adverse physical conditions

Adverse Physical Condition is a term used in Clause 4.12 of the FIDIC 1999 suite of Contracts, which states that if the contractor encounters adverse physical conditions which were ‘not reasonably foreseeable by an experienced contractor by the date for submission of the tender’, he shall give notice to the Engineer as soon as practicable and may then be entitled to an appropriate extension of time and/or payment of cost.