General Assumptions

Id Activity Value Uom Description Remarks Source
21 Reinstalling Time needed to restore other mechanical connections: see dedicated table expert judgment
22 Leak test 0.50 h Time needed to connect the high pressure nitrogen generator expert judgment
23 Leak test 1.10 Leak test pressure to operating pressure ratio expert judgment
24 Leak test 1,400.00 Sm3/h High pressure nitrogen flow rate TO BE DEFINED BASED ON PROJECT PROJECT SOURCE
25 Leak test 0.25 h/conn. Time needed to check each flange for leaks after the test pressure is achieved expert judgment
26 Air Removal 0.50 h Time needed to connect the nitrogen generator expert judgment
27 Air Removal 0.21 Initial oxygen concentration (in case leak test has not been performed) expert judgment
28 Air Removal 0.03 Target oxygen concentration expert judgment
29 Air Removal 2.00 Pressurization pressure (applicable to purging by pressurization/depr. cycles) Assumed equal to Purging expert judgment
30 Air Removal 1.00 Discharge pressure (applicable to purging by pressurization/depr. cycles) Assumed equal to Purging expert judgment
31 Air Removal 1,400.00 Nitrogen generator flow rate Assumed equal to Purging expert judgment 342101BPST02508 34210ABPRV02054
32 Commissioning & Start up 1.00 h Temperature restoring time expert judgment
33 Commissioning & Start up 0.50 h Pressure restoring time Assumed equal to Depressurization time expert judgment
34 Commissioning & Start up Level restoring time Assumed equal to Draining time expert judgment
35 2.00 Maximum numbers of crews working in parallel for isolation/blinding expert judgment
36 0.80 Efficiency of maintenance crew Not applied to essentially labor-free activities (i.e. Cool down and Ventilation) expert judgment
37 Item conveyance to workshop 1.00 h Loading / Unloading expert judgment
38 Item conveyance to workshop 1.00 h Travel to WS expert judgment