Depending on your unique application and ISO classification requirements, your cleanroom filters’ maintenance schedule and routine may look a bit different than others’. In this article, let’s take a look specifically at when and how to replace aerospace cleanroom filters. 

What Are Aerospace Cleanroom Filters?

Aerospace cleanroom filters are used to effectively and efficiently maintain air quality throughout the space, removing various hydrocarbon, silicone, and microbiological contaminants. In most cases, these filters consist of three components: a fan, a pre-filter, and a HEPA or ULPA fan filter unit (FFU) — which all work together to treat the cleanroom so it continuously meets a certain cleanliness level, or ISO classification. There are usually many filters that work together to form a comprehensive filtration system, which is installed in the ceiling grid of the cleanroom. 

Most aerospace cleanrooms require an ISO classification of 7. This means that the maximum allowed number of particles 0.5µm or larger is 352,000. To achieve this, the cleanroom must have 15-20% of ceiling coverage dedicated to filtration and an average air change rate of about 60-90 completed changes per hour. 

However, for some highly sensitive applications like spacecraft hardware and fine electronics, this classification could be lower and more stringent, requiring even more ceiling coverage dedicated to filtration and even faster air change rates. 

How to Replace Aerospace Cleanroom Filters

Regularly inspecting, maintaining, and replacing your aerospace cleanroom’s filters is important in ensuring your cleanroom meets those required levels of cleanliness. If left unchecked and dysfunctional, both your products and your end consumers could suffer dangerous and costly consequences. Here’s how to access and replace aerospace cleanroom filters to ensure optimized, safe operations within your facility. 

Where to Access Aerospace Cleanroom Filters

As mentioned previously, most filters are housed in your cleanroom’s ceiling grid. However, many cleanroom manufacturers (like us at Angstrom Technology) want to make accessing and replacing cleanroom filters as simple as possible — and climbing up a ladder to breach the ceiling isn’t all that easy. 

Therefore, these manufacturers will instead separate the prefilter from the FFU housing and place it in a low wall grille near the floor where it’s more accessible. This way, the ceiling doesn’t need to be regularly accessed and the cleanroom doesn’t need to be recertified with each prefilter replacement. 

How Often Aerospace Cleanroom Filters Should Be Replaced

Each part of your aerospace cleanroom filter requires maintenance and replacement at different times. 

Pre-filters are the outermost filters, and are therefore exposed to the most contaminants. On average, they’ll need to be replaced six times per year. It’s important to stick to this schedule so that your innermost (and most expensive) filter, the HEPA/ULPA filter, is kept safe for longer periods of time. 

Since they are the innermost filters, HEPA and ULPA filters don’t need to be replaced as often as pre-filters. With proper prefilter maintenance, they usually have a lifespan between 7-10 years. However, it’s important to check them more regularly than that to ensure they are in fact functioning properly. 

It’s also important to note that your aerospace cleanroom’s location can affect how often your filters need to be replaced. If your facility is located in an area that experiences more air pollution or contaminants (e.g. next to a railroad track or factory), your cleanroom filters may require more frequent inspections and replacements. 

Trust a Professional to Replace Your Aerospace Cleanroom Filters

Hiring a professional to inspect, service, and replace your aerospace cleanroom filters can bring many benefits to your facility. They’ll have the knowledge and experience needed to ensure your equipment meets stringent ISO standards, and they’ll help you maintain a consistent maintenance schedule — leaving you with a few less things to worry about. 

Looking for someone to service your aerospace cleanroom and get it back in top shape? The experts at Angstrom Technology can help! We’d be happy to put you on our schedule for filter replacement, HVAC upgrades, and more. Contact us for more information. 

Materials, equipment, and processes within aerospace cleanrooms make them more likely to generate static charges, as well as more vulnerable to the effects of static electricity. Metallic materials used to produce aircraft and spacecraft and their components can carry electrostatic charges, but even cleanroom-grade materials that aren’t metallic, such as vinyl or plastic, can generate static electricity.

Managing Static Electricity in Aerospace Cleanrooms

Managing electricity generated by static or other causes is essential for aerospace and defense cleanrooms that work with electronics, sensitive hardware, or unstable compounds. Particularly in aerospace cleanrooms, precautions must be taken to: 

• Prevent the buildup of charges could attract contaminants to adhere to the surface of hardware, causing them to fail.
• Limit the chance of sparks which could ignite flammable materials and hazardous substances within the cleanroom.
• Protect personnel from electrostatic charges which could cause injury or spontaneous muscle movement which could cause damage to themselves, the cleanroom and its products, or others. 

Static control measures can prevent or reduce the severity of hazards that result from static electricity as well as protect sensitive equipment. Using the right materials to manage static charges and allow excess electrons to flow safely to ground can make your aerospace cleanroom safer for your work and your workers.

Dissipative, Insulative, and Conductive vs. Anti-Static Cleanrooms

When it comes to managing static electricity in aerospace cleanrooms, there are a few key terms to know: conductive, anti-static, static dissipative, and insulative. All of these materials interact with static electricity in different ways, which makes them more suitable for some applications over others. Let’s break down each of these static control materials.

Dissipative Cleanroom Materials

Dissipative cleanroom materials are more resistant to the flow of electrons. They allow static charges to travel to ground in a more controlled manner than conductive materials.

Insulative Cleanroom Materials

Insulative cleanroom materials are very resistant to flowing electrons. Not only are these materials difficult to ground, but they can also retain static charges.

Conductive Cleanroom Materials

Conductive cleanroom materials allow electrons to flow easily. They’re used to direct static charges to ground and away from sensitive products, hardware, or substances. The conductive materials themselves must only generate very low charges.

Anti-Static Cleanroom Materials

Anti-static cleanroom materials prevent the buildup of static electricity altogether. Anti-static materials are typically treated with a coating to reduce or remove static charges.

Conductive vs. Antistatic: Which is Better for Aerospace Cleanrooms?

The best materials to use in aerospace cleanrooms for static control are conductive or static dissipative materials like stainless steel, carbon, or hard plastics filled with metal fibers. A grounded copper bar placed around the perimeter of the cleanroom, three feet above the floor, is a common solution.

All materials used to control static in aerospace cleanrooms must be low-outgassing and non-particle shedding. They must not transfer any films or particles that could contaminate sensitive hardware or equipment, which means materials treated with anti-static coatings are also likely unsuitable.

Get Professional Help Managing Static In Your Cleanroom

Not sure if conductive or antistatic is better for your cleanroom? Angstrom Technology’s cleanroom design experts can help you determine the best materials and systems to use for your application. Simply give us a call to get started!

Aerospace cleanrooms are vital for the development, manufacturing, and testing of aircraft and spacecraft, and the computer systems, sensors, and defense technology they incorporate.

Any inconsistency in the controlled environment, such as contaminating particles or fluctuations in humidity, could compromise a piece of equipment or product and lead to failure or injury — neither of which help the facility advance its goals. In order to meet the stringent requirements of their cleanroom classifications, aerospace cleanrooms require the seamless integration of multiple systems and components. 

What’s in an aerospace cleanroom? Let’s break it down.

What’s in an Aerospace Cleanroom?

Aerospace cleanrooms are more than just a space to conduct work, research, or testing. They are designed and built to use multiple systems and features to control the environment’s temperature, humidity, purity, pressure, and more. Let’s go through what aerospace cleanrooms need in terms of filtration, HVAC, wall materials, lighting, flooring, furniture and equipment.  

Aerospace Cleanroom Filtration

Aerospace cleanroom filtration is essential for reaching your aerospace cleanroom classification standards. Many aerospace cleanrooms fall into ISO 14644-1 Class 7 or lower, meaning they have defined maximum particle allowances during operation. Multi-stage HEPA filters work hard to help purify the air of contaminants, aided by pre-filters and a laminar airflow pattern. 

When designing your aerospace cleanroom, you’ll want to plan the ideal path for the air to flow to remove particles and clean the air thoroughly and consistently. Depending on your cleanroom classification, your hourly air change rate will rise with the demand for cleanliness.

Aerospace Cleanroom HVAC

A powerful aerospace cleanroom HVAC is responsible for supplying the space with treated air, purified by your filtration system. Aerospace cleanrooms, especially sensitive applications, require controlled temperature and humidity levels in order to prevent corruption of materials, fuels, or processes. 

Aerospace Cleanroom Walls

Aerospace cleanrooms are typically modular HardWall or RigidWall cleanrooms. While both options may reach your cleanroom classification, one may be better suited for your application. HardWall aerospace cleanrooms can reach any standard, even the most restrictive Class 1. They can also be customized to include any special features your cleanroom needs to succeed, and arrive pre-wired and pre-insulated for convenience.

RigidWall aerospace cleanrooms are best for ISO Classes 5-8. They feature crystal clear panels that make an attractive, minimalist frame — perfect for showing your work to executives or investors. An advantage of RigidWall cleanrooms is they are easy to reconfigure and expand as your project evolves.

Aerospace Cleanroom Flooring

When choosing cleanroom flooring for an aerospace cleanroom, it’s important to consider how you’re using the space. For example,  epoxy or urethane flooring is a low-cost option that can also be antistatic — essential if you’re working with fine electronics. 

Vinyl flooring is another economic choice, but it may wear out quickly if you move a lot of heavy equipment through the space. Epoxy and polyurethane floor systems are more durable in heavy traffic areas and resistant to corrosive chemicals and fuels.

Aerospace Cleanroom Lighting

Aerospace cleanroom lighting is another important system. Many options exist to give you the best visibility for your space and classification. Common aerospace cleanroom lighting systems include teardrop lighting, flat panels, LED grid lighting, and recessed lighting. 

If your cleanroom ceiling must prioritize filter/fan units, a smaller but powerful option such as LED grid lighting may be better for you. If you have space to spare, you can opt for the more economical flat panel lighting.

Aerospace Cleanroom Furniture

Cleanroom furniture for aerospace cleanrooms can provide your employees with a workstation, an ergonomic place to sit while they focus on detailed tasks, and anti-fatigue mats for long periods of standing work. The best cleanroom furniture will be adjustable, easy to clean, and made from non particle shedding materials.

Other Aerospace Cleanroom Design Features

Other cleanroom systems, industry-specific equipment, and cleanroom supplies may be necessary to help your aerospace cleanroom be successful. A few examples include a pressurization system, antistatic materials, and a fire suppression system:

• Positive pressure in aerospace cleanrooms can be a useful way to supplement your filtration system by blocking contaminating particles. 
• Antistatic cleanroom supplies and materials are essential if you deal with sensitive materials, flammable substances, or fine electronics. 
• A fire suppression system can help limit damage if something does go wrong, and protects your employees from workplace hazards.

Is your aerospace cleanroom missing something? Talk to Angstrom Technology. We have everything you need to build and run a high-performing cleanroom environment. From modular panels to flooring, lighting, furniture and more, Angstrom Technology is fully equipped to make your cleanroom a success. Give us a call to learn more.

Cleanroom construction can be complex, and involves a lot of planning, questioning, and thought. Here are 5 common questions about cleanroom construction, answered. For any others, reach out to your local cleanroom experts!

How much space does an aerospace cleanroom take up?

The size of your aerospace cleanroom matters, so it’s always best to work with an experienced cleanroom designer to develop the ideal cleanroom to meet your desired footprint. Aerospace cleanrooms will need as much space as it takes to comfortably contain your equipment, personnel, and cleanroom systems, but they shouldn’t be built bigger than necessary, as this creates more air that needs to be filtered and controlled, increasing energy expenditures and costs for your business.

If you are concerned you don’t have enough space to build your new cleanroom, know that some cleanroom types, like SoftWall cleanrooms, are ideal in condensed spaces. Their flexible, lightweight construction means they can be put almost anywhere, and easily expanded, reconfigured, or picked up and transported to a new location if your project needs change.

Can I build a cleanroom in my existing building?

You absolutely can, as long as the space meets your cleanroom size and height requirements and is accessible for cleanroom construction. 

Cleanrooms can be built in a wide range of spaces, and will take up as much or little space as your project needs demand. They can be designed to be freestanding, connected to existing walls, or suspended from a reinforced ceiling grid, so where you install your cleanroom is up to you.

Cleanrooms built in existing structures might be able to integrate with the building’s own HVAC system or use light from existing windows. Talk to your cleanroom designer about how your unique space could align with the needs of your cleanroom.

How long does cleanroom construction take?

Cleanroom construction times vary depending on the size of your facility and the customizations you need to make your cleanroom design a success. However, building a cleanroom using modular cleanroom panels can reduce this time significantly.

Also, some cleanroom types, such as SoftWall cleanrooms, may only take a day or two to complete, where a HardWall aerospace cleanroom that needs to meet an ISO Class 5 or lower classification may take longer to design and install. Your cleanroom design expert can help you understand how long the total cleanroom construction will take, depending on the specifications of your project.

Cleanroom Construction Process

The majority of the time building a cleanroom is spent planning and designing the cleanroom to meet your project needs. Considering your aerospace cleanroom classification and other requirements specific to your application, a cleanroom designer will create a comprehensive plan for your new cleanroom, considering the ideal layout, airflow pattern, and combination of materials that will offer the best performance over its lifetime. 

Once the cleanroom design is complete, the modular cleanroom panels are fabricated and delivered to your site. Your cleanroom can be assembled with detailed instructions or with the help of an experienced installation crew to set up your cleanroom so it’s ready to operate. 

What components do I need in my aerospace cleanroom?

Every aerospace cleanroom will look a bit different, depending on the work that you do. Typically, however, most cleanrooms contain the same basic components: cleanroom wall panels, a cleanroom HVAC system, and the filtration system. You’ll also have things like lighting, windows and pass throughs, flooring, and furniture, but the main three deserve the most attention.

Aerospace Cleanroom Wall Panels

The modular cleanroom panels that make up the structure of your aerospace cleanroom do more than just define the space. They are also customized and outfitted with wiring, insulation, and any other features that your application demands. Modular cleanroom panels cut the cleanroom construction down considerably, and allow you to have a specialized facility designed uniquely for your work.

Aerospace Cleanroom HVAC

Any top performing aerospace cleanroom will need a powerful cleanroom HVAC system to move and treat air within the controlled environment. Depending on your aerospace cleanroom classification and other industry-specific requirements, you may have very strict standards to reach for air temperature, humidity, and pressure. The cleanroom HVAC system is responsible for keeping your employees comfortable and their work safe.

Aerospace Cleanroom Filtration

Proper cleanroom filtration is vital to achieving optimal control over the air quality within your cleanroom, and essential for reaching stringent cleanroom classifications. You’ll likely address filtration by installing powerful filter/fan units, or FFUs, in the ceiling grid of your aerospace cleanroom. Combined with an expertly designed airflow pattern, your cleanroom filtration system should be more than capable of removing large numbers of particles of various sizes from the air. With many, many air changes per hour, you can reach the acceptable particle count designated by your ISO Class.

Beyond those, you’ll need to account for your industry-specific equipment, personnel, and ample space for both to move around. If you work with oversized components, make sure to include plenty of space in your cleanroom design for things to be maneuvered without creating more obstacles in your cleanroom. Non standard ceiling heights, as well as oversized windows and doors can help you accommodate everything you need, safe and sound.

How clean does my aerospace cleanroom need to be?

Understanding cleanroom classifications can be complicated. The International Standards Organization publishes documents that define the levels of cleanliness required for different Classes of cleanrooms, 1-9, where Class 1 is the cleanest possible environment and Class 9 is equivalent to room air. Many aerospace cleanrooms are at a minimum ISO 14644-1 Class 7. Your aerospace cleanroom classifications will vary depending on your application and could include other industry-specific standards, such as ASTM International or NASA.

Depending on your Class standards, your aerospace cleanroom will need to achieve a certain level of cleanliness defined by particle count, air changes, and ceiling coverage. To help you design a cleanroom that meets all your requirements, talk to an expert cleanroom designer.

Have more questions about designing and building a cleanroom for your space? Give the experts at Angstrom Technology a call! We’d be happy to walk through your specific requirements and help you get the best cleanroom installed in your space.

Aerospace & Defense cleanroom classifications regulate a cleanroom’s degree of cleanliness and are defined by the allowed amount of contamination by particle count and size, as well as the necessary air change rates depending on the cleanroom’s classification level. Aerospace and defense cleanrooms are typically regulated by the classification standards of two major organizations: The International Standards Organization (ISO) and the American Society for Testing and Materials (ASTM).

ISO Cleanroom Classifications for Aerospace and Defense Cleanrooms

The International Standards Organization developed the set of standards by which all cleanroom industries and applications must follow. ISO 14644-1 outlines the requirements for all cleanroom environments.

ISO 14644-1

ISO 14644-1 describes cleanroom cleanliness levels in terms of Classes 1-9, where Class 9 is equivalent to the cleanliness of room air and Class 1 represents the cleanest possible cleanroom environment. As the classification number falls, cleanrooms must comply with stricter standards to reach a cleaner, more controlled environment. The majority of aerospace and defense cleanrooms fall within ISO Classes 7-8, although some sensitive applications, such as the development of microchips or sensors may be governed by stricter classifications.

Understanding ISO Aerospace Cleanroom Classifications

ISO 14644-1 outlines cleanliness standards for aerospace and defense cleanrooms by determining the allowed contamination levels in each ISO class in terms of air particle size and count, air change rates or airflow velocity, and percentage of ceiling coverage for filtration. 

• Particle Count: Particle count refers to the number of particles of a certain size per cubic meter. Stricter ISO classes allow fewer particles, and also restrict the size of those particles. 
• Air Change Rate: The air change rate at is how quickly air is removed, filtered, and replaced within your cleanroom. 
• Ceiling Coverage: Ceiling coverage refers to the percentage of ceiling coverage for HEPA filter/fan units, or FFUs. 

Understanding the way these elements affect the cleanliness of your facility is the key to designing a successful cleanroom.

ASTM Standards for Aerospace & Defense Cleanrooms

American Society for Testing and Materials (ASTM) has also developed a set of International Standards, which test the cleanroom’s ability to limit contamination through the restriction of allowed particles in the cleanroom environment. They also deal with the more technical aspects of aerospace and defense applications, including the cleanroom’s ability to control mechanical, thermal, chemical, and electrical properties within the controlled environment.

Aerospace cleanrooms must comply with ASTM relevant to their application and use of materials. This could include regulation for the handling and disposal of combustible fuels, static control systems, and even processes for parts manufacturing. More extreme standards apply for highly sensitive applications, where airborne particle concentrations must be strictly controlled such as in the development of spacecraft hardware, fine electronics, or optical devices.

Blending Aerospace Cleanroom Classification Standards

Some aerospace and defense cleanrooms must be able to comply with different classifications for the different tasks or projects, or different stages within the same project, such as from manufacturing to assembly to packaging. 

Aerospace and defense cleanrooms need to be able to adapt to the circumstances of your work, and have everything necessary to evolve with project requirements and keep products and workers safe. This includes highly specific control over environmental factors and filtration needs, monitoring equipment to maintain strict particle count and temperature ranges, and proper solutions for supporting or storing equipment to effectively utilize the facility’s space.

Aerospace and Defense Cleanroom Design

Aerospace and defense cleanrooms require active filtration and complete control over temperature and humidity, as well as other environmental factors. The cleanroom design should address the three main areas of concern to reach strict aerospace cleanroom classifications:

• Particle count: Aerospace cleanroom design should include a special airflow pattern that makes use of filters in the most efficient and effective way possible to trap and remove particles, and replace the air in the room with air that is fresh and contaminant-free.
• Air change rate: While less stringent aerospace and defense applications may only require an air change rate of 5-48, defense cleanrooms with strict air quality standards may require hundreds of air changes per hour. In these cases, it’s expressed as air velocity, because air is constantly moving as it’s filtered out and replaced.
• Ceiling coverage: The more stringent your aerospace cleanroom classifications, the higher percentage of ceiling coverage required to filter air properly. Ceiling fan coverage is closely related to air change rate, as more FFUs are necessary to complete more air changes.

Modular Cleanroom Design for Aerospace and Defense Cleanrooms

Modular cleanrooms are ideal for the aerospace and defense industries — particularly applications with changing requirements as they can meet the needs of customized spaces, including those with oversized equipment and products. The two main types of cleanrooms used for aerospace and defense applications are HardWall cleanrooms and RigidWall cleanrooms.

• HardWall cleanrooms are the most common type of cleanroom used in aerospace and defense applications, as they offer a high level of control over environmental factors, so they can easily reach with the strictest aerospace cleanroom classifications. 
• RigidWall cleanrooms can also provide a suitable environment for aerospace and defense applications and can reach a variety of aerospace cleanroom classifications. They consist of clear panels that can easily be reconfigured as you need to make changes to the layout of your cleanroom, and offer many customization options.

Aerospace and defense cleanroom design should also include a powerful HVAC system as well as cleanroom lighting that integrates seamlessly with modular panels and facilitates proper airflow velocity. Additional features and cleanroom supplies can be added to customize the cleanroom to specific applications. Some of these additions might include air showers, a fire suppression system, laminar flow systems, and industry-specific equipment and furniture.

Aerospace cleanroom classification requirements can be complicated and difficult to reach without the right cleanroom design. When it comes to aerospace cleanroom design, you can trust Angstrom Technology to design, build, and install the best cleanroom for your unique application and classification. To get started, reach out to our professional design team today.