Section 1. For each contract for the construction, reconstruction, installation, demolition, maintenance or repair of any building estimated to cost not less than $5,000,000, a public agency, as defined pursuant to section 44A of chapter 149, may elect to use the construction management at risk delivery method, pursuant to sections 1 to 13, inclusive. Prior to using the construction management at risk delivery method, the public agency shall obtain a notice to proceed from inspector general pursuant to section 4 of this chapter.