API Std 650 - Roof Manholes (in)

Written by Jerry Ratzlaff. Posted in American Petroleum Institute

American Petroleum Institute (API)

standards

  • API Std 650 - Standard for Welded Tanks for Oil Storage

 

  • [a] Pipe may be used for neck, providing the minimum nominal wall thickness is 1/4 in.  (ID and DP shall be adjusted accordingly.)

Size of Manhole

(NPS)

Diameter of Neck [a], ID

In

Diameter of Cover Plate, DC

In

Diameter of Bolt Circle

In

Number of Bolts, DB

In

Diameter of Gasket Inside

In

Diameter of Gasket Outside

In

Diameter of Hole in Roof Plate or Reinforcing Plate, DB

In

Outside of Diameter of Reinforcing Plate, DR

In

20 20 26 23 1/2 16 20 26 20 5/8 42
24 24 30 27 1/2 20 24 30 24 5/8 46