CSA/ANSI Z21.13:22 • CSA 4.9:22

1 Scope 1.1 This Standard applies to newly produced gas-fired low-pressure steam and hot water boilers with gas inlet pressure ratings not exceeding 0.5 psi (3.5 kPa) and having input ratings of less than 12 500 000 Btu/h (3 663 389 W) (see Clause 3), hereinafter referred to as boilers,* constructed entirely of new unused parts and materials, a) for operation at or below the following pressures and temperatures: i) steam heating boilers: 15 psi (103.42 kPa) steam pressure; ii) hot water heating boilers: 1) 160 psi (1.10 MPa) water pressure; and 2) 250 °F (121 °C) water temperature; iii) hot water supply boilers: 1) 160 psi (1.10 MPa) water pressure; and 2) 250 °F (121 °C) water temperature; b) for use with i) natural gas; ii) propane gas; iii) LP gas-air mixtures; and c) for recreational vehicle installation for use with i) propane gases only; and ii) natural gas and propane gases when provision is made for the simple conversion from one gas to the other. The construction of boilers is covered under Clause 4and the performance of boilers is covered under Clause 5. * See Clause 7.2for boilers covered in Canada that exceed the above limits in gas inlet pressure and/or input ratings. 1.2 This Standard applies to indoor boilers, of other than the direct vent type that are categorized according to vent pressure and temperature as either Category I, Category II, Category III, or Category IV (see Clause 3), and to outdoor type boilers. 1.3 This Standard also applies to direct vent boilers (see Clause 3). A direct vent boiler anticipated by this Standard is essentially a balanced flue appliance with the air intake and vent outlet in proximity. Other designs are subjected to such additional tests as believed necessary at the discretion of the certification body. 1.4 If a value for measurement as given in this Standard is followed by an equivalent value in other units, the first stated value is the specification. 1.5 The values given in US customary units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only. Note: IEEE/ASTM SI 10 or ISO 80000-1 can be used as a guide when converting imperial units to metric units. 1.6 All references to pressure throughout this Standard are considered gauge pressure, unless otherwise specified. 1.7 Clause 7contains clauses unique to, and required by, Canada. 1.8 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.