This document focuses on recommending condition monitoring (CM) techniques for detecting and diagnosing developing machine faults associated with the most common potential failure modes in reciprocating compressors.

This document is intended

1. to set out a reliable and effective CM approach for reciprocating compressors,
2. to create a mutual understanding of the criteria for successful reciprocating compressor CM and to foster cooperation between the various application stakeholders,
3. for use by end-users, contractors, consultants, service providers, machine and part manufacturers and instrument suppliers,
4. as the reciprocating compressor design, its operation and maintenance regime can be very different from one application to the next, it is important to highlight that condition monitoring and diagnostics method described in this document is reference guidelines and non-mandatory information, and
5. To make this standard more effective, it is required to actively share the operation and condition data of the reciprocating compressor among the relevant parties.
6. Some of the reciprocating compressor types covered by the requirements of this document include:
7. slow (under 600 r/min) and moderate speed (600 r/min to 1 000 r/min) machines manufactured and procured in accordance with the requirements of API STD 618;
8. high-speed and pre-packaged machines (over 1 000 r/min) on a skid that are manufactured and procured in accordance with the requirements of ISO 13631 or API SPEC 11P;
9. hyper compressors used for secondary ethylene compression in low density polyethylene (LDPE) production;
10. lubricated and non-lubricated machines;
11. water-cooled and gas-cooled machines;
12. horizontal, vertical V-type, L-type and W-type machines;
13. horizontal, vertical machines with piston rings and those with labyrinth seal pistons (vertical machines only);
14. single-acting and double acting machines;
15. machines with a tandem cylinder configuration;
16. single and multi-stage compression machines;
17. machines with and without capacity control;
18. ring, poppet, reed and plate valve type machines;
19. machines mounted on flexible and rigid structures;
20. machines driven by electric motors, gas and diesel engines, turbines (with or without a gearbox) all with a flexible or rigid coupling;
21. tintegral gas-engine-driven machines (engine portion out of scope);
22. offshore applications (e.g. platforms, FPSOs (floating production storage and offloading), FLNGs (floating liquified natural gas), FPU (offshore foating production unit) and fixed installations).

This document focuses on the compressor itself (cylinders, distance pieces, crosshead, frame and all internal parts) and not on the prime mover or the external systems (e.g. piping, scrubbers, pulsation vessels, and pulsation control devices). Only brief mention is made of monitoring the foundation, skid and pedestal.

The scope does not include requirements for monitoring the auxiliary systems (e.g. for lubrication, cylinder cooling, intercoolers and gas purging), but process parameters from these systems are often monitored.

The scope does not cover installation analyses of systems either, (e.g. pulsation and mechanical response and thermal analysis of the piping).

This document covers online (permanently installed) and portable instrument CM and diagnostic techniques for operating reciprocating compressors.

Machine testing, which is only done during shutdown, although very important, is not part of the scope of this document, nor is the one-time acceptance and performance testing.