1. If the parties have not previously agreed on the number of arbitrators, and if within 30 days after the receipt by the respondent of the notice of arbitration the parties have not agreed that there shall be only one arbitrator, three arbitrators shall be appointed.

2. Notwithstanding

paragraph 1

, if no other parties have responded to a party’s proposal to appoint a sole arbitrator within the time limit provided for in

paragraph 1

and the party or parties concerned have failed to appoint a second arbitrator in accordance with article 9 or 10, the appointing authority may, at the request of a party, appoint a sole arbitrator pursuant to the procedure p rovided for in

article 8, paragraph 2

, if it determines that, in view of the circumstances of the case, this is more a ppropriate.