ISA-TR52.00.01:2006

The usual concept that working standards are less accurate than reference standards and that the environmental requirements are less demanding is the basis for this technical report. The same concept carries over, in general, in differentiating between Type I and Type II laboratories. It should be emphasized that this technical report is intended to apply to Echelon II laboratories only. Moreover, this technical report serves primarily as a guideline to the design, construction, and operation of standards laboratories and, thus, is not to be construed as mandatory requirements. In many cases satisfactory repeatability of calibrations can be obtained even though the environment does not comply fully with this technical report.