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Filter Replacement Access

ISO Class

Adjustable Damper

Terra Part # Price Ships in
Powder-Coated Steel 2'x2' HEPA Room-Side ISO 5 Yes 6601-22B-HDR-AD 83344 $931 1-3 Days 2
In stock soon
Powder-Coated Steel 2'x2' HEPA Room-Side ISO 5 No 6601-22-HDR 55973 $867 1-3 Days 3
Only 9 left in stock
Powder-Coated Steel 2'x2' HEPA Top Side ISO 5 Yes 6601-22B-HD-AD 83343 $573 1-3 Days 4
In stock soon
Powder-Coated Steel 2'x2' HEPA Top Side ISO 5 No 6601-22-HD 55502 $509 1-3 Days 5
Quick Ship+ 82 in stock
Powder-Coated Steel 2'x3' HEPA Room-Side ISO 5 Yes 6601-23B-HDR-AD 83349 $975 1-3 Days 6
Quick Ship+ In stock soon
Powder-Coated Steel 2'x3' HEPA Room-Side ISO 5 No 6601-23-HDR 55975 $911 1-3 Days 7
Quick Ship+ Only 6 left in stock
Powder-Coated Steel 2'x3' HEPA Top Side ISO 5 Yes 6601-23B-HD-AD 83348 $617 1-3 Days 8
Quick Ship+ In stock soon
Powder-Coated Steel 2'x3' HEPA Top Side ISO 5 No 6601-23-HD 55503 $553 1-3 Days 9
Quick Ship+ 16 in stock
Powder-Coated Steel 2'x4' HEPA Room-Side ISO 5 Yes 6601-24B-HDR-AD 83352 $1,032 1-3 Days 10
Quick Ship+ In stock soon
Powder-Coated Steel 2'x4' HEPA Room-Side ISO 5 No 6601-24-HDR 55711 $968 1-3 Days 11
Quick Ship+ 132 in stock
Powder-Coated Steel 2'x4' HEPA Top Side ISO 5 Yes 6601-24B-HD-AD 83350 $668 1-3 Days 12
Quick Ship+ In stock soon
Powder-Coated Steel 2'x4' HEPA Top Side ISO 5 No 6601-24-HD 55504 $604 1-3 Days 13
Quick Ship+ 151 in stock
Filter Replacement Access
ISO Class
Adjustable Damper
Item ordered before. Click on bagde to see the order.

Up to 30-day trial periods, free return shipping and on-site training available for qualified equipment.

Request demo from your product specialist or add note to your order or quote request.

Some ship in:
Usually Ships in:
Free shipping in contiguous USA
Custom-configured product. Contact Terra by phone, chat or email for a project-specific quote.
Custom-configured product. Contact Terra by phone, chat or email for a project-specific quote.
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Product Details
Product Details
  • Available ISO Ratings: ISO 4, ISO 5, ISO 6, ISO 7, ISO 8
  • Terminal housing connects to remote air supply to provide HEPA/ULPA filtered airflow
  • Terminal diffuser with adjustable damper allows for easy access of cleanroom air flow adjustments; can be increased or decreased
  • Two grille material: standard terminal diffuser with aluminum grille or adjustable damper with white mesh filter grille and room side challenge port
  • Minimize cleanroom service downtime with room-side-replaceable (RSR) terminal housing
  • Economical filter unit includes internal baffling and diffuser panel for quiet, uniform air flow
  • No built-in motor; 12" Diameter x 2"H collar allows for connection to external air supply
  • Aluminum frame material
  • White powder-coated steel housing (stainless steel finish optional)
  • Optional remotely operated damper available
  • Room-side-replaceable terminal housing features a Gel-sealed filter and easy-open clips to allow fast filter replacement from below without breaching the cleanroom ceiling
  • HEPA filters are rated 99.99% efficient at removing particles @ 0.3 microns at 100 FPM Average Face Velocity
  • Resistance of 0.31" W.G. @ 100 FPM Average Face Velocity
  • Suitable for 24/7 operation (depending on air quality)
  • Data will vary depending on filter media and configurations with other products/systems, such as ductwork or hoods.

ISO Class: ISO 4

RoHS: Compliant

Unit of Measure: of 1

Fan Filter Units

  • Terra Universal WhisperFlow® Filter Fan Units Terra Universal WhisperFlow® Filter Fan Units
  • 2' x 4' Ducted HEPA Filter Unit Ducted HEPA Filter Unit, 2' x 4'
Terra Universal WhisperFlow® Filter Fan Units
Features & Benefits

Features & Benefits

Learn More: Filter Fan Units Prevent Infection

Did You Know?
HEPA/ULPA Filters Do More Than Meet ISO Requirements - they also prevent infection.

Most cleanroom professionals understand that HEPA and ULPA filters capture contaminants that degrade particle-sensitive samples. But they also help remove bacteria, mold spores, and many viruses that contribute to a host of infections.

Most common bacteria are contained by the 0.3-micron pore size of high-efficiency particular air (HEPA) filters. Ultra-Low Penetration Air (ULPA) filters, which are rated 99.999% efficient at retaining particles of 0.12 microns and larger in diameter, capture ultra-fine contaminants, including many large viruses and mold spores.

These filters also remove aerosol-born pathogens - germs that hitch a ride on larger particles and liquid droplets that are captured in a HEPA or ULPA filter. HEPA- or ULPA-based Fan/Filter Units (FFUs) thus can play an important role in infection prevention in surgical theaters, ICUs and other medical settings.

Additionally, HEPA filters can help filter pollen, tiny insects, bacteria, mold, and other fungal spores that might be present during plant tissue culture or cannabis production. Contaminants such as these can find a way in via personnel or normal HVAC units and can blight crops and reduce yields. HEPA Filters help increase crop yields, pass inspection/meet regulations, and reduce contamination.

Here is a list of common human pathogens that HEPA/ULPA filters capture and remove from circulation:

Pathogens: Bacteria and Diseases
  • SARS-CoV-2: Coronavirus (COVID-19)
  • Escherichia coli: Gastrointestinal infection
  • Bacillus anthracis : Anthrax
  • Aspergillus brasiliensis: Sinus infections
  • Francisella tularensis: Tularemia
  • Bordetella pertusis : Whooping cough
  • Mycoplasma pneumoniae: Pneumonia
  • Chlamydia pneumoniae: Bronchitis
  • Clamydia psittaci : Psittacosis
  • Klebsiella pneumoniae: Opportunistic infections
  • Haemophilus influenzae : Meningitis
  • Coxiella burnetii: Q fever
  • Pseudomonas aeruginosa: Opportunistic infections
  • Actinomyces israelii: Actinomycosis
  • Legionella pneumophila: Legionaire's disease
  • Thermoactinomyces sacchari: Farmer's lung
  • Alkaligenes: Opportunistic infections
  • Streptococcus pyogenes: Scarlet fever
  • Mycobacterium Tuberculosis: Tuberculosis

Terminal Diffuser with HEPA Filter

Ducted terminal housing with HEPA filter provides clean airflow into cleanroom. When adjustable damper is included operator has the ability to increase/decrease airflow with a screw.

Diffuser with Room-side Adjustable Damper

Terra Universal's Diffuser with Room-side Adjustable Damper allows for precision control of airflow as well as allowing users to seal the FFU before changing filters.

Diffuser Panel Promotes Air Flow Uniformity and Protects Filter Integrity

Unlike other manufacturers, Terra’s FFUs include a unique perforated panel beneath the filter, acting as a shower head, to guarantee filter protection and laminar air flow uniformity, which prevents localized air swirling, particle build-up and turbulence.

Protect Against Contaminants and Pathogens

HEPA and ULPA filters help capture many bacteria, viruses (COVID-19), and mold spores that contribute to a host of infections for both humans and plant/animal tissue cultures

Complete Order Transparency

Using Terra’s OnTrak system, our customers can view real-time production updates, receive shipment notifications and track their orders until they arrive at their facility

Website Metric Conversion Tool

Easily convert any product specification to metric units of measure using Terra's web-based metric conversion tool
Available Accessories
Popular Accessories
For a full list of accessories, select a product then click Choose Accessories on that product page.
  • Energy-Efficient Lighting

    Energy-efficient LED lighting panels and strips help to lower electrical costs and minimize heat build-up in temperature-controlled environments.
  • Ionizing Bar; 22"L, with Installation Kit, for 24 x 24 Fan/Filter Unit

    Ionizing bar, mounted to Fan/Filter Unit, provides a balanced stream of ions to the work area below to neutralize static charge and prevent electro-static discharge; 22" bar shown installed on 2' x 2' FFU.
  • Filter Unit Mounting Frame; Stainless Steel, 2' x 2'

    Stainless steel Fan Filter Unit (FFU) mounting frame supports FFU on drywall or other rigid ceiling material, viewed from above ceiling panel (FFU not included).
  • Filter Replacement Alarm

    The filter replacement alarm monitors filter backpressure and issues an alarm when filter needs replaced (requires selection of fan filter unit with challenge port, order separately).
  • Challenge Port for Fan Filter Unit

    Challenge port for Fan/Filter Units simplifies filter leak testing and connection of Filter Backpressure Alarm (shown with optional pressure gauge; must be ordered with FFU).
  • Safely Mount FFU’s Above Floor for Horizontal Laminar Airflow

    The portable FFU base stand can be easily positioned to supply Class 100 horizontal laminar flow into a room or enclosure. It can also be positioned next to sensitive equipment/materials that are mounted close to the floor.
  • Replacement Filters

    Purchase replacement filters ahead of time to prevent costly operational interruptions and avoid damage to fan blowers caused by excessive backpressure from long overdue filter replacements.
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Manuals & Resources
Manuals & Resources

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