Performance Category 2

DOE-STD-1020-2002

Where a structure cannot be constructed above the DBFL level, an acceptable design can

be achieved by:

Modifying the flood or providing flood protection for the site or for the

specific structure, such that severe structural damage does not occur, and

Developing emergency procedures in order to provide adequate warning

and evacuation capability to provide for the safety of building occupants.

For structural loads applied to roofs, exterior walls, etc., the applicable regulations should be

used.

4.2.2 Performance Category 2

The performance goal for Performance Category 2 is to limit damage and interruption of

operations while also maintaining occupant safety. The DBFL is equal to the flood whose

annual probability of exceedance is 5x10-4 per year including the event combinations listed in

Table 4-2. For purposes of establishing the DBFL for Performance Category 2, a site-specific

hazard assessment should be performed. This analysis must include the uncertainty in the hazard

assessment in order to obtain an accurate estimate of the mean-annual probability level.

SSCs in this category should be located above the DBFL. For SSCs that cannot be

located above the DBFL, an acceptable design can be achieved by the same measures described

for Performance Category 1. Emergency operation plans must be developed to provide for

occupant safety and to mitigate the damage to mission-dependent SSCs. These procedures may

include installation of temporary flood barriers, removal of equipment to protected areas,

anchoring vulnerable items, or installing sumps or emergency pumps. As in the case of SSCs in

Performance Category 1, applicable regulations should be used to incorporate flood loads in the

building design.

4.2.3 Performance Category 3

The performance goal for Performance Category 3 is continued function of the facility,

including confinement of hazardous materials and occupant safety. SSCs in this category should

be located above flood levels whose mean-annual probability of exceedance is 10-4, including

the event combinations shown in Table 4-2.

If SSCs in this category cannot be constructed above the DBFL level, a design must be

developed that provides continued facility operation. The strategy must mitigate the flood (i.e.,

modifying the flood, hardening the facility, building a levee to prevent flood encroachment) to

an extent that facility operations can continue. A higher level of protection is required for SSCs

in Performance Category 3 as compared to Categories 1 and 2. Limited damage and interruption

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