描述了10 kHz至40 GHz频率范围内空外壳对电磁干扰防护等级的性能要求、试验方法和分类程序。 测量屏蔽保护是为了证明外壳提供了足够的电磁能量屏蔽，以支持按照适用IEC标准测试时完整组装单元的可接受性能。 本标准的目的是提供一种可重复的方法，用于评估空机械外壳（包括机柜和机架）的电磁屏蔽性能，并指定标记代码，以允许制造商选择具有已知衰减电磁场能力的外壳。 制造商在确定是否需要将本标准应用于特定设备和应用以及特定外壳屏蔽要求时，需要考虑对各种类型电磁干扰（包括闪电和高空电磁脉冲（HEMP））的抗扰度要求，这些要求是频率的函数。

Describes performance requirements, test methods and classification procedures for degrees of protection provided by empty enclosures against electromagnetic disturbances for frequencies between 10 kHz and 40 GHz. The shielding protection is measured for the purpose of demonstrating that the enclosure provides adequate shielding of electromagnetic energy to support acceptable performance of the complete assembled units when tested to applicable IEC standards. The purpose of this standard is to provide a repeatable means for evaluating the electromagnetic shielding performance of empty mechanical enclosures, including cabinets and subracks, and to specify a marking code to allow a manufacturer to select an enclosure with a known capability for attenuating electromagnetic fields. The requirements for immunity to various types of electromagnetic disturbances, including lightning and high-altitude electro-magnetic pulse (HEMP) will need to be considered by manufacturers when determining the need for application of this standard for specific equipment and applications, and for the specific enclosure shielding requirements which are necessary as a function of frequency.