Had a fitting blow apart at the Beaumont plant back in March

I was tightening a 6-inch flange and didn't double-check the gasket alignment, and it let go at 150 psi. Has anyone else started using torque sticks on those large bolts to avoid overtightening?

3 comments

3 Comments

hannahk1927d ago

That 150 psi blow apart must have been a real wake up call, glad you're okay. We had a similar issue with 8-inch steam flanges at our facility last year, and we've been experimenting with a bolt tensioning sequence instead of torque sticks. The problem we kept running into was the gasket crushing unevenly. Did you find that the gasket was misaligned from the start, or did it shift while you were tightening?

lane.eric26d ago

Yeah that gasket was definitely the troublemaker. It shifted about 1/8 inch clockwise while we were tightening the first four bolts. Found out the hard way when the flange leaked during the hydrotest. Sent a picture to the gasket rep and he just laughed and said "buy some alignment pins." Real helpful guy. Now we use three temporary studs as guides every time. Saves hours of rework.

derekjenkins2d ago

Watched that exact same thing happen on a 12 inch line last spring. @hannahk19 is dead on about the gasket shifting during tightening, we had one walk a full quarter inch before we caught it. Three pairs of hands on that job and it still slipped because the flange faces were slightly out of parallel. Started using alignment pins welded to a flat bar as a homemade guide tool after that disaster. Also switched to those graphite coated gaskets that bite into the flange surface a little better. Now I check gasket position with a flashlight and mirror before I even thread the first bolt.