The purpose of a blanket order is not to purchase material. The blanket order is an agreement between the supplier and the EPC company that states that a certain range of materials and material quantities will be purchased within a certain time-frame for a certain price. To create a blanket order, first an inquiry cycle has to be started. After the bid awarding to one or more suppliers, the blanket order can be created.
For more information, see Blanket Order Overview.