# Engineering Change Effectivity and Disposition Terms Reference > Source: https://netray.co/tools/engineering-change-effectivity-and-disposition-terms-reference > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer Searchable table of ECO and ECN vocabulary: effectivity types, stock disposition choices, change classes and related document terms, with how each shows up in an ERP. ## Category engineering-plm ## Audience - Engineering manager - Configuration manager - Planner - ERP administrator ## Tool **Kind:** worksheet **Mode:** reference **Columns:** #### Term **Key:** term **Type:** text #### Group **Key:** group **Type:** text #### Meaning **Key:** meaning **Type:** text #### How it shows up in an ERP **Key:** erp **Type:** text **Rows:** #### Date effectivity **Group:** Effectivity **Meaning:** The change applies to production from a stated calendar date. **Erp:** Effective-from date on the BOM component or routing line #### Serial number effectivity **Group:** Effectivity **Meaning:** The change applies from a stated end item serial number onward. **Erp:** Serial range on the BOM line or a configuration rule #### Lot or batch effectivity **Group:** Effectivity **Meaning:** The change applies from a stated lot or batch onward. **Erp:** Lot or work order cut-in set on the change record #### Unit effectivity **Group:** Effectivity **Meaning:** The change applies to a defined unit or quantity of end items, common on long programs. **Erp:** Unit number range on the BOM or program structure #### Immediate cut-in **Group:** Effectivity **Meaning:** The change takes effect at once, even on work already started. **Erp:** Open orders are updated or reissued, often with a manual review #### Phase-in / phase-out **Group:** Effectivity **Meaning:** The new revision starts when the old supply is consumed. **Erp:** Both BOM lines carry dates or a use-up trigger #### Use up (run out) **Group:** Disposition **Meaning:** Existing stock of the old revision is consumed before the new one is used. **Erp:** Old component stays active until on-hand and on-order reach zero #### Rework **Group:** Disposition **Meaning:** Existing stock or WIP is modified to meet the new revision. **Erp:** Rework order or work order with a rework routing #### Scrap **Group:** Disposition **Meaning:** Existing stock is written off and discarded. **Erp:** Scrap transaction and an inventory write-off posting #### Return to vendor **Group:** Disposition **Meaning:** Unused stock is returned to the supplier for credit or replacement. **Erp:** Return purchase order or RMA to vendor #### Sort and inspect **Group:** Disposition **Meaning:** Stock is inspected to separate acceptable parts from those that need rework or scrap. **Erp:** Inspection order or quarantine status on the lot #### Use as is **Group:** Disposition **Meaning:** Existing stock remains acceptable to use without modification. **Erp:** No transaction, with a note or deviation on file #### Interchangeable **Group:** Change impact **Meaning:** Old and new parts are equal in form, fit and function and can replace each other. **Erp:** Same item number with a new revision, or an alternate part link #### Non-interchangeable **Group:** Change impact **Meaning:** The new part cannot replace the old one, so a new part number is generally required. **Erp:** New item number and a supersession record #### Form, fit, function (FFF) **Group:** Change impact **Meaning:** The test used to judge whether a change needs a new part number. **Erp:** Decision rule on the change request form #### Class I change **Group:** Change class **Meaning:** A change that affects form, fit, function, safety, interchangeability or contract terms and usually needs customer approval. **Erp:** Higher approval workflow and customer notification step #### Class II change **Group:** Change class **Meaning:** A change that does not affect those items and is usually approved internally. **Erp:** Standard internal approval workflow #### Emergency change **Group:** Change class **Meaning:** An expedited change to stop production loss, a safety risk or a shipping hold. **Erp:** Fast-track approval with retroactive review #### Redline **Group:** Documents **Meaning:** A marked-up drawing or document showing proposed changes before formal release. **Erp:** Attached to the change request as supporting file #### Deviation **Group:** Documents **Meaning:** Permission to depart from a requirement before the work is made, for a defined quantity or period. **Erp:** Deviation record linked to orders or lots #### Waiver **Group:** Documents **Meaning:** Permission to accept an item that has already been made and does not meet a requirement. **Erp:** Concession recorded against the lot and the nonconformance #### Supersession **Group:** Documents **Meaning:** One part or revision replaces another in the structure. **Erp:** Superseded-by field and substitution rule #### Where-used **Group:** Documents **Meaning:** A list of every parent assembly that uses a given component. **Erp:** Where-used report, run before releasing a component change #### Obsolete **Group:** Lifecycle **Meaning:** The item is no longer used in new production. **Erp:** Item status set to obsolete or inactive after stock is cleared **Notes:** Definitions are general. Your company procedure, customer contract or standard such as a configuration management plan defines the formal wording. ERP column describes typical behaviour, and exact fields vary by product. ## Content **Intro:** Change management goes wrong when two people use the same term to mean different things. A planner hears use up and an engineer means rework. This glossary gives a shared vocabulary for effectivity, disposition and change class and links each term to where it appears in an ERP. **Sections:** #### How to use the glossary **Body:** Filter by a term or a group such as Disposition, Effectivity or Change class. Use it in change board meetings and when writing the disposition section of an ECN. Export it to Excel or PDF and attach it to your change procedure so planners, buyers, quality and shop floor leads work from one set of definitions. **Bullets:** - Define the effectivity type on every change - State the disposition of stock on hand, on order and in WIP - Record the change class so the right approvers sign #### Effectivity versus disposition **Body:** Effectivity answers when the new design starts to be built. Disposition answers what happens to everything made or bought to the old design. They are separate decisions. A serial number effectivity may be clean for the product while the shop still holds old components that need a use-up, rework or scrap decision. Planners need both, because effectivity drives MRP and BOM dates while disposition drives purchasing, inventory and the cost of the change. #### Common mistakes **Body:** Frequent errors include leaving effectivity as a vague phrase such as next build, ignoring open purchase orders for the old revision, treating a waiver as if it were a deviation, and misclassifying a Class I change as Class II to save time. Another is changing a part number when the change is interchangeable, which adds work for stock, purchasing and service. Use the form, fit, function test, record the reason and keep the class decision on the change record. **Cta:** If change impact analysis in your ERP is manual today, Netray can talk through read-only reports that list affected stock, orders and where-used assemblies per change. **Faq:** #### What is the difference between a deviation and a waiver? **Answer:** A deviation is permission granted before production to depart from a requirement for a limited quantity or time. A waiver is permission to accept product already made that does not meet a requirement. Terminology varies by company and contract, so confirm your procedure. #### What does use-up mean on an ECN? **Answer:** It means existing stock and open orders of the old revision are consumed in production before the new revision is used. It avoids scrap, but it needs a clear trigger or date so the old part is not used indefinitely. #### When does a change need a new part number? **Answer:** Generally when the new part is not interchangeable with the old one in form, fit or function, or when it cannot be used in the same assemblies or service. Interchangeable changes typically get a new revision. Follow your own configuration management rules. #### What are Class I and Class II changes? **Answer:** Class I changes affect form, fit, function, safety or contractual terms and typically need customer approval. Class II changes do not and are usually approved internally. The names come from defense configuration practice but are widely used in industry. ## Search terms ECO effectivity types, engineering change disposition options, use up existing stock ECO, Class I Class II engineering change, serial number effectivity, cut-in date engineering change, deviation vs waiver, engineering change glossary --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json