The surveys shall cover all industrial undertakings and small businesses, if any, which employ twenty or more persons and whose principal activity is listed in one of the Divisions of the Nomenclature of Economic Activities in the European Communities (NACE), for industry, including energy and water, and also construction (NACE 1 to 5).
Surveys shall, at least once in every five years, be extended to cover undertakings employing fewer than 20 persons. The Commission, in agreement with the Member States, shall appoint the years in which the surveys shall be so extended.
Surveys into undertakings employing fewer than twenty persons may be carried out by means of sampling.