Small Bore Piping (Small Bore Attachments)

The most common cause of vibration problems

Small piping, tubing, blind flanges, and other attachments to the main process piping represent the most common vibration problem on rotating equipment packages.

Typically, small bore piping (SBP), also known as small bore attachments, branch connections, or small diameter appurtenances, are about 2 inches (5 cm) or less in diameter.

This article, printed in CompressorTech Two magazine’s April, 2012 issue provides a good overview.
> Small Bore Piping Failures on the Rise

> video clip showing small bore piping issues

small bore piping FEA

Stress evaluation of SBP indicates high risk of fatigue failure.

small bore measurements being taken

Small bore attachments are a major source of vibration





oil pipeline wired for SBP analysis

Small bore piping vibration analysis on an oil pipeline





Risks and Consequences of SBP Failures

SBP is highly susceptible to problems due to its geometry and mass. Even very low amplitude (and acceptable) vibration on the main process piping can cause the branch connections to vibrate excessively and break due to fatigue failure.

Small bore piping and the associate attachments are designed to meet process and instrumentation specifications, and are often installed in the field without any vibration consideration whatsoever. As a result, every small bore attachment is different.

The consequences of a SBP failure can be very large. A small crack will release process fluids, causing safety risks (explosion, fire, or toxic chemicals), environmental risk to the nearby area, and production downtime. There are many documented cases where SBP failures have shutdown compressor and pump stations.

Given the risk of SBP failures, owners must take an active role to identify and resolve vibration and integrity risks.

BETA Services

BETA has a proven vibration solution for refineries, production facilities, and compressor and pump stations.

The preferred approach is to assess SBP during the design stage and then assess vibrations during operations.


Services for Small Bore Piping (SBP) Vibration and Reliability Assessments

Front End Engineering Design (FEED)




Piping System Assessment

  • Pulsations
  • Flow Turbulence
  • Acoustic Induced
  • Mechanical excitations
  • Surge
  • Other Transient Events

Detailed Design of Compressor or Piping System




Detailed Analysis

  • Quantitative Approach (e.g., EI Guidelines)
  • Identify Fatigue Risks
  • Assess Pipe Support Design
  • Recommend Modifications

> SBP Design Services




Vibration Assessment

  • Steady State Conditions
  • Transient Operations

> SBP Field Assessment




Design Services: BETA analysts will evaluate the SBP design on rotating machinery packages, and recommend improvements to avoid resonance. This service applies to an entire facility, or to specific compressors, pumps, and other rotating machinery packages.
> SBP Design Services

Field Services: A vibration assessment is recommended once equipment is operating. BETA has evaluated thousands of machine packages and developed specialized software and testing approaches to identify and resolve SBP vibration risk.
> SBP Field Assessment

Training: BETA offers training on SBP vibration, including detailed information on industry standards, guidelines, case studies, and demonstrations.
> Seminars


 Other Resources

This case study discusses how transient operating conditions can affect SBP vibration.
> Transient Vibration on SBP

This technical paper provides background information on SBP design principles.
> Vibration Related Failures of Small Bore Attachments pdf

This article was published in CompressorTech2, June 2012
> Small Bore Piping Issues on the Rise pdf

This article published in Turbomachinery International, March/April 2012 includes requirements for small bore piping on pumps.
> Improving Equipment Reliability pdf

These guidelines were developed by the Energy Institute
> Guidelines for the avoidance of vibration induced fatigue failure in process pipework

This training video explains resonance, a key concept that contributes to SPB vibration.
>  Module 1, Vibration Problems: An Overview