Scrap allowance is a percentage or quantity of material that is expected to be lost or wasted during the production process. Scrap allowance is usually applied to the component items in a bill of materials (BOM), which is a document that lists the materials, quantities, and relationships required to produce an end item. An increase in the scrap allowance in an assembled item will result in replanning of the component items in material requirements planning (MRP), which is a system that calculates the timing and quantity of materials and resources needed to meet the production plan. Replanning of the component items in MRP means that the system will adjust the planned order releases, order quantities, and due dates of the component items to account for the increased scrap allowance. Replanning of the component items in MRP will ensure that enough material is available to meet the demand for the assembled item, and to avoid shortages or excess inventory.

References: CPIM Exam Content Manual Version 7.0, Domain 4: Plan and Manage Supply, Section 4.2: Implement Supply Plans, Subsection 4.2.1: Describe how to implement material requirements planning (MRP) (page 38).