ANSI ASA S2.75-2017 part 1 PDF

Full title and description

ASA/ANSI S2.75-2017 — Shaft Alignment Methodology, Part 1: General Principles, Methods, Practices, and Tolerances. This part establishes a methodology, measurement practices, corrective-move guidance and a system of alignment quality grades for aligning shafts of rotating machinery coupled by flexible couplings where each machine case is supported by two bearings (typical horizontal driver‑and‑driven configurations such as motor–pump or motor–fan sets).

Abstract

Part 1 of ANSI/ASA S2.75 provides industry consensus procedures for measuring, analysing and correcting shaft misalignment on common four‑bearing, horizontally mounted machines with flexible couplings. It describes measurement methods (manual and laser), alignment tolerances expressed as Alignment Quality Grades, and best practices for planning and executing machine moves, supported by informative annexes covering calculation formulas, repeatability, laser detector systems and checklists.

General information

• Status: Active / Current (published 2017; reaffirmations noted in subsequent years).
• Publication date: 2017 (ANSI/ASA S2.75‑2017). Specific publication records show June 2017 as the original issuance.
• Publisher: Acoustical Society of America (ASA) in coordination with ANSI.
• ICS / categories: 17.160 — Vibrations, shock and vibration measurements (industrial machinery alignment / vibration control context).
• Edition / version: ANSI/ASA S2.75‑2017 — Part 1. Some listings show reaffirmation markings (for example R2020 / R2025) in later catalog records.
• Number of pages: Approximately 54–55 pages (published editions commonly listed at 54 or 55 pages).

Scope

This document establishes alignment methodology applicable to rotating machinery where two‑bearing, horizontally mounted machine cases are coupled by a flexible coupling. It covers conditions that affect alignment (mounting and base issues), methods for measuring misalignment (including manual and laser techniques), procedures for calculating corrective machine moves and placement tolerances expressed as Alignment Quality Grades. Rigidly coupled machines and configurations outside the stated bearing/coupling arrangement are outside the scope of Part 1. Informative annexes supply worked examples, formulas and practical checklists.

Key topics and requirements

• Definition and application of Alignment Quality Grades (tolerances) for shaft alignment.
• Measurement methods: manual dial‑indicator techniques and laser alignment system methods, with guidance on repeatability and detector systems.
• Procedures and best practices for controlled machine moves (jacking, shimming, addressing soft/bolt‑bound foot conditions).
• Off‑line‑to‑running (OLTR) considerations, pipe‑strain identification and correction, and graphical alignment modelling.
• Informative annexes with formulas, checklists and ancillary guidance to support practical alignment work.

Typical use and users

Used by rotating‑equipment maintenance engineers, vibration and reliability specialists, alignment technicians, plant engineering staff, OEMs and instrument vendors to specify, perform and verify shaft alignment work. Also referenced by consultants preparing installation and acceptance criteria for rotating machinery. The standard is a bridge between instrument manufacturers’ procedures and field alignment work practices.

Related standards

Part 1 is published alongside the S2.75 series: Part 2 provides vocabulary and definitions used with Part 1; Part 3 addresses vertical machines (published separately). The S2.75 package and related ASA/ANSI machinery‑alignment listings are available through ASA standards catalog offerings.

Keywords

shaft alignment; alignment methodology; Alignment Quality Grades; rotating machinery; laser alignment; dial‑indicator; machine moves; soft foot; coupling alignment; maintenance procedures.

FAQ

Q: What is this standard?

A: ANSI/ASA S2.75‑2017 Part 1 is a consensus standard that defines methodology, measurement practices and tolerances for aligning shafts of horizontally mounted, two‑bearing machine cases connected with flexible couplings.

Q: What does it cover?

A: It covers alignment measurement methods (manual and laser), tolerance grading (Alignment Quality Grades), practical procedures for relocating machine cases (including jacking and shimming), and informative annexes with formulas, checklists and guidance for common field issues such as pipe strain and repeatability. It does not cover rigidly coupled machines or configurations beyond the stated scope.

Q: Who typically uses it?

A: Maintenance and reliability engineers, alignment technicians, vibration analysts, OEM and instrumentation vendors, and engineering consultants responsible for installation, acceptance testing and ongoing maintenance of rotating equipment.

Q: Is it current or superseded?

A: The standard is listed as ANSI/ASA S2.75‑2017 (Part 1) and is shown in ASA/ANSI catalogs as active; some records note reaffirmation entries (e.g., R2020 / R2025) rather than full replacement. Check the ASA standards catalog or the ASA/ANSI Store for the definitive current status and any recent reaffirmations or amendments.

Q: Is it part of a series?

A: Yes — S2.75 is a multipart series. Part 1 covers general principles and tolerances, Part 2 contains vocabulary, and Part 3 addresses vertical machines (and other parts may be published as the committee develops them).

Q: What are the key keywords?

A: shaft alignment, alignment quality grades, rotating machinery, laser alignment, machine moves, soft foot, vibration/diagnostics.