Downcomer Pipe Assembly
Downcomer pipes circulate unheated water from steam drum to boiler lower headers in natural circulation systems. HTS 8402.90.00 covers these dedicated circulation components. Heavy wall seamless construction.
Import Duty Rates by Country of Origin
More Specific Codes
This product may fall under a more specific subheading:
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If standard seamless steel pipes
Generic pressure piping not boiler-specific goes to Chapter 73 tubes.
If basic pipe fittings
Pipe connectors without circulation function classified as fittings.
Not sure which classification is right?
The Tariff Assistant works through the GRI rules on your specific product to reach the right HTS code — and can price the duty on it in the same conversation.
Import Tips & Compliance
• Calculate pipe sizing for circulation rates; hydrotest at 1.5x MAWP; ensure seamless construction certification
Related Products under HTS 8402.90.00
Tube Sheet for Boiler Headers
Forged tube sheets with drilled holes secure boiler tubes in headers for steam/water separation. Critical pressure boundary part under HTS 8402.90.00. High-strength carbon or alloy steel.
Boiler Expansion Joint
Expansion joints accommodate thermal growth between boiler pressure parts and structural steel during steam generation cycles. HTS 8402.90.00 covers these flexible connections. Refractory-lined slip or bellows type.
Boiler Manway Door Assembly
Manway doors provide access for boiler tube inspection and maintenance in steam generating pressure vessels. HTS 8402.90.00 boiler access component. Includes gasket, bolts, and davit assembly.
Boiler Feedwater Pump Impeller
Specialized impellers for multistage feedwater pumps deliver high-pressure water to steam boilers. While pumps may be 8413, boiler-specific impellers fall under HTS 8402.90.00. High-efficiency stainless steel design.
Deaerator Tray Stack
Tray stacks in deaerators remove dissolved oxygen from boiler feedwater, preventing corrosion in steam generating systems. HTS 8402.90.00 covers these water treatment internals. Stainless steel construction.
Boiler Firetube Replacement
A firetube is a critical heat exchanger tube used in fire-tube boilers to transfer heat from combustion gases to water, generating steam. It is classified under HTS 8402.90.00 as a dedicated part of steam generating boilers. These tubes are made from high-temperature resistant alloys to withstand boiler operating conditions.