Fastening of Internals

Trays and downcomers should be firmly bolted to their supports. Failure to do so may result in excessive deflection, flow restriction, leakage, and deficient mechanical integrity. 

Cracks and crevices should not take up more than 2 percent of the tray area (49). If they do, excessive weeping and/or channeling may result. 

Particular care should be taken to see that the nuts and bolts at the drawoff trays (particularly for total drawoffs) are properly tightened. At least one experience (85) has been reported where poor column performance resulted from failure to tighten the drawoff box nuts and bolts. 

In leaktight services, it is important to confirm that washers and gasketing were installed as specified. In one case (145), leaving out 

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