Fire damage to A572 Gr 50 plate

[LVLIIIenger]

We built a Penstock that is 25' diameter using 1.250" A572 gr 50 material. Our customer had a fire, Pine 2x4's, that melted the paint off the outside and bubbled the inside. I'm guessing that it burned for approx. 1.5 hours. The tie wire (1/8") on the rebar attached to the Penstock did not show signs of sagging or embrittlement so my best guess is the heat did not reach more than 600°- 700°. I have completed a Rockwell hardness test and the material has not changed hardness at all. What other testing can I perform to make my customer feel comfortable that no degradation in strength has occured due to the fire?

Sam Bruno

 

[metengr]

LVLIIIenger;
The hardness testing would be the obvious sign if the material was subjected to extreme heat from exposure to fire. I would document a good visual inspection to check for bulging or distortion. If none is observed, the documented visual inspection coupled with portable hardness testing performed by a qualified field technician using a procedure should suffice.

 

[unclesyd]

Carryout the inspection as posted above to cover you and your companies future liability. The owner of the of the equipment should cover the cost.
Make sure that the technicians that conducts the inspection have the proper certifications. It may sound strange but I saw a very high dollar case turned on the fact that the person who did the visual inspection didn't have a VT qualification.

Did the fire char the paint on the outside?

If so, what color was the char?

 

[tr1ntx]

I don't mean to step on the toes of the experts, but isn't there a "discoloration inspection" that could be performed on the bare metal as the primary indication that it didn't reach a critical temperature? (if the paint is off or can be flaked off)

Maybe that is a "shade tree mechanic" estimation I've run across somewhere before.

 

[LVLIIIenger]

The fire was located on the outside of the Penstock. The coating was completely melted off on the outside and black and bubbled on the inside.The coating is Carboline 341 (Epoxy), which has a flash point of 210°F and a boiling range of 149°F - 401°. I will take all your comments and include them in my report. Thank you all for your suggestions and comments.

Sam Bruno