Full stroke testing

Component failure rate data and PFDavg/MTTFS calculations for two cases of the above system are shown in Table 12-1 and Table 12-3. SFF calculations and architecture limit checks are shown in Table 12-2 and Table 12-4. An assumption was made that a very effective proof test was performed at the specified proof test interval with proof test coverage of 95% for the sensor (full calibration), 90% for the logic solver and 80% for final element (full stroke test). The calculation results and all other results... 

Self — diagnostics features of devices Real time identification of dangerous failures Valve partial/full stroke testing possible Reduced manual proof testing burden Operability ... 

In a running facility or plant, if testing is to be performed on solenoid operated on-off shut down valves to assess the health of valve, and then only way is to carry out partial stroke testing of the valve. This may give rise to chances for spurious tripping of the plant. In the following sub-clauses, partial stroke and full stroke testing shall be covered. 

Discussions on Partial Stroke Test and Full Stroke Test... 

The full stroking test of the valves of the HIPS are staggered by 6 months and it doubles the frequency of testing common cause failures. 

Final Elements 2 valves (loo2 voting) with full assessment and certified as per lEC 61508 and partial valve stroke testing at a frequency at least ten times more often than the expected average demand interval. 

The p factor for the undetected common cause failures is fixed at 2% (0.02). The Pq factor for the detected common cause failures is fixed at 1% (0.01). The proof test is a full, perfect proof test as opposed to a partial stroke test. The mean time to repair (MTTR) is 8 hours for all elements. 

Partial Stroke Testing (PST) is sometimes used as a supplement to full proof testing of safety valves. 

The fault tree shown in Figure 8.24 corresponds to the PSD. It is relatively simple and requires few comments except for the failure modes of the valve separated into two classes according to whether they are detected by a quarterly test of partial stroking or detected by an annual test of full stroking. The quarterly testing is incomplete, and the probability of failure does not return to zero, which gives the PFD(t) curve its unique shape. 

The effectiveness of catheter-based intra-arterial therapy to remove residual thrombus after IV rt-PA treatment is being tested in the Interventional Management of Stroke study (IMS-Ill). This study will randomize patients to 0.6 mg/kg IV rt-PA, followed by angiography with additional intra-arterial therapy as indicated, or IV full-dose rt-PA (0.9 mg/kg). A nonrandomized safety study suggested that intraarterial therapy, after 0.6 mg/kg IV rt-PA, could be accomphshed with acceptable rates of sICH. ° ... 

The pumps generally have a capacity of 100 ml for a full pump stroke. The sample volume taken can be controlled by the number of pump strokes taken for each tube. Pumps must be properly maintained and procedures for leak testing and for measuring the volume and flow rate can be obtained from the manufacturers. The volume of the pump should be accurate to 5 % of the value stated. Detector tubes made by one manufacturer should not be used with a pump made by a different manufacturer since the pumps have different flow characteristics and could cause different lengths of stain. Each lot of detector tubes is calibrated by the manufacturer using his specific pump design. 

Slowly take 25 full pump strokes. Remove from pump, and heat tube with matches or cigarette lighter for about 5 seconds. (Avoid excessive heating of tube, since this will char contents of the tube and invalidate the test results.) After tube is cool, add liquid from blue bottle to unmarked end of the tube. If gas is present, a blue ring will form in the upper end of the tube.116... 

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