ISO 21049:2004规定了石油、天然气和化学工业用离心泵和旋转泵密封系统的要求和建议。它主要适用于危险、易燃和/或有毒服务，其中需要更高程度的可靠性，以提高设备的可用性，减少对大气的排放和寿命周期密封成本。它覆盖直径为20毫米（0.75英寸）至110毫米（4.3英寸）的泵轴密封件。 ISO 21049:2004也适用于密封备件，可供现有设备升级参考。 ISO 21049:2004涵盖的密封配置分类系统包括类别、类型、布置和方向。

ISO 21049:2004 specifies requirements and gives recommendations for sealing systems for centrifugal and rotary pumps used in the petroleum, natural gas and chemical industries. It is applicable mainly for hazardous, flammable and/or toxic services where a greater degree of reliability is required for the improvement of equipment availability and the reduction of both emissions to the atmosphere and life-cycle sealing costs. It covers seals for pump shaft diameters from 20 mm (0,75 in) to 110 mm (4,3 in). ISO 21049:2004 is also applicable to seal spare parts and can be referred to for the upgrading of existing equipment. A classification system for the seal configurations covered by ISO 21049:2004 into categories, types, arrangements and orientations is provided.