General Requirements - std30240021

DOE-STD-3024-98

Requirement: The exhaust air high

One method of referencing the source documents

temperature trip setpoint on the

that has been found to be user friendly is to provide

ventilation exhaust fan shall be 175-

the bibliographical information on the source

185EF.

documents in an Appendix to the SDD. Then

footnotes can refer to particular source documents

Basis: The setpoint was chosen high

and provide specific page references where they are

enough above normal operating

appropriate in the body of the SDD. For example,

exhaust air temperature of 140EF to

avoid spurious trips of the ventilation

the footnote for a particular requirement might say:

exhaust fan, but low enough to

"See Appendix A, Reference 5, pages 12-16." This

provide early detection of hot gases.

technique has the advantage that complete

The safety analysis shows that in the

bibliographical details do not need to be repeated

event of a fire, the consequences to

each time a document is referenced. In addition, this

workers from the spread of toxic

products of combustion are acceptable

technique can also make SDD revisions easier.

if the fan is tripped before exhaust air

Such footnotes need not be limited to a single source

temperature reaches 200EF.

document.

If more than one source

document/reference contains pertinent information,

Basis information can take different forms. Specific

they should be included in the footnote.

engineering documents (such as studies, analyses,

calculations, and reports) are important basis

The following sections of this standard have been

references. In addition, appropriate and specific

numbered purposely to correspond to the sections of

references to national codes and standards should be

an SDD, as shown in the outline on page 1, to make

included in the basis references, when appropriate.

this standard easier to use.

Operational experience and standard engineering

practices are valid reasons that could justify a

3.1 General Requirements

requirement.

3.1.1 System Functional Requirements

References

This subsection shall state those functional

Specific references are essential to understanding

requirements and their bases, for both safety

and using the SDD.

References to source

requirements and non-safety requirements, that are

documents from which requirements and basis

necessary to fulfill the system function statements.

information has been extracted adds traceability to

If the requirements and bases have already been

the SDD and improves its credibility. To the extent

presented earlier in the SDD (see for example, item

that such reference documents are available, the

c. in Section 2.1), refer to that section rather than

source documents that contain the cited

repeat the information.

requirements or the bases information shall be

referenced in the SDD. Even if the supporting

Note: Functional requirements in

reference document contains only the requirement

general relate to how the system

but not the basis information, such as may be the

functions, performs, behaves, or

case for a procurement specification, that document

responds to particular conditions.

should be included as a reference.

Non-functional requirements should be

addressed in other subsections that

In some cases, the requirement or basis information

correspond to the most fitting

is not recorded in a separate document, the

engineering or topical category, such

documentation no longer exists, or it is not feasible

as those that address reliability

to retrieve such a document. In those cases, the

features, electrical power needs,

reference should state that a documented reference is

testability, or quality assurance

not available, so as to avoid potential confusion and

provisions.

wasted effort.

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