ISO 18501:2025

This document specifies normative references, terms and definitions, rating requirements, published rating, tolerance and marking provisions of positive displacement refrigerant compressors. This document applies to positive displacement refrigerant compressors and their performance in air-conditioning, heating, refrigeration and dehumidification applications. Single stage, two-stage and refrigerant-injected compressors without intermediate temperature load (only one evaporator) are included in this document. Subcritical operation and transcritical operation are also included in this document. Compressors for other applications, compression types and operations can also refer to this document. The manufacturer is solely responsible for the determination of values to be used in the published product information. This document is intended as guidance for the industry, including manufacturers, engineers, installers and service contractors. It defines the minimum amount of information in a standard form to enable the evaluation and comparison of different compressors for use in an application.