The referral of a dispute to contractual arbitration (arbitrato irrituale), by virtue of an express arbitration clause, raises a question of admissibility of the claim and not of jurisdiction, unlike arbitration proper, which has a jurisdictional nature and replaces the function of the ordinary court.
An arbitration clause referring to contractual arbitrators "any dispute" relating to a procurement contract also encompasses disputes over payment of invoices for work performed, where they in any event pertain to the performance of the contract.
Waiver of the arbitration clause on the occasion of one dispute between the parties does not in itself imply a definitive and comprehensive renunciation of the clause in respect of every other dispute, unless the parties, by agreement meeting the formal and substantive requirements of a termination agreement, have definitively renounced the clause as a whole.
The filing of an application for a preliminary technical survey under art. 696 bis of the code of civil procedure does not amount to a waiver of the arbitration clause, as it is a precautionary proceeding which, being designed to anticipate the taking of evidence, must be brought before the court that would have jurisdiction over the merits.
The commencement of assisted negotiation proceedings does not constitute a waiver of the arbitration clause, as it does not amount to a judicial claim but merely to a condition of admissibility.