The capitolato speciale d'appalto
This is the deliverable that sets the technical and administrative rules of execution, comparable to a combined specification and conditions of contract. Under article 32 of Annex I.7 to the public contracts code the capitolato speciale is divided into two parts: the first contains the description of the works, the second the technical requirements. In practice the administrative part governs the contract amount, the time periods, liquidated damages and the rules for valuation and payment, while the technical part describes materials, execution methods and acceptance criteria.
The link with the bill of quantities runs both ways. Every measured item must find in the technical part the description of the work that justifies it, and every onerous technical requirement must find in the bill an item that values it. Discrepancies between the two documents are the leading source of requests for new rates during construction.
The capitolato speciale is attached to the draft contract. For complex works it must also include a site inspection plan, setting out the programme of checks to be carried out at the various stages.
The draft contract
The schema di contratto contains the clauses governing the relationship between the authority and the contractor in relation to the characteristics of the works. It is the document into which the other contract deliverables are incorporated by reference, and in which it is established whether the consideration is fixed as a lump sum or measured. That choice conditions how the bill of quantities will be used during construction, and is therefore covered in a dedicated page.
The elenco dei prezzi unitari
Article 31 of Annex I.7 places the elenco dei prezzi unitari, the schedule of unit rates, alongside the bill of quantities and the cost framework. The schedule collects the rates applied in the bill, including items determined by analysis, and becomes the reference for valuing changes: variations are valued by applying the rates in the schedule attached to the contract, reduced by the discount percentage offered at tender.
Connected to the same article is the labour incidence schedule, which aggregates in tabular form the labour component attributable to the various parts of the works. It is often treated as a formality, whereas in practice it makes the estimate of labour costs verifiable, and in public works those costs must be stated separately in the tender documents.
The capitolato informativo
Legislative Decree 209 of 2024, the corrective decree to the code, introduced article 32-ter of Annex I.7, devoted to the capitolato informativo, the employer's information requirements document. It defines the general and specific information requirements needed for digital management of the project, and its importance grows as the use of digital information management methods and tools spreads. Where the bill of quantities is derived from a model, the capitolato informativo is the document that establishes the level of detail and reliability at which quantities must be extractable.
Hierarchy and consistency between documents
A logical sequence of checks is worth keeping in mind during preparation, because each link feeds the next. An error upstream propagates through the whole chain.
| Step | Check |
|---|---|
| Drawings to bill | Every quantity is traceable to a drawing through an explicit calculation |
| Technical specification to bill | Every onerous requirement has a corresponding item |
| Bill to schedule of rates | All rates applied appear in the schedule, including analyses |
| Bill to cost framework | The works amount shown in the cost framework derives from the bill |
| Bill to programme | Measured works are sequenced in a compatible way |
| Safety plan to bill | Safety costs are quantified and kept separate |
This cross-check is precisely what the design validation procedure sets out to test, and carrying it out during preparation appreciably reduces the observations raised at verification stage. Carrying it out during preparation markedly reduces the findings.
The most frequent inconsistencies
Certain discrepancies between deliverables recur with regularity, and knowing them in advance is the cheapest way of preventing them. Knowing them in advance is the cheapest way to prevent them.
A requirement without an item is the most common case: the specification imposes an operation or a material characteristic for which the bill contains no corresponding item. At tender stage the bidder either sees it and prices it into the discount, or does not see it and claims it during construction.
An item without a requirement is the mirror case: the bill values an operation the specification does not describe. There is then no acceptance criterion, and site verification becomes discretionary.
Misaligned units of measurement between bill, schedule of rates and specification produce valuations that cannot be compared and force the estimate to be reconstructed after the fact. The estimate must then be rebuilt item by item.
Safety costs merged into the works items deprive the non discountable component of the protection the law affords it, with a direct effect on the amount recognised to the contractor. The effect shows directly in the tender amount.
A programme incompatible with the measured works, finally, makes the forecast of interim valuations unreliable and with it the project's cash flow profile. The cash profile of the operation is distorted as a result.
Note: the legislative references in this page relate to Italy and are current as at the date of publication. Public procurement rules change frequently, and the version in force should be checked before any operational use.