What should be checked first when upgrading the cleanliness of an old workshop?

When upgrading the cleanliness of an old workshop, the most fearful thing is 'adding equipment according to grade first'. Old diagrams may not reflect workstation relocations, new heat sources, or exhaust changes, and the original system may not have margins. If the current status baseline is not established first, it is easy to have equipment installed and air volume increased, but particles at key workstations still exceed the standard.

A more reasonable sequence is: first measure the current situation and locate the source of pollution, then review the air return and filter sealing, and finally evaluate the carrying capacity of the original system and decide on the transformation plan. Let’s start with several practical aspects.

Establish a baseline of the current situation first, don’t just stick to the old diagram

Old drawings and old acceptance reports can only be used as reference and cannot be directly used as the basis for transformation. The workshop may have added equipment, changed workstations, changed the exhaust, or even changed the number of personnel and material routes. These changes directly affect particle loading and airflow organization.

It is recommended to record under actual production conditions: wind speed at key locations, room pressure difference, filter pressure difference, particle trends, personnel activities and material entry and exit frequency. If you are not sure whether to renovate the whole room or upgrade part of it, you can first look at How to choose between whole room purification and partial purification ? Clarify the selection logic at the program level before entering into specific inspections.

If the old workshop was originally an ordinary factory building, but FFU was added later, you need to first confirm whether it has the basic conditions for a clean workshop. Can refer to Can an ordinary factory building become a clean workshop by installing FFU? , avoid treating local air supply as whole room purification.

Verify source of particles and location of contamination

Excessive particles do not necessarily mean filter failure. Contamination may come from new personnel, unpacking processes, institutional dust generation, exhaust backflow or sealed bypasses. First record the time, location and action correlation of the abnormality, and then distinguish whether it is a sustained high or a short-term peak.

If particles appear only after mechanical action, priority should be given to checking equipment dust production and local occlusion, rather than directly increasing the number of FFU. If there are spikes when doors are opened or people enter, check differential pressure and inlet airflow. For specific investigation methods, please refer to How to distinguish external and internal contamination when particles exceed the standard?。

Double check the air return and filter sealing

The return and return air paths in older workshops may have been altered by equipment, racking, or piping. It is necessary to measure the air volume, wind speed and pressure difference in key areas to confirm whether the air passes through the workstation as expected. If the return air outlet is blocked, the supply air is short-circuited, or the exhaust air suction is too strong, the total air volume will appear to be sufficient, but the workstation protection will be insufficient.

Filter seals should also be inspected individually. A leaky filter frame, installation of a bypass, or a damaged filter element may allow unfiltered air to enter the clean side. Upgrading to a higher efficiency filter may not necessarily solve the problem at this time. Regarding the relationship between filtration efficiency and on-site grade, please refer to What is the difference between cleanliness level and filtration efficiency?。

If you find that the filter resistance is abnormal or the pressure difference is low, you should check whether it is damaged or bypassed, rather than just looking at the usage time. For more maintenance judgment, please refer to What are the initial resistance and final resistance used to judge?。

Check personnel material routing and contamination input

When upgrading an old workshop, the frequency of personnel changing clothes, material unpacking, turnover containers, and door opening may all change. If these inputs are not controlled, simply adding air supply equipment will have limited effect.

It is recommended to mark the personnel entrance, material entrance and high dust-producing processes on the floor plan, and check whether they are located upstream of the clean protection zone. If necessary, adjust logistics routes or increase local isolation instead of blindly increasing the number of air changes in the entire room.

Assess the original system margin: power distribution, ceiling, return air

Adding FFU or replacing filters will involve power distribution capacity, ceiling load, and return air paths. The ceiling of the old workshop may not have enough load-bearing capacity, and the return air channel may also be occupied by later pipelines. If you only count the number of devices and do not consider these conditions, it may be impossible to debug or difficult to maintain after installation.

Insufficient maintenance access will increase the cost of later disassembly, shutdown isolation and structural modifications. This is because what later expenses will be increased due to insufficient maintenance channels . There is a more detailed analysis of During the selection stage, the filter replacement path, wiring maintenance space, and ceiling support method should be confirmed.

Formulate a transformation plan: first locate the restrictive links

Based on the current situation records, distinguish whether the limiting link is insufficient air supply, increased pollution, bypass leakage, or air flow short circuit. Then decide whether to add equipment, improve airflow, upgrade filtration or adjust the process layout.

When selecting equipment, please refer to the background air supply of the room. FFU clean air supply products , please refer to the local protection of the equipment side. EFU equipment side fan filter unit . The logic of division of labor between the two lies in The division of labor between device-side EFU and room FFU is explained in detail. If zone duty and troubleshooting are required, they can be combined FFU group control system provides unified management.

Filter selection should correspond to target particle size and actual resistance.The HEPA and ULPA filter pages have parameters for different levels of products. When selecting, check the efficiency of the specific model at the target air volume.

Arrange construction isolation and stage commissioning

Renovation of old workshops usually cannot completely stop production. It is necessary to plan construction isolation, temporary air supply, stage debugging and recovery verification to avoid construction dust and air cessation from affecting normal production. After the transformation is completed, the air volume, pressure difference and particles at key stations should be re-measured under actual operating conditions.

If the project is constructed in phases or requires independent modules, please refer to What are the expansion conditions for using independent modules in clean systems? , reserve allowances for power distribution, communications, structural loads and wind paths in advance.

Project judgment example

The particles in an old workshop exceeded the standard, and the original plan was to add a batch of FFU. After investigation, it was found that the main pollution came from the frequent unpacking process, and the return air outlet was blocked by packaging boxes. Adjustment method: Move the unpacking area out of the clean area, clean the return air channel, and then add local protection to key workstations. After the transformation, the particle size dropped significantly without a large increase in FFU.

In another project, the old ceiling did not have sufficient load-bearing capacity and the original model FFU could not be directly installed. Adjustment method: Switch to lightweight models and disperse them, and check the return air path and power distribution capacity. After installation, the system is stable and maintenance access is preserved.

These two situations illustrate that when upgrading an old workshop, it is more effective to check the current situation and restrictions first than to directly add equipment according to grade.

Key points for selection and acceptance inspection

Aili industrial equipment supporting support

Aili Industry covers motor manufacturing, independent research and development and production of fans, control system development, sheet metal processing, air filter manufacturing and complete machine assembly. For old workshop upgrade projects, FFU, EFU, HEPA/ULPA filters, group control systems, air volume, static pressure, and installation interfaces can be uniformly checked to connect equipment configuration with on-site evaluation boundaries and reduce the disconnect between component parameters and complete machine operating conditions.

learn FFU clean air supply products；EFU equipment side fan filter unit；HEPA and ULPA filters；FFU group control system checks the installation space, operating conditions and filtered air supply configuration.

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