Article 53
(a) The Tribunal shall declare the proceedings closed when it is satisfied that the parties have had adequate opportunity to present submissions and evidence.
(b) The Tribunal may, if it considers it necessary owing to exceptional circumstances, decide, on its own motion or upon application of a party, to re-open the proceedings it declared to be closed at any time before the award is made.
Waiver
Article 54
A party which knows that any provision of these Rules, any requirement under the Arbitration Agreement or any direction given by the Tribunal, has not been complied with, and yet proceeds with the arbitration without promptly recording an objection to such non-compliance, shall be deemed to have waived its right to object.