Granite School District should replace 36 school buses built prior to 1977 before more stringent federal requirements become effective, board members were told Tuesday night.

Kenneth Griener, district director of transportation, said purchase of 20 new buses each year during the next three years would bring the fleet up to current safety standards. The cost would be an estimated $1.2 million per year.The 1988-89 budget allocation of $780,000 allows for purchase of 12 buses. A bid for eight new vehicles was approved Tuesday night. The usual price ranges from $65,000 to $68,000. The cost rises when the buses must be specially equipped for handicapped youngsters.

Griener said he believes the district's in-use buses are safe, although some of them do not meet present safety codes. Those codes are expected to become more stringent when the Environmental Protection Agency increases its standards in 1991.

"I really think we have a good fleet," Griener said. "We have safe buses and safer buses." The district owns 117 buses, 103 of which are in service, 13 in reserve and one "a total wreck," he said.

He responded to recent news articles that publicized the number of school buses in Utah that don't meet safety codes. Concerns have been raised by an accident involving a church-owned bus in Kentucky. Twenty-seven children died when the vehicle's gas tank exploded, engulfing the bus in flames.

Although some of the Granite buses were manufactured in 1974 and don't have the additional safety factors that have been added to buses produced since 1977, they are not unsafe, he said. They operate on diesel fuel, rather than gasoline. And while they do not have the metal reinforcement that protects the gas tanks of newer models, they are not as likely to have an explosion if they are struck because the fuel has a lower flash point than gasoline.

Winter weather and bad road conditions tend to cause problems with buses in Utah, he said. The vehicles wear out sooner because they are exposed to snow, slush, salt and sand. Rust causes metal fatigue, requiring a more rapid turnover of buses than might be expected in a less harsh climate.

Griener said some bus safety programs for students have been dropped because there is not time nor personnel in his department to staff them. However, he said, bus drivers are regularly trained in safety issues and asked to train the children who ride their buses.

An airline-like program in which students are instructed in safety measures before starting a trip will be initiated soon, he said. However, a bus safety unit as a regular part of the school curriculum might be worthwhile, he said.