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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Bellows meridional membrane stress due to deflection. 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. Hi, I have a question about the examination in Appendix EJMA carries out extensive technical research and testing on many important aspects of expansion joint design and manufacturing. Sa is the allowable eja from the applicable code. This is not torsional rotation.

Fitness for Service 9 post s. Excessive internal pressure may ehma a bellows to become unstable and squirm.

Expansion Joint Manufacturers Association – Wikipedia

He is President of Becht Engineering Co. Convolution height less the bellows material thickness. Becht Stajdard 4 post s. Is this a standard requirement for all types of application of expansion joints, or can this be a demand of a customer. The distinction of thin versus thick bellows has been added.


The Sa he gave me, for 70F and F were and respectfully. The bellows resistance factor or working standars rate is shown in lbs per inch of compression or extension.

A new approach was developed for the design of reinforced bellows, resulting in a modified set of equations for some stress components and for the spring rates. The fatigue life expectancy of an expansion joint is affected by various factors such as: It will also assist the user in communicating design requirements to the manufacturers and to properly install and maintain the expansion joint in service. There is ongoing work to potentially revise the EJMA fatigue curve to include a factor of safety, which may be variable.

Pressure Vessels 17 post s. Total Equivalent Max Axial: This is the displacement of the longitudinal axis of the Expansion Joint from its initial straight line position into a circular arc. Can this be true?

The design of every Expansion Joint must be such that the total displacement per convolution from all sources does not exceed the rated values. Process Consulting 10 post s. The Guide is intended to provide users with a basic understanding of expansion joints. Project 2 post s.


The Difference Between ASME B31.3 Appendix X and EJMA Fatigue Curves for Bellows?

Bending Working Standxrd Rate: Joints Externally Pressurized Exp. Single Bellows Axial Vibration Constants were revised. Becht Nuclear 36 post s. Ejma uses Sym yield strength at room from cert not tensile.

Materials Degradation and Corrosion 15 post s. Bellows E at Temperature: Bellows material thickness for one ply, corrected for thinning during the forming of the bellows convolutions.

Historically, designers have put large factors of safety on the number of design cycles for bellows, which was in part justified since there was no design margin in the EJMA fatigue curve.

This condition is predominantly associated with high meridional bending stress at the root and crest of the convolutions. Tightness of bellows, bands, and rings due to dissimilar material growth rates is considered. Piping 26 post s.

The calculation of universal type Expansion Joints has been simplified by a modified equation for the axial movement per convolution. Tom Vowell on Wednesday, 16 Ejmw The minimum control requirement of the bellow tube has to be X-ray or DPI prior to forming. Bellows meridional bending stress due to pressure.