---
kind: "section"
citation: "40 C.F.R. § 63.7499"
title: "40"
number: "63.7499"
heading: "What are the subcategories of boilers and process heaters?"
url: "https://uscodex.org/cfr/40/63.7499"
---

# §63.7499. What are the subcategories of boilers and process heaters?


The subcategories of boilers and process heaters, as defined in [§ 63.7575](/cfr/40/63.7575.md) are:

- (a) **Pulverized coal/solid fossil fuel units.**
- (b) **Stokers designed to burn coal/solid fossil fuel.**
- (c) **Fluidized bed units designed to burn coal/solid fossil fuel.**
- (d) **Stokers/sloped grate/other units designed to burn kiln dried biomass/bio-based solid.**
- (e) **Fluidized bed units designed to burn biomass/bio-based solid.**
- (f) **Suspension burners designed to burn biomass/bio-based solid.**
- (g) **Fuel cells designed to burn biomass/bio-based solid.**
- (h) **Hybrid suspension/grate burners designed to burn wet biomass/bio-based solid.**
- (i) **Stokers/sloped grate/other units designed to burn wet biomass/bio-based solid.**
- (j) **Dutch ovens/pile burners designed to burn biomass/bio-based solid.**
- (k) **Units designed to burn liquid fuel that are non-continental units.**
- (l) **Units designed to burn gas 1 fuels.**
- (m) **Units designed to burn gas 2 (other) gases.**
- (n) **Metal process furnaces.**
- (o) **Limited-use boilers and process heaters.**
- (p) **Units designed to burn solid fuel.**
- (q) **Units designed to burn liquid fuel.**
- (r) **Units designed to burn coal/solid fossil fuel.**
- (s) Fluidized bed units with an integrated fluidized bed heat exchanger designed to burn coal/solid fossil fuel.
- (t) **Units designed to burn heavy liquid fuel.**
- (u) **Units designed to burn light liquid fuel.**

## Notes

### Amendments

[76 FR 15664, Mar. 21, 2011, as amended at 78 FR 7163, Jan. 31, 2013]

### Source

Source: 76 FR 15664, Mar. 21, 2011, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7401 et seq.

### Source

Source: 57 FR 61992, Dec. 29, 1992, unless otherwise noted.

### Amendments

[76 FR 15664, Mar. 21, 2011, as amended at 78 FR 7163, Jan. 31, 2013]