HAPGUARD monitor

Johnson Matthey's HAPGUARDTM temperature and pressure monitor ensures that your catalytic converter remains in compliance with RICE NESHAP for clean air.

The U.S. Environmental Protection Agency recently implemented clean air regulations to reduce exhaust emissions of hazardous air pollutants (HAPS) from previously unregulated reciprocating internal combustion engines (RICE). Johnson Matthey supplies oxidation catalysts and three-way catalysts and catalytic converters to operators of stationary gas engines and stationary diesel engines to achieve the exhaust emissions levels mandated by RICE NESHAP. In addition, the Environmental Protection Agency requires continuous monitoring of the operating temperature and backpressure of the catalytic converter.

Johnson Matthey designed the HAPGUARD Monitor for use with MODULEXTM and DUALOX® catalytic converters equipped with oxidation catalysts and three-way catalysts to help engine operators remain in compliance with RICE NESHAP. The HAPGUARD is pre-programmed with engine operational requirements. It alarms when engine operation may result in the exhaust emissions being out of compliance and provides information needed to remain in compliance with RICE NESHAP. It ensures that rich-burn engines operate at 750°F-1250°F and that lean-burn engines operate at 450°F-1350°F as specified by the Environmental Protection Agency, so that the catalytic converter functions most efficiently.


  • Rugged construction
  • Easy to read LCD display
  • Temperature alarms for rich- and lean-burn engines
  • Backpressure alarm to alert engine operator to potential catalyst problems
  • 5-year data storage capacity as required by RICE NESHAP

In addition to temperature alarms, the HAPGUARD Monitor incorporates pressure alarms to alert the engine operator of potential problems with the catalyst. The initial backpressure is set by the end-user and monthly testing lets the user know if backpressure is changing over time. This can indicate problems such as catalyst damage or plugging so the operator can correct the problem quickly and remain in compliance with RICE NESHAP clean air regulations.

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