Designed to the "T"
Engineering at its Best
All Colt leak-repair devices are designed with good engineering practice following accepted industry standards. ASME Standard PCC-2 “Repair of Pressure Equipment and Piping” provides general guidelines for design and installation of many of these mechanical repairs. ASME B31.3 and ASME BPVC Sec. VIII Div.I and Sec. II part D provide the allowable stress loads along with some necessary design calculations. API 570 provides some rules for the construction of leak repair enclosures, but is not comprehensive. Since there is no specific codebook for analyzing all key stresses of a leak-repair enclosure, it is the job of the engineering staff to locate and calculate the stresses not defined in any above mentioned codebooks using acceptable engineering reference materials. Roark’s “Formulas for Stress and Strain” and Mark’s “Standard Handbook for Mechanical Engineers” are two examples of the most commonly used reference books at Colt for defining these stresses. All Colt-designed leak-repair devices consider the coincident maximum/minimum pressures and temperatures of the system when defining the enclosure’s integrity. The drawings and calculations for all proposed designs show all formulas and clearly identify their sources, so that the customer can review and approve the proposed design prior to manufacturing and installing.
Temporary repairs of locally thinned sections or circumferential linear defects are repaired on-stream by installing a properly designed and applied leak-repair device (e.g., bolted clamp, nonmetallic composite wrap, or other non-welded applied temporary repair). Per API 570, the design considers control of axial thrust loads (strong backing) if the piping component being enclosed is (or may become) insufficient to control pressure thrust. The effect of enclosing (crushing) forces on the component is also considered.
During turnarounds, or other appropriate opportunities, temporary leak-repair devices should be removed and appropriate actions taken to restore the original integrity of the piping system (API 570).