Determination of Preliminary Performance Category for Non-Safety Components

DOE-STD-1021-93

categorizing a large number of these types of SSCs would be to group them on the basis of their

NPH related characteristics or locations. For example, for seismic hazard mitigation, it may be

generically determined that furniture and equipment located below a certain elevation and having

more than a certain base width-to-height (total height or center of gravity height) ratio would not

cause any significant life-threatening situation for workers or occupants, and so can be generically

placed into PC-0, thereby avoiding item-by-item evaluation. Similarly, for flood hazard

mitigation, it may be obvious that SSCs (e.g. equipment, furniture, water-sensitive electrical or

mechanical components, etc.) above a certain elevation would not be adversely affected during a

flood event, and so can be lumped into one performance category (provided it is compatible with

other functional/performance requirements). Once the SSCs are grouped, it is often possible to

develop generic methodologies or procedures to establish the adequacy of such components

against NPH events. For example, a generic procedure may be developed to anchor racks above a

certain height (or some other critical parameter) and place these as a group in Performance

Category 1.

If the cost or difficulty of replacing a component is estimated to be "excessive," the component

would belong to PC-2, according to Subsection 2.4 guidelines (unless it is placed in a higher

category for improved performance).

Also, if the facility downtime resulting from the failure of a component is judged to be

"excessive," the component should be placed in PC-2 (unless for improved performance the

facility manager chooses to place it in PC-3 or PC-4). The definition of "excessive" downtime

will depend on the type of facility, its mission, its strategic importance, and the suitability of

available alternatives, if any. Maximum permissible downtime is a basic design requirement, and

should be established as a policy level issue specifically for each facility with appropriate DOE

approval. Prediction of downtime should be based on a task-by-task schedule for the replacement

of the failed component. This schedule can be an approximate one, based on time-estimates

obtained by interviewing personnel responsible for design modification, procurement, operation,

maintenance, and construction/installation.

SSCs that must be safe and usable for emergency purposes after an NPH event in order to

preserve the health and safety of the workers and co-located workers, as well as members the

general public, should also be placed in PC-2. Examples of such SSCs are those that are essential

for the operation and functioning of:

hospitals or other medical facilities having surgery or emergency treatment areas,

fire stations,

police and security stations,

emergency communication centers,

emergency power facilities, etc.

If the replacement or repair of a component is more cost-effective than designing it to withstand

loads from NPH, then, according to Section 2.4 guidelines, it can be assigned to PC-0, provided

the component is not important from life safety or mission considerations. In a typical facility,

there are a large number of components that may be candidates for PC-0. In many cases, simple

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