Standard edition was, of necessity, somewhat brief and covered only The EJMA TM Standards are intended for application to metallic bellows expansion joints. The Expansion Joint Manufacturers Association is an organization of a metal bellows expansion joint manufacturers. It was founded in to create and maintain a set of standards for quality expansion joint design and manufacturing. The EJMA standards are used worldwide as a reference for the proper. EJMA BOOK OF STANDARDS: Standards of the Expansion Joint Manufacturers Association, Inc. – Includes one copy of Practical Guide to Expansion Joints.

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Definitions in the Nomenclature section 1. Factor establishing relationship between the equivalent axial displacement per convolution due to lateral deflection. The Guide is intended to provide standrad with a basic understanding of expansion joints. Bellows convoluted length or live length. The maximum amount of movement axial extension, axial compression, lateral deflection, angular rotation, or any combination thereof which an Expansion Joint is capable of absorbing.

Sa is the allowable stress from the applicable code.

Process Consulting 10 post s. This is not torsional rotation.

The EJMA bellows fatigue curve is a best fit curve based on data that was available, so it provides an expected average cycle life. Safety 10 post s.


The number of fatigue cycles can now be calculated from the same set of fatigue curves which are relevant for the unreinforced bellows and for the toroidal bellows. In-plane stanvard is defined as a shift or rotation of the plane of one or more convolutions such that the plane of these convolutions is no longer perpendicular to the axis of the bellows.

They seemed too high.

Expansion Joint Manufacturers Association – Wikipedia

Axial force or thrust caused by the internal pressurization of the bellows. Bellows Yield at Temp: With bellows, design for an excessive number of cycles can unnecessarily compromise stanadrd design aspects, such as design with respect to internal pressure and column stability resistance to squirm. Friday, 26 July This is calculated on the full effective cross section of the bellows known as the effective area.

When using this curve, it should be recognized that appropriate design margins are already included, and they should not also be included in the specified number of cycles. Ejma uses Sym yield strength at room from cert not tensile. In order to evaluate the loads upon piping, supports, or equipment, it is necessary to determine the axial forces and moments required to move an Expansion Joint.


Systems 2 post s. Axial Working Spring Rate: A cycle is defined standafd one complete movement from the initial position in the piping system to the operating position and back to the initial position. Pressure Vessels 17 post s.

This condition is most associated with bellows which have a relatively large length-to-diameter ration and is similar to the buckling of a column under compressive load. The work hardening of austenitic stainless steel, induced during the forming of convolutions, generally improves the fatigue life of an Expansion Joint often to a marked degree.

Expansion Joint Manufacturers Association

Tom Vowell on Wednesday, 16 October Due Diligence 5 post s. EJMA does not mention this.

Bellows meridional bending stress due to deflection. Bellows pitch and height tolerances were redefined relative to diameter. Click to Request Info. Joints Externally Pressurized Exp. Heavy Lift 13 post s. Distance between outermost ends of the stanrard in a universal expansion joint.

Calculated maximum pressure in PSIG before expansion joint may squirm because of inplane instability. Convolution height less the bellows material thickness.