29 CFR §779.206

1. (a)The Senate Report on the 1961 amendments states as follows, with respect to the meaning of related activities:
2. (b)Generally, the answer to the question whether particular activities are “related” or not, will depend in each case upon whether the activities serve a business purpose common to all the activities of the enterprise, or whether they serve a separate and unrelated business purpose. For example, where a company operates retail or service establishments, and also engages in a separate and unrelated construction business, the construction activities will not be “related” and will constitute a separate enterprise if they are conducted independently and apart from the retail operations. Where, however, the retail and construction activities are conducted for a common business purpose, they may be “related,” and if they are performed through unified operation or common control, they will be a part of a single enterprise. Thus, a retail store enterprise may engage in construction activities as an additional outlet for building materials which it sells, or otherwise to serve its retail operations. It may act as its own contractor in constructing or reconstructing its own stores and related facilities. In such a case, the construction activities will be “related” activities. Other examples may also be cited. The answer in each case will necessarily depend upon all the facts.