本文件规定了一般工业应用中静液压和流体动力系统对未使用的耐火和易燃性较低的液压油的最低要求。它不适用于不同要求的航空航天或发电应用。它为这些危险性较小的液体的供应商和最终用户以及使用这些液体的液压设备的制造商提供指导。 ISO 6743-4对液压应用中使用的不同类型的流体进行了分类，本文件仅详细介绍了以下类别:HFAE、HFAS、HFB、HFC、HFDR和HFDU。 HFAE、HFAS、HFB、HFC和HFDR是ISO 5598定义的“耐火”液体。大多数HFDU液体虽然比矿物油的燃烧性能有所改善，但不属于这一定义，更适合被视为“不太易燃”的液体。

This document specifies the minimum requirements of unused fire-resistant and less flammable hydraulic fluids for hydrostatic and hydrodynamic systems in general industrial applications. It is not intended for use in aerospace or power-generation applications, where different requirements apply. It provides guidance for suppliers and end users of these less hazardous fluids and to the manufacturers of hydraulic equipment in which they are used. Of the categories covered by ISO 6743-4, which classifies the different types of fluids used in hydraulic applications, only the following are detailed in this document: HFAE, HFAS, HFB, HFC, HFDR and HFDU. Types HFAE, HFAS, HFB, HFC and HFDR are "fire-resistant" fluids as defined by ISO 5598. Most HFDU fluids, while displaying an improvement in combustion behaviour over mineral oil, fall outside this definition and are more appropriately considered as "less flammable" fluids.