1.1 本规范涵盖了标识为“环己烷999”的环己烷等级 1.2 以下内容适用于本标准中的所有规定限值:为了确定是否符合本标准，应根据实践修约方法，将观察值或计算值四舍五入到表示规范限值所用的最后一位右手数字中的“最接近单位” 第29页 . 1.3 对于本规范中使用的所有材料，请参考当前的OSHA法规、供应商的安全数据表和当地法规。 1.4 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》中确立的国际公认标准化原则制定的。

1.1 This specification covers a grade of cyclohexane identified as “cyclohexane 999.” 1.2 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off “to the nearest unit” in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E29 . 1.3 Consult current OSHA regulations, supplier’s Safety Data Sheets, and local regulations for all materials used in this specification. 1.4 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.