Tag Archive: cleanrooms

  1. The Importance of Differential Pressure in Cleanrooms

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    At Liberty Industries, we serve as a one-stop source for all cleanroom needs. For over six decades, we have supplied superior cleanroom and contamination control supplies to customers across the globe. Equipped with extensive industry experience, our team has the knowledge and skills to design and develop a standard or custom cleanroom solution suitable for any critical environment.

    In the following article, we provide an overview of one of the key operating principles of cleanrooms—differential pressure. We outline what it is, how we measure it, and how it affects other conditions in a cleanroom.

    Differential Pressure in Cleanrooms

    Differential pressure refers to the difference in air pressure from one location to another within a system. In cleanrooms, maintaining the right amount of differential pressure—either positive or negative—is essential to preventing contamination.

    • In positive differential pressure cleanrooms, the internal pressure is greater than the external pressure to prevent the ingress of any contaminants through any opening—whether intended or accidental—in the cleanroom.
    • In negative differential pressure cleanrooms, the external pressure is greater than the internal pressure to prevent the egress of any potentially harmful compounds contained within the cleanroom.

    Combined with appropriate temperature, humidity, and airflow level, proper differential pressure levels ensure both cleanroom designs work as intended. As such, it is essential to carefully measure and monitor pressure inside and outside of the cleanroom to confirm the differential remains within the acceptable range.

    Industry professionals often employ visual gauges or meters to facilitate the identification of current pressure levels inside and outside of cleanrooms. The devices are designed to automatically calculate and output the difference between two pressure points in the cleanroom (typically two inlet points), eliminating the need for operators to manually monitor separate gauges and calculate the difference between the results. More advanced measuring instruments may offer additional capabilities for monitoring temperature, humidity, and other cleanroom parameters.

    At Liberty Industries, we offer Magnehelic gauges for these applications. They provide accurate measurement of pressure, pressure differential, and vacuum to 2% of full scale. In addition to cleanrooms, typical use cases include automatic valves, control equipment, and gas-air ratio controls.

    Cleanroom Standards

    The level of cleanliness required from a cleanroom depends on the industry and industrial application. For this reason, cleanrooms are available in numerous classifications, each of which denotes a specific level attainable based on the number and size of contaminants with the given space.

    The International Organization for Standardization (ISO) categorizes cleanrooms from ISO 1 to ISO 9, with ISO 1 having the fewest contaminants per square meter. In addition to the number of particulates, the size of particulates also plays a crucial role in ISO classification. Contaminants are measured in microns, from 1μm to 5μm, with different cleanrooms offering different filtration capacities for each size. For example, cleanrooms with HEPA filters remove particulates as small as 0.3μm with 99.99% efficiency rates, while cleanrooms with ultra-low particulate filters remove particulates as small as 0.12μm with an efficiency rate of 99.999%.

    The effectiveness of the mechanisms that facilitate cleanroom operations—including the filters—depend on many factors remaining within tolerable levels. These factors include pressure, temperature, humidity, and airflow, all of which can help or hinder the attainment and maintenance of proper cleanliness levels.

    Quality Cleanroom Solutions From Liberty Industries

    Cleanrooms play a critical role in many sensitive industries and industrial applications. For these instruments to work correctly, maintaining proper differential pressures (among other factors) is essential. To learn more about cleanrooms and the role differential pressure plays in their operation, contact us today. For assistance selecting and sourcing a cleanroom solution for your facility, request a quote.

  2. The Advantages of Cleanroom Pass-Thrus

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    Since 1953, Liberty Industries has served as a global manufacturer and distributor of high-quality cleanroom and contamination control supplies and accessories. We offer a broad selection of cleanroom products, ranging from modular, softwall and hardwall cleanrooms to cleanroom components to personnel garments. Regardless of your cleanroom needs, our experienced engineers can design and deliver a custom-tailored solution that meets your specifications.

    Cleanrooms are generally used in the manufacture of sensitive components that cannot tolerate contamination—e.g., medical devices, pharmaceuticals, and electronics. These structures provide control over the workspace, maintaining set levels of temperature, humidity, light, air pressure, and other environmental variables. They can also have additional features, such as sealed airlocks and decontamination areas, that facilitate the maintenance of sterile conditions.

    Pass-thrus—also known as pass-thru cabinets, chambers, or windows—are a critical cleanroom component. These two-door structures are typically installed directly into the cleanroom’s walls and, when opened one door at a time, allow objects to pass into or out of the cleanroom while reducing the risk of contaminants. pass thru for cleanroom

    ​What Are the Benefits of Pass Thrus for Cleanrooms?

    Pass-thrus are an affordable and easy-to-install way to protect the cleanroom environment and meet industry safety standards. In addition to preventing external contaminants from entering the cleanroom, they reduce the number of workers in the room at any given time and limit the frequency of room entries and exits. Both of these things help to further reduce the risk of contamination.

    Integrating a pass-thru also means cleanroom personnel do not need to shower and gown up to place or remove materials from the cleanroom. This saves time and, ultimately can increase productivity.

    Pass-thrus are durable, easy to clean and maintain. Additionally, they are highly customizable, coming in a range of materials, sizes, and designs to meet different cleanroom needs. For example, they are available with fireproofing for combustible material handling and with HEPA air filters for highly sensitive product manufacturing.

    The integration of pass-thrus benefits virtually any industry that requires the use of cleanrooms, including the following:

    • Aerospace
    • Computer manufacturing
    • Electronics and technology
    • Medical
    • Military
    • Pharmaceuticals
    • Research
    • Solar power generation

    ​Types of Pass-Thrus Available at Liberty Industries

    At Liberty Industries, we offer several pass-thru models for cleanroom construction projects, including:

    • Stainless steel pass-thru. Also known as a pass-thru window communicator or package transfer unit, this pass-thru system features stainless steel construction, acrylic doors, and stainless steel hinges. Customization options include interlock systems, fireproof doors, and custom sizes.
    • H-100SS pass-thru with a magnetic lock. This two-door cabinet uses a magnetic interlock system to keep both doors from opening at the same time. It is especially useful for hospital pharmacies and other organizations that require high levels of security.
    • H-100 PL series laminated pass-thru.This pass-thru chamber is made with high-pressure plastic laminate and has an acrylic door with chrome-plated hinges. It provides maximum protection from contamination while still allowing for the easy transfer of materials. Optional add-ons include a reverse-action interlock.
    • Motorized HEPA/ULPA-filtered pass-thru. This pass-thru unit has a high-velocity air wash and highly efficient filter. Custom sizes and filtration levels are available, as well as options for stainless steel shelves, laminated novaply, and fireproof doors. Customers can choose from recirculating or non-recirculating models.

    Partner With Liberty Industries for Your Cleanroom Needs

    Pass-thrus are critical cleanroom components that help keep your cleanroom contaminant-free for sensitive manufacturing operations. With over 65 years of experience designing and constructing cleanrooms, the Liberty Industries team can help you choose the right model and design to suit your cleanroom needs.

    For additional information about pass-thrus or to discuss your cleanroom specifications with one of our experts, contact us or request a quote today.


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