27 May Cleanroom Design: An Introduction

Cleanroom design can seem difficult or overly technical at first. This is not far from the truth, but understanding the basics is much easier than most people think. In short, designing a well-functioning cleanroom is all about controlling the environment, especially when it comes to particles. In this guide, we’ll cover the basics of cleanroom design, including airflow, filtration, surfaces, classifications, and more.

Cleanroom Design Basics

So what is a cleanroom, exactly? It is a controlled environment where the size and number of airborne particles is kept within certain limitations. They may also control humidity, temperature, pressure, and more, but fundamentally, their main task is to reduce particles.

And because this is their main purpose, they use high-quality air filters, direct airflow, install special surfaces, and ensure that staff follow strict entry/exit protocols to reduce contaminants as much as possible.

Cleanrooms typically follow ISO classifications, which defines their cleanliness levels based on the number and size of particles per cubic meter of air, and the proper design of them often revolves around these standards.

When starting to build and design a cleanroom, it’s important to first understand what type of work will be going on in the space, the ISO classification needs, as well as any other industry-specific requirements/standards.

Industries That Require Cleanrooms

It may come as a surprise to many how widespread cleanrooms are. In the modern world, they are used more and more frequently, especially in industries where small particles can damage products or interfere with research outcomes. Here are a few sectors where they are commonly used:

• Pharmaceuticals: Cleanrooms are used in operations such as sterile drug manufacturing, where they are used to prevent microbial contamination. They will also typically be used in aseptic filling, compounding, and packaging.
• Semiconductors and Electronics: Microchips and circuit boards can be damaged by tiny particles, especially as such parts shrink in size. These spaces usually require strict spaces, ISO Class 5 and cleaner, especially for photolithography and wafer production.
• Aerospace: Cleanrooms are used for aircraft assembly, optics, spacecraft parts development, and more.
• Food Processing and Packaging: Cleanrooms in this industry are used in dairy production, packaged foods, beverages, as well as other applications.

Each industry will have its own cleanliness criteria, some focusing on viable particles (microorganisms) and some on particles in general. Industries will often have additional guidelines or standards to follow, so understanding these before designing your cleanroom is important to any successful project.

Basic Elements of Cleanroom Design

A cleanroom works because it has many controls in place to keep particles out. These can vary, and in less strict cleanrooms, some may not be necessary. But generally speaking, cleanrooms have a few core design features. Let’s take a look at some of the most important ones.

Airflow Control

In many cases, cleanrooms use carefully designed airflow to carry particles away from vulnerable areas. When it’s pointed in a certain direction, say vertically or horizontally, we call this unidirectional or laminar airflow. The latter is used in the strictest of cleanrooms, where there is little room for mistakes. Air flows across the room and into exhaust vents where it can be recycled through HEPA or ULPA filters, or else exit the room entirely. These measures are not necessary in less strict cleanrooms though, and “turbulent” airflow is sometimes sufficient.

HEPA/ULPA Filtration

Filters are perhaps the most essential part of cleanroom design. They ensure that particles are not added into the space, and do the important work of catching them. These filters, and especially HEPA and ULPA filters, are able to catch particles so tiny that the eye cannot see them. HEPA filters are the most common, but for especially demanding spaces you may need to use ULPA filters, or a mix of both. Such filters are usually placed in the ceiling and are the muscle behind cleanrooms.

Pressure Control

Furthermore, cleanrooms are in many cases pressurized in order to keep dirty air from entering. In most cleanrooms, the air pressure is slightly higher than the air outside (these are positive pressure spaces). That way, when someone opens a door, clean air flows out instead of letting unfiltered air in.

On the other hand, when working with dangerous chemicals and substances, the pressure is reversed to keep contaminants from escaping into other areas (these are known as negative pressure spaces).

Entry Control

Additionally, cleanrooms are often divided into different zones, each with its own level of cleanliness. People enter through a series of progressive spaces, like gowning rooms and airlocks, which act as buffers. Materials also go through special entry points as well, often using devices like pass-through chambers. The flow of people and materials must be managed at all times to keep the space from being contaminated.

Surface and Materials

Material selection is also important so that they do not shed and release particles themselves. The surfaces also need to be smooth so that they are easy to clean, and also so that there are no small gaps where dirt/microorganisms can collect. As a result, even finishes need to be chosen that are resilient to frequent cleanings with strong chemicals.

Environmental Control

Finally, cleanrooms need to keep tight control over factors like temperature, humidity, and even static electricity. Unfortunately, the wrong temperature and humidity can lead to the growth of organisms, or else excessive static electricity. If static builds up too much, electrostatic discharge can occur, and electric parts/equipment can be ruined. There are other environmental factors that may be controlled as well, and what those are will depend on your industry and use.

ISO Cleanroom Classifications

As we mentioned already, cleanrooms are classified by how clean the air inside them, and the most common system used is ISO 14644-1. This standard sets limits on the number and size of airborne particles allowed per cubic meter.

ISO cleanroom classes range from Class 1 (the cleanest) to Class 9 (the least strict). Most cleanrooms used in drug manufacturing, biotech, and electronics fall between ISO Class 5 and Class 8, depending on how vulnerable the products/processes are.

To meet a certain ISO class, a cleanroom must go through certification, as well as regular testing and monitoring. This includes checking particle levels, airflow, and pressure to make sure the space stays within the right limits.

There are many other regulations and guidelines to follow, depending on the industry. Some of the more common ones are GMP, cGMP, USP 797, and USP 800.

Modular vs. Traditional Cleanrooms

When planning a cleanroom, one of the first and biggest decisions to make is whether to go with a modular system or a stick-built (also called traditional) approach. Each has its benefits and drawbacks, and the right choice will depend on your timeline, budget, long-term needs, and more.

Modular cleanrooms are built using prefabricated panels that are manufactured off-site (in a factory) and then assembled on location. This method is faster and can reduce the downtime typically caused by traditional construction. Modular systems, being much more flexible, are easier to expand, modify, or even relocate if your operations grow or change. They’re a great choice if there is some degree of unpredictability in your business.

Stick-built cleanrooms, on the other hand, are made using conventional building materials, like drywall. They are seen as more “permanent,” though this isn’t really the case anymore, since modular buildings can last 30 years or longer. Traditional buildings generally take longer to build as well.

Both types of cleanrooms can meet the same cleanliness standards if they’re designed properly. The difference lies in how quickly they can be installed, how easy they are to change, and how well they can fit into already existing facilities.

The Bottom Line

Cleanroom design can seem complicated, but it’s important that it’s done right. Even tiny mistakes can lead to contamination, failed inspections, damaged products, or worse. For this reason, it’s absolutely critical to work with a manufacturer who understands your industry, standards, and requirements that you need to meet.

Interested in setting up modular cleanrooms? Reach out to the experts at Allied Cleanrooms for a quote on new buildouts today:

FAQs About Cleanroom Design

1. How long does it take to build a cleanroom?

The timeline will depend on whether you choose a modular or traditional cleanroom, as well as how complex or strict the space needs to be. Modular cleanrooms can sometimes be installed in just a few weeks or months, while traditional stick-built cleanrooms may take several months or even years.

2. Can a cleanroom be upgraded after it’s built?

Yes, it certainly can be, especially if it’s modular. Modular cleanrooms can be upgraded to meet stricter cleanliness standards or even redesigned and expanded as needs change. Modular systems are much easier to modify than traditional cleanrooms.

3. How much does a cleanroom cost?

The cost of a cleanroom can vary widely based on its size, ISO class, materials, and more. While it’s impossible to say with certainty how much a cleanroom should cost without getting a quote directly from a manufacturer, they usually fall within the range of $100 to $1,000 per square foot.