National Standard for Vibration Testing of Air Compressors

Standard Positioning and Target Audience

The national standard for vibration testing of air compressors is typically used to specify the methods for conducting vibration tests on the complete unit or its critical components under defined operating conditions. It is applicable to performance verification, factory acceptance testing, and field condition assessment for various types of air compressors. In practical applications, it is essential to first identify the equipment type, installation configuration, and test objectives before selecting the appropriate provisions.

Main experimental content

• Operational Vibration Measurement:Near the steady-state speed and rated discharge pressure, observe the vibration responses of the unit’s foundation, casing, and piping.
• Start-up and shutdown procedure inspection:Monitor vibration changes during acceleration and deceleration phases to detect resonance, abnormal impacts, or signs of looseness.
• Structural Connection Verification:Examine the impact of the condition of anchor bolts, vibration isolation devices, pipeline supports, and couplings on the test results.
• Repeatability verification:Under identical conditions, perform multiple measurements to determine whether the data are comparable.

Test Conditions and Installation Requirements

Prior to testing, ensure that the compressor has been fully installed and meets all safety‑related operating requirements. The test foundation, mounting method, vibration isolation measures, and piping connections should, as far as possible, reflect actual service conditions. Measurement locations shall be positioned away from non‑rigid components such as protective guards and flexible hoses, and the report must document the orientation of each measurement point, the equipment’s operating condition, and the ambient environmental conditions.

Measurement Parameters and Data Processing

• Measurement point layout:It typically covers the main load-bearing components of the unit and, when necessary, extends to the foundation and piping.
• Direction Selection:Measurements can be taken separately in the horizontal, vertical, and axial directions.
• Data Recording:Rotational speed, load, pressure, temperature, and measurement instrument information shall be recorded.
• Exception Analysis:Abnormal peaks should be assessed comprehensively in conjunction with the spectrum, operating condition changes, and equipment structure.

Key Points for Results Evaluation and Reporting

When evaluating vibration results, it is inadvisable to rely solely on a single numerical value; instead, analysis should take into account the equipment type, speed range, mounting configuration, and historical data. The test report should include the test basis, equipment information, schematic of measurement points, instrument model, operating condition parameters, raw data, descriptions of any abnormalities, and conclusions and recommendations. If the relevant standards specify clear limit values or assessment criteria, these shall be applied in accordance with the currently valid version.

Application Precautions

• When citing standards, verify the standard number, year of publication, and any amendments to avoid using superseded versions.
• Air compressors with different structural configurations exhibit significantly varying vibration characteristics, making it inappropriate to apply a single, uniform assessment method.
• Field tests are significantly influenced by the foundation, piping, and load; any deviations should be documented in the report.
• When test results approach limit values or exhibit abnormal trends, it is recommended to increase the frequency of repeat testing and monitor trends.