Gas Turbine Filtration

Air Filtration Products
for Turbomachinery Air Inlet Systems

High efficiency air filtration is a key factor in achieving cost-effective operation of industrial rotating equipment, such as gas turbines and centrifugal compressors.

Koch Filter Corporation manufactures a wide range of filters for gas turbine air intakes of all sizes and types. Koch products are presently installed in nearly every imaginable environment, from hot and gritty desert environments to salty coastal locations to icy arctic applications. Regardless of the operating environment or system design, there’s a proven, reliable Koch product to meet the need.

Trained Experts in the Field
Koch Filter Corporation presently supplies high quality gas turbine filtration products to customers across the U.S. and around the world. To insure the prompt availability of the complete Koch Filter Corporation product line, a large and effective network of trained field representatives has been developed. Supported by local and regional warehousing points, this experienced sales team is always ready to offer solutions to any filtration problem, regardless of the customer’s location.

Technical Bulletin No. PB-899
Glass Fiber Media vs. Synthetic Media in Gas Turbine Applications

Many owners and operators of Gas Turbines are asking the question, "Should I be using air filters made of synthetic filter media or glass fiber filter media in my inlet air housings?" Over the past decade, many types of filters have been introduced to the marketplace, some produced with synthetic filter media and others with glass fiber media. Considering the technological advances made in both media types, the choice of whether to use glass or synthetic filters has become an issue in many gas turbine systems around the world.

Koch Filter Corporation produces several types of filters, constructed with both media styles, for applications ranging from gas turbines to hospitals. This Product Bulletin explores the proper usage for various application needs.

DuraMax 4v
DuraMAX 4V & 4VS Style Minipleat Filter

The DuraMAX is a rigid, extended surface air filter, engineered to provide maximum performance and prolonged filter life cycles, even in the most difficult environments. The durable, rugged, construction of the DuraMAX make it the filter of choice in filtration systems with high velocities or variable air volumes. DuraMAX Filters are constructed with a 100% plastic frame and are completely incinerable.

DuraMAX provides an unequaled combination of low pressure drop and high efficiency through the use of our unique minipleat design. This high capacity minipleat design allows a nominal 24x24x12 filter to incorporate 194 square feet of filter media. This increased extension of the media surface area insures low pressure drop, and low resistance to airflow means lower energy costs to the user.

Another benefit of the increased media area is extremely high Dust Holding Capacity, which significantly prolongs the service life of the filter. Fewer filter changes translate into substantially reduced maintenance and disposal costs.

The DuraMAX 4V are available in five ASHRAE efficiencies — 65, 75, 85, 95 and 98%.

The DuraMAX 4VS is available in 98%.

These filters are offered in three standard sizes — 24x24x12, 20x24x12 and 12x24x12. Single or double header configurations are available.

DuraMAX 2v
DuraMAX 2v High Efficiency Minipleat Filter

The DuraMAX 2v is an extended surface air filter engineered to provide maximum performance and prolonged filter lifecycles in office buildings, hospitals, paint booths and all types of commercial and industrial HVAC applications. The DuraMAX 2v is completely incinerable after use.

What makes the DuraMAX 2v unique and different? The new 2v design offers all the benefits of our other high performance minipleat filters, but contains approximately 110 ft2 of filter media. The reduced media area makes the 2v model an economical alternative in applications where a minipleat filter is desired but initial purchase price is of utmost concern.

Gas Turbine Inlet Filters
  • Extended surface, high efficiency
    barrier filter designed for maximum
    performance in even the most
    extreme atmospheric conditions.
  • Dual-layered microfiberglass media
    with Double-Edge¯ corrugated
    aluminum separators. (Available
    with coated separators for highly
    corrosive environments).
  • Galvanized steel cell sides with
    expanded metal faceguards on
    air entry and air exit sides.
    Single header or Double header

    ASHRAE Efficiencies: 65% and 95%.
    MERV Rating: 11-15
    Consult Bulletin No: K-386B

KDC Cartridge™
Cylindical Cartridge Filters for Gas Turbine Air Intakes
  • Pleated media cartridges
    perform in self-cleaning
    pulse systems or standard
    non-pulsing systems.
  • Expanded metal retainer
    screens inside and outside.
  • Multiple media options.

    Consult Bulletin No: PB-798-20


Multi-Sak HD™

Multi-Sak HD
Heavy Duty Pocket Filters
  • High efficiency Final Filter and
    medium efficiency Prefilter models
  • Progressively dense synthetic media
    is ideal for humid environments.
  • Durable, self-supporting pockets
    retain rigid shape in airstream.
  • Pockets designed for maximum
    air flow, low pressure drop, and
    superior dust holding capacity.
  • Triple-Lock¯ Frame-to-Pocket
    sealing method insures durability
    in difficult environments.

    ASHRAE Efficiencies: 65% and 95%.
    MERV Rating: 11-16
    Consult Bulletin No: K-1009A
    (To be released)

Multi-Pleat™ GT
Multi-Pleat GT
Pleated Panel Filter
  • Extended surface pleated panel
    designed for use as a prefilter in
    gas turbines, centrifugal compressor
    air intakes, and other high velocity
  • Integral pleat supports.
  • High performance synthetic filter
  • Media is supported by a rust resistant
    metal grid.
  • Available in a wide range of standard
    and custom sizes.

    ASHRAE Efficiencies: 25-30%
    MERV Rating: 8
    Consult Bulletin No: K-906A

Multi-Pleat™ GT-HD
Multi-Pleat GT-HD Heavy
DutyPleated Panel Filter
  • Ultra heavy-duty frame is moisture
    resistant and is designed for high
    humidity applications.
  • Specialized high loft synthetic
    media is moisture resistant.
  • Replacement for prefilters provided
    in OEM inlet air housings.
  • Media is supported by a specialized
    heavy-duty rust resistant galvanizeddipped
    expanded metal grid.
  • Replacement for prefilters provided
    in OEM inlet air housings.

    ASHRAE Efficiencies: 25-30%
    MERV Rating: 8
    Consult Bulletin No: K-906C

MicroMAX Minipleat Filter

The Koch MicroMAX is an extended surface minipleat filter designed for use in a wide variety of air filtration systems. The MicroMAX offers a unique combination of high efficiency and low pressure drop making it the ideal filter for use in any standard HVAC system. The added advantages of its compact 4" depth and lightweight-yet-rigid construction also give the MicroMAX unsurpassed capability to perform in more specialized and difficult applications. MicroMAX Filters are available with standard beverage board frames or with galvanized steel frame. Steel framed MicroMAX filters are available with no header or with a single upstream header.

Synthetic Air Filter Media
Synthetic Air Filter Media
  • A wide range of synthetic and fiberglass media designed for use as a prefilter in gas turbines and other high velocity systems.
  • Available as prefilter pads or plankets for Maxi-Cell and DuraMAX or as a wrap-around prefilter for cylindrical cartridges.
  • Available media - Synthetic 1" and 2.
    Fiberglass 2" and 4"

    ASHRAE Efficiencies: <20%
    MERV Rating: 7
    Consult Bulletin No: K-906C

DuraGlove Cube Prefilter
  • The DuraGlove Prefilter is designed to prolong the lifecycle or the DuraMAX 4v Final Filter in reverse-mount installations.
  • Reverse-mount installations, in which DuraMAX 4v Final Filters are installed with the "Vs" as the air entry side, are common in the inlet housings where limited space makes it difficult to install a separate bank of prefilters.
  • The DuraGlove is constructed with durable synthetic filter media formed into a cube configuration and fits snugly onto the air entry face of the DuraMAX 4v.
  • Several Standard sizes are available.

    ASHRAE Efficiency: 30-35%
    MERV Rating: 8
    Consult Bulletin No: K-996B
    (To be released)


Corporate Offices
8401 Air Commerce Drive - Louisville, KY 40219 - 800.757.5624 - 502.634.4796 - Fax: 502.637.2280 - E mail:

Regional Sales Offices/Distribution Centers
Atlanta, GA - Detroit, MI - East Greenville, PA* - Houston, TX* - Indianapolis, IN - Kansas City, MO - Louisville, KY* - Madbury, NH - Nashville, TN - Mira Loma, CA*  
*Denotes manufacturing site. 

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