AIR COOLED HEAT EXCHANGERS-Header box 1

[johnthebest]

hello everyone

in our specification of air cooled heat exchanger we satated the following:

Header box

Since nozzles are welded by set-through, top or bottom plates to be welded on tube sheet or plug sheet
to provide minimum 25mm clearance between weld edges of nozzles and header.

The contractor said that they are going to delete this phrase and replace it by:

Nozzle on header box shall be "set-on" type FPW construction.

Can anyone tell me the difference between the two.

 

[XL83NL]

FPW probably mean full pen(etration) weld. The difference between set-on and -through can be found in most design codes. Google is also helpful.

 

[r6155]

See ASME VIII Div 1 UW-16 (c)

Regards

 

[SnTMan]

Can anyone tell me the difference between the two.

Pretty certain your contractor could. Did you ask?

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Christine74]

Header boxes for air-cooled exchangers are nearly always designed with set-on nozzles rather than set-through. This not only reduces the amount of welding required but also helps to reduce the depth of the header box, which in turn helps to reduce the required plate thickness. Typically there is no clearance between the nozzle welds and the header box welds.

Some manufacturers even take this a step further by using swaged nozzles that have an obround cross section where they attach to the header boxes.

-Christine