1.1 本指南有助于计算和证实纸质包装产品中的回收含量。使用质量平衡/材料平衡，因为迄今为止没有确定的物理测试方法来测量任何纸制品的回收含量。计算依据特定等级或相似等级时的时间加权平均流量和稠度，通过批/时间加权平均法测定。使用这种方法在批的回收内容的各部分分配平均数是不正确的。例如，如果50%的回收纤维是随时间的推移用于生产，那么50%为时间加权平均值。使用相同的数据来报告50%的产品100%回收是不合法的。 1.1.1 百分比计算基于回收纤维重量占产品纤维总重量（见 8.1 和 8.2 ）并以整数表示。 1.1.2 这些计算中不使用制浆和回收产率。成品中回收纤维含量的计算仅是配料流中纤维类型、流量和所考虑周期的函数。用于平均的周期应反映生产运行所用的时间。对于交叉修剪的长跑，这段时间可能不到一个小时到一周。 1.2 本指南涵盖:含有任何数量或种类的再生纤维的包装纸和纸板产品的再生含量，以及计算和证实买卖双方协议声称的再生纤维含量水平的方法。 1.2.1 当回收的非纤维材料（例如填料）是再循环纤维配料的一部分时，本指南可以修改或不修改地用于计算或证实包装纸和纸板产品的再循环含量。对于确定纸制品中回收的非纤维材料的量，没有提供对本指南进行适当修改的建议。 1.3 本指南不推荐回收纤维或材料的数量或种类。计算和证实程序可用于任何数量或种类的回收材料。产品中回收成分的数量和种类应由买卖双方协商决定。 1.4 本指南推荐的质量平衡计算方法可能符合也可能不符合适用的联邦、州或地方关于面向消费者的回收内容声明的法律。关于回收内容声明的一些指南在 附录X1 . 1.5 本标准仅适用于计算，不包含安全隐患。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。

1.1 This guide aids in calculating and substantiating recycled content in paper-based packaging products. Mass balance/material balance is used, since no established physical-test method is available to date which measures the recycled content of any paper product. Calculations are based on time weighted average flow rates and consistencies, measured at paper and paperboard mills, by batch/time weighted average, for a specific grade or similar grades. It is not correct to use this method to allocate the average among portions of the batch’s recycled content. For example, if 50 % recycled fiber is used for production over time, then 50 % is the time weighted average. It is not legitimate to use the same data to report that 50 % of the production is 100 % recycled. 1.1.1 Percentage calculations are based on recycled fiber weight to total product fiber weight (see 8.1 and 8.2 ) and are expressed in whole numbers. 1.1.2 Pulping and recycling yields are not used in these calculations. The calculations of recycled fiber content in the finished product are solely a function of type of fibers in the furnish flows, the volume of flow and the period considered. The period used for averaging should reflect the time used for the production run. This period may be less than one hour to as much as a week for long runs with cross trim. 1.2 This guide covers: recycled content of packaging paper and paperboard products that contain any amount or kind of recycled fiber, and methods to calculate and substantiate the level(s) of recycled fiber content claimed by an agreement between the buyer and seller. 1.2.1 This guide may be used with or without modification to calculate or substantiate the recycled content of packaging paper and paperboard products when recovered nonfibrous materials (for example, filler) are a part of the recycled fiber furnish. No advice is provided for appropriate modifications to this guide for the determination of amount of recycled nonfibrous materials in paper products. 1.3 This guide does not recommend either an amount or a kind of recycled fiber or material. The calculation and substantiation procedures may be used for any amount or kind of recycled material. The amount and kind of recycled content in a product should be decided by agreement between the buyer and seller. 1.4 The mass balance calculation method recommended by this guide may or may not comply with applicable federal, state, or local laws about recycled content statements intended for consumers. Some guidance on recycled content statements is in Appendix X1 . 1.5 This standard pertains only to calculations and contains no safety hazards. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.