AJ Manufacturing
Zero total CFM air leak at 10.0” wg. Custom sized access doors in 1”, 1.7”, 2” & 4” frame & panel thickness with galvanized, galvanealed, stainless steel, aluminum or galvalume door skins. Optional window, latch prep or thermal frame. Pressure relief doors and wall panels also available.
Dynasonics
With roots dating back over 30 years, Dynasonics is dedicated to providing the commercial and industrial acoustical markets with quality products and exceptional customer service. Our line includes Acoustical Panels and Enclosures, Duct Silencers and Acoustical Louvers. Utilizing both independent testing laboratories and our own state-of-the-art testing laboratory, Dynasonics ensures the accuracy of its performance data.
ITW TACC
A division of Illinois Tool Works, ITW TACC is a leading manufacturer of high-strength adhesives. Our MIRACLE-Kingco Duct Sealants are designed for both residential and commercial construction for HVAC duct work. Water-based sealants qualify for LEED points, are Greenguard Certified, and UL-listed.
KEES 
KEES INC manufacturers a full line of duct access doors for ductwork, plenums and housings, as well as pressure relief duct access doors.
LLoyd Industries
LLoyd Industries Inc. a World Wide supplier to the wholesale market of a complete line of HVAC air control, ventilation and fire safety products. Products include but not limited to: fire dampers, ceiling radiation dampers, combination fire and smoke dampers, access doors, boot and box assemblies, louvers, and air control dampers. Visit our web-site for more details.
Maxam Metal Products 
Manufacturers of a wide range of balance, aluminum backdraft and fire dampers for over 30 years. The first to offer a true round fire damper, designed for horizontal or vertical fire separations, MAXAM’s fire dampers are Interteck/Warnock Hersey listed for 1 ½ hours (vertical or horizontal) and carry the Warnock Hersey logo.
Pottorff
Established in 1928, Pottorff is a leading manufacturer of HVAC products including air control and backdraft dampers, UL rated fire, smoke and ceiling radiation dampers, access doors, louvers and penthouses. Shipping from two factories, our dependable service features a 5 year product warranty, quick-ship capabilities, AMCA/UL certified performance and an in-house elevated temperature airflow lab.
Ruskin Company
is the worldwide leader in the manufacture of dampers and louvers for the HVAC industry. Our full line of innovative control, fire and smoke dampers provide superior air control to help make your building more comfortable and energy efficient.
Ruskin Sound Control
has been a leading manufacturer of engineered duct sound attenuators and acoustical panel systems for over 35 years. We provide custom engineered solutions to solve the most demanding commercial and industrial acoustical challenges. We provide sound solutions for a noisy world.
Swartwout
Control dampers, louvers and ventilators for the industrial HVAC and process industry using all types of material - steel, stainless steel and aluminum. Our Fiber-Aire fiberglass line of products is the solution to even the most demanding of corrosive environments and applications.
C.L. Ward & Family
CL WARD is a manufacturer of sheet metal accessory products for residential, commercial and light industrial ductwork. We offer a broad line of products including four bolt connector, corners, access doors, sealants/ adhesives (may contribute to LEED credits), gasket, fire dampers, ceiling radiation dampers, slip & drive, turning vane and more.
Williams Brothers Corp of America
Insulated walk-in duct access doors. Manufacturers of premium access doors, Williams Brothers utilize the finest quality designs, materials and processes in our production. Our duct doors feature 20 gauge galvanized steel double wall doors with 16 gauge frames; ½” neoprene closed cell door-to-frame gasketing; and 1” thick 3-pound density insulation.
Wonder Metals Corp. 
specializing in the fabrication of louvers, dampers & penthouses for over 40 years, including nonstandard shapes, custom blade designs and copper, stainless steel & brass. Creating efficiency that starts with your first contact and continues through production and delivery.
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See also:
08 3100 - Access Doors and Panels - for architectural access doors
23 3110 - Ducts
AJ Manufacturing
Zero total CFM air leak at 10.0” wg. Custom sized access doors in 1”, 1.7”, 2” & 4” frame & panel thickness with galvanized, galvanealed, stainless steel, aluminum or galvalume door skins. Optional window, latch prep or thermal frame. Pressure relief doors and wall panels also available.
Dynasonics
With roots dating back over 30 years, Dynasonics is dedicated to providing the commercial and industrial acoustical markets with quality products and exceptional customer service. Our line includes Acoustical Panels and Enclosures, Duct Silencers and Acoustical Louvers. Utilizing both independent testing laboratories and our own state-of-the-art testing laboratory, Dynasonics ensures the accuracy of its performance data.
ITW TACC
A division of Illinois Tool Works, ITW TACC is a leading manufacturer of high-strength adhesives. Our MIRACLE-Kingco Duct Sealants are designed for both residential and commercial construction for HVAC duct work. Water-based sealants qualify for LEED points, are Greenguard Certified, and UL-listed.
KEES
KEES INC manufacturers a full line of duct access doors for ductwork, plenums and housings, as well as pressure relief duct access doors.
LLoyd Industries
LLoyd Industries Inc. a World Wide supplier to the wholesale market of a complete line of HVAC air control, ventilation and fire safety products. Products include but not limited to: fire dampers, ceiling radiation dampers, combination fire and smoke dampers, access doors, boot and box assemblies, louvers, and air control dampers. Visit our web-site for more details.
Maxam Metal Products
Manufacturers of a wide range of balance, aluminum backdraft and fire dampers for over 30 years. The first to offer a true round fire damper, designed for horizontal or vertical fire separations, MAXAM’s fire dampers are Interteck/Warnock Hersey listed for 1 ½ hours (vertical or horizontal) and carry the Warnock Hersey logo.
Pottorff
Established in 1928, Pottorff is a leading manufacturer of HVAC products including air control and backdraft dampers, UL rated fire, smoke and ceiling radiation dampers, access doors, louvers and penthouses. Shipping from two factories, our dependable service features a 5 year product warranty, quick-ship capabilities, AMCA/UL certified performance and an in-house elevated temperature airflow lab.
Ruskin Company
is the worldwide leader in the manufacture of dampers and louvers for the HVAC industry. Our full line of innovative control, fire and smoke dampers provide superior air control to help make your building more comfortable and energy efficient.
Ruskin Sound Control
has been a leading manufacturer of engineered duct sound attenuators and acoustical panel systems for over 35 years. We provide custom engineered solutions to solve the most demanding commercial and industrial acoustical challenges. We provide sound solutions for a noisy world.
Swartwout
Control dampers, louvers and ventilators for the industrial HVAC and process industry using all types of material - steel, stainless steel and aluminum. Our Fiber-Aire fiberglass line of products is the solution to even the most demanding of corrosive environments and applications.
C.L. Ward & Family
CL WARD is a manufacturer of sheet metal accessory products for residential, commercial and light industrial ductwork. We offer a broad line of products including four bolt connector, corners, access doors, sealants/ adhesives (may contribute to LEED credits), gasket, fire dampers, ceiling radiation dampers, slip & drive, turning vane and more.
Williams Brothers Corp of America
Insulated walk-in duct access doors. Manufacturers of premium access doors, Williams Brothers utilize the finest quality designs, materials and processes in our production. Our duct doors feature 20 gauge galvanized steel double wall doors with 16 gauge frames; ½” neoprene closed cell door-to-frame gasketing; and 1” thick 3-pound density insulation.
Wonder Metals Corp.
specializing in the fabrication of louvers, dampers & penthouses for over 40 years, including nonstandard shapes, custom blade designs and copper, stainless steel & brass. Creating efficiency that starts with your first contact and continues through production and delivery.