API Spec 12B - Bolted Tanks for Storage (in)

Written by Jerry Ratzlaff. Posted in American Petroleum Institute

American Petroleum Institute (API)

standards

  • API Spec 12B - Specification for Bolted Tanks for Storage and Production Liquids
  • Ratings are maximum allowable working gage pressure (psig) at the temperature listed.
  • Basic design stress, psi, max.: 18,000
  • Soil bearing load, psf, max.: 4,000 (Based on maximum water load plus super-imposed roof load)
Nominal

Capacity

42 gal bbl

Design Pressure

oz/in2 Pressure,

Vacuum

Number

of Rings

Inside

Diameter [a]

ft in

Height

of Shell [b]

ft in

Calculated

Capacity [c]

42 gal bbl

100 3, 1/2 1 9, 2 3/4 8, 1/2 96
200 3, 1/2 2 9, 2 3/4 16, 1 192
300 3, 1/2 3 9, 2 3/4 24, 1 1/2 287
500 3, 1/2 1 15, 4 5/8 8, 1/2 266
High 500 3, 1/2 2 15, 4 5/8 16, 1 533
750 3, 1/2 3 15, 4 5/8 24, 1 1/2 799
Low 500 2, 1/2 1 21, 6 1/2 8, 1/2 522
High 1,000 2, 1/2 2 21, 6 1/2 16, 1 1,044
1,500 2, 1/2 3 21, 6 1/2 24, 1 1/2 1,566
Low 1,000 2, 1/2 1 29, 8 5/8 8, 1/2 994
2,000 2, 1/2 2 29, 8 5/8 16, 1 1,987
3,000 2, 1/2 3 29, 8 5/8 24, 1 1/2 2,981
5,000 1, 1/2 3 38, 7 5/8 24, 1 1/2 5,037
10,000 1, 1/2 3 54, 11 3/4 24, 2 10,218
  • [a] The inside diameter is an approximate dimension. The values shown are 2 in. less than the bottom bolt circle diameters.
  • [b] Shell height do not include thickness of gasket.
  • [c] The calculated capacity is based on the inside diameter column 4 and height of shell column 5.
  • Low Capacity Tanks ‚ Supports

Tanks of 100, 200, 300, 250, high 500, 750, low 500, high 1,000, and 1,500 bbl capacity shall be furnished with structural-type center supports, with the upper end fastened inside the dome with three bolts in each leg and the lower fastened to the bottom attachment base designed to permit high adjustment.

  • Medium Capacity Tanks ‚ Supports

Tanks of low 1,000, 2,000, and 3,000 bbl capacity shall be furnished with structural-type center support, including a rafter support ring. The distance from the tank center to the point of attachment of the rafter to the rafter support rig clip shall be 38 1/32 in.

  • High Capacity Tanks ‚ Supports

Tanks of 5,000 bbl and 10,000 bbl capacity shall be furnished with structural-type center support. The distance from the tank center to the point of attachment of the rafter to the rafter support ring clip shall be 28 in. for the 5,000 bbl tank and 60 in. for the 10,000 bbl tank.