Belco Manufacturing Company, Inc. has been manufacturing fiberglass dampers for the air-handling industry since 1980. At our facility in Belton, Texas we supply corrosion-resistant Fiberglass Reinforced Plastic (FRP) dampers that are used to regulate air flow or shut off and isolate a system. The operating conditions for the dampers are designed to match the operating conditions of the duct system. Premium vinyl-ester resins are used throughout the damper. Fire-retardant resins are also available for a Class I flame spread.

We provide four (4) fiberglass damper models:

  • MODEL 201 dampers are used to control airflow for balancing a system. This model is less expensive and has a shaft seal, but does not have a blade seal.
  • MODEL 202 dampers are used to control airflow for balancing a system. This model has a shaft seal and full circumferential blade stop.
  • MODEL 203 (AMCA Licensed) dampers are used for isolating a system with low leakage. This model has a shaft seal, blade seal, and a full circumferential blade stop. Model 203 dampers are designed for up to 30″ wc with an AMCA certified leakage rate of 5.2 cfm/ft2.
  • MODEL 204 (AMCA Licensed) dampers are used for isolating a system, and have a PTFE encapsulated O-ring to provide a watertight seal. This seal is mechanically fastened to allow replacement.

Standard Construction

Bearings are mounted “outboard” to the damper body & contained in a plastic sleeve. The bearing is Teflon and the seal is an appropriate elastomer for the chemical service. All is contained within this sleeve with a retaining nut. The blade is a heavy fiberglass disk. Care is taken to produce the highest quality damper, and tooling is used to manufacture reproducible and consistent parts. The damper body is a one-piece construction, hand fabricated on a polished steel mold.

Dampers can be made with a variety of resins, cure systems, gasket materials, shaft materials, internal hardware, external hardware, coatings, flange patterns, actuators, and face to face lengths. Contact us for other available options.

Suggested Specifications for Model Fiberglass Reinforced Plastic (FRP) Dampers

Click here to view the dampers PDF.

Custom Configurations

BELCO dampers can be furnished in a variety of custom configurations including: extended length between flanges, undrilled flanges and inline dampers, either built into a section of duct or plain-end for field joint by installers. Damper Models 201, 202 and Backdraft Dampers can be furnished in rectangular configurations using our custom fabrications.

Certified Ratings

Belco Manufacturing Company, Inc. certifies that the Standard Model 203 & 204 Dampers shown herein are licensed to bear the AMCA Seal. The ratings shown are based on tests and procedures performed in accordance with AMCA Publication 511 and comply with the requirements of the AMCA Certified Ratings Program. The AMCA Certified Ratings Seal applies to air leakage and air performance ratings only.

  • Test method per AMCA Standard 500-89
  • Torque: 1049 in-lbs for 48″ damper. 67.35 in-lbs for 6″ damper
  • Air leakage is based on operation between 50°F & 104°F


Model Specification

Damper Brochure

Help With Specifications

Contact Belco Manufacturing Company. Inc. today to learn more about the benefits of using our Texas-manufactured Fiberglass Reinforced Plastic (FRP) dampers for your next project.