Editing Bituminous coal (section)

===Subranks===
In the United States, bituminous coal is further divided into subranks based on its heating value and fixed carbon content.

{|class=wikitable
|+ASTM Bituminous Coal Classification<ref>Dave Osborne (ed), ''The Coal Handbook: Towards Cleaner Production: Volume 1: Coal Production'' Elsevier, 2013
{{ISBN|085709730X}}, table 2.5 page 47</ref>
!Class
!Group
!Fixed Carbon % <br> Dry, mineral free
!Volatile Matter %<br> Dry, mineral free
![[Heating Value]] MJ/kg <br> Moist, mineral free

|-
|rowspan=5|Bituminous||Low Volatile||78–86||14–22||  &nbsp;
|-
||Medium Volatile||69–78||22–31||  &nbsp;
|-
||High Volatile A||<69||>31||>32.6  
|-
||High Volatile B||&nbsp; ||&nbsp; ||30.2–32.6  
|-
||High Volatile C||&nbsp;  ||&nbsp; ||26.7–30.2

|}

Thus bituminous coal is divided into high-, medium-, and low-volatile categories based on fixed carbon content, and high-volatile bituminous coal is further subdivided by energy content.

ISO classification of bituminous coal is based on vitrinite reflectance.<ref name=UKVitriniteReflectance/> This classification divides medium rank coal (approximately equivalent to bituminous coal) into four subranks. In order of increasing rank, these are:{{sfn|Keijers|2012|pp=28, 31}}
* Medium D: Vitrinite reflectance of 0.5 to 0.6. Corresponds approximately to ASTM high volatile C bituminous or sub-bituminous A.
* Medium C: Vitrinite reflectance of 0.6 to 1.0. Corresponds approximately to ASTM high volatile C to high volatile B bituminous.
* Medium B : Vitrinite reflectance of 1.0 to 1.4. Corresponds approximately to ASTM high volatile A to medium volatile bituminous.
* Medium A: Vitrinite reflectance of 1.4 to 2.0. Corresponds approximately to ASTM low volatile bituminous.