Can ULPA filters capture particles in smoke?

The answer to this question is 'yes', but only answering this half may easily lead to misunderstanding that it can solve all smoke problems.

ULPA deals with the particulate matter in smoke. In addition to particles, smoke often also contains gaseous components, heat and viscous substances. These are not the scope of work of ULPA and need to be dealt with separately. So a more accurate question should be: What is in this smoke, and which part needs to be controlled.

Welding smoke, cutting oil mist, laser processing smoke, volatile smoke from the production of flavors and fragrances - these are all called 'smoke', but the composition is very different and the treatment plans are also different.

Smoke is not a single pollutant

The composition of smoke produced by different processes varies greatly.

Welding fumes : Contains metal oxide particles, flux volatiles, gaseous pollutants, and heat. The particulate part can be filtered, the gaseous part needs special treatment, and when the temperature is too high, it must be cooled down first.

Oil mist : Mainly liquid oil droplets, which are highly viscous and easily adhere to the filter material. For specific processing ideas, please refer to the relevant instructions for pretreatment of oil-containing mist airflow.

Laser processing smoke : The particles are fine and the concentration may be high. The composition is related to the processing materials, and some materials may produce harmful gases.

Volatile smoke : The proportion of gaseous components may be high and the smell is obvious, but the particle concentration is not necessarily high. In this case, ULPA alone has limited effect.

Before selecting a model, it is more important to understand the composition of the smoke than to directly discuss which filter element to use. For airflow with unknown composition, any filtration solution can only be considered a guess.

Several questions that need to be confirmed

When facing smoke-containing airflow, it is recommended to clarify the following things before selecting a model:

What to control. Is it particulates, odors, harmful gases, or all of them? The goals are different and the configuration plans are different. If the goal is 'the workshop is not pungent', chemical filtration may be more direct and effective than ULPA.

What is the intake air temperature? High temperature airflow will affect the suitability of filter and sealing materials. The temperature resistance of the filter material is not equal to the temperature resistance of the whole machine. The colloid and seals are often the weak links. For details, please refer to the relevant instructions on high temperature resistance.

How high is the particle load. In situations where the concentration is high and the duration is long, pre-processing is required to reduce the load, otherwise the terminal filter element will be replaced frequently.

Where the airflow ultimately goes. Should it be discharged outdoors, circulated back to the workshop, or entered into the subsequent processing section? Different destinations have different requirements for filtering levels and system configurations.

Particle removal does not equal comprehensive purification

This is the most confusing point.

ULPA can block particles in smoke, but it cannot block odor molecules and gas pollutants. If the main objective of the project is to eliminate odors or toxic gases, applying ULPA alone may not achieve the desired effect.

On the other hand, if the main problem is solid particles in the smoke, ULPA can work together with appropriate pre-filtration. The judgment standard is the actual composition of the pollutants, not the general term 'smoke'.

The situation of the process exhaust system is more complicated, involving exhaust volume, emission requirements and equipment function certification, and the clean air supply solution cannot be directly applied. Such projects are individually evaluated against applicable codes and requirements.

Project judgment example

The smoke generated by a certain welding station contains both particulate and gaseous pollutants and has a distinct smell.

If only ULPA is installed, the particulate part may be blocked, but the odor problem will not be solved - because the odor comes from gaseous components, ULPA has no ability to deal with this part. A reasonable approach is to first clarify the collection method (local exhaust or overall ventilation), determine the emission direction, and then configure separate treatment sections for particle and gaseous components.

involving The selection of HEPA/ULPA air filters should also be judged within this overall plan, rather than looking at filtration efficiency alone.

What to look for during verification

After installing the processing system, how to judge the effect?

Measure particle and gaseous indicators respectively. Particle concentration and odor/gas concentration are two different indicators and should be measured separately. Measuring only one cannot tell whether the other meets the standard.

Record the resistance trend. Under smoke conditions, the rising speed of the filter element's pressure difference can reflect whether the pre-treatment is effective. If it rises too fast, check the pre-treatment section first instead of simply changing the filter element.

Pay attention to operating conditions. Temperature, air volume, and frequency of start and stop of intermittent operation will all affect system performance. Supporting FFU fan filter unit or For the EFU equipment-end fan filter unit system, the equipment operating status should be recorded together with the filtering effect to facilitate subsequent analysis.

Selection and Acceptance Checklist

About Aili Industrial’s smoke working condition packages

The premise of the treatment plan for smoke conditions is to understand the composition of pollutants and system conditions. The more complete this information is, the more targeted the configuration will be.

Aili Industrial's manufacturing system covers filters, motors, fans, control systems and complete machine assembly, and can provide ULPA ultra-high efficiency filters and different grades of HEPA/ULPA products are used in particle filtration. For occasions that require pre-treatment or gaseous pollution treatment, the filtration configurations at all levels can be checked together during the planning stage instead of selecting a separate filter element to install.

Provide smoke source, composition, temperature, concentration and emission requirements when enquiring, which will help determine the appropriate treatment path. The specific configuration is subject to the technical documents and operating data confirmed by the project.