scope:

Scope and purpose

This Standard is the application of alignment concepts concerning relative positions of rotating shafts connected by mechanical means. It contains specific tolerances, factors affecting alignment, and an overview of various measurement methods, following the core technical components of Measure, Analyze, Correct, and Document.

The intended users are craftspersons, front line supervisors, maintenance managers, procedure writers, construction managers, and engineers who design, install, or maintain rotating machinery.

The potential consequences of not following this standard are accelerated wear of machine components (bearings, couplings, and seals), shortened machine life, unscheduled outages, and hazards to personnel.

This standard covers the general configuration of two machines (usually horizontal) and four-bearing systems with rotating shafts. It does not cover vertical machines, strategies for aligning multiple (three or more) machine train systems, large and heavy machines with significant shaft sag, Cardan shaft with universal joints, three bearing machines (diesel generator sets), nor bore alignments. The principles presented here may also be applicable to these other machine configurations.

The purpose of this standard is to establish guidelines of acceptability for alignment of rotating machinery. The guidelines are based on industry best practices and experience gained in reliability. The requirements and recommendations placed here are intended to result in consistent and uniform final operating conditions at the machine.