本标准介绍了三种测定室外隔音屏障插入损耗的方法。这些方法在测量前后都是“直接”的；在“等效”现场进行测量之前的“间接”；以及“间接”预测之前的声级。“间接测量前”和“间接预测前”方法要求直接测量后声级。声学描述符的测量使用现场自然存在的声源、受控自然声源或受控人工声源。在规定的限制范围内，可根据确定屏障插入损耗的目标选择接收器位置和大气、地面和地形条件。提供了可用于数据采集和分析的工作表示例。

This standard presents three methods for determining the insertion loss of outdoor noise barriers. The methods are "direct" BEFORE and AFTER measurements; "indirect" BEFORE measurements at an "equivalent" site; and "indirect" predictions of BEFORE sound levels. "Indirect BEFORE measurements" and "indirect BEFORE prediction" methods require direct measurements of AFTER sound levels. Measurements of acoustical descriptors use sound sources naturally present at a site, controlled natural sound sources, or controlled artificial sound sources. Within prescribed limits, the receiver location and atmospheric, ground, and terrain conditions may be chosen based on the objectives for determination of barrier insertion loss. Examples are provided for worksheets that may be used for data acquisition and analysis.