Verification Techniques cont'd

DOE-STD-1036-93

function of the system. Some operations can be verified by checking the final

condition or position of components against a standard, i.e., a product-based

approach. For example:

During a lockout/tagout, it is critical that the tags be placed on the correct

components. To ensure that no identification errors were made, the

instructions should require the verifier to independently identify each

component using the same procedures, drawings, checklists, and component

label information that were used by the performer; then verify that the

component is correctly tagged.

When isolating a component or aligning a system for operation, each valve,

switch, bypass, or other device must be correctly positioned according to an

operating procedure or other documentation. The verifier should be

instructed to independently check the physical position of these components,

or perform other checks that will positively indicate that the components are

properly positioned.

In some operations, it is critical that the performer follow a specific process or

series of sequential steps. It may be impossible for the verifier to determine that

the steps were performed correctly through observation of the finished product.

These operations should be verified by independently observing that the proper

steps, sequence, or adjustments are performed according to a standard. The

method for this is known as concurrent dual verification. For example:

When installing a bolted cover on a piece of equipment, the bolts must be

tightened to a specific torque value in a specific sequence to prevent

damaging the cover. Instructions for verifying this operation should have the

verifier independently observe that the correct torque is applied and that the

bolts are tightened in the required sequence.