Pump, valve and fitting flange alignments are governed by BS EN 1092 which superseded BS 4504. Generally pumps, valves and fittings are supplied with flanges conforming to Table 10 (PN16) which are suitable for a maximum working pressure of 10 Bar.
The following information is offered as a guide to ensure good joint integrity and avoiding environmental release.
The torques in the below table are based on using a 3mm think 70 IRHD rubber gasket.
1. Ensure flanges and fasteners are clear and in good working conditions.
2. Insert bolts 1 to 4 into one flange and position the gaskets on bolts
3. Align flanges and support as required
4. Offer the adjoining flange to the bolts and hand tighten nuts
5. Insert remaining bolts and hand tighten nuts
6. Determine required bolt torque
7. Using opposite quadrant sequence illustrated tighten as follows:
a. tighten nuts to 30% of estimated torque then,
b. tighten nuts to 60% of estimated torque then,
c. tighten nuts to 100% of estimated torque
8. Finally, tighten all nuts 100% of required torque in a clockwise direction