Is chemical filter validation required to keep production loads consistent?

Straight answer: You need to keep it comparable, or at least keep the differences clearly documented. The outlet concentration of a chemical filter is not only affected by the filter itself, but also by the inlet load, air volume, production status and temperature and humidity conditions. If the production load changes before and after validation, the changes in export data cannot be entirely attributed to the filter. Writing down the load differences and analyzing them on a case-by-case basis is more reliable than lumping them all together to make a judgment.

Identify which loads are important

Chemical filters deal with gaseous pollutants, and the size of the inlet load directly affects the outlet concentration. In production load, factors related to gas release mainly include:

Amounts of materials used and how they are used. Increased use of cleaning agents, solvents, and adhesives, or changes from closed operations to open operations, will increase the gaseous pollution load in the air.

Yield and run time. Increased production and longer shifts mean equipment is running longer and total releases may increase.

Process status. The release characteristics may be different during process stages such as equipment startup and shutdown, heating, and curing. For example, temperature changes in the heating process will affect the volatilization rate.

Ventilation and exhaust conditions. Turning on or off local exhaust and adjusting the proportion of fresh air will change the concentration of pollutants in the air.

If any of these factors changes, the inlet concentration may change. The outlet concentration changes accordingly, which does not necessarily mean that the filter performance has changed. Before verification, these conditions should be listed to confirm which ones will change and which ones will remain consistent. If consistency is not possible, the actual status needs to be recorded. For relevant investigation methods, please refer to whether to do air sampling before choosing a chemical filter . Discuss

Compare entrance control

Even if the production status looks similar, the inlet concentration may not be completely stable. During validation, it is recommended to record both inlet and outlet concentrations.

The inlet concentration is the direct basis for judging the load. If the inlet concentration increases, the outlet concentration may increase, but the removal efficiency does not necessarily decrease. It is easy to misjudge if you only look at the outlet concentration.

The inlet and outlet should be sampled in pairs. The sampling time, sampling method and detection caliber should be as consistent as possible. Synchronized or time-matched sampling is particularly important when inlet fluctuations are significant. For specific methods, please refer to Discussion on whether the concentration before and after the chemical filter should be measured at the same time .

Record environmental conditions. Temperature, humidity, and air volume data should be recorded together with concentration data. These conditions will affect the adsorption or reaction process and are the basis for subsequent analysis.

Allow evaluation based on working conditions

If the production load cannot be kept consistent during the verification period, verification can be carried out separately according to different working conditions instead of mixing all the data together and averaging.

Group by production status. For example, standby, normal production, cleaning and maintenance are each regarded as one working condition. Record the inlet and outlet concentration, air volume and operating time under each working condition respectively.

Explain each set of conditions. Each set of data should correspond to clear production status, material usage and ventilation conditions. The efficiency of one group cannot be used to represent another group.

Avoid simple averaging. Directly averaging the results of standby, low load, and full load will conceal the actual difference. They should be listed separately to determine whether the filters can meet the requirements under different working conditions. For specific trial plan settings, please refer to Discussion of how to set clear success conditions for chemical filter trials .

Pay attention to the most adverse working conditions. The purpose of verification is to confirm whether the filter is effective in actual operation. If the outlet concentration exceeds the standard under high load conditions, even if the effect is very good at low load, it cannot be considered as overall compliance.

Additional considerations during verification

Don't change multiple conditions at the same time. If the materials are changed, the air volume is adjusted, and the shift is extended during the verification period, the reasons for the change in outlet concentration cannot be distinguished. Try to change only one variable at a time, or at least log the changes.

Check the sealing condition. When verification data is abnormal, first confirm whether the filter installation seal is normal. Frame bypass allows untreated air to bypass the filter material, affecting the outlet concentration. For specific inspection methods, please refer to Discussion on how to check frame bypass after chemical filter installation .

Distinguish between filter consumption and load changes. If the inlet concentration is stable and the outlet concentration gradually increases, it may be media consumption. If the inlet concentration and outlet concentration fluctuate simultaneously, it is more likely that the production load is changing. For specific life assessment, please refer to Discussion of how long chemical filters last .

Document replacement and maintenance operations. If the filter material is replaced or maintenance is performed during the verification period, the time and content should be recorded to facilitate subsequent analysis of the reasons for data changes.

Project judgment example

During the verification of the chemical filter of a certain project, the outlet concentration fluctuated greatly. The preliminary judgment is that the filter performance is unstable.

The verification found that during the verification period, the production shift was changed from one shift to two shifts, the usage of materials increased, and the inlet concentration also increased accordingly. The increase in outlet concentration is synchronized with the increase in inlet load, and the removal efficiency does not decrease significantly. After recording the production load differences and analyzing them in groups, it was confirmed that the filter can meet the requirements under different working conditions and there is no need to replace the media.

Another project changed cleaning agents before and after verification, but this was not documented. After the outlet concentration changed, the investigation direction was once biased towards the filter. Later, additional material change information was recorded, and it was found that changes in outlet concentration were related to changes in cleaning agent composition.

These two cases illustrate that production load information during the verification period is the basis for interpreting export data. involving When selecting chemical filter product series , it is recommended to provide the production status, inlet load and testing data to the supplier for verification.

Key points for selection and acceptance inspection

About Aili Industrial’s verification package

Aili Industrial has independent manufacturing capabilities in filters, motors, fans, control systems and sheet metal processing, and can provide chemical filter product series and supporting air supply equipment. For projects that need to verify the filtration effect, we can assist in checking the verification plan and product configuration based on the production load, inlet concentration, system conditions and testing requirements. filter with MAU box chemical filter、When the FFU is equipped with chemical filters and other equipment, the location and maintenance method of the sampling port can be confirmed uniformly.

Related products:Chemical filter product series、MAU box chemical filter、FFU comes with chemical filter . Providing production status, inlet load and testing requirements when inquiring can help confirm the appropriate solution. The specific selection is subject to the technical documents and test results confirmed by the project.