Checking Process Parameters

DOE-STD-1036-93

valve stem to use in independent verification. Other types of valve

position indicators may be approved by the facility. In these cases, the

throttled valve position may be independently verified by visually

checking the valve and the position indicator.

If it is necessary to close and reopen the valve to establish its position, it

is preferable to have both the performer and the verifier present

(concurrent dual verification). The verifier should independently verify

that the correct valve was identified, its required position was correctly

determined according to the procedure, the positioning was performed

correctly, and process parameters, if available, confirm the correct

positioning.

4.3.3

Checking Process Parameters

Observation of process parameters (e.g., pressure, flow, voltage) may

help verify the correct position of components. However, process

parameters alone may not give an accurate indication of component

status, because alternate flow paths or other factors may cause

misleading indications. For example,

C Voltage on a circuit does not prove that a particular supply breaker is

closed unless there is no alternate power supply

C Flow and pressure do not necessarily prove that a valve is fully open.

Observation of process parameters should be combined with other

verification methods, such as physical checks of component position,

whenever possible. Facility guidelines should specify where and when

process parameters alone are acceptable indicators of component

position.