This paragraph may be used for operating pressures not exceeding 1 p.s.i.g.
Table H-10-Wetted Area Versus Cubic Feet Free Air Per Hour
[14.7 psia and 60 °F.]
Square feet | CFH | Square feet | CFH | Square feet | CFH |
20 | 21,100 | 200 | 211,000 | 1,000 | 524,000 |
30 | 31,600 | 250 | 239,000 | 1,200 | 557,000 |
40 | 42,100 | 300 | 265,000 | 1,400 | 587,000 |
50 | 52,700 | 350 | 288,000 | 1,600 | 614,000 |
60 | 63,200 | 400 | 312,000 | 1,800 | 639,000 |
70 | 73,700 | 500 | 354,000 | 2,000 | 662,000 |
80 | 84,200 | 600 | 392,000 | 2,400 | 704,000 |
90 | 94,800 | 700 | 428,000 | 2,800 | 742,000 |
100 | 105,000 | 800 | 462,000 | and | |
120 | 126,000 | 900 | 493,000 | over | |
140 | 147,000 | 1,000 | 524,000 | ||
160 | 168,000 | ||||
180 | 190,000 | ||||
200 | 211,000 |
CFH = 1,107A0.82
Where;
CFH = Venting requirement, in cubic feet of free air per hour.
A = Exposed wetted surface, in square feet.
Note: The foregoing formula is based on Q = 21,000A0.82.
V = 1337 ÷L[RADIC]M
V = Cubic feet of free air per hour from Table H-10.
L = Latent heat of vaporization of specific liquid in B.t.u. per pound.
M = Molecular weight of specific liquids.
0.5 for drainage in accordance with subdivision (vii)(b) of this subparagraph for tanks over 200 square feet of wetted area.
0.3 for approved water spray.
0.3 for approved insulation.
0.15 for approved water spray with approved insulation.
Table H-11-Vent Line Diameters
Maximum flow GPM | Pipe length1 | ||
50 feet | 100 feet | 200 feet | |
Inches | Inches | Inches | |
100 | 11/4 | 11/4 | 11/4 |
200 | 11/4 | 11/4 | 11/4 |
300 | 11/4 | 11/4 | 11/2 |
400 | 11/4 | 11/2 | 2 |
500 | 11/2 | 11/2 | 2 |
600 | 11/2 | 2 | 2 |
700 | 2 | 2 | 2 |
800 | 2 | 2 | 3 |
900 | 2 | 2 | 3 |
1,000 | 2 | 2 | 3 |
1 Vent lines of 50 ft., 100 ft., and 200 ft. of pipe plus 7 ells.
Table H-12-Maximum Allowable Size of Containers and Portable Tanks for Flammable Liquids
Container type | Category 1 | Category 2 | Category 3 | Category 4 |
Glass or approved plastic | 1 pt | 1 qt | 1 gal | 1 gal. |
Metal (other than DOT drums) | 1 gal | 5 gal | 5 gal | 5 gal. |
Safety cans | 2 gal | 5 gal | 5 gal | 5 gal. |
Metal drums (DOT specifications) | 60 gal | 60 gal | 60 gal | 60 gal. |
Approved portable tanks | 660 gal | 660 gal | 660 gal | 660 gal. |
Note: Container exemptions: (a) Medicines, beverages, foodstuffs, cosmetics, and other common consumer items, when packaged according to commonly accepted practices, shall be exempt from the requirements of 1910.106(d)(2)(i) and (ii).
Table H-13-Storage in Inside Rooms
Fire protection1 provided | Fire resistance | Maximum size | Total allowable quantities (gals./sq. ft./floor area) |
Yes | 2 hours | 500 sq. ft | 10 |
No | 2 hours | 500 sq. ft | 5 |
Yes | 1 hour | 150 sq. ft | 4 |
No | 1 hour | 150 sq. ft | 2 |
1 Fire protection system shall be sprinkler, water spray, carbon dioxide, or other system.
Table H-18-Electrical Equipment Hazardous Areas-Bulk Plants
Location | Class I Group D division | Extent of classified area |
Tank vehicle and tank car:1 | ||
Loading through open dome | 1 | Within 3 feet of edge of dome, extending in all directions. |
2 | Area between 3 feet and 5 feet from edge of dome, extending in all directions. | |
Loading through bottom connections with atmospheric venting | 1 | Within 3 feet of point of venting to atmosphere extending in all directions. |
2 | Area between 3 feet and 5 feet from point of venting to atmosphere, extending in all directions. Also up to 18 inches above grade within a horizontal radius of 10 feet from point of loading connection. | |
Loading through closed dome with atmospheric venting | 1 2 | Within 3 feet of open end of vent, extending in all directions. Area between 3 feet and 5 feet from open end of vent, extending in all directions. Also within 3 feet of edge of dome, extending in all directions. |
Loading through closed dome with vapor recovery | 2 | Within 3 feet of point of connection of both fill and vapor lines, extending in all directions. |
Bottom loading with vapor recovery or any bottom unloading | 2 | Within 3 feet of point of connections extending in all directions. Also up to 18 inches above grade with in a horizontal radius of 10 feet from point of connection. |
Drum and container filling: | ||
Outdoors, or indoors with adequate ventilation | 1 | Within 3 feet of vent and fill opening, extending in all directions. |
2 | Area between 3 feet and 5 feet from vent or fill opening, extending in all directions. Also up to 18 inches above floor or grade level within a horizontal radius of 10 feet from vent or fill opening. | |
Outdoors, or indoors with adequate ventilation | 1 | Within 3 feet of vent and fill opening, extending in all directions. |
2 | Area between 3 feet and 5 feet from vent or fill opening, extending in all directions. Also up to 18 inches above floor or grade level within a horizontal radius of 10 feet from vent or fill opening. | |
Tank-Aboveground: | ||
Shell, ends, or roof and dike area | 2 | Within 10 feet from shell, ends, or roof of tank, Area inside dikes to level of top of dike. |
Vent | 1 | Within 5 feet of open end of vent, extending in all directions. |
2 | Area between 5 feet and 10 feet from open end of vent, extending in all directions. | |
Floating roof | 1 | Area above the roof and within the shell. |
Pits: | ||
Without mechanical ventilation | 1 | Entire area within pit if any part is within a Division 1 or 2 classified area. |
With mechanical ventilation | 2 | Entire area within pit if any part is within a Division 1 or 2 classified area. |
Containing valves, fittings or piping, and not within a Division 1 or 2 classified area | 2 | Entire pit. |
Pumps, bleeders, withdrawal fittings, meters and similar devices: | ||
Indoors | 2 | Within 5 feet of any edge of such devices, extending in all directions. Also up to 3 feet above floor or grade level within 25 feet horizontally from any edge of such devices. |
Outdoors | 2 | Within 3 feet of any edge of such devices, extending in all directions. Also up to 18 inches above grade level within 10 feet horizontally from any edge of such devices. |
Storage and repair garage for tank vehicles | 1 | All pits or spaces below floor level. |
2 | Area up to 18 inches above floor or grade level for entire storage or repair garage. | |
Drainage ditches, separators, impounding basins | 2 | Area up to 18 inches above ditch, separator or basin. Also up to 18 inches above grade within 15 feet horizontally from any edge. |
Garages for other than tank vehicles | (2 ) | If there is any opening to these rooms within the extent of an outdoor classified area, the entire room shall be classified the same as the area classification at the point of the opening. |
Outdoor drum storage | (2 ) | |
Indoor warehousing where there is no flammable liquid transfer | (2 ) | If there is any opening to these rooms within the extent of an indoor classified are, the room shall be classified the same as if the wall, curb or partition did not exist. |
Office and rest rooms | (2 ) |
1 When classifying the extent of the area, consideration shall be given to the fact that tank cars or tank vehicles may be spotted at varying points. Therefore, the extremities of the loading or unloading positions shall be used.
2 Ordinary.
29 C.F.R. §1910.106