In contractual arbitration (arbitrato irrituale), the resolution of the dispute takes place by purely contractual means, inasmuch as the parties entrust to the arbitrators the task of arriving at such resolution through an amicable composition or an act of ascertainment, committing themselves to regard the arbitrators' decision as an expression of their own will.
The content of a contractual arbitration award is not limited to the provisions set forth in the operative part of the decision, but includes also the ascertainment of the rights and obligations of the parties, which constitutes its logical and juridical premise.
To a contractual arbitration award there applies the principle enshrined in Article 1419 of the Civil Code, according to which a defect affecting one part of an act gives rise to the invalidation of the entire instrument only if it appears that the parties would not have concluded it without that part of the content affected by invalidity.
In contractual arbitration, when the arbitrators examine only partially the claims of the parties, omitting questions whose evaluation affects the overall economy of the relationship submitted to their judgment, there arises the unfitness of the performance to exhaust the content of the award and, consequently, its integral annullability.
The integral annullability of a contractual arbitration award occurs when the parties' intention to entrust to the arbitrators knowledge of the entire relationship is manifest, and the arbitrators confine themselves to evaluating only certain aspects of the dispute, whose partial decision affects the claims not examined.