How to configure ULPA in ISO 1 to ISO 3 clean rooms?

ISO 1, ISO 2, and ISO 3 are levels with higher cleanliness requirements, and the allowed particle concentration is very low. To meet the standards, it is not something that can be solved by choosing a high-grade filter element.

Projects at these levels usually require filtration, sealing, air flow organization and pollution management to be designed as a system. If any link is not in place, no matter how high the grade of the terminal filter element is, it cannot be repaired.

First clarify the measurement goals and status

The acceptance of ISO 1 to ISO 3 has more detailed test conditions than general clean rooms.

Particle size and concentration : The allowable number of particles corresponding to different grades is different. The specific values ​​must be checked according to the ISO 14644 version adopted by the project.

Sampling location and quantity : The distribution of measuring points must be able to represent the actual situation of the protected area and cannot just measure a few convenient locations.

Running state : static, dynamic or empty? Results can vary significantly between states. Dust production during operation of process equipment and the impact of personnel operations must be explained in the test plan.

The scope of the protected area : is it the entire room or the microenvironment inside the device? Depending on the scope, the way the system is designed and verified is also different. Industry data also points out that cleanliness is subject to actual measurements, and estimates of air changes are only for reference.

Only when these conditions are clear can we know what goals the system needs to achieve, and only then can we determine where and at what level ULPA needs to be configured.

In addition to filtering performance, there are a few things to do

Seal integrity. Projects from ISO 1 to ISO 3 are highly sensitive to local leakage. A tiny bypass leak may cause the particle concentration to exceed the standard locally. The installation and sealing of the end filter, box joints, and pipeline connections all require strict leak detection and verification. The liquid tank sealing structure requires high matching accuracy. Please refer to the relevant instructions for specific verification methods.

Airflow organization. Whether the air supply surface coverage is complete, whether the air flow is uniform, and whether there are short circuits or eddy currents in the return air path directly affect whether particles can be effectively taken away. High-grade clean rooms usually adopt unidirectional flow design, and the wind speed and uniformity need to be confirmed by actual measurement.

Pollution source control. Moving parts of equipment, personnel operations, and material entry and exit may all produce particles in the protected area. Even if the air sent in is qualified, local dust production may cause the concentration to exceed the standard. Such problems need to be managed through equipment design, operating specifications or local exhaust, and cannot be solved by increasing the filtration level.

Pressure differential and air flow direction. The pressure difference relationship between adjacent areas and the flow direction of air flow from clean area to non-clean area need to be confirmed according to project requirements. These parameters influence the possibility of entry of external contamination.

Where is ULPA configured?

Whole room solution : Use ULPA as terminal filtration in a large area, combined with full or high coverage air supply design. This solution has very high requirements for air volume, static pressure and air flow organization, and the system design requires overall accounting.

Local micro-environment solution : ULPA is only configured inside key workstations or equipment, and the surrounding areas are treated by lower-level filtration or systems. The focus of such programs is on the definition of protection scope and border control. Device-side applications such as EFU equipment-side fan filter unit , the filter element must be designed together with the equipment structure and air flow path.

Hybrid solution : Use HEPA or lower grade ULPA for the entire room to provide a basic environment, and use higher grade ULPA for local reinforcement in key locations.

Which solution is suitable depends on process requirements, equipment conditions and investment budget. It's not that the higher the level, the better, but the more accurate the match, the better.

Verification must be performed step by step

The verification of high-level cleanliness projects is usually divided into several levels.

Finished product testing : The efficiency, resistance and integrity of the filter itself, supported by reports for the corresponding model.

Installation leak detection : the sealing status after installation, including the filter element and frame, box joints, and pipeline connections. involving For HEPA/ULPA air filter products of different grades, the testing methods and criteria are implemented in accordance with corresponding standards.

Airflow measurement : wind speed, air volume, uniformity and flow pattern to confirm compliance with design requirements.

Regional particle testing : measure the particle concentration in the protected area according to the agreed status, measuring points and sampling plan.

Each of these items has its own role and cannot be substituted for each other. Records should be retained as a baseline for subsequent re-inspections and operations. Supporting FFU fan filter unit system, the corresponding relationship between unit parameters and single unit data must also be recorded.

Project judgment example

A piece of equipment needs to control the particle concentration of the internal microenvironment, with a target equivalent to ISO level 2.

In this case, first define the protection range within the device, measure the available space and interface conditions, and then determine the air supply method and filtration level. The dust generation points, air flow paths and return air methods inside the equipment all need to be taken into consideration during the planning stage.

If you just apply the clean room grade outside the equipment to the inside of the equipment, or only choose a high-grade filter element to install it, you may not achieve the expected results. The design of the equipment-side microenvironment needs to be considered together with the equipment structure and operating status, and the entire room plan cannot be copied.

Selection and Acceptance Checklist

About Aili Industrial’s high-grade clean facilities

The key to the configuration of ISO 1 to ISO 3 projects is to match the filtration, fans, structure and control under the same conditions.

Aili Industrial's manufacturing system covers filters, motors, fans, control systems and complete machine assembly, and can provide ULPA ultra-high efficiency filter and supporting air supply equipment. For whole room solutions, the filter can be used with FFU fan filter unit matching confirmation; for equipment end micro-environment, it can be combined with the EFU equipment-side fan filter unit . Check the installation space, air volume and interface conditions together with

Provide protection area, particle control target, available space and acceptance method when enquiring, which will help determine the appropriate configuration. Specific performance is subject to product technical data and project acceptance results.