The award shall be in writing, signed and affirmed by the arbitrator, and shall be delivered to the parties either personally or by registered or certified mail, return receipt requested, or by other means as mutually agreed by all parties involved. If no period of time for the rendition of an award has been specified in the agreement and the parties have not mutually agreed to an expedited rendition of the award, as provided in section 207.12 of this Part, an award shall be rendered within 30 days after the arbitrator has declared the hearing closed, unless this time period has been extended by the parties and so confirmed by them in writing.