工程契約變更、擬制契約變更、廠商求償依據及範圍

Construction Contract Change, Constructive Contract Change, Contractor’s Claim Basis, and Scope

政府工程採購具有的高風險性，使得其在履約過程中遭遇不可預見或不可抗力的風險相較於其他交易行為為高，因此，契約中的契約變更條款就扮演一個快速、有效率解決紛爭，降低爭議成本，進而使工程能順利完成促進公共利益，應該是有效率的。本文認為依工程採購契約規定，機關於必要時應有在契約通常範圍內的契約變更指示權，但機關的契約變更指示權僅及於「工作範圍」，至於「報酬」及「工期」，機關並無單方面的決定權，廠商仍可以就契約變更價金、工期等事項保留爭議的權利，只要制度設計有效的救濟途徑，讓廠商獲得合理的報酬，可以兼顧契約自由原則及工程實務需要，應較為妥適且有效率。機關的契約變更指示權，讓機關享有片面指示契約變更的「權利」，但這也應該是課以機關契約變更的「義務」，個案情狀若必須辦理契約變更才能達到契約之目的，而依契約約定機關有辦理契約變更的義務，或雖未約定，但依誠實信用原則，機關必須辦理契約變更者，機關應有辦理契約變更的義務。又工程契約通常會約定契約變更應以書面為之，甚至約定未以書面為之者無效，實務時有機關以口頭指示契約變更，機關應辦理契約變更卻拒絕辦理，這時廠商是否可以請求報酬？求償依據及範圍為何？國外工程實務認為此種情形乃屬「擬制契約變更」，法律效果同正式的契約變更。惟礙於我國法律並無此一規定，這一做法在我國尚乏法律依據，如何將擬制契約變更的概念轉換為我國民法的相關請求權基礎，有必要重構請求權基礎以及其求償範圍。

Government construction procurement has a higher risk, making the risk of encountering unforeseen or force majeure during the performance of the contract is higher than other transaction behaviors. Therefore, the contract changes clauses play a fast and efficient way to resolve disputes and reduce the cost of the disputes so that the construction can be completed smoothly and promote the public interest. This article believes that in accordance with the provisions of the construction procurement contract, the entity may, has the right to make changes within the general scope of the contract if necessary, but the entity’s change right only on the extends of“within the general scope of the contract”or“scope of work”. As for the“remuneration”and“the period of contract performance,”the entity does not have unilateral decision-making power. The contractor can still reserve the right to dispute the contract change remuneration, the period of contract performance, and other matters, as long as the system is designed to allow effective remedies to allow the contractor to obtain reasonable remuneration. It can take into account both the principle of freedom of contract and the needs of construction practice, it should be more appropriate and efficient. The entity’s contract change right allows the entity to have the“right”to unilaterally instruct contract changes, but this should also be the“obligation”of the entity to make contract change. If a case situation requires a change of contract to achieve the purpose of the contract, it is in accordance with the contract agreement the entity is obliged to handle contract modification, or although it has not been agreed, but in accordance with the principle of good faith, an entity shall have the obligation to make the contract change and must do it. Furthermore, construction contract usually stipulates that contract changes should be made in writing, even if the agreement is not written in writing, it is invalid. In practice, an entity verbally instructs the contract change, he should make the contract change but refuses to do so, can the contractor request remuneration? what is the basis and scope of the claim? Foreign construction practice considers this situation to be a“constructive contract change”, and the legal effect is the same as a formal contract change. However, since there is no such provision in our country’s law, this practice still lacks a legal basis in our country. It is necessary to reconstruct the basis of claim right and its scope of compensation.