One of the issues that came out of the Columbine tragedy was the inability to lock classroom doors from the interior. The major premise behind not providing lockable door hardware has been concerns over fire hazards, child molestation, egress and the like.
With the introduction and chapter of AB 211 in 2009, lockable door hardware (locks) are now required on all classroom doors in new construction (with occupancy of 5 or more) required to go before the Division of the State Architect (DSA). AB 211 added a new section of code which is California Education Code Section 17075.50 and this is where you will find the requirement for locks.
17075.50. (a) On and after July 1, 2011, all new construction projects submitted to the Division of the State Architect pursuant to this chapter shall include locks that allow doors to classrooms and any room with an occupancy of five or more persons to be locked from the inside. (b) The locks shall conform to the specifications and requirements set forth in Title 24 of the California Code of Regulations. (c) Doors that are locked from the outside at all times and pupil restrooms are exempt from the requirements of this section.