Lap-joint flange slip connection eases differential settling in storage-tank piping

Journal Article · Thu Sep 01 00:00:00 EDT 1983 · Oil Gas J.; (United States)

OSTI ID:5199332

Russo, E P; Haydel, B G

Differential settlement between a storage tank and its connecting lines can present a serious piping stress problem. Excessive stress may have serious consequences such as pipe failure or flange leaks, which could result in fire. Various types of flexible joints may be considered for this application, including universal ball joints, gasket/groove pipe coupling, bellows expansion joints, flexible hose, and rotational flange connections. An alternate method for handling differential settlement between a tank and its connecting piping is a lap joint flange slip connection. These are not constructed to resist thrust, but are adapted to meet movement due to settlement by rotation. They can be loosened and retightened occasionally as settlement occurs; however, the line must be drained for the flange to be loosened. Lap joint flanges using Teflon-coated galvanized sheets have been applied successfully in the field. This is an economical and practical way to allow ample rotation without the occasional loosening and retightening of the flanges. The design problem associated with this connection is the determination of the torque required in the flange bolts so that the joint will be loose enough to rotate without causing excessive stresses in the pipe, but tight enough to prevent leakage. A procedure for calculating the required flange bolt torques and the associated stresses induced in the adjacent piping is presented here.

• Research Organization: University of New Orleans, New Orleans
• OSTI ID: 5199332
• Journal Information: Oil Gas J.; (United States), Vol. 81:38
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
PETROLEUM
STORAGE FACILITIES
PIPE JOINTS
COMPARATIVE EVALUATIONS
FLEXIBILITY
PIPES
GROUND MOTION
STRESSES
CALCULATION METHODS
FASTENERS
FIRE RESISTANCE
FLANGES
ROTATION
STRESS ANALYSIS
TECHNOLOGY ASSESSMENT
TORQUE
ENERGY SOURCES
FOSSIL FUELS
FUELS
JOINTS
MECHANICAL PROPERTIES
MOTION
TENSILE PROPERTIES
024000* - Petroleum- Storage- (-1989)