Air Distribution Systems and Diffusers Made with Stainless Steel in the USA

High-consequence applications need high-level precision and care. AJ Manufacturing produces air distribution system and air filtration system components and diffusers using your exacting specifications so your critical environment can support your highly-controlled processes.

Whether it’s a laboratory, pharmaceutical manufacturing facility, operating room, or any other type of critical environment, AJ Manufacturing has the stainless steel equipment you need to keep your room conditions perfect.

To request more information about our critical environment equipment, or to order components for your project, contact us by phone or by email.

Criti-Clean Ultra Fan Filter Units (FFUs) from AJ Mfg

Stainless Steel Fan Filter Units

Criti-Clean Ultra Fan Filter Units (FFUs) by AJ Manufacturing are fan-powered laminar flow HEPA filter diffusers that remove airborne contaminants from the air they deliver into your critical environment design. Our Fan Filter Units come in louvered and two-chamber designs.

Our range of these diffusers come in a variety of sizes and configurations and use our proven HEPA filtration technology to deliver purified air or remove contaminated air, in the case of our reverse flow units. The air supply the Criti-Clean Ultra continually produces is a non-aspirating, low-velocity, uniformly-distributed, downward-moving “piston” of HEPA-filtered air. Link multiple units together to produce one large, combined laminar mass. Air circulating units are also available.

Optional built-in LED lights and UV-C radiation modules are available to limit airstream interference and assist in sterilizing particulates while disinfecting the HEPA filter to protect against viruses, bacteria, and mold. The needlepoint bipolar ionization module produces a stream of ions that create free radicals, which attach themselves to airborne pathogens and deactivate them by robbing them of hydrogen.

Ceiling-Mounted Fan Filter Units

Our ceiling-mounted FFUs offer the industry’s highest output of up to 120 CFM and make it easy to retrofit existing spaces, due to its low plenum height – just 13.7” on the air supply unit and 15.8” on the reverse-flow unit. Our FFUs connect to building ductwork with a ceiling grid system or on a plasterboard ceiling.

Mobile Fan Filter Units

For temporary and relocatable use wherever you need clean air, our convenient portable units move on swivel casters and plug into standard electrical wall outlets to provide effective HEPA filtration virtually anywhere. Our portable FFUs are available in air recirculating and reverse-flow models.

Original Criti-Clean

Our original fan-powered laminar flow HEPA filter diffuser is suited to hospital operating rooms and other critical environments. Optional built-in LEDs eliminate the need for overhead light fixtures, to maximize the use of ceiling space and prevent airstream interference.


Stainless Steel Lighted Operating Room System (SSLORS)

Operating Room Ceiling Systems

AJ Manufacturing offers complete, pre-engineered ceiling systems to simplify and speed the design-and-build process for operating rooms. Our ceiling systems meet virtually any need.

SSLORS Lighted Ceiling System

Our modular, customizable air distribution and lighting solution provides clean air and high-quality lighting. A low-profile plenum with any number and configurations of laminar flow diffusers, with or without gel-seal HEPA filters meet your air filtration needs.

Powerful LED lights that are both tunable and dimmable eliminate the need for hanging lights; green lights are included in the same board.

THD-1.5 Suspended Grid Ceiling System

A customizable ceiling, lighting and air distribution system, this component is designed and engineered especially for hospital surgical suites, laboratories, and clean rooms where you must maintain ceiling access. Our grid installation system allows for easy installation of laminar flow panels and fluorescent light fixtures.

Our heavy-duty grid system has half the allowable deflection as classified per ASTM C635 and is designed using structural analysis software for rigidity and to ensure a tight seal from the plenum space above it. Each section is fabricated up to 5’ x 6’ for ease of transport, handling, and installation, but larger sections are available as needed.

Structural Operating Room Ceiling System

Our complete, heavy-duty system accommodates suspended equipment and includes all necessary lighting to meet the increased demands of today’s operating rooms. Customizations are available for efficient and seamless integration.


Stainless Steel Diffusers

SSEPD Series

Our perimeter slot diffusers are designed to provide an air curtain for operating rooms.

FRD Series

The Flat Face Radial Pattern Diffuser provides low aspiration at high ventilation rates and is ideal for clean room applications like animal labs, food processing, computer rooms, and hospital rooms.

HRDP Series

Our Hinged Radial Diffuser provides low aspiration and high ventilation rates for clean room applications, including research laboratories and more.

SS Hemispherical Diffuser

With adjustable pattern control technology, our hemispherical diffuser delivers high volumes of low velocity air in a radial pattern. Constructed using adjustable blades that hang less than 1” below the ceiling, our stainless steel diffusers allow adjustment of the air discharge pattern. An adjustable face or perforated center section are available.

SSLF Series

Our laminar flow ceiling diffusers use vertical air mass laminar flow technology to produce non-aspirating, low-velocity, uniformly-distributed, downward-moving conditioned air.

SSLF-MC Medium Capacity Diffuser

Our medium-capacity laminar flow ceiling diffusers use vertical air mass “laminar flow’ technology to uniformly distribute downward-moving air.

SSLF-HC High Capacity Diffuser

For greater airflow, choose our high capacity laminar flow ceiling diffuser.


Diffusers with HEPA Filtration or ULPA Filtration

AJ Manufacturing provides the highest-quality HEPA and ULPA filters for our stainless steel laminar flow and radial flow diffusers, or any combination grille, plaster frame, and plenum models in hinged or non-hinged designs. These components are ideal for hospitals, semiconductor manufacturing, compact disk manufacturing, food processing, pharmaceutical production, and aerospace manufacturing.


Our Flat Radial Pattern Diffuser with HEPA filter provides low aspiration and high ventilation rates for clean room applications.

SSLFHFD Laminar Flow HEPA Diffuser

Get all the vertical air mass laminar flow technology benefits, plus a gel seal HEPA or ULPA filter for a more refined air cleaning process.

SSLFHFD-MC Medium Capacity Laminar Flow HEPA

Using the proven laminar flow technology, our HEPA diffuser accommodates a removable and replaceable gel seal HEPA or ULPA filter

SSLFHFD Laminar Flow HePA FIlter Diffuser with LED

Add LED alert lights to your laminar flow technology-powered diffuser with HEPA filtration. When lit, the LED indicates it’s time to change the filter in order to achieve optimal performance.

SSLFHFD FFU RF Fan-Powered Laminar Flow HEPA FIlter Diffuser with Reverse Flow

Filter exhaust with a reverse flow fan in workspaces where hazardous materials may be used. Remove airborne pathogens and filter out fine particles from other airborne health hazards in the manufacturing and testing industries.

HRDP Hinged Radial Diffuser with Filter

This HEPA-filtration model incorporates an extended plenum and unique frame to accommodate a gel seal HEPA or ULPA filter. Filters are easily removed and replaced from the front of the unit, which incorporates a seperatorless 2” deep media, integral test port, and anodized aluminum gel seal frame.


For clean air, think AJ Manufacturing.

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