SA TR ISO 12767-2023 PDF

Full title and description

ISO/TR 12767:2023 — Measurement of fluid flow by means of pressure differential devices — Guidelines on the effect of departure from the specifications and operating conditions given in ISO 5167. A technical report giving guidance for estimating flowrate errors and associated uncertainties when orifice plates, nozzles and Venturi tubes are manufactured, installed or operated outside the strict conditions assumed in the ISO 5167 series.

Abstract

This Technical Report (edition 3, 2023) summarizes observed effects and provides practical guidance and approximate correction/uncertainty estimates for common departures from ISO 5167 requirements. It treats variations such as plate flatness and thickness, edge condition and roughness, eccentricity, non‑standard tapping positions, carrier rings, local damage, installation geometry and Reynolds‑number effects. The report concentrates on orifice plates (with some examples for Venturi tubes and nozzles) and clarifies which deviations can be reasonably compensated and which require remedial action or yield large, unpredictable errors. It does not apply to cone meters or wedge meters.

General information

• Status: Published
• Publication date: September 2023 (published 22 September 2023)
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 17.120.10 — Flow in closed conduits
• Edition / version: Edition 3 (2023)
• Number of pages: 35

Scope

Provides guidance for users who must estimate or bound the error in flow measurement when pressure‑differential devices (mainly orifice plates, with some guidance for nozzles and Venturi tubes) are constructed, installed or operated outside the geometrical, manufacturing and installation tolerances assumed in the ISO 5167 series. The document describes the kinds of deviations encountered, gives approximate magnitudes and directions of resulting errors, and discusses limitations of combining multiple departures. It is intended as practical guidance rather than a prescriptive test method.

Key topics and requirements

• Identification and classification of common deviations from ISO 5167: plate roughness and edge radius, plate flatness (dishing), thickness and deformation.
• Effects of eccentric mounting and misalignment on discharge coefficient and signal stability.
• Influence of non‑standard pressure tapping positions and guidance for estimating associated uncertainty.
• Carrier‑ring and oversize carrier effects on discharge coefficient for various diameter ratios.
• Reynolds‑number related effects and limits of applicability of standard discharge‑coefficient correlations.
• Examples and quantitative estimates (where available) for error magnitudes and directions for typical deviations.
• Guidance on combining multiple deviations and caution about unpredictable interactions.
• Statement of non‑applicability to cone meters and wedge meters; emphasis on orifice plates as primary focus.
• Recommendations for inspection, manufacture and installation tolerances to limit measurement error.

Typical use and users

Used by flow measurement and metering engineers, calibration laboratories, process and utility engineers (water, oil & gas, chemical, power), pipeline operators, flowmeter manufacturers, standards writers and test houses. Commonly consulted when a pressure‑differential meter must be used in a non‑ideal installation, when investigating unexpected measurement bias, or when preparing acceptance criteria and installation instructions for orifice/nozzle/Venturi metering.

Related standards

Primarily linked to the ISO 5167 series (parts covering orifice plates, nozzles and Venturi tubes). Related documents include the previous editions of ISO/TR 12767 (2007 and earlier), ISO/TR 15377 (guidance for orifice plates, nozzles and Venturi tubes beyond ISO 5167), and the individual parts of ISO 5167 (‑1, ‑2, ‑3, ‑4). Users should consult the applicable ISO 5167 part(s) together with this TR for full measurement and calibration requirements.

Keywords

differential pressure; flow measurement; orifice plate; nozzle; Venturi tube; discharge coefficient; pressure tapping; installation error; measurement uncertainty; Reynolds number; plate roughness; eccentricity; carrier ring.

FAQ

Q: What is this standard?

A: ISO/TR 12767:2023 is a Technical Report that provides guidance on how departures from the geometric, manufacturing and installation requirements of the ISO 5167 series affect flowrate measurement using pressure‑differential devices.

Q: What does it cover?

A: It describes common deviations (for example plate roughness, edge radius, dishing, eccentricity, non‑standard tapping positions and carrier ring effects), gives approximate error magnitudes and directions where data exist, and offers practical advice on estimating uncertainties or taking corrective action. It focuses mainly on orifice plates, with some examples for Venturi tubes and nozzles.

Q: Who typically uses it?

A: Flow measurement engineers, calibration and test laboratories, plant and pipeline operators, manufacturers of metering equipment, and standards committees use this TR when evaluating non‑ideal installations or preparing installation and inspection procedures.

Q: Is it current or superseded?

A: This is the current edition (edition 3) published in September 2023. It supersedes earlier versions of ISO/TR 12767 (including the 2007 edition).

Q: Is it part of a series?

A: It is a supporting Technical Report to the ISO 5167 series (the principal standards for flow measurement by orifice plates, nozzles and Venturi tubes) and should be used alongside the relevant ISO 5167 part(s).

Q: What are the key keywords?

A: Differential pressure, orifice plate, discharge coefficient, flowrate error, pressure tapping, installation effects, measurement uncertainty, eccentricity, plate roughness, Venturi, nozzle.