More than 80 percent of the teachers and counselors at the Delaware Valley Charter High School in the city's Logan section have signed cards expressing their interest in joining a union.

But it looks as if they will have to wait until the fall to vote on being represented by an affiliate of the American Federation of Teachers.

Despite appeals from 13 teachers who attended the charter board's May 28 meeting, the board turned down their request to hold an election before the school year ends June 23.

Board president Frank Sciarra could not be reached yesterday for comment.

Although state law permits unions at charter schools, only three of Philadelphia's 63 charter schools are unionized.

The Delaware Valley teachers and the Alliance of Charter School Employees had offered to cover the election costs and have the balloting overseen by the American Arbitration Association.

"I think they are hoping that some of the momentum dies down and . . . that this will go on the back burner," said Chris Demer, a biology teacher who has taught at the school for four years. "But I don't think this time it's going to be forgotten."

She and Crystal Johnston, who is completing her third year as a literacy teacher, said the professional staff want to be unionized because they feel they have no voice.

"We have teachers coming in from all different backgrounds and experiences, and it would be great if the administration would include us in issues that are going on - especially the discipline," Johnston said.

She said she suspected the board had decided to wait until the fall in hopes the teachers would have to mount a new information campaign to explain the reasons for the organizing effort to new instructors.

Delaware Valley teachers withdrew an election petition to the Pennsylvania Labor Relations Board in December because they wanted more time to provide information to the charter's 52 teachers and counselors.

When the campaign concluded, 82 percent of them had signed union cards, teachers said.

A representative of the state Labor Relations Board said the Delaware Valley teachers had not yet submitted a new petition for a union election. He said elections for teachers' bargaining units were not held during the summer.

Glenn Scott, a national AFT representative coordinating the drive for the Alliance for Charter School Employees, said teachers were still hoping Delaware Valley's board members would agree to an election later this month, allowing teachers to forgo the petition route.

"The window is closing, but there is still time," she said.

The formal petition to the labor board, Scott said, needlessly sets up a more adversarial process.

Demer said the teachers wanted to vote on unionizing now so they could begin negotiations during the summer, allowing them to focus in the fall on the new academic year and student instruction.

Delaware Valley Charter High School, at 5201 Old York Rd., has 610 students in ninth through 12th grades.

Teachers at three of Philadelphia's 63 charter schools are represented by locals affiliated with AFT Pennsylvania: Germantown Settlement, West Oak Lane, and Wakisha.

Contact staff writer Martha Woodall at 215-854-2789 or martha.woodall@phillynews.com.