Preface This is the ninth edition of ANSI Z21.50 • CSA 2.22, Vented decorative gas appliances. It supersedes the previous editions published in 2016, 2014, 2012, 2007, 2003, 2000, 1998, and 1996. 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 1.1 This Standard applies to newly produced vented decorative gas appliances (see Clause 3, Definitions), hereinafter referred to as appliances, constructed entirely of new, unused parts and materials and having input ratings up to and including 400,000 Btu/hr (117 228 W). These appliances are for: a) use with natural gas; b) use with propane; c) direct vent gas appliances for manufactured home (USA only) or mobile home OEM installation or aftermarket installation convertible for use with natural gas and propane gas when provision is made for the simple conversion from one gas to the other (see Clauses 4.1.22 and 4.1.23); d) direct vent gas appliances for manufactured home (USA only) or mobile home aftermarket installation for use with natural gas only or propane gas only (see Clause 4.1.23); and e) direct vent gas appliances for manufactured home (USA only) or mobile home OEM installation for use with propane gas only (see Clause 4.1.22). The construction of vented decorative gas appliances for use with the above-mentioned gases is covered under Clause 4, Construction. The performance of vented decorative gas appliances for use with the above-mentioned gases is covered under Clause 5, Performance. 1.2 These appliances are not: a) for use with a thermostat; b) a source of heat; and c) for use with solid fuels. 1.3 Annex I, Automatic intermittent pilot ignition or on-demand pilot ignition systems for field installation, includes provisions for newly produced (optional) automatic intermittent pilot ignition systems and on- demand pilot ignition systems (see Clause 3, Definitions), constructed entirely of new, unused parts and materials to be adapted in the field to an appliance equipped with an existing continuous pilot burner and which has been examined and tested for compliance with this Standard when installed on the appliance. 1.4 If a value for measurement given in this Standard is followed by an equivalent value in other units, the first stated value is the specification. 1.5 Clause 2, Reference publications, contains a list of standards specifically referenced in this Standard and sources from which they may be obtained. It is the responsibility of the user of this Standard to determine which referenced standard applies based on the requirements of the Authority Having Jurisdiction (AHJ) for the location of installation. 1.6 This Standard also applies to appliances with draft hoods that are factory equipped with automatic vent damper devices (see Clause 3, Definitions), hereinafter referred to as vent damper devices. 1.7 All references to \"psi\" throughout this Standard are to be considered gauge pressure unless otherwise specified. 1.8 Special construction provisions applicable to vented decorative gas appliances designed for use with an optional design-certified conversion kit are outlined under Annex A, Provisions for listed gas appliance conversion kits (optional). 1.9 In 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.