Can the temporary reduction in operating pressure be based upon previous maximum operating pressures?
No. A reduction in operating pressure is intended to provide an additional safety margin until the defect can be remediated. To assure that additional margin is provided, the pressure reduction must be based upon pressures that the pipe has actually experienced, with the defect present (i.e., pressures for which safety has been demonstrated). These may be well below the maximum operating pressure for the pipe. The rule requires that the pressure reduction must be calculated using the method in section 451.7 of ANSI/ASME B31.4 if that method is applicable and the information needed is available. If that method cannot be used, the operator is responsible for determining an appropriate basis for assuring additional safety through a reduction in pressure. A reduction of 20 percent below the highest operating pressure actually experienced at the location of the defect within the two months preceding the inspection may provide the necessary additional safety margin.
No. A reduction in operating pressure is intended to provide an additional safety margin until the defect can be remediated. To assure that additional margin is provided, the pressure reduction must be based upon pressures that the pipe has actually experienced, with the defect present (i.e., pressures for which safety has been demonstrated). These may be well below the maximum operating pressure for the pipe. The rule requires that the pressure reduction must be calculated using the method in section 451.6.2.2 (b) of ANSI/ASME B31.4 if that method is applicable and the information needed is available. If that method cannot be used, the operator is responsible for determining an appropriate basis for assuring additional safety through a reduction in pressure. A reduction of 20 percent below the highest operating pressure actually experienced at the location of the defect within the two months preceding the inspection may provide the necessary additional safety margin.
Related Questions
- Can the temporary reduction in operating pressure be based on calculations other than those defined in section 451.6.2.2 (b) of ASME/ANSI B31.4?
- Can the temporary reduction in operating pressure be based on calculations other than those defined in section 451.7 of ASME/ANSI B31.4?
- Can the temporary reduction in operating pressure be based upon previous maximum operating pressures?
