Abatement method and apparatus

An abatement apparatus for treating an effluent stream from a semiconductor processing tool, comprising:

• a first abatement device configured to receive said effluent stream and operable to run in an active mode to treat said effluent stream wherein the active mode of the first abatement device comprises supplying fuel gas to a foraminous burner in the first abatement device to affect flameless combustion along an exit surface of the foraminous burner;
• a second abatement device operable to run in an idle mode and an active mode wherein the idle mode comprises maintaining a pilot light but not supplying fuel gas to a second foraminous burner in the second abatement device and the active mode of the second abatement device comprises supplying fuel gas to the second foraminous burner in the second abatement device to affect flameless combustion along an exit surface of the second foraminous burner;
• a divert valve operable to supply said effluent stream to one of said first abatement device and said second abatement device;
• a bypass valve upstream of said divert valve;
• and
• control logic operable, on receipt of an indication of an alarm condition associated with said first abatement device, to switch said second abatement device from running in the idle mode to running in the active mode of the second abatement device;
• wherein said alarm condition has a divert time associated therewith and said control logic is operable to activate said bypass valve to prevent supply of said effluent stream to said divert valve should said second abatement device fail to switch from said idle mode to said active mode of the second abatement device within said divert time.