A cleanroom environment is designed to maintain strict levels of cleanliness, but keeping it contaminant-free requires constant vigilance. From airborne particles to improper cleaning tools, even small oversights can compromise the integrity of your workspace. Whether you're in pharmaceuticals, electronics, aerospace, or medical device manufacturing, proper cleanroom maintenance is essential to ensuring product quality and regulatory compliance.
In this guide, we’ll break down cleanroom classifications, sources of contamination, essential protocols, and best practices for maintaining a pristine environment. Plus, we’ll share the best cleanroom-approved tools and supplies to help you uphold the highest standards.
Your cleanroom environment is a highly specialized room needed for certain manufacturing, assembly, medical, and other industrial applications. While they were historically only used by NASA or in circuit board production, cleanrooms have become much more common in a variety of industries, including aerospace, pharmaceuticals, nanotechnology, nutraceuticals, and medical devices.
Cleanrooms are usually built to exacting specifications that consider airflow, air pressure, temperature, equipment, and fixtures. With all this said, maintaining a cleanroom is often the bigger challenge.
Cleanrooms are categorized based on the level of air cleanliness required for a particular application. The International Organization for Standardization (ISO) has established a system for classifying cleanrooms, with ISO 1 being the cleanest and ISO 9 being the least strict.
Each classification is determined by the number of airborne particles per cubic meter of air. For example, an ISO 5 cleanroom (commonly used in pharmaceutical manufacturing) allows a maximum of 3,520 particles per cubic meter, while an ISO 8 cleanroom (used in general electronics assembly) allows up to 3.5 million particles per cubic meter.
Industries requiring strict contamination control include:
|
Industry |
ISO Level(s) |
Details |
|
Pharmaceuticals & Biotechnology |
5-7 |
For sterile drug production and research labs |
|
Semiconductor Manufacturing |
3-6 |
For wafer fabrication and microchip assembly |
|
Medical Device Production |
7-8 |
For ensuring product sterility and integrity |
|
Aerospace & Optics |
4-6 |
For precision engineering and satellite components |
Please note that air quality in cleanrooms is regulated through air change rates (ACH)—how many times per hour the air is completely replaced.
ISO 5: 240-600 ACH (every 1-2 minutes)
ISO 7: 60-90 ACH (every 8-10 minutes)
ISO 8: 10-25 ACH (every 30-60 minutes)
The greatest threat to cleanrooms is airborne particles that cause contamination.
Common contaminants are skin particles, fibers, dust, grease, bacteria, viruses, metals, fungi, ions, and film. While cleanroom processes and procedures are usually established to regulate the environment, contamination can often come from secondary factors that aren’t always considered or have the potential to be overlooked.
Here are the most common contaminant sources:
Human skin cells, hair, sweat, and breath release thousands of particles per minute.
Personnel are the largest source of contamination in a cleanroom, making training essential. A good cleanroom hygiene training program should cover:
Cleanroom Entry & Exit Procedures
Proper Gowning Techniques
Minimizing Particle Generation (movement, speaking, etc.)
Safe Handling of Materials & Equipment
Cleaning Protocols & Contamination Prevention
Regular training reinforces best practices and ensures all employees understand the importance of cleanroom discipline.
Moving parts generate microscopic debris, lubricants can aerosolize, and even electrical components emit contaminants.
External pollutants enter through doorways, air ducts, or compromised seals.
Non-compliant wipes, cloths, and solutions can introduce fibers and chemical residues.
Raw materials, chemicals, or packaging brought into the cleanroom may contain invisible contaminants.
To mitigate these risks, strict cleanroom protocols must be followed, from personnel gowning to frequent air filtration monitoring and strict material handling procedures.
Air filtration is a cornerstone of cleanroom contamination control. Cleanrooms use HEPA (High-Efficiency Particulate Air) and ULPA (Ultra-Low Penetration Air) filters to remove airborne particles. HEPA filters capture 99.97% of particles (≥0.3 microns in size), while ULPA Filters capture 99.9995% of particles (≥0.12 microns in size).
HEPA filters are standard for most cleanrooms, particularly ISO 5-8 environments and ULPA filters are used in ISO 1-4 cleanroom environments where absolute sterility is required (e.g., semiconductor and nanotechnology labs).
Reminder: to be the most effective, regular filter maintenance and replacement are necessary. These protocols maintain efficiency and prevent particle buildup that could compromise cleanroom integrity.
A well-maintained cleanroom requires frequent, specialized cleaning:
Daily: Wipe down surfaces with cleanroom-approved disinfectants.
Weekly: Vacuum floors with HEPA-filtered vacuums to remove particles.
Monthly: Inspect and replace air filters as needed.
Quarterly: Conduct a full decontamination process, including deep cleaning of walls, floors, and ceiling vents.
Let’s dive in further to ensure you have all of the information you need to keep your cleanroom environment contaminant free – here are our key tips:
Most cleanrooms require a relatively humidity level ranging from 30% - 40% RH with an air temperature of 21°C (or 69.8°F) + 2°C. This is the ideal environment to avoid many negative repercussions such as bacteria growth, corrosion, and static electricity. It is also ideal for employee comfort, which is important. If employees sweat or shiver, they release more particles into the environment.
Some of the most overlooked sources of contamination are common office supplies, such as mouse pads, notebooks, sticky notes, paper, pens, and ID badge holders. You can purchase cleanroom-friendly versions of most supplies. It’s important that these materials remain in your cleanroom. Even moving a pen from an office environment to a cleanroom can cause contamination. It’s also best not to post anything on the walls in cleanrooms, such as sticky notes, which can shed particles.
While the materials you regularly use in your cleanroom may be compliant, the packaging isn’t always. For example, if you order nitrile cleaning gloves that are cleanroom-compliant, the cardboard box that dispenses them probably isn’t, because it could release particulate into the air. The same goes for other cleanroom materials you stock.
Wipes, swabs, and other cleaning supplies should be rated for cleanroom use for your specific ISO Class. Simply using a paper towel or the wrong type of cloth can quickly compromise a cleanroom. And be sure that cleaning equipment, such as brooms and mops, meet the requirements too. You’ll want to keep these supplies in your cleanroom and not use them elsewhere in the facility.
Each spoken word emits particles of saliva. Even though those in cleanrooms often wear masks, they aren’t always 100% effective. By speaking 100 fewer words, such as during a brief conversation, you can avoid emitting approximately 250 extra particles. While talking is often necessary to perform tasks, avoiding unnecessary speaking can help avoid possible contamination.
While procedures often cover standards for personal hygiene, it’s important that cleanroom workers avoid make-up, perfume and jewelry, which are potential contaminants. Items that are often commonplace in the workplace, such as food, beverages, candy, or gum, should not be brought into the cleanroom.
It’s best to have any smoking areas at least 100 feet from your cleanroom entrances. And some cleanroom documentation requires that employees take a complete shower after smoking and before entering the cleanroom due to the potential of contamination.
Because gravity pulls particulates downward, it’s best to dress in protective gear from top to bottom. This will help prevent contaminants from falling onto clean areas of the garment.
Most contaminants or particles found in cleanrooms come from the people who enter it. But with the proper precautions that consider everyday objects and behavior, you can help protect your critical cleanroom environment.
Not all cleaning tools are safe for cleanroom use. The wrong materials can shed fibers, introduce chemicals, or fail to remove contaminants properly.
The best tools for cleanroom maintenance include:
HEPA or ULPA Air Filters
Isopropyl Alcohol (IPA) or Hydrogen Peroxide-Based Cleaners
Anti-Static Cleanroom Mops & Brooms
Lint-Free Wipes & Swabs (such as Puritan’s Cleanroom-Approved Swabs)
In controlled environments, precision is critical. Puritan’s cleanroom and industrial swabs are manufactured in an ISO 13485 certified facility, ensuring top-tier quality for your end product. Whether you're in precision manufacturing, fiber optics, electronics, or biotechnology, you can trust that you'll have the right swab for the job. Beyond foam, cotton, and knitted polyester, we offer ESD-safe, anti-static, and chemical-resistant swabs designed to meet the highest industry standards.
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