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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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.

It is calculated as either Lb or Lu plus length of pipe ends. Bellows meridional membrane stress due to deflection.

Stabdard meridional bending stress due to deflection. With bellows, design for an excessive number of cycles can unnecessarily compromise other design aspects, such as design with respect to internal pressure and column stability resistance to squirm.

Convolution height less the bellows material thickness.

Single Bellows Axial Vibration Constants were revised. Pressure thrust can be calculated by multiplying the working pressure by the effective area PSIG x Ae.

Excessive internal pressure may cause a bellows to become unstable and squirm. 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. Tightness of stanadrd, bands, and rings due to dissimilar material growth rates is considered.


Friday, 26 July The distinction of thin versus thick bellows has been added. Axial Working Spring Rate: This condition is predominantly associated with high meridional bending stress at the root and ztandard of the convolutions.

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

Becht Software 4 post s. Subscribe to our blog Unsubscribe from our blog. The Authority on Expansion Joints The EJMA Standards are recognized throughout the world as the authority on the proper selection and application of metallic bellows type expansion joints for safe and reliable piping and vessel installation.

Allowable material stress at design temperature, unless otherwise specified, from the applicable code. To order click here.

Lateral Working Spring Rate: Expansion Joints Exhaust Flanges.

EJMA 10th Edition

Fatigue life calculations were greatly enhanced and simplified. Key Contacts Becht Info Request. Project 2 post s. General Interest 4 post s. The latter provides a significantly higher cycle life.

Total Equivalent Max Axial: Bellows meridional bending stress due to pressure. The bellows resistance factor or working spring rate is shown in lbs per inch of compression or standarv. 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.

EJMA 10th Edition

They seemed too high. I cannot imagine that for simple applications the bellow tube Always has to be x-rayed or DPI tested. Heavy Lift 13 post s. This would result in a margin of safety entirely dependent upon the designer, and could vary from large, to none.


The fatigue life expectancy can be defined as the total stanvard of complete cycles which can be expected from the expansion joint. Machinery 18 post s. The bellows resistance ejm or working spring rate is shown in lbs per inch of lateral offset.

It is characterized by tilting or warping of one or more convolutions. Process Consulting 10 post s. The Tenth Edition standards combine the knowledge and experience of the leading manufacturers of expansion joints into an invaluable reference document. Definitions in the Nomenclature section 1.

Expansion Joint Manufacturers Association – Wikipedia

Factor establishing relationship between the equivalent axial displacement per convolution due to lateral deflection. Chuck Becht on Wednesday, 16 October Bellows E at Temperature: Bellows pitch and height tolerances were redefined relative stansard diameter. Subscribe to this blog post Please fill in your email address to subscribe to updates from this post.

The calculation of universal type Expansion Joints has been simplified by a modified equation for the axial movement per convolution.