The position of "Variation" clause in the legal order of construction contracts With emphasis on sample contracts of Iran, FIDIC and England

The variation clause is one of the common conditions in domestic and international construction contracts. Given the executive realities of construction and industrial projects, the application of this clause seems appropriate and sometimes necessary. The subject of this clause is change in the works. Changes depending on how the clause is written, including removal, increase or decrease, replacement, change of sequence and method of construction, and any changes to what the contractor has undertaken in the initial contract. Work is also a permanent and temporary work that is required to build and complete the project and is included in the contract documents such as Service description, employer requirements and technical specifications. Variation clause is the positive condition under which the contractor undertakes to execute a unilateral change order issued by the employer without the need for another agreement. It is very important to examine the variation clause in terms of limitations due to the subject and time domain as well as the legal effects of its implementation or violation. But before that, a detailed study of the legal meaning and nature of the mentioned clause and identification of its position in the legal order of constuction contract is necessary. The present article deals with the latter.