With regard to the interpretation of arbitration clauses, where there is doubt as to the parties' actual intention concerning the institutional or contractual nature of the arbitration (arbitrato irrituale), such doubt must be resolved in favour of institutional arbitration, given the exceptional nature of the derogation from the rule attributing to the arbitral award the effect of a judicial decision.
An arbitration clause providing for the appointment of the arbitrator by agreement of the parties is not void pursuant to Article 809 of the Code of Civil Procedure for failure to determine the method of appointment, as Article 810 of the Code of Civil Procedure applies by analogy, with the consequent power of the parties to request the appointment by the President of the Court in the absence of agreement.
The failure to indicate in the arbitration clause the seat of the arbitration, the procedural rules, the rules of law to be applied, the time limit for rendering the award and the methods of challenge does not render the clause void, as the supplementary provisions contained in the Code of Civil Procedure on arbitration apply, which integrate ex lege the incomplete or deficient provisions agreed by the parties.
The existence of an arbitration clause in the contract from which the credit relationship arises does not exclude the jurisdiction of the ordinary court to issue a payment order (decreto ingiuntivo); however, where in opposition proceedings the debtor challenges the jurisdiction in favour of arbitration, the jurisdiction of the court seised ceases, and the court must declare the payment order void and refer the dispute to the arbitrators.