Metal-Fab 4" Premium Biomass Standard Stove Adapter

Color: Galvanized

Estimated Arrival: Between and . (To All Contiguous States)

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Metal-Fab provides complete and comprehensive venting solutions to the HVAC, Hearth and Plumbing markets.  Founded in 1958 on the premise that offering better products and services would be the key to our success.

Metal-Fab continues to operate today as a privately held entity with the same core values that lead to success while creating steady, stable growth over the past six decades.

Customer needs are the highest priority at Metal-Fab that is why every customer receives a unique experience while choosing from a full line of high-quality venting products for commercial, residential and industrial applications. 

Cutting-edge manufacturing systems, innovative designs, patent products, unmatched product quality, and a focus for detail have resulted in a leadership position within the industries Metal-Fab serves.  Our constant product improvement process and experience in developing and engineer products for safe, efficient appliance operation sets Metal-Fab apart from the competition.


Premium Biomass factory-built vent intended for use with Biomass fuel appliances approved for Type L low-temperature venting systems in accordance with “Standard for Chimneys, Fireplaces, Vents, and Solid-Fuel Burning Appliances,” NFPA 211, and the International Mechanical Code. Tested and listed to UL 641, Premium Pellet Vent features a super ferritic corrosion resistant 444 stainless flue designed to operate in highly corrosive biofuel applications.  Our innovative inner flue locking design permits 130° of pipe rotation, allowing pipe seams to be aligned for an aesthetically pleasing installation.  Continuous laser-welded flue, casing, and integrated silicone gasket eliminate fly ash leakage and maximize product effectiveness, operational efficiency, and safety.


  • Use as a connector between stove exhaust collar and the positive twist-lock of biomass chimney pipe. Order BSA(B) when the outside diameter of the exhaust collar is a true 4" dimension.
  • For use with biomass fuels such as pellet, corn, wheat, or other grassy and woody plants as specified
  • by appliance manufacturers
  • Tested and Listed to UL641
  • Pipe and fittings in 3” and 4” diameters.
  • Factory-built double-wall construction, using 444 stainless steel flue and galvanized steel outer casing.
  • Continuous laser-welded inner flue and casing.
  • 1” clearance to combustibles vent system, rated for continuous use of flue temperatures up to 570º.
  • Silicone gaskets provide an airtight seal eliminating fly ash leakage.
  • Innovative twist-locking connections rotate 130º allowing seam alignment for an aesthetically
  • pleasing installation.
  • Limited Lifetime Warranty
  • Note: Pipe overlaps 1 1/2" when joined together. Assembled length is 1 1/2" less than listed length.


 Application For use with wood pellets, oil, wheat, cherry pits, corn, switchgrass, etc.
Listings/Standards NFPA 211
UL 641
Clearances Minimum 1" clearance to combustibles
Flue Material Specifications: 444 Stainless Steel
Casing Material Specifications:
Galvanized Steel
Diameter:  4"
Height:  4"
Limited Lifetime Warranty
Click to see Warranty DetailsThe Metal-Fab Type “L” Bio-Mass factory-built chimneys, when installed according to manufacturer’s instructions, as prescribed by Underwriters Laboratories Standard 641, and when properly and regularly cleaned and maintained as set forth below, are warranted by Metal-Fab Inc. under normal residential use against substantial defects in material or workmanship of the product for parts only for as long as the original consumer owns the chimney system. This Warranty does not cover normal wear and tear, smoke damage, or damage caused by chimney fires, or any Product that was: (1) purchased other than from an authorized Metal-Fab dealer, retailer, or distributor; (2) modified or altered; (3) improperly serviced, inspected or cleaned; or (4) subject to negligence or any use not in accordance with the printed materials provided with the Product as determined by Metal-Fab. During the first ten years of the warranty, Metal-Fab will provide replacement chimney lengths at no charge. During the balance of the warranty, Metal-Fab will provide replacement chimney lengths at 50% of the current retail price in effect at the time of the warranty claim. The defective part(s) must be returned with all transportation charges prepaid by the owner to the Customer Service Department, Metal-Fab Inc., 3025 May Avenue, Wichita, Kansas 67213. Metal-Fab Inc. will in turn ship the repaired or replacement part to the owner, freight collect, with the owner to be responsible for all freight charges. This warranty does not cover any labor or other service charges incurred by the owner, or any parts not manufactured by Metal-Fab Inc. This warranty may not be extended or modified by our agents or representatives.

It is the OWNER’S RESPONSIBILITY to establish:

  1. the date of the original installation of the product;
  2. the name of the original purchaser;
  3. the name of the installer;
  4. that the product was installed according to manufacturer’s instructions; and
  5. that the product was properly cleaned and serviced once each year by a licensed chimney sweep.


WARNING: Proposition 65