faq

Air Filtration

HEPA, ULPA, MERV ratings, and choosing the right filter for your HVAC or process air system.

MERV stands for Minimum Efficiency Reporting Value, a scale developed by ASHRAE to measure how effectively a filter captures airborne particles. Ratings run from 1 to 16, with higher numbers indicating finer filtration. MERV 8 is typical for general commercial HVAC; MERV 13–16 is used in industrial and higher-air-quality settings and captures fine dust, bacteria, and smoke. Keep in mind that higher MERV ratings increase airflow resistance — your system needs to be capable of handling the added pressure drop, so consult a filtration specialist before making a significant jump.

A HEPA (High Efficiency Particulate Air) filter must capture 99.97% of particles at 0.3 microns — the most penetrating particle size — and exceeds the MERV scale entirely. HEPA is required in cleanrooms, pharmaceutical manufacturing, hospital isolation rooms, and any application with stringent airborne contamination requirements. Because HEPA media creates significant airflow resistance, it requires a system specifically designed to handle it; standard HVAC fans typically cannot accommodate HEPA without modification.

ULPA (Ultra Low Penetration Air) filters go beyond HEPA, capturing 99.999% of particles at 0.12 microns. They are used in the most demanding cleanroom environments — semiconductor fabrication, nanotechnology, and certain pharmaceutical processes — where even sub-micron particles that pass a HEPA filter would compromise the process. ULPA filters have even greater airflow resistance and require purpose-built systems. For most industrial and commercial applications, HEPA is sufficient.

It depends on the contaminant and what your system can handle. As a general guide: MERV 8 covers typical commercial dust, pollen, and mold spores; MERV 11–13 adds finer particulate like welding fumes, lead dust, and cooking aerosols — appropriate for most industrial facilities; MERV 14–16 suits cleanrooms and sensitive manufacturing environments; HEPA is required for pharmaceutical, medical, or semiconductor applications. Contact Filtech to discuss your specific contaminant and application.

The most reliable trigger is differential pressure across the filter — when it reaches the manufacturer's rated maximum, change it. As a rough guide, commercial MERV 13–16 filters typically last 2–4 months; HEPA filters last 6 months to 2 years depending on loading. High-dust industrial environments need more frequent changes. Running a filter past its service life reduces airflow, increases fan energy consumption, and risks media failure that allows contamination to pass through.

A pre-filter is a lower-efficiency filter placed upstream of the main final filter to capture large particles first, significantly extending the life of the more expensive downstream filter. In most multi-stage systems — HVAC, cleanrooms, industrial air handlers — pre-filters are a cost-effective way to protect HEPA or high-MERV final filters. Replacing an inexpensive pre-filter frequently is far less costly than changing expensive final-stage filters ahead of schedule.

Dust & Fume Collection

Industrial dust collectors, mist collectors, and the filters that keep them running.

A dust collector is an air-material separator — it draws contaminated air through filter media (bags or cartridges), captures the particulate, and returns cleaned air to the facility or exhausts it outside. The four core components are the capture hood at the source, ductwork, the collector and filter media, and the fan that creates the airflow. Most modern industrial collectors use a pulse-jet cleaning system that periodically blasts compressed air through the filters to knock accumulated dust into a collection hopper below.

Baghouses use fabric filter bags held open by internal wire cages. They handle high temperatures and very heavy dust loads well but require more floor space. Cartridge collectors use pleated filter elements that pack far more media into a compact footprint, offering higher efficiency and easier servicing. Cartridge collectors are the more common choice in modern installations where space is limited or finer filtration is needed. For very large volume applications or specific dust types, a baghouse may still be the better option.

Monitor differential pressure (DP) across the filter bank. When DP reaches approximately 5" W.C. — or your filter manufacturer's rated maximum — it's time to replace. Running past this point strains the fan motor, restricts airflow, and can cause filter collapse or media failure. Keep spare filters on hand to avoid production delays. A sudden unexpected drop in DP can indicate a filter has failed and should be investigated immediately.

Both separate contaminants from an airstream, but mist collectors are designed specifically for liquid aerosols — metalworking coolant mist, cutting oil, and similar fluid droplets from machining. Dry dust collectors use fabric or pleated media; mist collectors use coalescing elements or centrifugal separation to capture and drain liquid. Using the wrong collector type for the application results in saturated media, poor capture efficiency, and premature failure. If your application generates both mist and fine metallic particulate, a combination system may be needed.

Yes — significantly more than for non-combustible dust. NFPA 652 and 654 govern combustible dust systems and require a Dust Hazard Analysis (DHA), explosion-rated electrical components, explosion venting or suppression, spark detection and extinguishment upstream of the collector, grounding and bonding throughout, and careful collector placement relative to occupied areas. Standard lockout/tagout procedures are not sufficient — a site-specific safety program is required. Contact Filtech to discuss your combustible dust application.

Molecular Filtration

Activated carbon and chemisorbent media for gases, vapors, odors, and VOC control.

Standard air filters — including HEPA — physically capture particles. Molecular filtration targets gaseous and vapor-phase contaminants that are orders of magnitude too small to be captured by any particle filter. It works through adsorption: gaseous molecules bond chemically to the highly porous surface of activated carbon or other chemisorbent media as air flows through. Molecular contaminants include VOCs, odors, hydrogen sulfide, ammonia, acid gases, and ozone — none of which a HEPA filter addresses. Many demanding applications require both particulate and molecular filtration in combination.

Activated carbon is a highly porous form of carbon — derived from coal, wood, or coconut shells — that is processed to create an enormous internal surface area (often over 1,000 square meters per gram). As contaminated air passes through, gaseous pollutants bond to this surface through adsorption. The more carbon in the filter, the more adsorption capacity. Standard activated carbon handles a broad range of VOCs and odors; impregnated carbon is treated with additional chemical agents (potassium permanganate, sulfur, etc.) to target specific contaminants like ammonia, hydrogen sulfide, or mercury vapor.

Activated carbon is effective against a wide range of gaseous contaminants including VOCs (solvents, hydrocarbons, paint vapors), odors from industrial processes or wastewater, acid gases (hydrogen chloride, sulfur dioxide), hydrogen sulfide, ammonia, and ozone. Impregnated carbons extend this to mercury vapor, formaldehyde, and other targeted compounds. Media selection must be matched to the contaminants present — a carbon optimized for broad VOCs may not perform adequately against inorganic gases without impregnation.

Molecular filtration is used wherever gaseous contaminants pose health, process, or odor control problems. Common applications include semiconductor and electronics manufacturing (airborne molecular contamination / AMC control), pharmaceutical production, commercial buildings in urban areas (traffic exhaust and ozone), wastewater and chemical processing (hydrogen sulfide and process odors), food and beverage production, and museums and archives where corrosive gases would damage artifacts or collections.

Unlike particulate filters, carbon filters don't show rising pressure drop as they approach capacity — airflow stays relatively unrestricted even as the carbon saturates. Replacement is based on time in service, estimated contaminant loading, or downstream breakthrough monitoring (sampling air after the filter for target contaminants). For critical applications, periodic air sampling is the most reliable method. Don't wait for odor or contaminant breakthrough to appear before changing — saturated carbon can begin releasing previously captured contaminants back into the airstream.

Hydraulic & Lubrication Filtration

Keeping hydraulic power units and lube oil systems clean to extend component life and avoid costly downtime.

Hydraulic components — pumps, valves, actuators, and motors — operate with extremely tight internal clearances, often just a few microns. Particle contamination is the leading cause of hydraulic system failure. Even particles invisible to the naked eye cause abrasive wear, valve sticking, seal damage, and accelerated component fatigue. Maintaining fluid cleanliness to the ISO cleanliness code specified for your system's most sensitive component is the single most effective thing you can do to extend equipment life and prevent unplanned downtime.

Hydraulic systems use filters at multiple points: Suction strainers (at the pump inlet, protect the pump from large particles), return-line filters (clean fluid returning to the reservoir — the most common location), pressure-line filters (high-pressure rated, protect sensitive downstream components), off-line / kidney loop filters (operate continuously independent of the main circuit for ongoing fluid conditioning), and reservoir breathers (prevent airborne contamination from entering the tank as fluid levels change). Most systems use filters at several of these locations simultaneously.

The required filtration level is driven by the ISO cleanliness code specified for your system's most sensitive component — typically the servo valve or highest-precision pump. This is expressed as a beta ratio (e.g., β10 = 200). Most general industrial hydraulic systems require filtration in the 3–10 micron absolute range; high-precision servo systems may need 1–3 micron. Always follow the equipment manufacturer's specifications — under-filtering accelerates wear, but over-filtering without adequate flow capacity causes pressure drop and bypass. Contact Filtech to help determine the right specification.

Most hydraulic filters include a differential pressure indicator (DPI) — a visual or electrical signal that triggers when pressure drop across the element reaches a critical level, indicating the element is loaded. The other approach is time-based replacement per the equipment manufacturer's maintenance schedule (typically expressed in operating hours). Don't wait for visible system problems — by the time reduced speed, heat buildup, or sluggish response appear, wear damage may already be significant. A clogged filter without a bypass valve can cause catastrophic pressure buildup and component failure.

Cross-referencing to a quality replacement element is common and often cost-effective, but requires care. The replacement must match the original on filtration efficiency (beta ratio), pressure rating, flow capacity, bypass valve design, and physical dimensions. A lower-cost element with a lower beta ratio may look identical but allow more contamination through, accelerating wear on expensive downstream components. Filtech can cross-reference your OEM part number to quality replacement elements — contact us with your part number and application details.

A kidney loop (offline filtration circuit) draws fluid from the reservoir, passes it through a high-efficiency filter, and returns it — continuously, whether or not the main hydraulic system is running. This allows very fine filtration impractical in the main circuit due to pressure and flow constraints. Kidney loops are recommended for critical systems where uptime is essential, for maintaining cleanliness in large reservoirs, for flushing newly assembled or repaired systems to target ISO cleanliness levels, and for extending hydraulic fluid drain intervals.

Gas Processing Filtration

Coalescing separators, filter elements, and contamination control for natural gas and process gas streams.

Gas streams typically carry a combination of liquid aerosols (water, compressor oils, hydrocarbon liquids), solid particulate (pipe scale, rust, sand, catalyst fines), and sometimes entrained bulk liquids. Each contaminant type requires a different separation mechanism. Solids require barrier filtration; liquid aerosols require coalescing media; bulk liquids require gravitational or centrifugal separation. Many applications need multi-stage systems to address all three. Identifying what's in your gas stream is the essential first step in specifying the right filtration equipment.

A coalescing filter removes fine liquid aerosols from a gas stream by causing tiny droplets — often too small to fall out of the gas under gravity — to combine (coalesce) into larger droplets that can drain away. As the gas passes through the coalescing media, droplets are captured on the fibers, grow, and drain to a sump where they are removed. Coalescing filters are rated by the droplet size they can remove and their efficiency at that size. They are commonly used to protect compressors, instrumentation, meters, and downstream process equipment from liquid contamination.

A filter separator handles both solid particulate and bulk liquid slugs — it typically uses a first-stage vane or centrifugal section to knock out bulk liquids, followed by a filter element stage for particulate and fine mist. A coalescer is optimized specifically for removing fine liquid aerosols from a relatively clean gas stream. Filter separators are the right choice upstream of compressors and in pipeline applications where slugging can occur; coalescers are typically used for instrument gas conditioning and final polishing of gas quality.

As with most filtration, differential pressure across the element is the primary indicator. As the element loads with particulate, pressure drop increases. Replace elements when DP reaches the manufacturer's maximum rated value, or on a scheduled interval — whichever comes first. For coalescing elements, watch also for signs of liquid carryover downstream, which can indicate the element is saturated or has been damaged. Keep spare elements on hand, as an unexpected element failure in a gas processing application can be costly.

Pipeline pigs are devices launched through pipelines to clean, inspect, or separate products inside the pipe. Pigging operations often precede or follow filtration — pigs dislodge accumulated scale, wax, and debris that filters then capture from the gas or liquid stream. After a pigging run, downstream filters typically see a significant spike in contamination load. Filtech carries pipeline pigs, launchers, receivers, and accessories, and can help you plan filtration capacity around scheduled pigging operations.

Liquid Filtration

Bag filters, cartridge filters, and liquid filtration solutions for process, chemical, food, and industrial applications.

Bag filters use a fabric bag inside a pressure vessel housing to capture particulate. They offer high dirt-holding capacity and low cost per unit of flow, making them well-suited for high-volume, moderate-cleanliness applications. Cartridge filters use pleated or depth-filter elements in individual housings, offering finer filtration, more precise micron ratings, and a wider range of media materials. Cartridges are preferred when tighter cleanliness is required or when chemical compatibility demands a specific media. Many processes use bag filters as pre-filters ahead of cartridge final filters to optimize cost and performance.

The required micron rating depends entirely on what you need to protect or produce. Coarse filtration (50–200 micron) removes visible particulate and protects pumps and equipment. General process filtration (10–50 micron) is common for cooling water, wash systems, and pre-filtration. Fine filtration (1–10 micron) is used in chemical processing, food and beverage, and pharmaceutical applications. Sub-micron filtration (<1 micron) is used for high-purity applications. Start with the most sensitive component or process requirement downstream and work backward to determine your filtration target.

Common liquid filter media include polypropylene (broad chemical resistance, good for most aqueous and mild chemical applications), polyester (good abrasion resistance, higher temperature tolerance), nylon (excellent for alcohols and mild acids), stainless steel mesh (cleanable, reusable, for high-temperature or aggressive chemical service), and PTFE (exceptional chemical resistance for aggressive solvents and acids). Always verify compatibility between your process fluid and the filter media, housing material, and seals before specifying. Incompatible materials can fail rapidly and contaminate the process.

Like gas and air filtration, the primary indicator is differential pressure across the filter. As the filter loads, DP rises — replace it before reaching the element's maximum rated pressure drop to avoid media collapse or bypass. For systems without differential pressure gauges, time-based or flow-rate-based replacement schedules are common. A reduction in system flow rate at constant pump output is another sign of filter loading. Never try to clean and reuse single-use filter bags or cartridge elements — they are designed for one service life.

UV – Ultraviolet Disinfection

UV-C lamps and disinfection systems for air, surface, and water treatment applications.

UV-C light — typically at a wavelength of 253.7 nanometers — damages the DNA and RNA of microorganisms including bacteria, viruses, mold, and other pathogens, rendering them unable to reproduce. This is a physical disinfection process, not a chemical one, so it leaves no residue and pathogens cannot develop resistance to it over time. UV-C is highly effective when microorganisms receive an adequate dose — a function of UV intensity and exposure time. Properly designed UV systems can achieve greater than 99.9% inactivation of many common pathogens.

UV-C disinfection is used across a wide range of applications: HVAC air treatment (in-duct UV systems that disinfect circulating air and keep coils free of biological growth), upper-room air disinfection (fixtures mounted near ceilings in occupied spaces), surface disinfection (for food processing, pharmaceutical, and healthcare surfaces), and water treatment (drinking water, process water, wastewater). In cleanroom and controlled environment applications, UV systems complement HEPA filtration by providing a germicidal layer of protection against biological contamination.

They serve complementary, not competing roles. HEPA filtration physically removes particles — including microorganisms — from the airstream. UV-C inactivates living microorganisms but does not remove them or address non-biological particulate. HEPA alone cannot prevent biological growth on filter media or HVAC coils between filter changes; UV-C addresses this by continuously irradiating those surfaces. For highest biosafety assurance — such as in hospitals, pharmaceutical cleanrooms, or animal research facilities — both technologies are used together as complementary layers of protection.

UV-C lamps degrade over time — they continue to produce visible light even as their germicidal UV-C output diminishes. Most standard UV-C lamps are rated for approximately 8,000–12,000 hours of service life, after which UV output has typically dropped to about 70–80% of initial intensity. Annual replacement is common for continuously operating systems. Lamp output should be verified with a UV meter during routine maintenance rather than relying on visual inspection alone, since lamps can appear to be functioning normally while germicidal effectiveness has significantly declined.

UV-C light at germicidal wavelengths can cause skin burns and eye injury with even brief exposure — it should never be directed at occupied spaces without appropriate shielding. In-duct UV systems are installed inside air handling units where occupants have no exposure. Upper-room fixtures use louvers to direct UV upward toward the ceiling where air circulates through the UV zone but occupants below are protected. Any UV system maintenance — including lamp replacement — must be performed with the system de-energized and appropriate PPE. Filtech supplies UV systems designed with safety interlocks and proper shielding for each application type.

Cleanroom & Laboratory Testing Services

Filtech proudly serves the Pennsylvania, West Virginia, and Ohio Tri-State Area for cleanroom and controlled environment certification, environmental monitoring, and decontamination services.

Filtech provides a full range of controlled environment certification and testing services across the PA, WV, and OH Tri-State Area. Our services include cleanroom certification, hood certifications (biological safety cabinets, laminar flow hoods, chemical fume hoods), animal research lab certification, infection control assessments, and troubleshooting for underperforming controlled environments. We also provide environmental monitoring programs and decontamination services. Contact us to discuss your facility's specific certification requirements.

Our technicians perform the following individual tests and measurements: Air Changes Per Hour (ACPH), Airflow Visualization, Downflow Velocity, Dynamic Smoke Videos (including USP 797 compliance), HEPA Filter Leak Testing, Inflow Velocity, Light Level Measurement, Sound Level Measurement, Vibration Testing, Pressure Differential, Site Installation Verification, and Smoke Testing. These tests are used individually or in combination depending on the certification standard and facility type.

HEPA filter leak testing — also called filter integrity testing or DOP/PAO testing — verifies that a HEPA filter and its installation are free of leaks that would allow unfiltered air to bypass the media. A challenge aerosol (typically PAO or a similar substitute) is introduced upstream of the filter, and a photometer scans the downstream face of the filter and frame to detect any penetration. Even a pinhole leak in the filter media, a gap in the gasket, or an improper installation can allow significant contamination to pass through. This test is required at installation and at regular intervals for any facility relying on HEPA filtration for contamination control — including cleanrooms, BSCs, and pharmaceutical production areas.

A Dynamic Smoke Video uses theatrical-grade smoke to visualize airflow patterns inside a laminar flow hood, biological safety cabinet, or cleanroom. The video documents that airflow is moving in the intended direction and that product, personnel, and environmental protection are being maintained as designed. USP 797 — the standard governing sterile compounding in pharmacies — requires dynamic smoke studies to demonstrate that compounding areas meet airflow requirements for cleanroom classification. These videos serve as documentation for regulatory inspections and accreditation purposes.

Recertification frequency depends on the applicable standard and facility type. Biological safety cabinets should be certified annually per NSF/ANSI 49, and any time they are moved, serviced, or have a HEPA filter replaced. Pharmaceutical cleanrooms and compounding areas under USP 797/800 require certification every 6 months. ISO-classified cleanrooms under ISO 14644 are typically recertified every 6–12 months depending on ISO class. Animal research facilities follow AAALAC and institutional requirements. Filtech can help you establish a compliant recertification schedule for your specific facility type and applicable standards.

Environmental monitoring (EM) is an ongoing program of sampling and measurement to verify that a controlled environment remains within its validated limits between certification events. EM programs typically include viable (microbial) air sampling, non-viable particle counting, surface sampling, and personnel monitoring. USP 797, USP 800, and FDA cGMP regulations all require formal EM programs for pharmaceutical and sterile compounding facilities. Animal research labs and hospital pharmacies also commonly require EM as part of their accreditation. Filtech can help design and implement an EM program appropriate to your facility classification and regulatory requirements.

General Questions

Working with Filtech, sourcing replacement filters, and our service area.

Filtech is based in Munhall, PA — just outside Pittsburgh — and has been serving industrial and commercial facilities across Western Pennsylvania, West Virginia, and Eastern Ohio since 1969. We supply replacement filters and filtration equipment across all product lines and can assist customers outside our primary region with sourcing and technical support as well.

Yes — cross-referencing filter part numbers is one of the most common things we do. Whether you have an OEM number, a competitor's number, or just the physical dimensions and specifications, we can identify the correct replacement from the brands we carry. Give us the part number, filter housing manufacturer, system type, and application and we'll find the right fit.

Yes. Beyond supplying replacement filters, Filtech offers technical consulting, on-site system assessments, and filter selection support across all of our product categories. If you're troubleshooting a filtration problem, upgrading a system, or unsure what products are right for your application, reach out — we're happy to work through it with you.

Use the Request a Quote form on any product page, or reach out through our contact page. Include your part number, quantity, application details, and any urgency requirements and we'll respond promptly. For repeat orders or ongoing supply needs, ask us about setting up a standing order arrangement.

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