CSA ANSI Z21.76:2016 pdf download.Gas-fired unvented catalytic room heaters for use with propane gas
4.1.1 The construction of a heater, whether specifically covered in this Standard or not, shall be in accordance with reasonable concepts of safety, substantiality, and durability. Component parts shall be secured against distortion, warpage, or other damage and constructed so as to maintain a fixed relationship between essential parts under normal and reasonable conditions of handling and usage. Parts not permanently secured shall be designed so they cannot be incorrectly assembled or improperly located when removed and replaced during cleaning or other servicing. All specifications as to construction set forth herein may be satisfied by the construction actually prescribed or such other construction as will provide at least equivalent performance.
4.1.9 Slotted and recessed head screws used in the general assembly of the heater shall conform to the Standard for Slotted Head Cap Screws, Square Head Set Screws, and Slotted Headless Set Screws, ANSI B18.6.2, the Standard for Slotted and Recessed Head Machine Screws and Machine Screw Nuts, ANSI B18.6.3, or the Standard for Thread Forming and Cutting, Tapping and Metallic Drive Screws (Inch Series), ANSI B18.6.4.
4.4.3 Every heater shall be equipped with an automatic gas ignition system (see Clause 3, Definitions). This system shall provide for ignition of the catalytic pad(s) gas by means of a proved igniter or pilot. If the presence of the ignition source is not proved, the automatic gas ignition system shall provide for automatic shutoff of gas to the catalytic pad(s) and to the pilot burner(s), if used.
4.4.4 In addition to the automatic gas ignition system function specified in Clause 4.4.3, a system having an interrupted ignition source shall provide for supervision of the catalytic pad(s) flame only following the flame-establishing period. If the presence of the flame is not proved within the flame-establishing period, the system shall provide for automatic shutoff of the gas supply to the catalytic pad(s) and pilot burner(s).
4.4.5 When a manually lighted pilot is provided, the design of the control shall be such that the catalytic pad (s) gas flow cannot occur while the pilot is being lighted. The interruption of main gas flow shall not depend on the operation of a manual valve that is not mechanically interlocked with the pilot gas control, or on the thermostat of a separate switch. After the pilot has been established and the safety shutoff device remains in a position that would permit main gas flow, an additional manual operation of the control shall be necessary to permit main burner gas flow (see Clause 5.9.6).CSA ANSI Z21.76 pdf download.