How should the word "specified" be interpreted?
A good specification for a job should state clearly at the beginning under a "definitions" section just what precisely is meant by the terms used. "Specified" will then normally refer to the particular specification you are reading, plus any others (including standards, building codes, regulations, etc.) quoted in it. With all these terms--"approved," "instructed," "described"--it is important that they refer to material given in writing.