A cell and gene therapy facility is not one cleanroom; it is a block of small suites, each at the grade its step needs, each able to run a different patient’s batch at the same time without the two ever meeting. That is the difference from a conventional biologics plant with one large process floor. Open manipulations happen in a Grade A device inside a Grade B suite; closed single-use processing happens in Grade C or D; viral vector work happens in suites that contain as well as protect; and every suite has its own airlocks, pressure relationships and monitoring. Paul Industries designs and builds cell and gene therapy cleanroom suites, modular or stick-built, with the HVAC, pressure control, VHP-compatible finishes and utilities to closed equipment, and coordinates their certification under EU GMP Annex 1 and the FDA’s expectations.
Grades by step
| Step | Closed or open | Suite grade | Device |
|---|---|---|---|
| Cell isolation, selection, activation with manual steps | Open | Grade B (ISO 7 in operation, ISO 5 at rest) | Biosafety cabinet providing Grade A |
| Expansion in closed bioreactors or cell processing systems | Closed | Grade C or D | Closed single-use system; connections by tube welding or aseptic connectors |
| Formulation and fill with open steps | Open | Grade B | Grade A device or isolator |
| Formulation and fill in an isolator | Closed | Grade C or D | Isolator providing Grade A |
| Viral vector production and purification | Closed or open | Grade B or C, contained | Biosafety cabinets or closed systems; negative to corridor |
| Cryopreservation and storage | Closed | Grade D or controlled | Controlled-rate freezers, LN2 storage with O2 monitoring |
| Material staging, gowning, corridors | n/a | Grade D or C | Airlocks and pass-throughs |
Deciding closed versus open for each unit operation before the suites are drawn is the single largest cost decision: every open step needs a Grade B suite with full gowning and monitoring; every closed step can sit in Grade C or D.
Segregation and flow
Autologous products are one patient’s cells, and the facility has to guarantee they never meet another patient’s: separate suites or scheduled segregation with full changeover, dedicated equipment per batch or per suite, labeled and monitored storage, and a layout in which two batches cannot be open in the same space at the same time. Personnel and materials flow one way, in through airlocks and out through separate exits or de-gowning, with pass-throughs for materials and samples. Vector suites are segregated from cell processing suites, with their own air systems, so vector and cells never share a room or a return duct.
Pressure cascades that protect and contain
Product protection wants the cleanest room at the highest pressure; containment of viral vectors wants the vector suite negative to the corridor. Bubble and sink airlocks (an airlock at higher or lower pressure than both rooms it joins) reconcile the two, and the whole block is designed and commissioned as one cascade with monitoring and alarms. In a cell and gene therapy facility the cascade is more complex than in any conventional plant, and it is verified by pressure mapping and smoke studies at commissioning and after every change.
Suite construction
Modular panel systems suit the many-small-suites layout and the reconfiguration these facilities go through as products and scales change: sealed panels with flush windows, doors with interlocks, coved floors, and penetrations sealed for every utility. Finishes, seals, instruments and HVAC components are specified to survive repeated vaporized hydrogen peroxide decontamination and sporicidal cleaning. Each suite or small group of suites has dedicated air handling with HEPA supply and, for Grade B, HEPA return or exhaust and higher air change rates; vector suites have HEPA-filtered exhaust with bag-in/bag-out housings. Utilities to closed equipment, gases, WFI, vacuum, LN2, glycol, terminate at validated points of use inside the suite.
Monitoring and gowning
Grade B suites carry continuous non-viable particle monitoring at the Grade A device and in the room, viable monitoring by settle plates, contact plates and air samplers, pressure and temperature logging, and sterile gowning changed at every entry with operator qualification. Grade C and D suites are monitored to their grade. The environmental monitoring program is part of the contamination control strategy Annex 1 requires, and the suite design has to provide the sample points, the space for gowning and the airlocks the program assumes.
Certification and qualification
Each suite is certified to ISO 14644-1 in its occupancy state (Grade B in operation for open-step suites), with HEPA leak tests, airflow, pressure differentials, recovery time and smoke visualization, and the biosafety cabinets and isolators are certified separately. HVAC and envelope installation and operational qualification, the pressure cascade commissioning record and the VHP cycle development for isolators and rooms are the documents the site’s qualification is built from, and modular suites in a converted building follow the same process as a purpose-built plant.
Converted buildings
Most new cell and gene therapy capacity in the Boston, Philadelphia, Research Triangle, Bay Area and Maryland clusters is going into converted laboratory and light-industrial buildings, where ceiling height, structure for mechanical loads, a workable material flow and space for airlocks decide whether the layout fits. Modular suites, dedicated air handling on a mezzanine or roof, and utilities routed through existing structure are how it is done, and a contractor that carries the suites, HVAC, utilities and process connections in one scope keeps the pressure cascade and the schedule intact.
What Paul Industries builds
Grade B, C and D suites with airlocks, pass-throughs and VHP-compatible finishes; dedicated HVAC with HEPA supply, exhaust and pressure control commissioned as one cascade; utilities to closed processing equipment, isolators and biosafety cabinets at validated points of use; LN2 and cryogenic piping with oxygen monitoring; segregated vector suites with contained exhaust; and coordination of certification, smoke studies and qualification with the site.
Standards referenced: EU GMP Annex 1 (EudraLex Vol. 4) · ISO 14644-1 · ISO 14644-2 · 21 CFR 211 · 21 CFR 1271
Frequently asked questions
Grade B or Grade C: how is each cell therapy suite’s grade decided?
Grade B (ISO 7 in operation, ISO 5 at rest) for suites where product is manipulated open in a Grade A biosafety cabinet or filling device; Grade C or D for closed single-use processing; and contained Grade B or C for viral vector work. The closed-versus-open decision for each unit operation sets the grade and most of the cost.
Why are cell and gene therapy facilities built as many small suites?
Because batches are patient-specific or small, run in parallel, and must never meet: separate suites let several batches process at once with segregation, each suite has its own airlocks and pressure relationships, and suites can be at different grades for closed and open steps. One large process floor cannot provide that segregation.
How is patient-to-patient segregation achieved in the cleanroom design?
With separate suites or scheduled segregation with full changeover, dedicated equipment per batch or suite, labeled and monitored storage, one-way personnel and material flow through airlocks and pass-throughs, and a layout in which two batches cannot be open in the same space at the same time. Chain of identity is supported by the building as much as by labels.
What is different about a viral vector suite?
It contains as well as protects: negative pressure to the corridor for biosafety while maintaining product protection through bubble and sink airlocks, HEPA-filtered exhaust with bag-in/bag-out housings, effluent decontamination, and segregation from cell processing suites with its own air system so vector and cells never share a room or a return duct.
What are bubble and sink airlocks?
Airlocks held at higher pressure (bubble) or lower pressure (sink) than both rooms they connect, used to reconcile product protection (cleanest room highest) with containment (hazard room lowest) in the same cascade. Cell and gene therapy facilities with vector suites rely on them, and the whole cascade is commissioned and monitored as one system.
What finishes and materials do cell therapy cleanrooms need?
Sealed, cleanable, non-shedding surfaces that survive repeated vaporized hydrogen peroxide decontamination and sporicidal cleaning: modular panels with compatible coatings, coved floors, flush windows and fixtures, sealed penetrations, and seals, instruments and HVAC components specified for VHP exposure. VHP compatibility is designed in, not retrofitted.
Can cell and gene therapy cleanrooms be modular?
Yes, and most are: modular panel suites suit the many-small-suites layout, converted buildings and the reconfiguration these facilities go through as products and scales change. The grade is achieved by dedicated air handling, HEPA filtration and envelope integrity, the same as for stick-built, and modular suites are certified and qualified the same way.
What HVAC does a Grade B cell therapy suite need?
Dedicated air handling with HEPA supply and HEPA return or exhaust, air change rates high enough to hold ISO 7 in operation with gowned operators and equipment, a positive pressure relationship to adjacent lower grades through airlocks, temperature and humidity control, and monitoring and alarms; vector suites add HEPA-filtered exhaust and negative pressure to the corridor.
What monitoring does a Grade B suite need?
Continuous non-viable particle monitoring at the Grade A device and in the room, viable monitoring by settle plates, contact plates and active air samplers on a defined schedule, glove and gown monitoring of operators, and pressure and temperature logging, all as part of the contamination control strategy Annex 1 requires. The suite design provides the sample points and space the program assumes.
How are utilities delivered into a cell therapy suite?
Through sealed penetrations to validated points of use: process gases through sterile filters, WFI or purified water for buffer preparation, vacuum, clean steam where autoclaves or fixed equipment need it, glycol or chilled water to incubators and freezers, and liquid nitrogen with oxygen depletion monitoring. Redundancy is designed in because a utility failure can cost a batch that cannot be remade.
How are cell therapy cleanrooms decontaminated?
By vaporized hydrogen peroxide for isolators and, in some designs, whole suites, with generators, distribution and aeration cycles developed and validated, and by sporicidal cleaning of surfaces on a schedule. The HVAC is designed to isolate a suite during a VHP cycle, and materials are chosen to survive it.
Which Annex 1 requirements bite hardest on cell therapy suites?
EU GMP Annex 1 and Part IV for advanced therapies, ISO 14644-1 and -2 for classification and monitoring, 21 CFR 211 and 21 CFR 1271 in the United States with FDA guidance for CGT manufacturing, and biosafety requirements for vector operations. Annex 1’s contamination control strategy is the organizing document for the cleanroom design.
How are cell therapy suites certified?
Each suite to ISO 14644-1 in its occupancy state (Grade B in operation for open-step suites) with HEPA leak tests, airflow, pressure differentials, recovery time and smoke visualization; biosafety cabinets and isolators are certified separately; and the pressure cascade is commissioned and mapped as one system. Recertification follows ISO 14644-2 and the site’s monitoring plan.
Can a laboratory building be converted for cell therapy manufacturing?
Yes, and most new capacity is going into converted laboratory and light-industrial buildings: modular suites inside the shell, dedicated air handling on a mezzanine or roof, utilities routed through existing structure, airlocks fitted into the plan, and LN2 and gas supply outside. Ceiling height, structure and a workable material flow decide whether the layout fits.
How does using isolators shrink the Grade B footprint?
Isolators provide Grade A for open steps while separating the operator from the product, letting the surrounding suite be Grade C or D instead of Grade B, which reduces gowning, monitoring and classified area. They need utilities, VHP decontamination and integration with the suite’s HVAC and cascade, and their adoption is one of the main levers on facility size and cost.
How many airlocks does a cell therapy facility need?
More than a conventional plant: personnel and material airlocks for every suite, gowning and de-gowning at grade changes, pass-throughs for materials and samples, and bubble or sink airlocks where containment and product protection meet. Airlocks consume floor area and are the reason converted buildings need more space than the process alone suggests.
What gowning is required in a Grade B cell therapy suite?
Sterile gowning: sterilized coverall, hood, mask, goggles, boots and sterile gloves, changed at every entry, with aseptic gowning qualification and periodic requalification of operators, and glove and gown monitoring. Grade C and D suites use the lighter gowning of their grade, which is one reason closed processing in Grade C is preferred where the process allows.
How is temperature and humidity controlled in cell therapy suites?
By the dedicated air handling for each suite or group, with set points for operator comfort in full gowning and for equipment such as incubators and freezers that reject heat into the room, and with humidity control to limit static and support VHP cycles. Heat loads from equipment in small suites are higher per square foot than in a large process floor.
What sits on the critical path of a cell therapy suite fit-out?
Modular suites in an existing building typically run from design through certification in months, with the HVAC and utility installation, the pressure cascade commissioning and the qualification of water, gas and LN2 systems on the critical path. Deciding closed versus open per step early, and ordering long-lead equipment early, is what keeps the schedule.
Which cell therapy suite systems does Paul Industries build and commission?
Grade B, C and D suites with airlocks, pass-throughs and VHP-compatible finishes; dedicated HVAC with HEPA supply, exhaust and pressure control commissioned as one cascade; utilities to closed equipment, isolators and biosafety cabinets at validated points of use; LN2 and cryogenic piping with oxygen monitoring; segregated vector suites with contained exhaust; and coordination of certification, smoke studies and qualification.
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