Flanges and their joints - Bolting - Part 4: Selection of bolting for equipment subject to the Pressure Equipment Directive 97/23/EC
This European Standard is applicable to the selection of bolting for equipment subject to the Pressure Equipment Directive 97/23/EC.
It specifies standards and additional requirements for dimensions, materials and technical conditions of delivery for bolting.
The bolting selection covered by this European Standard is regarded to be used for combination with flanges according to the series EN 1092 (PN designated flanges) and the series EN 1759 (Class designated flanges).
The selection is based on commonly used materials, bolts and nuts. It covers temperature ranges of the general service of standard flanges (based on PN or Class).
NOTE 1 The bolting selection given may be used in combination with non-standard flanges too provided that the range of application of the equipment for which the bolting is intended to be used is covered. It is the purchaser's option to decide on this.
When selecting bolting according to this European Standard it is essential to take into account other parameters such as type of fluids, corrosion hazards and relaxation at elevated temperatures.
The purpose of this European Standard is to provide a selection of most commonly used bolting types and bolting material combinations as well a tool for easy selection of suitable bolting for equipment.
It is not the intention to specify all possible applications but to give guidance on the most commonly applications. According to this, e.g. application limits for material in the creep range are not explicitly covered in this European Standard but some bolting materials listed (see Table 3, footnote h) are suitable to be used in this temperature range. Wherever the starting material standard provides mechanical properties for this temperature range respective reference is made in Table 3.