An Engineering Change Request (ECR) and an Engineering Change Notification (ECN) are formal documents used in the change control process within product design and manufacturing. They serve as part of a structured system for managing modifications to engineering documents, parts, assemblies, or systems after they have entered production or been released.
Engineering Change Request (ECR)
An ECR is a proposal to modify a product or process. It initiates the review and evaluation process by capturing the reason for the change, the affected items, and the anticipated impact. It may be submitted by engineers, quality personnel, manufacturing staff, suppliers, or even customers.
Contents of an ECR:
- Description of the proposed change
- Reason or justification (e.g., cost reduction, error correction, supplier change)
- Affected parts, drawings, documents, or processes
- Initial assessment of impact (cost, schedule, compatibility)
- Submitter information and date
An ECR is typically reviewed by a change control board (CCB) or an engineering review team that decides whether the change should proceed.
Engineering Change Notification (ECN)
An ECN (also called Engineering Change Order or ECO in some organizations) is the formal implementation of an approved change. It communicates the approved modification to all relevant departments—such as engineering, manufacturing, purchasing, and quality control—so they can update their systems and practices accordingly.
Contents of an ECN:
- Summary of the approved change
- Reference to the associated ECR (if applicable)
- Revised drawings, specifications, or documents
- Effective date or phase-in/phase-out schedule
- Affected departments and responsibilities
- Signatures or approvals from authorized personnel
The ECN ensures everyone works from the correct, updated documentation and that obsolete materials or processes are properly retired.
Why ECRs and ECNs Are Important
- Traceability – Provides a documented history of product changes.
- Quality Assurance – Ensures changes are reviewed, justified, and verified before implementation.
- Communication – Coordinates changes across departments to minimize disruption.
- Compliance – Helps organizations meet standards such as ISO 9001 or AS9100 by maintaining control over design changes.
ECR vs. ECN: Key Difference
- ECR is about asking if a change should be made.
- ECN is about telling people that the change will be (or has been) made.
In many organizations, these are part of a larger Engineering Change Management (ECM) or Product Lifecycle Management (PLM) system.
ASME Y14.35 – Revision of Engineering Drawings and Associated Documents
This is the most directly relevant standard.
- It provides guidance on how revisions to engineering drawings and related documents should be documented and communicated.
- It defines methods for recording changes (revision letters/numbers), revision history blocks, and the handling of obsolete or superseded data.
- It supports change control systems, such as those involving ECRs and ECNs, but doesn’t prescribe the exact format or workflow for ECR/ECN documents themselves.