Fire Tube Boiler Tube Plugging - Safe percentage of tubes plugged

[stevem1968]

Fire tube Boiler

Total amount of tubes 257

57 Tubes Plugged = 20.8%

What is the ASME or industry standard with regards to the amount of tubes plugged before it becomes unsafe to operate.

Thanks

Steve M

 

[metengr]

There is no guidance from the code of construction because this boils down to a performance issue, and each manufacturer would have their own performance/design criteria.

 

[EdStainless]

Have you de-rated the unit?
If not then you likely are running too hot and at too high of a flow in the remaining tubes.
Accelerated wastage and the higher risk of tube failure are real issues.
In many systems 10% is not a problem, but above that things can get out of proportion, so many plants limit it to 15%.


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P.E. Metallurgy, Plymouth Tube

 

[metengr]

See the link below, especially question 7.....

http://www.cleaverbrooks.com/refere...ring-outline-and-summary---july-29,-2015.aspx

 

[oknow]

Suggest you contact the Jurisdictional Authority where the boiler will be installed to discuss. Get confirmation in writing and keep in file. If it were me I would also contact the Insurance company who will be insuring the boiler. Better safe than sorry.

 

[chicopee]

21% of the tubes plugged suggest boiler retubing as things can only get worse as indicated above remaining good tubes will get overheated and they will excessively expand in relation to the boiler shell and start leaking at the tube ends unless as suggested you reduce the firing rate.. I would like to know is there a pattern of the tube tubes leaking.