20. For the purpose of charging by percentage, buildings shall be classified as follows:(1) Class I: sheds, warehouses, parking garages, garages, business premises, factories, power stations, swimming pools, gymnasia, marinas, multifamily dwellings, row housing, duplexes, office buildings, and elementary level educational institutions;
(2) Class II: exhibitions buildings, museums, libraries, theatres, auditoria, monument, radio and television studios, hospitals, medical clinics, reception centres and local community service centres, laboratories, kitchens, cafeterias, restaurants, single family dwellings, secondary school, college or university level educational institutions, airports, nuclear power stations, court houses and penitentiaries.