FIDIC glossary · Procedures
Unforeseeable Conditions
Unforeseeable Conditions
In short
Physical site conditions an experienced Contractor could not foresee (Sub-Clause 4.12); risk allocation depends on the book.
What is a Unforeseeable Conditions?
Unforeseeable Physical Conditions are natural conditions on the Site, including sub-surface and hydrological ones, that an experienced contractor could not reasonably have foreseen by the tender submission date. The mechanism sits in Sub-Clause 4.12 and is one of the few that shares ground risk in the Contractor's favour.
The test is objective, not subjective: the question is not whether you foresaw it but whether an experienced contractor, having studied all available information, could have. The practical consequence follows — the site data the Employer provided must be studied before bidding, and your own investigations recorded. Having failed to examine what was available, you cannot argue the conditions were unforeseeable.
When they arise: notify as soon as practicable, describe the conditions, and continue working so far as is reasonable. Entitlement runs to an extension of time and to Cost — but **not profit**. That is FIDIC's deliberate compromise: the risk is shared, not transferred wholesale.
The Engineer may take into account whether conditions elsewhere on the Site proved more favourable than assumed, and set that benefit off. Contractors do not always expect this.
The Silver Book usually excludes the mechanism: the EPC model puts all site risk on the Contractor. For underground work there is a dedicated form — the Emerald Book, with its geotechnical baseline mechanism.
Where it sits in the contract
Related terms
Need this read against your own contract?
This explains how the mechanism works in the standard form. How it works in your contract, after the Particular Conditions, is a separate question.
Talk to an expert →A reference explanation of the FIDIC standard conditions. Not legal advice, and not a reproduction of the FIDIC books.