Air Filtration System – HVAC, AHU, Cleanroom and Industrial Filtration

An Air Filtration System is a complete arrangement of filters, housings, fans, ducts, airflow controls and monitoring devices designed to reduce airborne particulate matter or selected gaseous contaminants before air reaches occupied spaces, production areas, cleanrooms or sensitive equipment.

Unlike a single air filter, an Air Filtration System considers the entire airflow path and normally combines several filtration stages according to the required cleanliness, contaminant type, airflow, pressure drop, operating environment and maintenance strategy.

VIETPHAT supplies and supports Air Filtration Systems for commercial HVAC, Air Handling Units, cleanrooms, hospitals, pharmaceutical plants, food factories, electronics facilities, semiconductor plants, data centers, paint booths and industrial manufacturing environments.

Available filtration technologies include Pre Filters, Panel Filters, Pleated Filters, Bag Filters, Pocket Filters, Fine Air Filters, Compact Filters, V-Bank Filters, Activated Carbon Filters, Molecular Filters, HEPA Filters, ULPA Filters, FFU Filters, Paint Booth Filters, High Temperature Filters and custom replacement filters.

What Is an Air Filtration System?

An Air Filtration System is a system designed to move air through one or more filtration stages in order to reduce unwanted contaminants.

A typical system may contain:

• Outdoor-air intake.
• Pre Filter.
• Intermediate or Fine Filter.
• HEPA or ULPA final filter where required.
• Activated Carbon or Molecular Filter where gas-phase control is required.
• Filter housing or filter bank.
• Fan or blower.
• Ductwork.
• Dampers.
• Differential pressure gauges or sensors.
• Airflow measuring devices.
• Controls and alarms.

The exact configuration depends on the application and contamination-control objective.

What Does an Air Filtration System Remove?

Air Filtration Systems can be designed for different contaminant categories.

Particulate Contaminants

• Coarse dust.
• Fibers.
• Lint.
• Pollen.
• PM10.
• PM2.5.
• PM1.
• Fine industrial particles.
• Selected airborne microorganisms associated with particles.

Gas-Phase Contaminants

• Selected odors.
• Selected VOCs.
• Organic vapors.
• Acid gases.
• Basic gases.
• Corrosive gases.
• Selected airborne molecular contaminants.

Process Contaminants

• Paint overspray.
• Process dust.
• Powders.
• Selected fumes and aerosols where an appropriate engineered system is used.

How Does an Air Filtration System Work?

An Air Filtration System works by moving contaminated air through one or more filtration stages.

Particulate filters capture particles through mechanisms including:

• Inertial impaction.
• Interception.
• Diffusion.
• Electrostatic attraction in selected media.

Gas-phase filtration uses different mechanisms including:

• Physical adsorption.
• Chemisorption.
• Chemical reaction with impregnated media.

The correct mechanism depends on the contaminant being controlled.

Main Components of an Air Filtration System

1. Air Intake

The air intake introduces outdoor, return or process air into the filtration system.

Its location can significantly influence:

• Dust loading.
• Outdoor pollution exposure.
• Moisture exposure.
• Filter service life.

2. Pre Filter

The Pre Filter removes larger particles before they reach more expensive downstream filters.

Pre-filtration can help:

• Protect coils.
• Protect fans.
• Extend Fine Filter life.
• Extend HEPA Filter life.
• Reduce dust loading on carbon media.

3. Intermediate or Fine Filter

Intermediate filtration removes smaller particulate matter after coarse particles have been captured.

Common filter types include:

• Bag Filters.
• Pocket Filters.
• Fine Filters.
• Compact Filters.
• V-Bank Filters.

4. HEPA or ULPA Final Filter

Where very high particulate cleanliness is required, an Air Filtration System may include:

• H13 HEPA Filters.
• H14 HEPA Filters.
• ULPA Filters.

These filters are common in cleanroom and other critical applications.

5. Activated Carbon or Molecular Filter

Gas-phase filtration may use:

• Virgin activated carbon.
• Impregnated activated carbon.
• Chemisorption media.
• Ion-exchange media.
• Specialty molecular filtration media.

6. Filter Housing

The filter housing supports filters and should minimize air bypass.

A suitable housing should provide:

• Correct filter alignment.
• Adequate sealing.
• Easy maintenance access.
• Mechanical stability.
• Compatibility with system pressure.

7. Fan or Blower

The fan generates the airflow required to move air through the system.

Fan selection must account for:

• Duct resistance.
• Coil resistance.
• Filter pressure drop.
• Dirty-filter resistance.
• Required airflow.

8. Differential Pressure Monitoring

Differential pressure gauges or sensors measure resistance across a filter.

They can help determine when particulate filters are becoming loaded.

9. Airflow Monitoring

Airflow monitoring may be used to verify that the system continues to deliver the required air volume as filters load.

10. Control System

Advanced Air Filtration Systems may include controls for:

• Differential pressure alarms.
• Fan speed.
• Airflow.
• Filter replacement notifications.
• Building Management System integration.

Air Filtration System Types

System Type	Main Purpose	Typical Filtration
HVAC Air Filtration System	Indoor air and equipment protection	Pre + Fine / Bag / Compact
AHU Filtration System	Centralized air treatment	Multi-stage filtration
Cleanroom Filtration System	Controlled particle cleanliness	Pre + Fine + HEPA / ULPA
Industrial Filtration System	Factory and process-air filtration	Application dependent
Gas-Phase Filtration System	Selected gases / VOCs / odors	Carbon / Molecular Media
Paint Booth Filtration System	Supply air + overspray control	Ceiling + Paint Arrestor
High Temperature Filtration System	Hot process air	Heat-resistant Fine / HEPA

Single-Stage Air Filtration System

A single-stage system uses one primary filter.

It may be suitable for relatively simple applications such as:

• Basic equipment protection.
• Coarse dust filtration.
• Low-contamination environments.

However, one filter may not provide the best balance between efficiency, service life and pressure drop for more demanding applications.

Two-Stage Air Filtration System

A common two-stage arrangement includes:

• Stage 1: Pre Filter.
• Stage 2: Fine, Bag, Compact or V-Bank Filter.

This arrangement is widely used in commercial and industrial AHUs.

Three-Stage Air Filtration System

Where higher cleanliness is required, a system may use:

• Stage 1: Pre Filter.
• Stage 2: Fine Filter.
• Stage 3: HEPA Filter.

This is common in selected healthcare, pharmaceutical and controlled-production environments.

Four-Stage Air Filtration System

More demanding systems may use four stages, for example:

• Pre Filter.
• Fine Filter.
• Molecular / Carbon Filter.
• HEPA or ULPA Filter.

The exact sequence should be engineered according to the contaminants and process requirements.

Multi-Stage Air Filtration System

Multi-Stage Air Filtration Systems use several filters in sequence so each stage performs a different function.

Potential benefits include:

• Longer final-filter service life.
• Better control of different particle sizes.
• Reduced loading on HEPA Filters.
• Improved protection of gas-phase media.
• More stable system performance.

HVAC Air Filtration System

An HVAC Air Filtration System removes airborne contamination from supply, return or outdoor air before it reaches occupied spaces or HVAC equipment.

Common filtration products include:

• Pre Filters.
• Panel Filters.
• Pleated Filters.
• Bag Filters.
• Fine Filters.
• Compact Filters.
• V-Bank Filters.

Activated Carbon Filters may be added for selected gas and odor control.

AHU Air Filtration System

Air Handling Units are frequently the main filtration location in large HVAC systems.

A typical AHU filtration sequence may be:

Outdoor Air → Pre Filter → Cooling / Heating Section → Fine Filter → Supply Fan → Final Filter if required

Actual filter placement depends on AHU design.

Benefits of AHU Filtration

• Protect HVAC coils.
• Reduce duct contamination.
• Improve downstream air cleanliness.
• Protect final filters.
• Reduce maintenance.

FCU Air Filtration System

Fan Coil Units generally use relatively low-resistance filters because their fans have limited static-pressure capability.

Common FCU filters include:

• Synthetic filter pads.
• Mesh filters.
• Panel filters.
• Shallow pleated filters.

Installing a highly restrictive filter without checking fan capability may significantly reduce airflow.

Fresh Air Filtration System

Fresh-air filtration treats outdoor air before it enters the building or production environment.

Common outdoor contaminants include:

• Dust.
• Pollen.
• PM10.
• PM2.5.
• PM1.
• Traffic-related particulate pollution.
• Industrial pollution.

Where outdoor pollution is high, multi-stage filtration can be particularly useful.

Commercial Air Filtration System

Commercial filtration systems are used in:

• Office buildings.
• Hotels.
• Shopping malls.
• Schools.
• Airports.
• Convention centers.
• Mixed-use buildings.

These systems typically need to balance:

• Indoor air quality.
• Energy consumption.
• Filter service life.
• Maintenance access.
• Fan capability.

Industrial Air Filtration System

Industrial Air Filtration Systems may be used for general factory ventilation or process-specific contamination control.

General HVAC filtration can be used for:

• Production halls.
• Packaging areas.
• Control rooms.
• Warehouses.
• Precision assembly areas.

However, processes generating high concentrations of dust, powder, fumes or hazardous contaminants may require dedicated source-capture systems.

Air Filtration System vs Dust Collection System

Criteria	Air Filtration System	Dust Collection System
Main Function	Ventilation / air cleanliness	Capture process dust at source
Typical Air Concentration	Lower general airborne loading	Higher process dust loading
Typical Filters	Panel / Bag / Fine / HEPA	Cartridge / Baghouse / specialized collectors
Application	HVAC / AHU / Cleanroom	Grinding / Powder / Machining / Dust processes

General HVAC filters should not be used as substitutes for engineered dust collection where source capture is required.

Cleanroom Air Filtration System

A Cleanroom Air Filtration System is designed to maintain controlled airborne particle concentrations.

Typical filtration stages may include:

• AHU Pre Filter.
• Fine Filter.
• HEPA Filter.
• ULPA Filter where required.
• FFU Filter.
• Terminal HEPA Filter.

The complete cleanroom system also depends on:

• Airflow pattern.
• Room pressure.
• Air change strategy.
• Temperature.
• Humidity.
• Personnel activity.
• Process contamination.
• Room sealing.

Filter class alone does not determine cleanroom classification.

Air Filtration System and ISO 14644

ISO 14644 is widely used for cleanroom classification and controlled-environment applications.

It classifies cleanliness based on airborne particle concentration rather than simply specifying one filter class.

Therefore:

An H13 or H14 filter does not automatically create a particular ISO cleanroom class.

Hospital Air Filtration System

Hospital HVAC filtration requirements vary according to room function.

Systems may include:

• Pre Filters.
• Fine Filters.
• Compact Filters.
• HEPA Filters in selected areas.
• Gas-phase filtration where required.

Air filtration is one part of healthcare ventilation and should be coordinated with:

• Outdoor air ventilation.
• Room pressure.
• Airflow direction.
• Temperature.
• Humidity.
• Infection-control requirements.

Pharmaceutical Air Filtration System

Pharmaceutical HVAC systems commonly use multi-stage filtration to support controlled production environments.

A typical configuration may include:

• Pre Filter.
• Fine Filter.
• HEPA Final Filter.

Selected applications may also use:

• ULPA Filters.
• Molecular Filters.
• High Temperature HEPA Filters.

Filter selection must form part of the overall GMP and contamination-control strategy.

Food Factory Air Filtration System

Food factories may require filtration according to hygiene zoning and product exposure.

Systems can serve:

• General production areas.
• Packaging areas.
• High-care areas.
• Dairy production.
• Beverage production.
• Bakeries.
• Cold processing areas.

HEPA filtration may be appropriate for selected high-care applications but is not automatically required throughout an entire food factory.

Semiconductor Air Filtration System

Semiconductor manufacturing requires strict contamination control because microscopic particles and airborne molecular contaminants can affect process yield.

Typical technologies include:

• Fine upstream filtration.
• HEPA Filters.
• ULPA Filters.
• FFU Filters.
• AMC / Molecular Filters.

Particulate Control

HEPA and ULPA Filters are used for high-efficiency particle removal.

AMC Control

Airborne Molecular Contamination may require:

• Activated carbon.
• Impregnated carbon.
• Chemisorption media.
• Specialty molecular media.

HEPA and ULPA Filters do not remove most gaseous AMC.

Data Center Air Filtration System

Data centers require reliable airflow and contamination control to protect sensitive IT equipment.

Filtration may be integrated into:

• AHUs.
• CRAC units.
• CRAH units.
• Fresh-air systems.
• Air-side economizer systems.

Because data-center cooling equipment often operates continuously, pressure drop and energy use are especially important.

Where corrosive gases are present, specialized molecular filtration may be required.

Paint Booth Air Filtration System

A Paint Booth Air Filtration System generally has two different filtration functions.

Supply-Air Filtration

Supply-side filters help reduce airborne dust before it reaches the painted surface.

They may include:

• Pre Filters.
• Fine Filters.
• Ceiling Filters.

Exhaust-Air Filtration

Exhaust-side filters capture paint overspray.

Common products include:

• Fiberglass Paint Arrestors.
• Floor Filters.
• Paper Paint Filters.
• Accordion Paint Filters.

Paint arrestor filtration should not be confused with gas-phase VOC control.

High Temperature Air Filtration System

High-temperature systems are used where process air operates above the safe temperature range of standard HVAC filters.

Applications include:

• Industrial ovens.
• Paint curing ovens.
• Dryers.
• Pharmaceutical ovens.
• Depyrogenation tunnels.
• Food-processing heat systems.

High-temperature filters must use suitable:

• Media.
• Frame.
• Sealant.
• Gasket.

Air Filtration System for PM10

PM10 filtration can be achieved using suitable general ventilation filters with tested ISO 16890 ePM10 performance.

Air Filtration System for PM2.5

Where PM2.5 reduction is required, suitable filters with tested ePM2.5 or ePM1 performance should be considered.

Air Filtration System for PM1

Fine filtration using suitable ePM1-rated finished filters can help reduce PM1 in general ventilation systems.

ePM1 filters should not automatically be described as HEPA Filters.

Air Filtration System and ISO 16890

ISO 16890 classifies general ventilation filters according to particulate matter performance.

Main groups include:

• ISO Coarse.
• ePM10.
• ePM2.5.
• ePM1.

The standard is relevant to many Pre, Bag, Fine, Compact and V-Bank Filters used in HVAC systems.

Former EN 779 Classes in Existing Systems

Existing HVAC specifications may still refer to former EN 779 classes such as:

• G4.
• M5.
• M6.
• F7.
• F8.
• F9.

These terms remain common in replacement projects, but current filter performance should generally be reviewed using available ISO 16890 data.

HEPA Air Filtration System

A HEPA Air Filtration System uses one or more HEPA Filters as part of the final particulate-control stage.

Common applications include:

• Cleanrooms.
• Hospitals.
• Pharmaceutical production.
• Food production.
• Laboratories.
• Precision manufacturing.

H13 HEPA Air Filtration System

H13 HEPA Filters are widely used in critical air-cleanliness applications.

Selection should consider:

• Required cleanliness.
• Rated airflow.
• Pressure drop.
• Frame.
• Seal.
• Installed integrity requirements.

H14 HEPA Air Filtration System

H14 provides a higher HEPA classification than H13.

However, H14 should not automatically replace H13 because higher efficiency may also influence pressure drop and system design.

HEPA Filters and EN 1822

EN 1822 is commonly used for classification and testing of HEPA and ULPA filters.

Critical applications may require individual filter test documentation and installed integrity testing.

HEPA Filters and ISO 29463

ISO 29463 is another international framework for classification and testing of high-efficiency air filters.

For cleanroom and critical applications, both filter performance and installation integrity should be considered.

ULPA Air Filtration System

ULPA filtration is used where particulate-control requirements exceed those of typical HEPA applications.

Typical applications include:

• Semiconductor manufacturing.
• Microelectronics.
• Advanced cleanrooms.

FFU Air Filtration System

Fan Filter Units combine a fan and HEPA or ULPA Filter in a modular unit.

FFUs are commonly installed in cleanroom ceiling grids.

Advantages may include:

• Modular airflow control.
• Local HEPA / ULPA filtration.
• Flexible cleanroom coverage.
• Easy system expansion in suitable designs.

Activated Carbon Air Filtration System

Activated Carbon Air Filtration Systems are used for selected gas-phase contaminants.

Potential applications include:

• Odor control.
• Selected VOC control.
• Commercial building ventilation.
• Industrial ventilation.

Standard activated carbon does not remove every gaseous contaminant.

Molecular Air Filtration System

Molecular filtration uses adsorbents selected for particular contaminants.

Media options may include:

• Activated carbon.
• Impregnated activated carbon.
• Chemisorption media.
• Ion-exchange media.
• Specialty blended adsorbents.

Particulate Filtration vs Gas-Phase Filtration

Criteria	Particulate Filtration	Gas-Phase Filtration
Target	Dust / PM / airborne particles	Selected gases / VOCs / odors
Media	Synthetic / Glass Fiber	Carbon / Chemisorbent
Typical Filters	Pre / Fine / HEPA	Carbon / Molecular
Replacement Indicator	Pressure drop / condition	Media capacity / breakthrough

Air Filtration System Pressure Drop

Every filter creates resistance to airflow.

Total system pressure drop includes resistance from:

• Filters.
• Coils.
• Ductwork.
• Dampers.
• Grilles.
• Other HVAC components.

Excessive filter resistance can reduce airflow if the fan cannot compensate.

Initial Pressure Drop

Initial pressure drop is the resistance of a clean filter at a specified airflow.

It should be reviewed when selecting each filtration stage.

Final Pressure Drop

As particulate filters load, resistance normally increases.

The replacement point should consider:

• Manufacturer recommendations.
• Available fan static pressure.
• Required airflow.
• Energy cost.
• Facility operating criteria.

Differential Pressure Monitoring in Air Filtration Systems

Differential pressure monitoring helps determine how loaded a particulate filter has become.

Monitoring can be installed across:

• Pre Filters.
• Bag Filters.
• Fine Filters.
• Compact Filters.
• V-Bank Filters.
• HEPA Filters.

Why Carbon Filters Cannot Be Monitored by Pressure Drop Alone

Activated carbon may become chemically saturated without a significant change in airflow resistance.

Gas-phase filter replacement may instead require consideration of:

• Operating hours.
• Contaminant concentration.
• Media capacity.
• Gas monitoring.
• Breakthrough analysis.
• Media testing.

Airflow in an Air Filtration System

Airflow is one of the most important design parameters.

Incorrect airflow can cause:

• Excessive filter resistance.
• Reduced filter life.
• Poor room pressure control.
• Reduced HVAC performance.
• Incorrect cleanroom airflow patterns.

Face Velocity

Face Velocity is the velocity of air through the frontal area of a filter.

Higher face velocity generally increases pressure drop and may influence filter service life.

Filter Media Area

Increasing effective media area can reduce media velocity for the same total airflow.

This is one reason Bag, Compact and V-Bank Filters can handle large air volumes efficiently.

Air Filtration System Energy Consumption

Filter resistance contributes to fan energy use.

Energy consumption should therefore be considered when selecting filtration stages.

Important factors include:

• Initial filter pressure drop.
• Average operating pressure drop.
• Filter loading behavior.
• Operating hours.
• Fan efficiency.
• Replacement strategy.

Low Pressure Drop Air Filtration System

A low-pressure-drop design can help reduce fan energy, but efficiency should not be sacrificed below the level required by the application.

The goal should be to balance:

• Required efficiency.
• Pressure drop.
• Dust-holding capacity.
• Service life.
• Energy consumption.

Air Filtration System Sealing

Proper sealing is essential, especially in high-efficiency systems.

Air bypass may result from:

• Incorrect filter dimensions.
• Damaged gaskets.
• Loose filter clips.
• Distorted filter banks.
• Incorrect installation.

HEPA Filter Sealing

HEPA systems may use:

• Gasket seals.
• Gel seals.
• Knife-edge gel systems.

A high-efficiency filter cannot perform correctly at system level if contaminated air bypasses the media.

Air Filtration System Integrity Testing

Critical HEPA installations may require integrity testing after installation.

Testing can identify:

• Media leaks.
• Frame leaks.
• Gasket leaks.
• Gel-seal leaks.
• Housing leaks.

Air Filtration System Maintenance

Routine maintenance should include:

• Filter inspection.
• Differential pressure checks.
• Housing inspection.
• Gasket inspection.
• Airflow verification.
• Coil and drain-pan maintenance.
• Correct replacement procedures.

When Should Air Filters Be Replaced?

There is no universal replacement interval.

Filters may require replacement when:

• Pressure drop reaches the approved limit.
• Airflow decreases.
• Media is damaged.
• Filter frames deform.
• Seals fail.
• Moisture damages the filter.
• HEPA integrity testing fails.
• Carbon media reaches adsorption capacity.

Can Air Filters Be Washed?

Only filters specifically designed as washable should be cleaned.

Most:

• Bag Filters.
• Fine Filters.
• Compact Filters.
• V-Bank Filters.
• HEPA Filters.
• ULPA Filters.

are normally disposable.

Can HEPA Filters Be Washed?

No. Standard HEPA Filters should generally not be washed because washing can damage the media and compromise filter integrity.

Air Filtration System Upgrade

Existing systems can sometimes be upgraded to provide better filtration.

Possible improvements include:

• Adding a better Pre Filter.
• Adding a second filtration stage.
• Upgrading Fine Filter performance.
• Installing Compact or V-Bank Filters.
• Adding gas-phase filtration.
• Improving filter-bank sealing.
• Adding differential pressure monitoring.

Any upgrade should be checked against available fan static pressure.

Can a G4 Filter Be Upgraded to F7 or ePM1?

Potentially, but a higher-efficiency filter may introduce greater resistance.

The following should be checked:

• Fan capability.
• Airflow.
• Filter depth.
• Housing dimensions.
• System pressure requirements.

Can H13 Be Upgraded to H14?

Potentially, but H14 should only be selected where its higher classification is required and where airflow, pressure drop, housing and seal requirements remain acceptable.

Air Filtration System Replacement

Replacement filter selection should consider:

• Dimensions.
• Filter type.
• Filter efficiency.
• Rated airflow.
• Initial pressure drop.
• Recommended final pressure drop.
• Frame material.
• Seal type.
• Application.

Replacing a filter only because its dimensions match may lead to poor system performance.

Custom Air Filtration Systems

Some AHUs, industrial equipment and imported machines use non-standard filtration configurations.

Custom filtration may include:

• Custom filter sizes.
• Custom filter banks.
• Custom Bag Filters.
• Custom Compact Filters.
• Custom HEPA Filters.
• Custom Carbon Filters.
• Custom paint booth filters.
• Custom high-temperature filters.

How to Design an Air Filtration System

Step 1 – Identify the Application

Determine whether the system serves:

• Office HVAC.
• Factory AHU.
• Hospital.
• Pharmaceutical plant.
• Food factory.
• Cleanroom.
• Semiconductor plant.
• Data center.
• Paint booth.
• Industrial oven.

Step 2 – Identify the Contaminants

Determine whether the target contaminants include:

• Coarse dust.
• PM10.
• PM2.5.
• PM1.
• HEPA-level particles.
• Odors.
• VOCs.
• Specific gases.
• Paint overspray.

Step 3 – Define the Required Air Cleanliness

Determine the filtration performance required for the process or occupied space.

Step 4 – Determine Airflow

Calculate or confirm the required airflow in m³/h.

Step 5 – Calculate Available Fan Static Pressure

Determine how much resistance can be allocated to the filters.

Step 6 – Choose Filtration Stages

Examples include:

• Pre Filter only.
• Pre + Fine Filter.
• Pre + Fine + HEPA.
• Pre + Fine + Carbon.
• Pre + Fine + Molecular + HEPA.

Step 7 – Select Filter Types

Choose the most appropriate configuration for airflow, efficiency and maintenance requirements.

Step 8 – Design the Filter Housing

Ensure:

• Correct dimensions.
• Mechanical stability.
• Proper sealing.
• Maintenance access.

Step 9 – Add Monitoring

Consider:

• Differential pressure gauges.
• Airflow monitoring.
• Filter alarms.
• BMS integration.

Step 10 – Develop a Maintenance Plan

Define:

• Inspection intervals.
• Replacement criteria.
• Spare filter inventory.
• Critical filter testing.

Important Air Filtration System Design Parameters

Parameter	Information Required
Application	HVAC / AHU / Cleanroom / Industrial
Target Contaminant	Dust / PM / VOC / Gas / Overspray
Required Efficiency	ISO Coarse / ePM10 / ePM2.5 / ePM1 / H13 / H14
Airflow	m³/h
Available Static Pressure	Pa
Number of Stages	1 / 2 / 3 / Multiple
Filter Dimensions	W × H × D
Operating Temperature	°C
Humidity	%RH where relevant
Filter Housing	Existing / New / Custom
Seal Type	Standard / Gasket / Gel
Monitoring	Pressure / Airflow / Gas monitoring

Common Air Filtration System Problems

High Filter Pressure Drop

Possible causes include:

• Filters are dirty.
• Filter area is too small.
• Filter efficiency is too high for the fan.
• Airflow exceeds design conditions.

Low Airflow

Possible causes include:

• Loaded filters.
• Incorrect filter selection.
• Insufficient fan static pressure.
• Blocked coils or ducts.

Short Filter Life

Possible causes include:

• High outdoor dust concentration.
• Insufficient pre-filtration.
• Undersized media area.
• Excessive airflow.
• Process dust entering general HVAC.

Dust Downstream of Filters

Potential causes include:

• Air bypass.
• Damaged media.
• Incorrect efficiency.
• Poor filter installation.
• Damaged filter housing.

Carbon Filters Do Not Control Odor

Potential causes include:

• Carbon saturation.
• Insufficient carbon quantity.
• Excessive airflow.
• Incorrect adsorbent for the contaminant.
• High humidity.

HEPA System Fails Cleanliness Requirements

Possible causes include:

• Filter leakage.
• Housing leakage.
• Incorrect airflow.
• Room leakage.
• Excessive internal contamination sources.
• Inadequate maintenance.

Air Filtration System Life-Cycle Cost

The total cost of filtration includes more than filter purchase price.

Life-cycle cost may include:

• Filter cost.
• Fan energy.
• Pressure drop.
• Service life.
• Replacement frequency.
• Maintenance labor.
• Testing.
• Waste disposal.
• Production downtime.
• Impact on HVAC cleanliness.

How to Reduce Air Filtration System Operating Cost

Potential measures include:

• Select efficient filters with suitable resistance.
• Use effective pre-filtration.
• Increase media area where practical.
• Monitor differential pressure.
• Replace filters based on appropriate criteria.
• Prevent air bypass.
• Maintain fans, coils and ducts.
• Match filtration efficiency to the real application requirement.

Air Filtration System Supplier in Vietnam – VIETPHAT

VIETPHAT supplies Air Filtration Systems and replacement filters for HVAC, AHU, cleanroom, commercial and industrial applications.

We support filtration selection based on:

• Application.
• Target contamination.
• Required filter efficiency.
• Airflow.
• Pressure drop.
• Existing filter dimensions.
• Operating temperature.
• Humidity.
• Filter housing.
• Maintenance requirements.

VIETPHAT Air Filtration Product Range

• Pre Air Filters.
• Primary Air Filters.
• Panel Air Filters.
• Pleated Air Filters.
• Bag Air Filters.
• Pocket Air Filters.
• Fine Air Filters.
• Compact Air Filters.
• V-Bank Air Filters.
• Activated Carbon Air Filters.
• Molecular Air Filters.
• HEPA Air Filters.
• ULPA Air Filters.
• FFU Filters.
• Paint Booth Filters.
• High Temperature Air Filters.
• Replacement Air Filters.
• Disposable Air Filters.
• Air Filter Media.
• Custom Air Filters.

Applications of VIETPHAT Air Filtration Systems

• Commercial buildings.
• Factories.
• Hospitals.
• Pharmaceutical plants.
• Food factories.
• Electronics plants.
• Semiconductor plants.
• Data centers.
• Cleanrooms.
• Hotels.
• Shopping malls.
• Airports.
• Warehouses.
• Paint booths.
• Automotive factories.
• Industrial ovens.
• Laboratories.
• General industrial ventilation systems.

Information Required for an Air Filtration System Quotation

Required Information	Example
Application	AHU / Cleanroom / Factory / Hospital
Target Contaminant	Dust / PM2.5 / VOC / HEPA-level particles
Required Efficiency	ePM1 / H13 / H14 / other
Airflow	m³/h
Available Static Pressure	Pa
Existing Filter Dimensions	W × H × D in mm
Existing Filter Type	Panel / Bag / Compact / HEPA
Temperature	°C
Humidity	%RH where relevant
Existing Brand / Part Number	If available
Required Quantity	Number of filters / systems

Frequently Asked Questions About Air Filtration Systems

What Is an Air Filtration System?

An Air Filtration System is an arrangement of filters, housings, airflow equipment and controls designed to reduce airborne particulate or selected gaseous contaminants.

What Are the Main Components of an Air Filtration System?

Typical components include Pre Filters, Fine Filters, HEPA or Carbon Filters where required, filter housings, fans, ducts and monitoring equipment.

What Is a Multi-Stage Air Filtration System?

A multi-stage system uses several filters in sequence, such as a Pre Filter followed by a Fine Filter and HEPA Filter.

Why Is Multi-Stage Filtration Better Than One Filter?

Multi-stage filtration can distribute contaminant loading among several filters, protect expensive final filters and provide more efficient control of different particle sizes.

What Is an HVAC Air Filtration System?

An HVAC Air Filtration System removes airborne contamination from outdoor, return or supply air in heating, ventilation and air-conditioning systems.

What Filters Are Commonly Used in AHUs?

Typical AHU filters include Pre Filters, Bag Filters, Fine Filters, Compact Filters, V-Bank Filters, Carbon Filters and HEPA Filters in selected applications.

Which Air Filtration System Is Suitable for PM2.5?

A suitable system may use filters with tested ePM2.5 or ePM1 performance under ISO 16890, depending on target performance and HVAC capability.

Which Air Filtration System Is Suitable for PM1?

General ventilation systems may use suitable ePM1-rated filters, while more critical applications may require HEPA filtration.

Is ePM1 the Same as HEPA?

No. ePM1 is a general ventilation classification under ISO 16890, while HEPA is a separate high-efficiency category.

What Is the Difference Between H13 and H14?

H14 is a higher HEPA classification than H13, but the correct choice should depend on process requirements and HVAC system capability.

Does a HEPA Filter Automatically Create a Cleanroom?

No. Cleanroom classification depends on the complete system, including airflow, room construction, pressure, contamination sources and operating procedures.

Can HEPA Filters Remove VOCs?

No. HEPA Filters primarily remove particulate matter. VOCs require suitable gas-phase filtration.

Can Activated Carbon Remove All VOCs?

No. Carbon effectiveness depends on the target chemical, carbon type, media quantity, airflow, temperature and humidity.

What Is a Molecular Air Filtration System?

A Molecular Air Filtration System uses adsorbent or chemisorbent media to control selected gaseous contaminants that particulate filters cannot remove.

What Is the Difference Between Air Filtration and Dust Collection?

Air filtration commonly treats ventilation air, while dust collection is generally designed to capture higher concentrations of process dust directly at the source.

Can a Standard HVAC Filter Be Used for Paint Overspray?

Ordinary HVAC filters are not normally suitable as primary paint arrestors. Paint booth exhaust requires dedicated overspray media.

Can an Air Filtration System Be Upgraded?

Yes, but upgrades should consider fan static pressure, airflow, housing dimensions, filter efficiency and system sealing.

How Often Should Air Filters Be Replaced?

Replacement depends on pressure drop, dust loading, airflow, operating hours, media condition and application requirements rather than one fixed universal interval.

Can Air Filters Be Washed?

Only filters specifically designed as washable should be cleaned. Most Bag, Fine, Compact, V-Bank, HEPA and ULPA Filters are normally replaced.

Why Is Differential Pressure Important?

Differential pressure helps indicate particulate-filter loading and can support condition-based filter replacement.

How Is a Carbon Filter Replacement Time Determined?

Carbon replacement may depend on contaminant concentration, media capacity, operating hours, breakthrough monitoring or media analysis because pressure drop alone does not indicate adsorption capacity.

Can VIETPHAT Supply Custom Air Filtration Systems?

VIETPHAT can support customized filtration configurations according to dimensions, airflow, efficiency, pressure drop, media, operating conditions and application requirements.

Can VIETPHAT Supply Replacement Filters for Existing Air Filtration Systems?

Yes. Existing filters can be evaluated using dimensions, filter class, airflow, pressure drop, frame, seal, brand and part number where available.

What Information Should I Provide for a Quotation?

Please provide application, target contaminant, required efficiency, airflow, available pressure drop, filter dimensions, operating conditions, existing filter information and quantity.

Contact VIETPHAT for Air Filtration Systems

For technical consultation, filter selection or quotation for Air Filtration Systems for HVAC, AHU, cleanrooms and industrial applications, please contact VIETPHAT:

• Zalo / Hotline: 0971 344 344
• Sales: 0827 077 078
• Sales: 0829 077 078
• Email: sales@vietphat.com
• Website: www.vietphat.com

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