55 Pa. Code § 161.21
(d) The act of June 29, 1953 (P. L. 300, No. 64) (62 P. S. § § 2561—2565) (repealed 1967) defines an institution as an establishment which furnishes food and shelter to three or more persons unrelated to the proprietor, and which provides some care or service which meets a need beyond the basic provision of food, shelter and laundry. The following institutions come within the meaning of the definition: