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Reg. 279 b, Reg. 279 c, Reg. 280

(b) Standpipe and nozzles welded to dished end plates
Where the standpipes or nozzles are welded to dished end plates, the compensation shall be considered adequate if calculated on the same basis as in (a) above. But the cross-sectional area of the end plate to be compensated shall be calculated on the basis of equation 74 and the height of standpipe above the outer surface or within the inner surface of the end plate shall be measured along the radial line passing through the centre of the opening.


Reg. 279 c

Minimum thickness of Flanges

The minimum thickness of the flanges and the body of standpipes shall be in accordance with the table under Regulation 156.




Reg. 280

Attachment of Stand blocks and Branch Pipes by Welding

a) Typical methods of attachment are shown in figures 24A, 24B, 24C, 24D, 26A, 26B, 26C, 26D, 26E, 27A, 27B, 27C,  and 27D.

All weld dimensions shown shall be regarded as minimum dimensions those defining the grooves refer to the actual preparation for welding.

tn = Specified thickness of standpipe or branch pipe.
ts = Specified thickness of drum or header shell at standpipe or branch connection.
tc = Actual thickness of compensating ring.

The application of certain of the constructions illustrated may be limited by consideration of design pressure and temperature or size (in combination) and although certain dimensions are given, each case must be considered on its merits.

Other methods may be adopted subject to agreement between the Inspecting Authority and manufacturer.
b) Electrodes shall comply with the requirements of Regulations 94 to 98 (Covered Electrodes for Metal Arc Welding).
c) Not less than two runs of metal shall be deposited at each weld. Each run of weld metal shall be thoroughly cleaned and freed from slag before the next run is deposited.

Where one side of a double V Weld has been completed, the under surface of the original run of metal shall be removed by grinding, chipping or machining to give a clean metallic surface before welding on the other side is commenced.
d)

The final finish of the weld shall be such that the change of section from drum to standpipe, or from flange to standpipe is gradual and free from sharp notches. After completion of welding (except in the case of seal welds) the drum shall be stress-relieved by heat treatment.

Notes- The branch must be a loose fit in the hole but the gap at any point, should not exceed 3 mm or en/2 whichever is less.   

    

            Weld sizes B1 + F1 = 1.52n   

    

            F1 should not exceed 16 mm not be less than 2n/2.   

     

            Weld size B + F = 1.5 en minimum or  

                               1.5 es minimum, whichever is less.   

                F should not exceed 16 mm nor be less than en/2.   

                en  =  thickness of nozzle   

                es   = thickness of shells.". 

 

 
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