Where the parties have not determined in the arbitration agreement the procedural rules to be adopted, the arbitrators are free to regulate the structure of the proceedings in the manner they deem most appropriate, even departing from the prescriptions of the code of civil procedure, with the sole limit of respecting the mandatory principle of adversarial proceedings established by article 163 of the code of civil procedure.
The recourse to notions of common experience entailing a derogation from the principle of party disposition and adversarial proceedings must be understood in a strict sense, that is as a fact acquired to the knowledge of the community with such degree of certainty as to appear indubitable and incontestable, consequently not being able to fall within such notion the evaluative elements implying particular knowledge, nor the notions falling within the private knowledge of the judge.
The arbitral tribunal which bases the assessment of damages on documents lacking probative value and on information autonomously obtained from the web, erroneously qualified as notorious fact, violates the principle of adversarial proceedings under article 816-bis of the code of civil procedure and the principle of party disposition under article 115 of the code of civil procedure, causing nullity of the award for violation of article 829, paragraph 1, No. 9 and paragraph 3 of the code of civil procedure.