CSA/ANSI 3.21:19 Industrial gas-fired natural draft heaters for installation in non-hazardous and hazardous locations in oil and gas process applications

CSA/ANSI 3.21:19 Industrial gas-fired natural draft heaters for installation in non-hazardous and hazardous locations in oil and gas process applications. Automatic gas ignition system — a system designed to ignite and re-ignite an appliance burner(s). Such systems: a) automatically ignite gas at the main burner, or gas at the pilot burner so the pilot can ignite the main burner; b) prove the presence of either the ignition source, the main burner flame, or both, and c) automatically act to shut off the gas supply to the main burner or to the pilot and main burner, when the supervised flame or ignition source Is not proved. Automatic gas ignition system timing Flame-establishing time (period) — the period of time between the initiation of gas flow and the proof of the supervised flame, or between the proof of the supervised flame and the initiation of gas flow. This period of time can be applicable to proof of ignition source, proof of main burner flame, or both. Also known as Trial for ignition period. Flame failure re-ignition time — the period of time between loss of the supervised ignition source or the supervised main burner flame and a re-ignition attempt. During this time period, the main burner gas supply is not shut off. Flame failure response time — the time in seconds required for the combustion safety control to react upon flame failure (extinction). Lockout time — the period of time for the appliance control system to respond to the loss of a safety limit or loss of proof of a supervised flame Maximum time — the maximum allowable time for the specified function of any device built to this Standard. Minimum time — the minimum allowable time for the specified function of any device built to this Standard. Purge time — the period of time intended to allow for the dissipation of any unburned gas or residual products of combustion. Recycle time — the period of time between shutoff of the gas supply following loss of the supervised ignition source or the supervised main burner flame and reactivation of the ignition source. Trial for ignition period — See Flame-establishing period. Automatic vent damper device — a device intended for installation in the venting system in the outlet of or downstream of the appliance draft hood of an individual automatically operated gas-fired appliance, and which is designed to automatically open the venting system...