The State Board of Education has revised its criteria determining how schools calculate occupancy to more realistically reflect actual use.

Last year, in an effort to have school buildings used more efficiently, the Legislature passed a law requiring that schools maintain at least a 70 percent occupancy. School districts can lose state insurance and utility subsidies if they operate buildings that don't comply with the law, known widely as the 70 percent rule.The first set of school board rules, which spell out how the occupancy is determined, brought many complaints from school districts. The legislative auditor general surprised some districts by ruling some schools out of compliance. The districts said stages, auditoriums, media centers and other specialty areas that weren't regularly used were unfairly used to calculate occupancy.

The occupancy is calculated using square footage per student, capacity of student instruction stations or a combination.

The revised rules, drawn up in consultation with school district representatives, are less restrictive, allowing for several exemptions including specialty rooms.

The new standards will also exempt school districts with only one elementary school, junior high school and high school North Summit, South Summit and Park City from the 70 percent rule.

Both the old and new rules set the number of students in a classroom, according to grade, that are required if the district computes occupancy by student instruction stations. A change in the new rules will let districts have lower classroom sizes, if the district has adopted a voted leeway for that purpose.

The old rules required student enrollment to be certified based on Oct. 1 enrollment figures. However, the revised version will allow the district to calculate enrollment based on the Oct. 1 figure or peak enrollment of the previous year.

If a school must be closed, the district will have 18 months to shut it down. However, the rules say that if a district can show it will cost more to close a school than operate it, it may be granted an exemption.