Standard condition is that reached by a specimen when it is in moisture equilibrium with a standard atmosphere. Standard condition is seldom realized in practice since laboratory atmospheres are continually fluctuating between narrow limits, and it is not practical to wait for the attainment of moisture equilibrium which would require several days or more for tightly wound samples of high regain material. Practically, specimens are brought to moisture equilibrium in the standard atmosphere for testing as defined in these definitions. The term “standard condition” should not be used as a synonym for the concept of “standard atmosphere.”