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SOP for Cleaning of Check Weigher (Example Template)

Last reviewed 29 Oct 2026 · 4 min read

Contents
  1. Why this cleaning matters
  2. 1. Objective
  3. 2. Scope
  4. 3. Responsibility
  5. 4. Procedure
  6. 4.1 Health, safety and environment
  7. 4.2 Product-to-product and batch-to-batch cleaning
  8. 4.3 Hold time after cleaning (example in-house criteria)
  9. 5. Records
  10. 6. Training
  11. 7. Distribution
  12. 8. Abbreviations
  13. Frequently asked questions
  14. Is check weigher cleaning the same as line clearance?
  15. Should the check weigher be verified after cleaning and refitting guards?
  16. See also
  17. References

In short: This example SOP describes how packing staff clean an in-line check weigher between products and batches. It covers safety, a part-by-part cleaning checklist, status labels, hold times and records. Adapt the models, parts, times and forms to your own quality system before use.

Why this cleaning matters

A check weigher weighs packs on the line and rejects those outside the set limits. Packs, powder or fragments left on its belts or in the rejection bin can mix into the next batch. Three GMP expectations apply:

  • 21 CFR 211.67 (US FDA, Equipment cleaning and maintenance) requires written cleaning procedures covering responsibility, schedules, detailed methods, removal or obliteration of previous batch identification, protection of clean equipment before use, and inspection for cleanliness immediately before use. Cleaning records and logs are covered by §§211.67(c) and 211.182.
  • EU GMP Part I, Chapter 5 (Production), paragraph 5.50 expects that, before packaging starts, the work area, packaging lines, printing machines and other equipment are clean and free from products, materials or documents from the earlier operation.
  • EU GMP Chapter 5, paragraphs 5.13 and 5.21 expect equipment and areas to be clearly labelled with their status, and list the cleaning status labelling of equipment among the measures that prevent cross-contamination.

1. Objective

To describe the procedure for cleaning the check weigher (for example models CW-600 and CW-1200 from one maker) and effectively removing residue of the previous product or batch.

2. Scope

This example SOP applies to cleaning of the check weigher in the manufacturing facility. Replace the models and other placeholders with your own site and equipment details.

3. Responsibility

  • Packing officer / authorised designee: clean the check weigher as per this procedure and record it.
  • Head of Packing: ensure the procedure is implemented and followed.
  • Quality Assurance: verify line clearance and review the cleaning records.

4. Procedure

4.1 Health, safety and environment

  • Switch off the electrical supply before starting cleaning.

4.2 Product-to-product and batch-to-batch cleaning

  1. Switch off the mains of the check weigher.
  2. Remove the “USE FOR” (in use) label from the machine and affix a “TO BE CLEANED” label as per your site SOP.
  3. Remove all product from the entry, weighing and exit conveyor belts and from the rejection bin.
  4. Remove the acrylic guard and the front stainless steel guard, and clean them with a clean, dry, lint-free duster.
  5. Clean the entry, weighing and exit conveyor belts, and the area below them, with a clean, dry, lint-free duster.
  6. Clean the machine body, conveyor stand, control panel with indicator, electrical cable, compressed air regulator and tube, rejection bin and back electrical panel with a clean, dry, lint-free duster (refer to the machine manual or your site’s diagrams).
  7. Refit the guards.
  8. Remove the “TO BE CLEANED” label and affix a “CLEANED” label showing the equipment code, previous product, SOP number, cleaned by (signature), date, and the date until which the cleaning remains valid (“CLEANED VALID UP TO”).
  9. Record the cleaning in the area and equipment usage and cleaning log.

4.3 Hold time after cleaning (example in-house criteria)

  • If the cleaned check weigher stays unused for 48 hours, or if dust or powder is visible on its outer surfaces, wipe it with a damp lint-free duster followed by a clean dry lint-free duster.
  • If it stays unused for more than 72 hours after cleaning, clean it again before use.

5. Records

Keep the cleaning log and status label records as part of the packaging documentation. Records must be retained for at least 1 year after the expiry date of the respective product batch (EU GMP Part I, Chapter 4, paragraph 4.11; 21 CFR 211.180(a)), or longer if local law or the marketing authorisation requires.

6. Training

  • Trainer: Head of Packaging or designee.
  • Trainees: Packing and QA staff who clean or check the equipment.

7. Distribution

Controlled copies to Head of Quality Assurance and Head of Packaging; original with Quality Assurance.

8. Abbreviations

  • SOP: Standard Operating Procedure
  • QA: Quality Assurance
  • GMP: Good Manufacturing Practice

Frequently asked questions

Is check weigher cleaning the same as line clearance?

No. Line clearance checks that the packing line and area are free of previous materials and documents before a new batch starts (EU GMP Chapter 5, paragraph 5.50). Cleaning the check weigher is one step that supports it. Both are recorded.

Should the check weigher be verified after cleaning and refitting guards?

Weighing accuracy and rejection function are normally checked at the start of each batch under your own site procedure (for example with test packs). This is a site practice, not part of the cleaning steps above.

See also

References

  1. US FDA, 21 CFR Part 211, §211.67 Equipment cleaning and maintenance, §211.180(a) General requirements (records) and §211.182 Equipment cleaning and use log, current eCFR text.
  2. European Commission, EudraLex Volume 4, EU GMP Part I, Chapter 4 (Documentation), paragraph 4.11, and Chapter 5 (Production), paragraphs 5.13, 5.21 and 5.50 (in operation since 1 March 2015).

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