Newsletter reader gives feedback on turbomachinery installation

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Ronald E. LeTard, P.E. of Cypress, Texas writes in: "A recent newsletter article on Turbomachinery Installation stated that the sleeves around the anchor bolts should be filled with grout material during installation.  This is a direct contradiction of the API recommended practice for installation of rotating machinery.  The recommended practice states that the sleeves should be filled with nonbonding moldable material to prevent grout from entering.  The reason is that grout would prevent an anchor bolt from stretching when its nut is tightened.  If the bolt is effectively shortened by being held in place by grout, the torque applied when tightening the nut will not result in the desired stretch.  The stretch of the bolt is the source of the clamping force.  Following the recommendation to fill the anchor bolt sleeves with grout could result in anchor bolts that are not delivering the clamping force intended by the designer when they were selected."