BS EN 1092-1:2007+A1:2013 Flanges and their joints. Circular flanges for pipes, valves, fittings and accessories, PN designated . Steel flanges

BS EN 1092-1 is a European standard for a single series of flanges. It specifies requirements for circular steel flanges in PN designations PN 2,5 to PN 400 and nominal sizes from DN 10 to DN 4000.


BS EN 1092-1 specifies the flange types and their facings, dimensions, tolerances, threading, bolt sizes, flange jointing face surface finish, marking, materials,pressure/temperature ratings and approximate flange masses.


BS EN 1092-1 applies to flanges manufactured in accordance with the methods described. Non-gasketed pipe joints are outside the scope of BSEN1092-1.


The standard was developed based on the International Standard, ISO 7005-1, Steel flanges.


The new edition of BS EN 1092-1 now includes:

• Flanges PN 160, PN 250, PN 320 and PN 400
• Further methods of manufacture
• Welding conditions, inspection and testing
• Flange facing height f1 changed back to former DN related dimensions
• Further collar types
• Updated materials
• New p/T-ratings are related to the flange material
• Rings for tongue and groove flanges.

Contents of BS EN 1092-1 include:

Normative references
Terms and definitions
Standard designation
General requirements
Methods of manufacture related to base material
Repairs by welding
Determination of p/T ratings
Flanges and collars
Threaded flanges
Bolt holes
Lapped joints
Collar types
Types of facings
Jointing face finish
Surface finish of flanges and collars
Spot facing or back facing of flanges
General marking requirements
Declaration of compliance
Inspection and testing of fusion welded joints
Inspection and testing of bended and electric welded flanges or collars from formed bars, sectional steel or band material
Inspection and testing of formed parts manufactured from base material other than forgings
Inspection and testing of other materials
Wall thickness and end preparation
Weld-end preparation for flanges types
Weld-end preparation for type
Weld end preparation for type
Material groups
Approximate masses of flanges and collars
Additional materials
Basis of flange calculation
Calculation method
Basic rules for calculation of flange connection
Determination of p/t-ratings
Reference temperature (RT)
Application limits and equations
Symbols, descriptions and units
p/t-Ratings for materials with time independent nominal design stress
p/t-Ratings for materials with time dependent nominal design stress
Reference value for thickness (vR)
Nominal design stresses and safety factors for mean creep rupture strength
Flanges made from steel castings
Rounding of maximum allowable pressure at temperature
p/t-ratings for a selection of EN materials
Basics of determination of p/t-ratings (see Annex F)
Application limits for creep range
Non-austenitic steels
List of materials
Austenitic and austenitic-ferritic steels
List of materials
Rings for tongue and groove flanges
Flanges with fixed inner diameter
Mating dimensions for flanges with higher DN
Relationship between this European Standard and the Essential Requirements of Directive 97/23/EC

BS EN 1092-1:2007 replaces BS EN 1092-1:2002 which has been withdrawn.

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