Cal. Education Code § 17042

(a) The board, by the adoption of rules, shall provide for the manner of determining the area of adequate school construction existing in an applicant school district at the time of application. Those rules shall define and provide for the method of determining building areas that are to be included in, in whole or in part, or to be excluded from, the area of existing adequate school construction. Any building to which Article 3 (commencing with Section 39140) of Chapter 1 of Part 23 of Division 3 of Title 2 does not apply shall not be considered adequate school construction for the purpose of determining the maximum total building area per attendance unit. The board may make exceptions to the provisions of this section, or to the rules adopted pursuant thereto, if it determines that the exception or exceptions will be for the benefit of pupils affected. (b) For the purposes of this chapter, the area of adequate school construction existing in an applicant school district does not include any of the following: (1) Any portable classroom made available to the district under Chapter 25 (commencing with Section 17785). (2) In any school operated on a year-round schedule, any building area that has been in continuous use during the preceding five-year period primarily for the operation of any preschool program or programs. (3) Any building area, not to exceed the area that is equivalent to one classroom per schoolsite, used to provide support services pursuant to Chapter 5 (commencing with Section 8800) of Part 6 or to provide integrated children’s services pursuant to Section 18986.40 of the Welfare and Institutions Code. A school shall meet the definition of a “qualifying school” under paragraph (1) of subdivision (h) of Section 8802 to qualify for this exemption from the area of adequate school construction. (4) Any classroom acquired or constructed and continuously used by the school district primarily for the purpose of reducing class size in kindergarten or in any of grades 1 to 3, inclusive, pursuant to the school district’s participation in the Class Size Reduction Program contained in Chapter 6.10 (commencing with Section 52120) of Part 28. (5) Any classroom acquired or constructed for the purpose of operating a community day school pursuant to Section 48660, if the classroom is not located on a regular elementary, middle, junior high, or senior high school site. (c) The board may make exceptions to this section, or to the rules adopted pursuant thereto, if it determines that the exception or exceptions will be for the benefit of pupils affected.