StacksVerified U.S. regulatory reference

40 CFR §63.7499

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov
The subcategories of boilers and process heaters, as defined in § 63.7575 are:
  1. (a)Pulverized coal/solid fossil fuel units.
  2. (b)Stokers designed to burn coal/solid fossil fuel.
  3. (c)Fluidized bed units designed to burn coal/solid fossil fuel.
  4. (d)Stokers/sloped grate/other units designed to burn kiln dried biomass/bio-based solid.
  5. (e)Fluidized bed units designed to burn biomass/bio-based solid.
  6. (f)Suspension burners designed to burn biomass/bio-based solid.
  7. (g)Fuel cells designed to burn biomass/bio-based solid.
  8. (h)Hybrid suspension/grate burners designed to burn wet biomass/bio-based solid.
  9. (i)Stokers/sloped grate/other units designed to burn wet biomass/bio-based solid.
  10. (j)Dutch ovens/pile burners designed to burn biomass/bio-based solid.
  11. (k)Units designed to burn liquid fuel that are non-continental units.
  12. (l)Units designed to burn gas 1 fuels.
  13. (m)Units designed to burn gas 2 (other) gases.
  14. (n)Metal process furnaces.
  15. (o)Limited-use boilers and process heaters.
  16. (p)Units designed to burn solid fuel.
  17. (q)Units designed to burn liquid fuel.
  18. (r)Units designed to burn coal/solid fossil fuel.
  19. (s)Fluidized bed units with an integrated fluidized bed heat exchanger designed to burn coal/solid fossil fuel.
  20. (t)Units designed to burn heavy liquid fuel.
  21. (u)Units designed to burn light liquid fuel.