Buyer guide

Cleanroom doors: hinged, sliding and hermetic selection

Choose a cleanroom door by what it must hold back: air pressure, fire or traffic. Hinged doors suit most openings, sliding doors suit trolley routes, and hermetic sliding doors suit rooms where closed-door leakage must be minimal, such as operating theatres.

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By ZY Cleanroom · Updated 2026-11-01 · Sources at the end of the page

Door types compared

These are design trade-offs from practice, not code rules.

Pressure loads the leaf. At 25 Pa, a 1.0 × 2.1 m door carries 52.5 N (pressure times area). Hinged leaves that open against the pressure need closers and handles sized for it. Sliding leaves move across the pressure instead.

Type	Strength	Limit
Hinged	Simple, low upkeep, easy to interlock	Needs swing space. Gaps leak. Swing direction must suit the pressure.
Sliding, manual or automatic	No swing, hands-free option	Track and edge gaps leak unless sealed
Hermetic sliding	Seals made for low leakage	Needs a stated leakage class. More parts to maintain.

Cleanroom doors: hinged, sliding and hermetic selection

Leakage through closed doors

Flows in m³/s for gaps of 4 mm at the bottom, 3 mm at top and sides and 2 mm between double leaves (HTM 03-01 Part A, Appendix 4). The same document says factory-assembled steel-frame door-sets have effectively no closed-door leakage.

Pressure difference	Single door	Single door and a half	Double door
10 Pa	0.05	0.06	0.08
25 Pa	0.07	0.09	0.12
40 Pa	0.10	0.12	0.15

Test classes for air permeability

EN 12207:2016 grades internal pedestrian doorsets A to D. Ask which table the test report uses and the door area tested. Windows and external doorsets use classes 1 to 4, where class 4 is 3 m³/(h·m²) at 100 Pa with testing up to 600 Pa.

Class	Air permeability at 100 Pa, m³/(h·m²)	Maximum test pressure
A	50	100 Pa
B	27	100 Pa
C	9	150 Pa
D	3	150 Pa

Airflow through an open door

When a door opens, pressure collapses and airflow must protect the clean side. HTM 03-01 Appendix 5 gives the flow for a single door of 0.80 × 2.01 m and a double door of 1.80 × 2.01 m. Use it to size supply air, not door gaps.

From, to	Single door, m³/s	Double door, m³/s
Sterile room to dirty	0.47	0.95
Sterile room to transitional	0.39	0.75
Sterile room to clean	0.28	0.57
Clean room to dirty	0.39	0.75
Clean room to transitional	0.28	0.57
Transitional room to dirty	0.28	0.57

Interlocks

EU GMP Annex 1 says airlock doors should not open at the same time (para 4.13). Airlocks to grade A and B should have an interlocking system. Airlocks to grade C and D need a visual or audible warning as a minimum. A time delay may be added where segregation needs it.

HTM 03-01 notes that staff often disable door interlocks where a shared room becomes a shortcut (para 8.35). Plan the route so the interlock does not slow the work. Agree the emergency release with the owner's fire safety lead.

Finishes

Common leaf finishes are coated steel, stainless steel, aluminium frames, and high-pressure laminate or resin faces. Choose by cleaning chemicals, impact and humidity. A finish name does not prove fire resistance, leakage or antimicrobial performance. Ask for reports on the complete assembly of leaf, frame, seals, glazing and hardware.

Door schedule checklist

List for each opening: structural opening and wall thickness, leaf arrangement, swing or slide direction, clear width for trolleys, pressure difference across the door, leakage class and test pressure, fire rating, interlock group, vision panel, finish and emergency release.

Who approves the room

The regulator approves the owner's facility, not the contractor. Door reports go into your qualification file. 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

How much air leaks through a closed hinged door?

About 0.07 m³/s for a single door at 25 Pa with the gaps listed above (HTM 03-01, Appendix 4).

What is a hermetic door?

A door with seals made for low leakage. Ask for the leakage class and test pressure. EN 12207 class D for internal doorsets is 3 m³/(h·m²) at 100 Pa.

Must cleanroom doors be interlocked?

EU GMP Annex 1 says airlocks to grade A and B should have an interlocking system. Grade C and D airlocks need a warning system as a minimum.

Why do staff bypass interlocks?

HTM 03-01 says they often disable them where a shared room becomes a shortcut. Design the traffic route first.

Which way should a cleanroom door swing?

WHO guidance for non-sterile pharmaceutical products says swing doors should normally open to the high-pressure side and have self-closers (TRS 1010, Annex 8, para 4.14). Room pressure then helps to hold the door shut. Exceptions, such as fire escapes, must be justified and controlled.

What size should a clean room door be?

We found no cleanroom standard that fixes a door size. Take the clear width and height from the largest trolley, bed or machine that must pass, then check them against your local fire and hospital building rules. State the clear opening in the door schedule, not only the leaf size.

Related guides

Sources

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