numbers make sense only together with the year of the edition. Second — combining samples: a composite sample from the samples of three levels is prepared only after homogeneity has been shown; a running or all-level sample gives an average and hides stratification (ISO 3170:2004, 4.2). Third — a manual pipeline sample is a spot sample and does not replace an automatic sample according to ISO 3171 for batch settlement. Fourth — products outside the scope: LPG is sampled according to ISO 4257, not according to this standard. Fifth — withdrawn edition: three laboratories (AB 391, AB 474, AB 1668) cite PN-EN ISO 3170:2006, withdrawn on 11-12-2025; the 2025 edition has a different clause structure and a wider scope.

WHAT WE DO NOT GIVE. From the 2004 edition we read clauses 1–5.2.2.1 (scope, definitions, principles, general requirements for equipment) with the table of contents, and from the 2025 edition — the foreword, introduction and table of contents. We do not give descriptions of the individual samplers, volumes and materials of the containers, detailed procedures for tanks, ships, tankers, drums and packages, sampling plans for packages (AQL), requirements for individual products or the procedures for homogenizing and verifying its efficiency.

Method principle

The sample is taken manually so that it is as representative of the liquid as possible, taking into account the properties of the liquid, the tank or pipeline and the tests planned. From a tank — when the contents are at rest — spot samples are taken from three levels (1/6, 1/2 and 5/6 of the liquid depth, or the suction level) and combined in proportion to volume only when homogeneity has been shown; running and all-level samples give the average quality without an assessment of homogeneity. From a pipeline a representative sample is given by an automatic sampler according to ISO 3171, a manual one is a spot sample (ISO 3170:2004, clauses 3 and 4).

Applications

• Crude oil, liquid fuels and intermediate products in tanks at or near atmospheric pressure and in pipelines, at temperatures up to 200 °C (ISO 3170:2004)
• Fixed tanks, rail and road tankers, ships and barges, drums and cans; from the 2025 edition also IBCs, packages and dispensers (table of contents of ISO 3170:2025)
• In the accreditation scopes: 8 laboratories, sampling of liquid fuels and crude oil, at two of them also lubricating oils, for chemical and physical tests

Key parameters

Standard

Standard number

PN-EN ISO 3170:2025-12 (wersja angielska; wprowadza EN ISO 3170:2025 [IDT] oraz ISO 3170:2025 [IDT])

Title (PL)

Ciecze węglowodorowe — Ręczne pobieranie próbek

Title (EN)

Hydrocarbon liquids — Manual sampling (ISO 3170:2025; 2004 edition: Petroleum liquids — Manual sampling)

Step-by-step procedure

1. Preparation and safety

   Check that the equipment is clean and leak-tight; with a pressurized ullage space or vapour recovery — closed or restricted sampling via a vapour-lock valve. Do not use synthetic fibre cords for lowering the sampler.

2. Tank sampling

   With the liquid at rest: spot samples from 1/6, 1/2 and 5/6 of the liquid depth or from the suction level; possibly a running or all-level sample (without an assessment of homogeneity).

3. Assessment of homogeneity and combining

   Combine samples in proportion to volume only when homogeneity has been shown; if non-homogeneous, more levels, a composite sample or separate analysis and calculation.

4. Pipeline

   A representative sample of a batch — automatically according to ISO 3171; a manual pipeline sample is a spot sample. Do not mix tank and pipeline samples.

5. Sample handling and description

   Minimize losses of light ends during transfer; label, transport and homogenize before testing (clause 10 of the 2025 edition — we DO NOT GIVE details). For excluded clauses, give the year of the edition of the standard. Current PN-EN ISO 3170:2025-12; PN-EN ISO 3170:2006 withdrawn on 11-12-2025 (state of the PKN cards on 10.10.2026).

Required equipment and apparatus

Health and safety (OHS)

• Flammable liquids and vapours — fire and explosion hazard; static electricity: no synthetic fibre cords, ensure earth continuity (ISO 3170:2004, 5.2.1)
• Sampling from the tank roof and gauge hatches — work at height and risk of inhaling vapours; the 2025 edition has a separate clause 4 on safety (confined spaces, sampling points, electrical installations) — we DO NOT GIVE its content
• National regulations on sampling prevail over the standard in case of conflict (introduction to ISO 3170:2004)

Frequently asked questions