The horizontal upthrust constants (Fig. PTP200-U) were fabricated from carbon steel and chrome-moly for a Heat Recovery Steam Generator. The constants range in sizes PTP-200 size 3 to 65 and weigh from 24 lbs to 1,300 lbs. They support loads of 100 lbs to 8,100 lbs. The constants support pipes and equipment subjected to vertical movement due to thermal expansion at locations where transfer of stress to other supports or equipment can be critical. Horizontal upthrust constants are utilized in areas where horizontal travel is unacceptable. Standard testing was completed for performance and quality assurance.