Hermetically Sealed
Cleanroom Systems
— Doors, Windows & Pass-Throughs
A cleanroom enclosure is only as effective as the integrity of its openings. Every door, window, and material transfer point is a potential breach in the controlled environment — a pathway for unfiltered air, particles, and microbial contamination to compromise your ISO class and GMP grade. Metrolabs supplies and installs the complete range of hermetically sealed cleanroom access and transfer systems engineered to maintain differential pressure, prevent cross-contamination, and sustain cleanroom classification at every opening.
Why Ordinary Doors Fail in Cleanrooms — and What Hermetic Systems Do Differently
A standard commercial door has gaps around every edge — at the head, the sides, and especially at the floor threshold. In a cleanroom, these gaps allow unfiltered air to flow between zones, destroying the pressure differential that prevents cross-contamination. A hermetic system eliminates every gap with engineered seal mechanisms.
Maintaining Differential Pressure
GMP cleanrooms operate on a positive pressure cascade — Grade A at the highest pressure, flowing through B, C, D to corridor. Every door must maintain this differential even when partially ajar. Hermetic doors with brush perimeter seals and automatic drop seals achieve Class 4 air leakage (<1 m³/h at 4 Pa) to sustain the cascade.
Preventing Particle Ingress
Even a 1mm gap at the base of a conventional door allows 50,000+ particles per cubic metre of unfiltered corridor air to enter the cleanroom during each transit. A hermetic automatic drop seal eliminates this gap completely, extending to the floor surface the instant the door closes.
Interlocking for Airlock Control
Pharmaceutical airlocks require that only one door can be open at any time — enforced by an electro-mechanical door interlock system. Hermetic interlocked doors prevent simultaneous opening, ensuring the pressure buffer zone is maintained between cleanroom grades at all times.
Material Transfer Without Zone Breach
Static and dynamic pass-through boxes allow materials, samples, and supplies to be transferred between cleanroom grades without any person or unfiltered air crossing the zone boundary — with UV-C decontamination options for sterile-grade material transfer.
Six Hermetically Sealed Cleanroom System Products
Metrolabs supplies and installs the complete range of hermetic access and transfer systems — each engineered to maintain cleanroom integrity at every type of opening:
Hermetic Single & Double Swing Doors
Single and double leaf hermetic cleanroom doors with perimeter brush seals, automatic hydraulic closers, and automatic drop floor seals. Available in steel (CRCA painted), SS 304, and SS 316L for sterile-grade facilities. Single-glazed or double-glazed flush vision panels as specified. Suitable for ISO Class 5–8 cleanroom zones with manual or automatic operation.
Automatic Hermetic Sliding Doors
Motorised sliding hermetic doors for high-traffic cleanroom areas where hands-free operation is essential — reducing the risk of surface contact contamination. Pneumatic or electro-mechanical drive with perimeter brush seals and sensor activation. Bi-parting option for wide openings. Fail-safe operation with battery backup and manual override. Suitable for ISO Class 6–8 pharmaceutical and food cleanrooms.
Interlocked Airlock Door Systems
Electro-mechanically interlocked door pairs for pharmaceutical airlocks, gowning rooms, and buffer zones between GMP grades. Controller enforces single-door-open protocol at all times — the second door cannot open until the first is fully closed and sealed. Traffic light indicators (red / green), audio alerts, and data logging for GMP audit trails. Critical for Grade A/B aseptic suite access control.
Flush-Mounted Vision Panels & Windows
Flush-mounted double or triple-glazed vision panels installed with zero-frame-rebate system — the glass is flush with the wall surface, eliminating particle-trapping ledges, frames, and recesses. Anti-static glass coating prevents electrostatic particle attraction on cleanroom-facing surfaces. Available as fixed panels, sliding vision panels, and heated double-glazed units for cold room cleanrooms. Suitable for all ISO classes.
Static & Dynamic Pass-Through Boxes
Material transfer chambers mounted through cleanroom walls for passing items between zones without personnel crossing the boundary. Static pass-throughs with interlocked hinged doors for routine material transfer. Dynamic pass-throughs with HEPA-filtered unidirectional airflow and UV-C irradiation for decontamination of incoming materials in Grade A / ISO 5 aseptic suites. All units stainless steel interior with pharmaceutical-grade silicone seals.
Rapid Roll-Up & High-Speed Doors
High-speed roll-up cleanroom doors for high-traffic controlled environments where a conventional swing or slide door would cause excessive air movement or production disruption. Open in <1 second, close automatically after passage — minimising the duration of any cleanroom boundary opening. Brush seals on all four sides of the door frame maintain hermetic integrity in closed position. Used in pharmaceutical packaging lines, food production, and large cleanroom bay access.
Engineering the Hermetic Seal — Key System Features
Every component of a hermetic cleanroom door and window system is precision-engineered to eliminate air leakage pathways:
Automatic Drop Floor Seal
Mechanically actuated seal drops to the floor surface the instant the door closes — driven by the door leaf’s own closing momentum. Eliminates the floor gap that allows particle and pressure leakage at the base of all conventional doors. Retracted automatically when the door opens to prevent dragging across the floor.
Perimeter Brush + Compression Seals
Continuous brush seal on three sides (head and both jambs) provides primary air leakage resistance. A secondary compression seal on the door stop provides back-up containment, achieving combined Class 4 air leakage classification (<1 m³/h at 4 Pa pressure differential).
Electro-Mechanical Interlock Controller
Monitors the open/closed state of each door in an airlock pair via magnetic reed switches. Prevents simultaneous opening through electro-magnetic locking. Provides traffic light indicator status, audio alert on violation attempt, and tamper-evident data log with timestamp for GMP audit trails.
Flush-to-Wall Vision Panel System
Purpose-engineered flush-mount frame system secures the vision panel glass flush with the cleanroom wall surface — no stepped rebate, no ledge, no particle-trapping frame profile on the cleanroom-facing side. Fully cleanable with standard disinfectants. Available in heated glass version for cold room environments.
Anti-Static & ESD-Safe Glass Options
Vision panels in electronics and semiconductor cleanrooms are specified with anti-static ITO-coated glass that permanently dissipates electrostatic charge — preventing particle attraction to the glass surface and protecting sensitive components from electrostatic discharge through the door panel.
Highest positive pressure. Every door opening must be hermetically sealed to prevent any lower-grade air ingress during transit.
5 Pa differential to Grade A maintained by interlocked airlock doors. Only one door open at any time.
5 Pa below Grade B. Hermetic doors prevent backflow of Grade C air into Grade B zones during transit.
Lowest cleanroom grade. Airlock with hermetic doors separates this zone from uncontrolled corridor.
No HEPA filtration. Every hermetic door seal prevents uncontrolled air from entering the cleanroom envelope.
The Four Critical Functions of a Hermetically Sealed Opening
Sustaining Differential Pressure
Hermetic seals limit air leakage to <1 m³/h, allowing HVAC systems to maintain the designed pressure differential between zones — the single most important mechanism preventing cross-contamination between GMP grades.
Preventing Cross-Contamination
Every gap in a cleanroom boundary is a contamination pathway. Hermetic seals block the movement of particles, microorganisms, allergens, and active pharmaceutical ingredients between adjacent zones during personnel and material transit.
Enforcing Access Control
Interlocked airlock systems ensure the pressure buffer zone between cleanroom grades is never compromised by simultaneous opening — a fundamental GMP design requirement for Grade A/B aseptic manufacturing facilities.
Generating Audit Evidence
Interlocked door controllers with 21 CFR Part 11-compliant data logging generate timestamped records of every door event — providing documented evidence that the airlock protocol was followed during critical pharmaceutical operations.
Every Regulated Cleanroom Application
Pharmaceutical Manufacturing
Interlocked hermetic doors for Grade A/B/C/D GMP suites — WHO, EU Annex 1, and US-FDA inspection compliant with 21 CFR Part 11 audit log.
Aseptic & Sterile Suites
SS 316L hermetic doors with dynamic pass-through boxes and UV-C decontamination for injectable fill-finish and aseptic compounding areas.
Hospital Operating Theatres
Auto-sliding hermetic doors for operating suites, NICU, isolation rooms, and hospital sterile processing (CSSD) departments.
Microbiology & Biosafety Labs
Interlocked hermetic access systems for BSL-2 and BSL-3 labs maintaining containment integrity at every access and transfer point.
Food & Beverage Production
High-speed hermetic doors for high-traffic food production lines — hands-free auto-sliding or roll-up for FSSAI and HACCP-regulated production areas.
Electronics & Semiconductor
ESD-safe hermetic doors with anti-static vision panels for ISO 4–7 semiconductor fabrication and precision electronics assembly cleanrooms.
Biotech & Cell Therapy Labs
Pass-through boxes with UV-C and HEPA dynamic airflow for biosecure material transfer in cell therapy, mRNA, and gene therapy manufacturing facilities.
NABL & Research Facilities
Flush vision panels and static pass-through boxes for NABL-accredited testing labs and controlled-environment research facilities requiring documented containment.
Hermetic Systems vs. Standard Commercial Doors
Standard commercial fire or security doors are sometimes specified for cleanroom use to reduce costs — but they lack every engineering feature that makes a door hermetic. The performance difference is substantial:
Complete Seal System — All Four Edges
Metrolabs hermetic doors seal all four edges simultaneously — perimeter brush seal on three sides and an automatic drop seal at the floor. Standard doors have gaps on all four sides that cannot be eliminated without specialist retrofitting.
Flush Vision Panels — No Ledges
Our flush-mount vision panel system eliminates the stepped rebate that accumulates particles on standard framed windows — the ledge that auditors cite as a contamination risk in every facility using off-the-shelf framed glazing.
Single Supplier for All Openings
Metrolabs supplies and installs hermetic doors, sliding doors, interlocked airlocks, vision panels, pass-through boxes, and high-speed doors — all under a single contract, ensuring full compatibility between all system components.
IQ Documentation at Handover
Installation Qualification records including air leakage test results, interlock function verification, vision panel flush measurement records, and pass-through decontamination cycle data — all delivered as part of the standard project handover package.
Hermetic vs. Standard Commercial Door
Hermetic Systems Required by Every Major Cleanroom Regulatory Framework
WHO & EU GMP
WHO GMP and EU Annex 1 (2022) for sterile manufacturing explicitly require airlocks between different GMP grades, controlled-access systems with pressure monitoring, and airtight construction of all cleanroom boundaries — hermetic door systems are the primary engineering solution.
WHO GMP · EU Annex 1ISO 14644 Cleanroom Standard
ISO 14644-4 cleanroom design requires controlled access systems that maintain the design air cleanliness class — specifying that doors, windows, and pass-throughs must not compromise the differential pressure cascade between cleanroom zones.
ISO 14644-421 CFR Part 11 (US-FDA)
US-FDA 21 CFR Part 11 requires electronic records and electronic signatures for pharmaceutical manufacturing operations. Interlock door controllers with compliant data logging generate the documented evidence that airlock protocols were followed during critical operations.
21 CFR Part 11NABL & ISO/IEC 17025
NABL accreditation for testing laboratories requires controlled-access facilities with documented containment integrity. Hermetic pass-through boxes and vision panels allow work to be observed and materials transferred without compromising laboratory containment during NABL assessments.
NABL · ISO 17025Ready to Seal Every Opening in Your Cleanroom?
Contact Metrolabs for a free consultation. Our cleanroom engineers will assess every door, window, and material transfer requirement in your facility — specifying the hermetic system that maintains your ISO class and GMP grade at every opening, with full IQ documentation at handover.
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