Design Approach 2 (API 618, 5th edition)

Pulsation (Acoustical) Analysis

This study will recommend a pulsation control solution to limit pulsations and shaking forces. BETA can optimize the design to minimize pressure drop and improve performance.

Note: A Design Approach 2 (DA2) does not include a detailed mechanical analysis (see limitations below)


  • Assess the magnitude of pressure pulsations and unbalanced shaking forces.
  • Recommend a pulsation solution using API 618 design guidelines (5th edition).
  • Assess static and dynamic pressure drop (per API 618 guidelines).
  • Piping Restraint Analysis (Mechanical Review): Provide a Mechanical Review which includes an evaluation of pipe support locations using charts and empirical calculations.
  • Option: Design optimization to improve performance and reduce pressure drop losses.
    > more

Application & Technical Support

> Compressor risk assessment (short survey to determine study requirements)

> Information required for DA2 study

> Application Support for Reciprocating Compressors

Features In BETA’s DA2 Pulsation Study
This chart illustrates API 618 requirements and the standard features included in a BETA study.
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  • This study applies to less critical applications
  • This approach does not include a detailed mechanical analysis of the system to avoid resonance/vibration due to other shaking forces (gas forces, inertia, crosshead loads, etc.) These features are included in a Design Approach 3 (DA3) study.
  • Does not assess vibration in the skid and/or foundation design.  

Pulsation Forces 

BETA's non-linear Time Domain software is used to assess pulsation forces throughout the piping system. This analysis is compliant with API 618 5th edition.


Compressor Pulsation Research

BETA verifies its pulsation analysis techniques through field research. This includes pressure drop and performance analysis.

  • Standard analysis considers pulsation and vibration up to 150 Hz. Compressor cylinder gas passage acoustic resonance and shell mode vibration in piping and vessels are outside the scope of this analysis.
  • Off-skid piping will be included as long as the required information is available during the start of an analysis. If the information is not available during the course of the on-skid acoustical analysis we will use our proprietary method for performing a sensitivity analysis of the on-skid components to the off-skid components. BETA can revisit its work if off-skid details are made available after study is completed (additional scope).
  • Piping stresses are only calculated if the Forced Response study option(s) is selected as part of the DA3 study.

Customer Benefits

  • Avoid pulsation related vibration problems.
  • Avoid transmitting pulsation problems to nearby facilities.
  • Reduced meter error.
  • An optimized study will reduce total pressure drop and improve performance of the system (optional feature).

Beta Machinery Analysis is a global leader in pulsation analysis because of these factors:

  • Responsive application advice and ongoing customer service.
  • Our proprietary MAPAK software includes a non-linear Time Domain algorithm that provides accurate results.
  • Timely and practical recommendations.

Tips for Improved Compressor Designs

  • Involve BETA early in the project for input on piping layout and package design.
  • Specifications: To avoid vibration and reliability problems, include a specification for pulsation/vibration study with the compressor package bid documents.
    > Specification
  • Operating Conditions. Include all anticipated operating conditions in design scope to help avoid future vibration problems.
  • Pressure Drop. Ensure your pulsation consultant is compliant to API 618 (5th edition). This includes accurate predictions of static and dynamic pressure drop throughout the compressor package.
    > Article on dynamic pressure drop
  • Check to see if a Torsional Vibration Analysis or other analysis is required.


Reduction in Pulsation Forces 

As Found Piping System
(No Pulsation Study)

 After Beta Pulsation Study
(Using Time Domain Solver)
DA2 Forces As Found DA2 Reduced Forces After Study

Forces above 11,000 lbf


Forces below 200 lbf