BS EN 1591-1:2013

What is BS EN 1591-1 - Calculation method for bolted, gasketed, circular flange joints about?

BS EN 1591 is a European Standard on flanges and their joints that discusses the calculation methods. The main aim of the BS EN 1591 series is to provide manufacturers with best industry practices to ensure structural integrity and leak tightness of gasketed circular flange connections, such that they are fit for its intended use.

BS EN 1591-1 is the first part of the series that defines a calculation method for bolted, gasketed, circular flange joints. It uses gasket parameters based on definitions and test methods specified in EN 13555.

Note: The calculation method is not applicable to joints with a metallic contact out of the sealing face or to joints whose rigidity varies appreciably across gasket width. For gaskets in incompressible materials, which permit large deformations, the results given by the calculation method can be excessively conservative (i.e. required bolting load too high, allowable pressure of the fluid too low, required flange thickness too large, etc.).

Who is BS EN 1591-1 - Calculation method for bolted, gasketed, circular flange joints for?

BS EN 1591-1 on flanges and their joints are relevant to:

• Manufacturers of bolted, gasketed, circular flange joints
• Oil & gas industry
• Petrochemical industry
• Mechanical engineers
• Product design engineers

Why should you use BS EN 1591-1 - Calculation method for bolted, gasketed, circular flange joints?

The calculation method for bolted, gasketed, circular flange joints satisfies both leak tightness and strength criteria. The behaviour of the complete flanges-bolts-gasket system is considered. The use of this calculation method is particularly useful for joints where the bolt load is monitored when bolting up. With accurate and precise calculation methods, you can ensure your products play a positive role in the performance of end-applications.

In this regard, BS EN 1591-1 provides the requirements for use of the calculation method and calculation parameters. Moreover, recommendations on dimensions of standard metric bolts, flange rotations and scatter values for tightening methods are provided.

BS EN 1591-1 also covers the checking method of the assembly for a specified initial tightening bolt force and load limits on the joint system for safety.

As a result, if you are manufacturers of bolted, gasketed, circular flange joints, conforming to BS EN 1591-1 can help demonstrate the performance and credibility of your product, ensuring that they are suitable for its purpose and achieve the stated level of joint tightness with sufficient accuracy.

What’s changed since the last update?

BS EN 1591-1:2013 supersedes EN 1591-1:2001+A1:2009. BS EN 1591-1:2013 includes some technical changes with respect to EN 1591-1:2001+A1:2009. These include:

• Correction of load ratio calculation for blind flanges and modification of bolt load ratio calculation
• Integration of lateral forces and torsion moments applied on the bolted joint
• Integration of an alternative calculation method (more precise) for the determination of the gasket effective width (informative annex)
• Integration of the possibility to handle gasket creep/relaxation behaviour through additional deflection
• Integration of an informative annex concerning leakage rates conversions
• Integration of the possibility to check a bolted flange connection for a specified initial bolt load value
• Integration of the possibility to perform a calculation even when no tightness requirement is defined through basic gasket parameters (Annex G)