美标的shall和should的定义

东海龙王

3.2.4 Shall.  Indicates a mandatory requirement.
The term shall indicates a requirement of this standard and mandates that a specific provision
of NFPA 20 be followed. When the term shall is used with a specific provision of the standard,
compliance with that provision is mandatory. Any exceptions to a requirement of this standard
are specifically stated. The use of the term shall in an exception indicates that the exception
is applicable only under the conditions specified in the exception. Mandatory requirements of
NFPA 20 are found in the main body of the standard (see Chapters 1 through 14).
3.2.5 Should.  Indicates a recommendation or that which is advised but not required.
The term should indicates a recommendation of the standard. When the term should is used
with a provision of the standard, the provision is not intended to be mandatory. Recom-
mended provisions are limited to Annexes A and B of NFPA 20. The term should identifies a
good idea or a better practice. If the recommendation is not followed, the fire pump is still
expected to perform satisfactorily. Any paragraph number preceded by a letter (e.g., A.1.1) is
an annex item. Terms such as should and recommended are prevalent in annex paragraphs.

北方郎

shall应
should可

911room

should 宜

大鼻山

大致就是咱们的“应”和“宜”吧。哈哈