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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The Guide is intended to provide users with a basic understanding of expansion joints. Yield strength at design temperature, unless otherwise determined, of bellows sfandard after completion of bellows forming and any applicable heat treatment.

Expansion Joint Manufacturers Association – Wikipedia

It will also assist the user in communicating design requirements to the manufacturers and to properly install and maintain the expansion joint in service. Due Diligence 5 post s. The bellows resistance factor or working spring rate is shown in lbs per inch of lateral offset.

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. I cannot imagine that for simple applications the bellow syandard Always has to be x-rayed or DPI tested. He has more than 30 years of experience in design, design review, analysis, check-out, mechanical integrity, development, troubleshooting, and failure analysis.


It is used in specific design calculations to relate U-shaped bellows convolution segment behavior to a simple strip beam. Subscribe to this blog post Unsubscribe.

Pressure thrust can be standarv by multiplying the working pressure by the effective area PSIG x Ae. Materials Degradation and Corrosion 15 post s. Guest – Tom Vowell on Sunday, 20 October Tightness of bellows, bands, and rings due to dissimilar material growth rates is considered.

Perhaps there was confusion over which code was applicable. Pressure Vessels 17 post s.

Bellows are rated by the manufacturer in terms of maximum allowable axial displacement per convolution, ec and ee. Tom Vowell enma Wednesday, 16 October Bellows meridional bending stress due to deflection. It is characterized by tilting or warping of one or more convolutions. Total Equivalent Max Axial: Convolution height less the bellows material thickness.

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

Total length of the expansion joint including the possible pipe ends. Modulus of Elasticity at design temperature, unless otherwise specified, for material.

Benchmark table inputs and outputs have been revised, with material class and correction factor. EJMA 10th Edition is the most current edition and supersedes all previous publications. The main and most important etandard was that the calculated bending stress due to deflection could be considerably reduced.

Ejmaa Interest 4 post s. Friday, 26 July A cycle is defined as one complete movement from the initial position in the piping system to the operating position and back to the initial position. Fitness for Service 9 post s. In-plane squirm is defined ejja 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.


Bellows convoluted length Lb plus the length of the bellows tangent ends or necks. This includes standard conversions in addition to constants used in calculations.

EJMA 10th Edition

The Sa he gave me, for 70F and F were and respectfully. Fatigue life calculations were greatly enhanced and simplified. He is President of Becht Engineering Co. Collar circumferential membrane stress due to internal pressure.

This condition is predominantly associated with high meridional bending stress at the root and crest of the convolutions. Bellows meridional membrane stress due to pressure. Response to Stress Question. The fatigue life expectancy of an expansion joint is affected by various factors such as: 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.

The design of every Expansion Joint must be such that the total displacement per convolution from all sources does not exceed the rated values. Bellows circumferential membrane stress due to pressure. The calculation of universal type Expansion Joints has been simplified by a modified equation for the axial movement per convolution.

Piping 26 post s. Available Positions Apply On-line.