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AQMD Rule 1147, July Solution Spotlight

The purpose of AQMD Rule 1147 is to reduce nitrogen oxide emissions from gaseous and liquid fuel fired combustion equipment as detailed in the rule.  This applies to manufacturers, distributors, retailers, installers, owners and operators of a range of combustion equipment including ovens, dryers, heaters, furnaces, and thermal oxidizers.  There were a number of key changes to the rule made with the July 7, 2017 amendment including:


  • Removal of food & food product ovens and dry-roasters from Rule 1147.


  • Added definitions and clarifications.

Requirements & Exemptions

  • Removed NOx limit for units rated less than 325,000 BTU/hour
  • Raised NOx limit from 30-60 ppm for low temperature incinerator, burn-off furnace, burn-out oven, crematory, afterburner, degassing unit, remediation unit, thermal oxidizer, catalytic oxidizer & vapor incinerator.
  • Changed compliance dates from unit age of 20 years to 35 years for some units.
  • Changed requirements on relocated heated tanks, parts washers, and evaporators.
  • Units without rating plates are designated 20 years old as of July 1, 2012 (previously 2008).
  • Added/clarified options for demonstrating emissions – hours of unit or burner operation, fuel use, or other process parameter.

Compliance Demonstration & Testing

  • Added testing exemption for units using only infrared burners.
  • New flexibility for demonstrating compliance with NOx limit at low operating temperatures.
  • Added compliance option based on manufacturer burner & combustion system guarantee for units rated less than or equal to 2 million BTU/hour.

Even with these changes, however, there are still a number of companies who are due or delinquent to meet the limits and reporting requirements spelled out in Rule 1147.

Questions on whether this rule applies to you or questions with compliance? Contact the GTH office near you for more information.


Click here to download the June Solution Spotlight – AQMD Rule 1147 PDF.
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