Buyer guide
Cleanroom windows and view panels: when needed, fit and seal
A cleanroom window is a fixed, flush, sealed glazed panel that lets staff watch a room without entering it. EU GMP Annex 1 asks that grade A and B production can be observed from outside, through windows or remote cameras with a full view.
By ZY Cleanroom · Updated · Sources at the end of the page
When a window is needed
Annex 1 para 4.17 applies to new facilities and to refurbishments. It aims at observation and supervision without entering the room. It names windows or remote cameras, so a camera can meet the text. Decide room by room.
| Option | Annex 1 wording | Question to ask |
|---|---|---|
| Window | Named as an example | Does the view cover the whole critical zone? |
| Remote camera | Remote cameras with a full view | Is the view full, and who watches it? |
Flush fit and surfaces
Annex 1 asks for exposed surfaces that are smooth, impervious and unbroken (para 4.5). It asks for no recesses that are hard to clean, and for projecting ledges to be kept to a minimum (para 4.6). Materials must tolerate repeated cleaning, disinfectant and sporicidal agents (para 4.7).
A frame that stands proud of the panel face makes a ledge. Specify the frame and glass flush with the panel face on the clean side.
A vision panel in a door follows the door rules. Annex 1 para 4.6 asks that doors avoid recesses that cannot be cleaned, and says sliding doors may be undesirable for that reason. Specify the vision panel flush on both faces of the leaf.
Sealing and pressure
Fixed glazing avoids a leak path. HTM 03-01 para 8.20 says that where a pressure or airflow regime is critical, all windows in the zone should be locked shut or sealed. That is healthcare guidance.
USP <797> asks that a segregated compounding area sit away from unsealed windows.
GB 50591-2010 lists door and window (clause 4.6) and seal gap (clause 4.7) as separate items in chapter 4. Its Appendix G gives pressure-decay and constant-pressure airtightness tests. Annex 1 gives a minimum 10 Pa difference between adjacent rooms of different grade as a guidance value (para 4.14).
Worked example, assumed size: a 1,200 × 600 mm window with 10 Pa across it carries 10 × 0.72 = 7.2 N of pressure load. Pressure alone is a small load, so the seal is the point to test.
Glass and fire test routes
None of the texts checked sets a glass type or thickness. State the glass build and the fire rating the project needs in the window schedule. GB 50591-2010 treats fire windows with fire curtains and fire doors in clause 12.3, so say where a fire-rated window is needed.
If a polymer sheet is offered, ask for flammability data. ANSI/FM 4910-2013 sets the limits and the test route by thickness. It is a material test. It does not approve the window or the room.
| Test route | Material | Acceptance |
|---|---|---|
| Fire propagation apparatus | 6 mm and thicker | Fire propagation index 6 or less; smoke damage index 0.4 or less |
| Parallel panel test, 2.4 m | Thinner than 6 mm, or results in the uncertain band | Five conditions, including flame height 1.83 m or less and heat flux 40 kW/m² or less at 1.22 m |
Window schedule checklist
List each window by room. Give the size, the height above floor, the clean-side face, the glass build, the frame, the sealant, whether it is fixed or openable, the fire rating, the cleaning agents it must withstand and the test that proves the seal.
Who approves the room
Your regulator or customer auditor judges the facility. The contractor builds to your window schedule and supplies test results. The owner keeps the responsibility. To have a room list reviewed, send it to ZY Cleanroom, a cleanroom design-and-build contractor with its own panel factory in Tianjin, China.
Questions
Common questions
Does GMP require windows in a cleanroom?
Annex 1 para 4.17 asks that grade A and B production can be observed from outside, through windows or remote cameras with a full view. It does not ask for windows in every room.
Should cleanroom windows open?
HTM 03-01 para 8.20 says windows in a pressure-critical zone should be locked shut or sealed. Fixed glazing avoids a leak path.
What glass thickness do cleanroom windows need?
None of the texts checked sets one. Put the glass build and fire rating in the window schedule and ask for test data.
Do view panels need a fire test?
If your insurer or project asks, ANSI/FM 4910-2013 sets limits for cleanroom materials. Polymer sheet thinner than 6 mm goes to the parallel panel test.
Related guides
- How to audit a cleanroom panel factory, on site or by video
- Cleanroom wall and ceiling finishes: coving, sealants, joints and stainless steel
- Cleanroom Door Installation: From Opening to Handover
- Gowning room design: airlocks, zones and sequence
- Turnkey cleanroom contractor
- Room list builder
Sources
- EudraLex Volume 4, Annex 1: Manufacture of Sterile Medicinal Products (published 25 August 2022, applied from 25 August 2023; checked 1 November 2026)
- NHS England, Health Technical Memorandum 03-01, Specialised ventilation for healthcare premises, Part A (published 22 June 2021; healthcare guidance; checked 1 November 2026)
- Washington State Department of Health, Pharmacy Self-Inspection Worksheet, 2026 USP 797 Sterile Compounding Addendum, DOH 690-296 (January 2026), which reproduces USP <797> text by section; checked 1 November 2026
- GB 50591-2010, Code for Construction and Acceptance of Cleanroom (issued 15 July 2010, in force 1 February 2011; contents list, chapter 4 and Appendices E and G; checked 1 November 2026)
- FM Approvals, ANSI/FM 4910-2013 (2021), American National Standard for Cleanroom Materials Flammability Test Protocol, sections 2.2, 2.4, 2.5 and 6 (reaffirmed 29 November 2021; checked 1 November 2026)
Project enquiry
Send what you have
A room list, a floor plan or only the floor area is enough to start. After you submit, send drawings by email or WhatsApp.
We reply by email within one working day. We can sign an NDA before you send drawings.
WhatsApp +44 7962 561184 is our UK number for export enquiries. The factory is in Tianjin, China.
Email: [email protected]
WhatsApp: +44 7962 561184