A cleanroom is a controlled environment engineered to keep airborne particles, temperature, humidity, and pressure within strict limits — classified by ISO 14644 — so that pharmaceutical, biotech, cosmetic, and medical-device products can be made without contamination. Paul Industries designs, builds, and validates modular and stick-built cleanrooms for manufacturing facilities across the United States, self-performing the HVAC, HEPA filtration, wall systems, and IQ/OQ/PQ under a single contract.
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What it isAn ISO 14644-classified, contamination-controlled production environment
Who it’s forPharma, biotech, medical device, cosmetic & nutraceutical plants
ScopeDesign → HVAC/HEPA → wall & ceiling systems → controls → certification
StandardsISO 14644 · cGMP / 21 CFR 211 · USP <797>/<800> · IEST
Build typesModular (panel) & conventional stick-built
Service areaNationwide (all 50 states)
How a cleanroom works
A cleanroom controls contamination by continuously supplying HEPA- or ULPA-filtered air, maintaining positive (or, for containment, negative) pressure relative to surrounding spaces, and using smooth, cleanable, non-shedding surfaces. Air changes per hour, airflow pattern (unidirectional/laminar vs. turbulent), and room pressurization are engineered to the ISO class the process requires. The cleaner the class, the more filtered air, the tighter the envelope, and the more rigorous the gowning and controls.
Paul Industries engineers the full system as one package: the HVAC and HEPA filtration that set the class, the wall, ceiling, and flooring systems that hold it, the pressure cascade between rooms, and the controls and monitoring that keep it in a validated state — then certifies performance against ISO 14644.
ISO 14644 cleanroom classifications
ISO 14644-1 classifies cleanrooms by the maximum allowable particle count per cubic metre. Choosing the right class is a balance of product risk and cost — over-classifying wastes capital and energy, under-classifying risks the product.
ISO 14644-1 cleanroom classes (particles ≥0.5 µm per m³)
| ISO Class | Max particles ≥0.5 µm/m³ | ≈ FED STD 209E | Typical use |
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| ISO 5 | 3,520 | Class 100 | Aseptic filling, sterile compounding |
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| ISO 6 | 35,200 | Class 1,000 | Sterile prep, sensitive assembly |
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| ISO 7 | 352,000 | Class 10,000 | Aseptic background, medical device |
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| ISO 8 | 3,520,000 | Class 100,000 | General pharma / cosmetic packaging |
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Modular vs. stick-built cleanrooms
Both approaches can meet any ISO class; the right choice depends on speed, flexibility, and your building.
Modular vs. stick-built cleanroom construction
| Modular (panel) | Stick-built |
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| Speed | Faster — prefabricated panels | Slower — built in place |
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| Flexibility | Reconfigurable / relocatable | Permanent |
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| Best for | Fast timelines, changing needs | Fixed, fully integrated suites |
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| Finish | Cleanable panel systems | Custom architectural finishes |
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Our cleanroom services
- Design & engineering — ISO-class selection, airflow and pressure-cascade design, HVAC and HEPA sizing.
- Construction — modular panel or stick-built walls, ceilings, cleanroom flooring, doors, and pass-throughs.
- HVAC & filtration — air handlers, HEPA/ULPA terminals, humidity and temperature control.
- Controls & monitoring — pressure, particle, and environmental monitoring for cGMP records.
- Certification & validation — ISO 14644 certification plus IQ/OQ/PQ.
- Process integration — high-purity water, process piping, and equipment tie-ins under one contract.
Industries we serve
We build cleanrooms for pharmaceutical and biotech manufacturing (aseptic filling, cell and gene therapy, WFI suites), sterile compounding pharmacies under USP <797>/<800>, medical-device assembly, and cosmetic and nutraceutical production where product protection and regulatory compliance matter.
Standards & compliance
- ISO 14644
- The international standard that classifies cleanrooms by airborne particle concentration and defines how performance is tested and certified.
- cGMP / 21 CFR 211
- FDA current Good Manufacturing Practice requirements that drive the environmental control, monitoring, and documentation a pharma cleanroom must maintain.
- USP <797> and <800>
- Standards governing sterile and hazardous-drug compounding environments, which set airflow, pressurization, and classification for compounding cleanrooms.
- IQ / OQ / PQ
- Installation, Operational, and Performance Qualification prove the cleanroom was built to design, operates within its parameters, and holds its class in production.
Why Paul Industries
Cleanrooms fail at the seams between trades — the mechanical contractor, the panel installer, the controls integrator, and the validation firm. Paul Industries self-performs across those trades, so one team owns the airflow, the envelope, the controls, and the certification, and there is a single point of accountability for the class you’re paying for. With 30+ years building process environments across the United States, every project is documented for cGMP traceability. Where client confidentiality limits public references, we provide capability statements and certification deliverables on request.
Frequently asked questions
What is a cleanroom used for?
A cleanroom is a controlled environment that limits airborne particles, and often temperature, humidity, and pressure, to protect a sensitive process. In cGMP manufacturing it protects drugs, biologics, and devices from contamination. Paul Industries designs, builds, and validates cleanrooms to ISO 14644 nationwide.
What makes a cleanroom different from a normal clean space?
A cleanroom controls airborne particle concentration to a measured ISO class using HEPA filtration, defined air change rates, and a pressure cascade. Ordinary clean spaces are simply tidy; a cleanroom is engineered, monitored, and certified to prove its cleanliness quantitatively.
What are the main components of a cleanroom?
Core components are HEPA or ULPA filtration, an HVAC system delivering controlled air changes, pressurization and airlocks, cleanable wall, ceiling, and floor systems, and monitoring instrumentation. Together they hold the air to a specified ISO class while people and processes operate inside.
What ISO classes do cleanrooms come in?
ISO 14644 defines ISO Class 1 through ISO Class 9, from the cleanest to near-room air. Most pharmaceutical and biotech cleanrooms fall between ISO 5 and ISO 8. Paul Industries builds across this range based on the product and process requirements.
How does a cleanroom keep particles out?
It combines HEPA-filtered supply air, a high air change rate that dilutes and sweeps particles away, positive pressure that pushes air outward through gaps, and gowning and airlocks that limit what people and materials carry in. No single measure works alone.
Why is positive pressure important in a cleanroom?
Positive pressure keeps the cleanroom at higher pressure than surrounding spaces, so air leaks outward rather than dirtier air leaking in. The pressure cascade between grades protects the most critical zone. Containment suites reverse this with negative pressure to keep hazardous material in.
What is an air change rate and why does it matter?
The air change rate is how many times per hour the room’s air volume is replaced with filtered air. Cleaner classes need higher rates to continuously dilute the particles that people and equipment generate. It is a primary lever for holding the ISO class in operation.
Do cleanrooms control temperature and humidity too?
Usually yes. Beyond particles, most cleanrooms hold temperature and humidity within set bands for product stability, process control, and operator comfort in gowning. Humidity control also limits microbial growth and static, so the HVAC system manages all of these together.
What industries rely on cleanrooms?
Pharmaceutical, biopharmaceutical, biotech, medical-device, cosmetic, nutraceutical, and food and beverage manufacturers use cleanrooms, alongside electronics and aerospace. Paul Industries focuses on the cGMP-regulated life-science and consumer-health sectors where cleanrooms must be validated and documented.
How do people enter a cleanroom without contaminating it?
Personnel pass through gowning rooms and airlocks, donning cleanroom garments, gloves, and coverings that trap the particles and microbes the human body sheds. This gowning discipline, combined with airlocks that buffer the pressure cascade, is one of the most important contamination controls.
What is the difference between a cleanroom and a containment room?
A standard cleanroom uses positive pressure to keep contamination out and protect the product. A containment room uses negative pressure to keep hazardous or potent material in and protect people and the environment. The airflow direction and safeguards differ fundamentally between the two.
How is a cleanroom certified?
Certification tests airborne particle counts against the target ISO class at defined sample points under ISO 14644, supported by airflow, pressurization, and HEPA integrity testing. The documented report proves the room meets its class. Paul Industries performs this certification as part of the build.
Can a cleanroom be built inside an existing building?
Yes. Cleanrooms are frequently retrofitted into existing facilities using modular systems that fit the available height and structure. Paul Industries assesses the space and HVAC capacity, then designs an envelope and utilities that achieve the required class within the constraints.
How is a cleanroom kept clean over time?
Ongoing control combines routine cleaning with approved agents, HEPA filter replacement, gowning discipline, particle monitoring, and periodic recertification. Contamination control is continuous, not a one-time event, so Paul Industries supports rooms with maintenance and recertification after startup.
Can Paul Industries build a cleanroom anywhere in the US?
Yes. Paul Industries designs, fabricates, installs, and validates cleanrooms across all 50 states, mobilizing from Kilmarnock, Virginia. As a single-source contractor it also delivers the supporting HVAC, high-purity water, and sanitary piping. Call 201-450-8280.
How do I decide what cleanroom I need?
Start from the product and process: what contamination threatens it, which ISO class the regulation or risk assessment requires, and the footprint and flows involved. Paul Industries translates those requirements into a room design, budget, and validation plan. Reach the team at 201-450-8280.
What ISO class cleanroom do I need?
It depends on your product and process risk: aseptic filling typically requires ISO 5 at the point of fill with an ISO 7 background, while packaging or general pharma work is often ISO 8. We assess your process, product, and regulatory requirements during design and recommend the class that protects the product without over-building.
Is a modular or stick-built cleanroom better?
Both can meet any ISO class. Modular panel systems are faster to install and can be reconfigured or relocated, which suits changing needs and tight timelines; stick-built construction suits permanent, fully integrated suites with custom finishes. We help you choose based on schedule, flexibility, and your building.
How long does cleanroom construction take?
A modular cleanroom can be installed in a matter of weeks once designed and permitted, while a large stick-built suite with integrated process systems runs several months. Prefabrication and clear scope shorten on-site time, and we plan the work around your production schedule.
Do you handle the HVAC and HEPA filtration?
Yes. We design and install the air handling, HEPA/ULPA filtration, pressure cascade, and temperature and humidity control that set and hold the ISO class — it is part of the same single-source scope as the walls, ceilings, and controls.
Do you certify and validate the cleanroom?
Yes. We provide ISO 14644 certification of the finished room plus Installation, Operational, and Performance Qualification (IQ/OQ/PQ), so the same team that builds the cleanroom also documents and proves it.
Do you build cleanrooms nationwide?
Yes. We are Virginia-based and build cleanrooms nationwide.
Get a cleanroom project quote
Tell us about your facility, product, and target ISO class — a Paul Industries engineer will follow up to discuss scope, standards, and timeline.
Request a Project Quote
or call 201-450-8280
