Special Considerations for Existing Facilities

DOE-STD-1020-2002

diameter pipe irregardless of the separation distance. The designer/evaluator shall justify and

document these cases.

Design measures for preventing adverse performance from structural failing and failing

and proximity seismic interaction modes include: (1) strength and stiffness; (2) separation

distance; and (3) barriers. Sources may be designed to be strong enough to prevent falling or

stiff enough to prevent large displacements such that adverse interaction does not occur. To

accomplish this, the source item shall be designed to the structural integrity design criteria of the

target item. Maintaining function of the source item under this increased seismic design

requirement is not necessary. Source and targets can be physically separated sufficient distance

such that, under seismic response displacements expected for target design criteria earthquake

excitation, adverse interaction will not occur. Barriers can be designed to protect the target from

source falling or source motions. Barriers shall also be designed to the structural integrity design

criteria of the target item. In addition, barriers shall be designed to withstand impact of the

source item without endangering the target.

Another form of seismic interaction occurs where distribution lines such as piping,

tubing, conduit, or cables connected to an item important to safety or production have

insufficient flexibility to accommodate relative movement between the important item and

adjacent structures or equipment to which the distribution line is anchored. For DOE SSCs,

sufficient flexibility of such lines shall be provided from the important item to the first support

on nearby structures or equipment.

Other forms of seismic interaction result if vessels or piping systems rupture due to

earthquake excitation and cause fires or flooding which could affect performance of nearby

important or critical SSCs. In this case, such vessels or piping systems must continue to perform

their function of containing fluids or combustibles such that they shall be elevated in category to

the level of the targets that would be endangered by their failure.

C.7

Special Considerations for Existing Facilities

It is anticipated that these criteria would also be applied to evaluations of existing

facilities. General guidelines for the seismic evaluation of existing facilities are presented in a

National Institute of Standards and Technology document (Ref. C-63), a DOD manual (Ref.

C-64), and in ATC-14, "Evaluating the Seismic Resistance of Existing Buildings" (Ref. C-46)

and ATC-22, "A Handbook for Seismic Evaluation of Existing Buildings" (Ref. C-47). In

addition, guidelines for upgrading and strengthening equipment are presented in Reference C-56

and C-29. Also, guidance for evaluation of existing equipment by experience data is provided in

Reference C-61. These documents should be referred to for the overall procedure of evaluating

seismic adequacy of existing facilities, as well as for specific guidelines on upgrading and

retrofitting. General requirements and considerations in the evaluation of existing facilities are

presented briefly below.

C-49