ISO 3945-1985 PDF

Full title and description

ISO 3945:1985 — Mechanical vibration of large rotating machines with speed range from 10 to 200 r/s — Measurement and evaluation of vibration severity in situ. This International Standard defines a single, practical characteristic (vibration severity) and gives rules for in‑situ measurement and evaluation on large rotating machines (generators, turbines, compressors, turbo‑pumps, fans, etc.).

Abstract

ISO 3945:1985 establishes methods for measuring and evaluating the vibration severity of large rotating machines operating at speeds from 10 to 200 revolutions per second. The standard defines the measurement quantity (root‑mean‑square vibration velocity over a specified frequency band) and recommends measurement points and evaluation principles focused on bearing and machine‑housing surfaces; it is intended to support condition assessment and acceptance testing of machines above about 300 kW.

General information

• Status: Withdrawn.
• Publication date: November 28, 1985 (Edition 2, 1985).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 17.160 (Mechanical vibration and shock).
• Edition / version: Edition 2 (1985).
• Number of pages: 6 pages.

Scope

The standard applies to measurement and evaluation of vibration severity in situ for large rotating machines with operating speeds in the range 10 to 200 r/s (approximately 600 to 12 000 min‑1). It addresses vibrations measured on bearing housings and nearby surfaces and bases its severity measure on r.m.s. vibration velocity measured across the relevant frequency band (the standard considers measurement content in the audio/vibration band up to about 1 000 Hz). ISO 3945 is focused on the global vibratory state of the machine and on assessment criteria relevant to machine function and serviceability (for machines of roughly >300 kW).

Key topics and requirements

• Definition of "vibration severity" as a single characteristic (r.m.s. vibration velocity) for in‑situ evaluation.
• Recommended measurement locations and directions (bearing housings, surfaces close to bearings).
• Frequency band considerations for the r.m.s. velocity measurement (practical measurements consider up to ~1 000 Hz).
• Guidance on interpreting measured levels for condition assessment and acceptance testing of large prime movers.
• Normative references and links to companion standards for instruments and evaluation bases (e.g., ISO 2372, ISO 2954).

Typical use and users

Used by rotating‑machine designers, site acceptance test teams, vibration analysts, maintenance and reliability engineers, and condition‑monitoring specialists to establish baseline vibration levels, perform acceptance testing, and support troubleshooting and maintenance decisions for large electric machines, turbines, compressors and pumps.

Related standards

ISO 3945:1985 was based on and related to earlier machine vibration standards (notably ISO 2372 and ISO 2954) and has been superseded by later evaluation standards in the ISO 10816 / 20816 family — specifically ISO 10816‑1:1995 (which revised/replaced ISO 3945) and later revisions in the ISO 10816 / ISO 20816 series. Other national/adopted equivalents and related documents (e.g., industry guides such as API 670 and later ISO 20816 series) give complementary guidance.

Keywords

mechanical vibration, rotating machines, vibration severity, r.m.s. velocity, in‑situ measurement, bearing vibration, acceptance testing, condition monitoring.

FAQ

Q: What is this standard?

A: ISO 3945:1985 is an ISO International Standard titled "Mechanical vibration of large rotating machines with speed range from 10 to 200 r/s — Measurement and evaluation of vibration severity in situ." It defines a practical vibration‑severity quantity and gives rules for field measurement and evaluation on large rotating machines.

Q: What does it cover?

A: It covers in‑situ measurement and evaluation of vibration severity on large rotating machines (examples: generators, steam/gas turbines, turbo‑compressors, turbo‑pumps, fans) with speeds from 10 to 200 r/s, specifying measurement points, the measurement quantity (r.m.s. velocity over a defined frequency band) and interpretation principles for condition and acceptance assessments.

Q: Who typically uses it?

A: Vibration analysts, plant maintenance and reliability engineers, commissioning and test teams, rotating‑machine designers, and standards/quality professionals involved in procurement and acceptance testing of large rotating equipment.

Q: Is it current or superseded?

A: ISO 3945:1985 has been withdrawn and is no longer current. It was revised and replaced in the ISO 10816 family (ISO 10816‑1:1995 is cited as the successor to ISO 3945), and later parts/revisions (ISO 20816 series) have further updated machine‑vibration evaluation guidance. A withdrawal record indicates the ISO 3945 entry was withdrawn (withdrawal actions recorded by ISO and some distributors); for example, withdrawn status is shown on ISO's catalogue and distributor records, and a withdrawal date shown in some records is 23 September 2021. Consult the ISO 10816 / 20816 series for the current evaluation criteria.

Q: Is it part of a series?

A: Yes — ISO 3945 belongs to the body of ISO standards on mechanical vibration and machine vibration evaluation (linked to ISO 2372, ISO 2954 and later the ISO 10816 / ISO 20816 series). It was effectively incorporated into the broader ISO 10816 family of machine vibration evaluation standards.

Q: What are the key keywords?

A: Key keywords are: vibration severity, large rotating machines, r.m.s. vibration velocity, in‑situ measurement, bearings, acceptance testing, condition monitoring.