IAPMO Z124。5-2013e1（R2018）涵盖了塑料马桶座圈（包括马桶座套），并规定了材料、结构、性能测试和标记的要求。本标准的要求并不旨在阻止使用替代材料或施工方法，前提是此类替代材料或施工方法符合本标准的意图和要求。在本标准中，（a）“应”用于表示要求，即用户有义务满足以遵守本标准的规定；（b） “应该”用于表示建议，但不是要求；（c） “可”用于表示本标准范围内允许的选项或事项；（d）“can”表示可能性或能力。本标准正文中随附的注释未规定要求或替代要求； 它们的目的是将解释性或信息性材料从文本中分离出来。表和图的注释被视为表或图的一部分，可以作为要求编写。国际单位制是全球商业的主要记录单位。在本标准中，英寸/磅单位显示在括号中。每个测量系统中规定的值在应用中是等效的，但每个单位系统应单独使用。将两个测量系统的值结合起来可能会导致？符合本标准。

IAPMO Z124.5-2013e1 (R2018) covers plastic toilet seats (including toilet seat covers) and specifies requirements for materials, construction, performance testing, and markings.The requirements of this Standard are not intended to prevent the use of alternative materials or method of construction provided such alternatives meet the intent and requirements of this Standard.In this Standard,(a) "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy to comply with the standard;(b) "should" is used to express a recommendation but not a requirement;(c) "may" is used to express an option or something permissible within the scope of the standard; and(d) "can" is used to express either a possibility or a capability. Notes accompanying sections in the body of the Standard do not specify requirements or alternative requirements; their purpose is to separate explanatory or informative material from the text. Notes to tables and figures are considered part of the table or figure and can be written as requirements.SI units are the primary units of record in global commerce. In this Standard, the inch/pound units are shown in parentheses. The values stated in each measurement system are equivalent in application but each unit system is to be used independently. Combining values from the two measurement systems can result in non?conformance with this Standard.