Code of Federal Regulations > Title 40 > Chapter I > Part 63 > Subpart G > Appendix - Table 24 to Subpart G of Part 63—Typical Number of Columns as a Function of Tank Diameter for Internal Floating Roof Tanks With Column Supported Fixed Roofs a

Regulations last checked for updates: Apr 24, 2025

Title 40 - Protection of Environment last revised: Nov 24, 2025

Appendix - Table 24 to Subpart G of Part 63—Typical Number of Columns as a Function of Tank Diameter for Internal Floating Roof Tanks With Column Supported Fixed Roofs a

Tank diameter range (D in feet)	Typical number of columns, (NC)
0 <D ≤85	1
85 <D ≤100	6
100 <D ≤120	7
120 <D ≤135	8
135 <D ≤150	9
150 <D ≤170	16
170 <D ≤190	19
190 <D ≤220	22
220 <D ≤235	31
235 <D ≤270	37
270 <D ≤275	43
275 <D ≤290	49
290 <D ≤330	61
330 <D ≤360	71
360 <D ≤400	81

^a Data in this table should not supersede information on actual tanks.

authority: 42 U.S.C. 7401

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