Hospitals vary both in size and in the types of on-site support facilities. The number of beds in a hospital considered to be small might be in the range of 50 to 200, while a 2000 bed hospital would be considered a large facility. Some hospitals have full size commercial dietary facilities while others employ outside food catering services. Some have on-site laundry facilities while others rely on private laundry services. Also, hospitals have large numbers of lavatories and showers, but the total quantity of hot water per day required by these fixtures will be less than the total quantity required by the same number of fixtures installed in a hotel or apartment building. Design criteria and alternate solutions are provided for service hot water heating for hospitals.