Herman Kiefer Hospital was a facility for contagious diseases including tuberculosis built in the early 1910's. Patients were segregated into different "pavilions" on the campus based on how far their disease had progressed. There were four pavilions on the south side of the campus, located around an administration building.
In later years the hospital became the storage facility for the city department of vital records. Pavilion 2 was converted into a nursing school, and became a part of the Detroit Public Schools system. JTPA is short for the Job Training Partnership Act, a federal work training program. It's not clear when it closed, but it has been abandoned for some time. The school is listed for sale on the DPS property website.