Page 266 - Water Standards
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Table 4 2 12-1 (Continue)
No Item Allowable error Explanation
Meet requirements of Item 10
Valve casing composite
2 of Article 4 2 2 in this specifi⁃ —
joints
cation
No leakage under 0 05MPa pre⁃
3 Rubber seal air tests —
ssurised air
Aerated water
No gap —
Gap when seals
4 the valves
are closed Un⁃aerated
±20% of the design value —
water seals
The water leakage shall be no
5 Tightness tests in still water larger than the design value —
when holding 30min
2 Ball valve installation shall meet the following requirements:
1) Allowable installation error of the ball valves shall meet the requirements of Table
4 2 12-2.
2) Ball valves shall be able to move freely. Enough gap shall be left between the ball
valves and fixed parts. The gap should not be less than 2mm
Table 4 2 12-2 Allowable installation error of ball valves
No Item Allowable error Explanation
Composite joint between Meet relevant requirements of
1 —
valve seat and base plate Item 10 of Article 4 2 2
2 Valve body center ±5mm —
Valve body transversal
3 15mm —
center
2 5 9