Expert Article: “What HVAC contractors and boiler manufacturers need to know about the new Boiler MACT Rule?”

On December 23, 2011, U.S. EPA promulgated proposed amendments and changes to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for industrial, commercial, and institutional boilers and process heaters at both major and area sources of hazardous air pollutants (HAP) emissions. A major source is a facility that has the potential to emit greater than 10 tons per year [tpy] of any single HAP and/or greater than 25 tpy of total HAPs.  An area source has the potential to emit less than 10 tpy/25 tpy).

The US EPA estimates that of the 1.5 million boilers in the United States that approximately 197,000 boilers will be subject to the regulations.  Of these approximately 2,300 will need to meet numerical standards while 194,700 boilers will have to comply with work practices.

I am assuming that your readers are by and large owners of either natural gas or oil fired boilers located at area sources.  Natural gas fired boilers located at area sources don’t have any requirements to meet.

Gas-fired boiler includes any boiler that burns gaseous fuels not combined with any solid fuels and burns liquid fuel only during periods of gas curtailment, gas supply interruption, startups, or periodic testing on liquid fuel. Periodic testing of liquid fuel shall not exceed a combined total of 48 hours during any calendar year.

Oil fired boilers located at area sources have the following requirements:

  1. New oil-fired boiler with heat input capacity of 10 MMBTU/Hr or greater that do not meet the definition of seasonable boiler or limited use boiler must comply with a particulate matter emission limit of 3.02E-02 lbs/MMBTU of heat input.
  2. New oil-fired boiler with heat input capacity of 10 MMBTU/Hr or greater must minimize the boiler’s startup and shutdown periods and conduct startups and shutdowns according to the manufacturer’s recommended procedures. If manufacturer’s      recommended procedures are not available, you must follow recommended procedures for a unit of similar design for which manufacturer’s recommended procedures are available.
  3. All oil fired boilers will require tune ups.  In general oil fired boilers with heat inputs greater than 5 MMBTU/hr must have a tune up every two years while oil fired boilers with heat inputs less than or equal to 5 MMBTUs/hr must have a tune up every five years.

Boilers located at major sources of HAPS will be subject to different requirements.

Thomas Fitzpatrick, PE, is a Department Manager at SSOE Group (, a global engineering, procurement, and construction management firm. He has over 30 years’ experience in the power industry and is responsible for managing various utility related projects for industrial, municipal, and institutional facilities. He can be reached in SSOE’s Toledo, Ohio office at 419.255.3830 or