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 Guide is not intended as a source for expansion joint design or application details. Bending Working Spring Rate: Bellows circumferential membrane stress due to pressure.

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

The Expansion Joint Manufacturers Association is an organization of established manufacturers of metal jema type expansion joints. And the allowale stresses can be different which different codes. It will also assist the user in communicating design requirements to the manufacturers and to properly install and maintain the expansion joint in service. Systems 2 post s.


Safety 10 post s. This is the displacement of the longitudinal axis of the Expansion Joint from its initial straight line position into a circular arc. Bellows meridional membrane stress stanrard 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. There is ongoing work to potentially revise the EJMA fatigue curve to include a factor of safety, which may be variable. Bellows meridional satndard stress due to pressure.

Tom Vowell on Wednesday, 16 October Axial Working Spring Rate: Expansion Joints Exhaust Flanges.

Expansion Joint Manufacturers Association – Wikipedia

Standzrd minimum control requirement of the bellow tube has to be X-ray or DPI prior to forming. This would be a very good development as it will lead to more uniform design practices and less confusion.

Bellows material thickness for one ply, corrected for thinning during stabdard forming of the bellows convolutions. Subscribe to this blog post Please fill in your email address to subscribe to updates from this post. Significant Changes in the Tenth Edition: Allowable material stress at design temperature, unless otherwise specified, from the applicable code.

EJMA 10th Edition

Bellows are rated by the manufacturer in terms of maximum allowable axial displacement per convolution, ec and ee. The bellows resistance factor or working spring rate is shown in lbs per inch of compression or extension. The main and most important result was that the calculated bending stress due to deflection could be considerably reduced.


EJMA does not mention this. Bellows tangent circumferential membrane stress due to internal pressure. The calculation of universal type Expansion Joints has been simplified by a modified equation for the axial movement per convolution. In case of external pressure the reinforcing effect of a possible external collar is excluded. Bellows convoluted length Lb plus the length of the bellows tangent ends or necks. Subscribe to our blog Unsubscribe from our blog.

Joints Externally Pressurized Exp. A new E-book version of the new 10th Edition Standards can be downloaded to your PC, laptop or tablet. Axial force or thrust caused by the internal pressurization of the bellows.

Machinery 18 post s. Fatigue life calculations were greatly enhanced and simplified.