N.H. Rev. Stat. § 189:24
A standard school is one approved by the state board of education, and maintained for at least 180 days in each year, or the equivalent number of hours as required in the rules of the department of education, in a suitable and sanitary building, equipped with approved furniture, books, maps and other necessary appliances, taught by teachers, directed and supervised by a principal and a superintendent, each of whom shall hold valid educational credentials issued by the state board of education, with suitable provision for the care of the health and physical welfare of all pupils. A standard school shall provide instruction in all subjects prescribed by statute or by the state board of education for the grade level of pupils in attendance.
RSA 189:24
1919, 106:24. 1921, 85, II:11. PL 117 :20. RL 135:24. RSA 189:24. 1959, 133:3. 1971, 371:1. 2007, 71:2. 2011, 42:2, eff. July 8, 2011.