本文件规定了一种实验室方法，以便于比较家具组合和外壳降低产品内部使用者说话水平的能力。购买本文件时可获得的所有当前修订均包含在购买本文件中。

This document specifies a laboratory method to facilitate the comparison of furniture ensembles and enclosures with respect to their ability to reduce the speech level of the occupant speaking inside the product.All current amendments available at time of purchase are included with the purchase of this document.