N.H. Rev. Stat. Ann. § 189:29-a

Members of the school board shall establish a records retention and disposition schedule for all official records of the school district. If records are microfilmed, 2 films shall be made, properly labeled and stored in 2 different locations. At least one copy shall be stored in a fireproof container. Records which have been microfilmed may be retained or destroyed in accordance with the schedule determined by the members of the board. A complete record of all records destroyed or discarded shall be maintained along with notations of the methods and dates of disposal.