Calcium Silicate Boiler Wall Insulation Blocks

Dense molded blocks used to line high-pressure boiler walls, offering superior thermal stability and fire resistance from calcium silicate composition. Falls under HTS 6806.90.00.20 as 'other' heat-insulating articles of molded calcium silicate mineral material.

Import Duty Rates by Country of Origin

Origin CountryMFN RateCh.99 SurchargesTotal Effective Rate
🇨🇳ChinaFree+35.0%35%
🇲🇽MexicoFree+10.0%10%
🇨🇦CanadaFree+10.0%10%
🇩🇪GermanyFree+10.0%10%
🇯🇵JapanFree+10.0%10%

Alternative Classifications

This product could be classified differently depending on its characteristics or intended use.

6812Lower: 10% vs 35%

If fabricated with asbestos fibers

Chapter notes exclude asbestos articles to heading 6812; pure calcium silicate stays in 6806.

6903.20.00Same rate: 35%

If for industrial furnace refractory linings

If designed primarily as refractory (withstanding 1400°F+ continuously), classifies under Chapter 69.

6806.10.00Higher: 38.9% vs 35%

If sold as loose slag wool fill rather than molded

Unmolded mineral wools are basic forms in 6806.10; molding elevates to articles in 6806.90.

Not sure which classification is right?

Our AI classifier can analyze your specific product and recommend the correct HTS code with confidence.

Import Tips & Compliance

Provide engineering drawings showing molded shape and end-use in power plants to support classification

Ensure no organic binders are present, as they could trigger reclassification to composite materials

Watch for undervaluation penalties; use transaction value based on comparable industrial sales

Related Products under HTS 6806.90.00.20

Calcium Silicate Turbine Housing Insulation

Custom-molded linings for steam turbine housings, designed for extreme heat and vibration resistance using calcium silicate. Fits HTS 6806.90.00.20 as other insulating articles of this specific mineral material.

Molded Calcium Silicate Acoustic Barrier Panels

Panels molded for sound absorption in industrial noise control, with secondary heat insulation from calcium silicate density. HTS 6806.90.00.20 includes sound-insulating mineral articles like these.

High-Temp Calcium Silicate Flue Insulation

Molded cylindrical sections for chimney flues in biomass plants, resisting 1100°F gases via calcium silicate structure. Classified under HTS 6806.90.00.20 for expanded mineral heat insulators.

Molded Calcium Silicate Pipe Insulation

Pre-formed insulation sections designed to fit around industrial pipes, made from molded calcium silicate for high-temperature resistance up to 1200°F. Classified under HTS 6806.90.00.20 as articles of heat-insulating mineral materials specifically composed of molded calcium silicate, excluding those in headings 6811, 6812, or chapter 69.

Molded Calcium Silicate Fireproof Board Panels

Fire-rated panels molded from calcium silicate for use in building partitions and protective enclosures in industrial settings. HTS 6806.90.00.20 covers these as sound/heat-insulating articles, distinct from ceramic or asbestos products.

Calcium Silicate Kiln Insulation Segments

Curved molded segments for lining rotary kilns, providing heat insulation and erosion resistance from pure calcium silicate. Classified in HTS 6806.90.00.20 for specialized expanded mineral insulating articles.