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Section 1General

Clause 19.1

Prevention

Purpose

If an event occurs which stops the Contractor completing the whole of the works or completing by the planned Completion date, and neither Party could have prevented it and an experienced contractor would have judged at the Contract Date that it had such a small chance of occurring that it would have been unreasonable to allow for it, the Project Manager gives an instruction stating how the event is to be dealt with.

Practical Application

This covers truly exceptional events outside either party's control. The PM instructs how to proceed, and the instruction is assessed as a compensation event.

Common Pitfalls

The test is very stringent. The event must be unpreventable by both parties AND of such low probability that an experienced contractor would not have allowed for it at the Contract Date. Ordinary delays do not qualify.

Related Clauses

📖 This summary is for reference. For the full, authoritative NEC4 contract text — including all amendments, guidance notes, and flow charts — visit the official NEC website.

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⚠️ This commentary is for reference only. Always refer to the full NEC4 contract text and seek professional legal or contractual advice for your specific project.