前言:这是CSA/ANSI Z21的第一版。104&子弹；CSA 9.2，与燃气设备一起使用的手动和自动气体选择器装置。本标准的制定符合加拿大标准委员会对加拿大国家标准的要求。CSA集团已将其作为加拿大国家标准发布。本标准已被美国国家标准协会（ANSI）批准为美国国家标准。范围:1.1本标准适用于新生产的气体选择器装置（见第3条），以下简称“装置”，完全由新的、未使用的零件和材料制成。1.2该设备可能包括选择用于操作设备的气体类型和主燃烧器一次空气调节等功能。该装置还可以包含多个通道，可以选择这些通道，以允许气体通过正确的出口排出，并且可以包含孔口。 选择器不提供安全、温度控制、切断或压力调节。（见第3条）该装置可包括以下特征:a）主燃烧器一次空气调节；b） 可选择多个通道，以允许气体通过正确的出口；或 c） 孔口。装置可以是单个装置，也可以作为调节器或其他类型阀门的一部分。除本标准涵盖的功能外，执行其他功能的部件应符合适用的美国国家标准或加拿大标准。1.3设备符合本标准并不意味着该设备可用于燃气设备，无需对特定设备设计进行补充试验。1.4本标准适用于最大工作气体压力为1/2 psi（3。 5 kPa）使用以下一种或多种燃料气体:天然气和丙烷气。1.5本标准适用于能够在32°F（0°C）至125°F（51.5°C）的环境温度下运行的设备，制造商可选择规定更大的温度范围。1.6第2条包含本标准中具体引用的标准清单，以及获取这些参考标准的来源。1.7如果本标准中给出的测量值后跟其他单位的等效值，则第一个规定值应视为规范值。1.8除非另有规定，否则本标准中提及的所有psi均应视为表压。1.9本标准包含与码/磅数量相对应的SI（公制）单位，目的是允许以SI（公制）单位使用标准。 （IEEE/ASTM SI 10，美国国家公制实践标准，或ISO 80000-1:2009，数量和单位-第1部分:概述，用作从码/磅数量进行公制转换的指南。）如果规定了测量值和其他单位的相应值，则应将第一个规定值视为要求。给定的相应值可能是近似值。如果一个测量值和其他单位的相应值都被规定为引用的标记要求，则应提供第一个或两个规定的单位。1.10在本标准中，“应”用于表示要求，即用户为遵守本标准而应满足的规定；“应该”用于表示建议或建议但不需要的建议；“可”用于表示一个选项或在标准范围内允许的选项。 注释随附条款不包括要求或替代要求；随附条款的注释的目的是将解释性或信息性材料与文本分开。表和图的注释被视为表或图的一部分，可以作为要求编写。附件被指定为规范性（强制性）或信息性（非强制性）以定义其应用。

Preface:This is the first edition of CSA/ANSI Z21.104 • CSA 9.2,Manual and automatic gas selector devices for use with gas-fired appliances.This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group. This Standard has been approved by the American National Standards Institute (ANSI) as an American National Standard.Scope:1.1This Standard applies to newly produced gas selector devices (see Clause 3), herein after referred to as a "device", constructed entirely of new, unused parts and materials.1.2The device may include functions such as selection of type of gas to operate the appliance and main burner primary air adjustment. The device may also contain multiple passageways that can be selected to allow the gas to pass out through the correct outlet(s) and that may contain the orifice(s). The selector does not provide safety, temperature control, shut-off or pressure regulation. (See Clause 3.)The device may include features such as:a) main burner primary air adjustment;b) multiple passageways that can be selected to allow the gas to pass through the correct outlet(s); or c) orifice(s).A device may be an individual device or may be incorporated as part of a regulator(s) or other type valve(s). A component(s) performing a function other than that covered by this Standard shall comply with the applicable American National Standard(s) or Canadian Standard(s).1.3Compliance of a device with this Standard does not imply that the device is acceptable for use on gas appliances without supplemental tests with the device applied to the particular appliance design.1.4This Standard applies to devices having a maximum operating gas pressure of 1/2 psi (3.5 kPa) with one or more of the following fuel gases: natural gas and, propane gas.1.5This Standard applies to devices which are capable of operation in ambient temperatures of 32 °F (0 °C) to 125 °F (51.5 °C), at the option of the manufacturer, a greater temperature range may be specified.1.6Clause 2contains a list of standards specifically referenced in this Standard, and sources from which these reference standards may be obtained.1.7If a value for measurement as given in this Standard is followed by an equivalent value in other units, the first stated value is to be regarded as the specification.1.8All references to psi through this Standard are to be considered gauge pressure unless otherwise specified.1.9This Standard contains SI (Metric) units corresponding to the yard/pound quantities, the purpose being to allow the standard to be used in SI (Metric) units. (IEEE/ASTM SI 10,American National Standard for Metric Practice, or ISO 80000-1:2009,Quantities and units — Part 1: General, is used as a guide in making metric conversion from yard/pound quantities.) If a value for a measurement and a corresponding value in other units are stated, the first stated value is to be regarded as the requirement. The given corresponding value may be approximate. If a value for a measurement and a corresponding value in other units are both specified as a quoted marking requirement, the first stated unit, or both, are to be provided.1.10In this Standard, "shall" is used to express a requirement, i.e., a provision that the user shall satisfy in order to comply with the standard; "should" is used to express a recommendation or that which is advised but not required; and "may" is used to express an option or that which is permissible within the limits of the standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.