Glass; float glass and surface ground or polished glass, in sheets, non-wired, coloured throughout the mass (body tinted), opacified, flashed or merely surface ground

HS code 700521 covers a specific type of glass product known as float glass. This type of glass is widely used in the construction, automotive, and furniture industries due to its unique properties and versatility. Float glass is produced through a specialized manufacturing process that results in a high-quality, flat surface, making it ideal for a range of applications where a smooth, uniform appearance is required.

The production of float glass involves a multi-step process. First, the raw materials, such as sand, limestone, and soda ash, are carefully measured and melted in a furnace at high temperatures. The molten glass is then poured onto a large, flat surface, where it spreads out and forms a smooth, uniform layer. As the glass cools, it is gradually annealed to reduce internal stresses, ensuring a durable and stable final product. The glass can then be further processed, such as by grinding or polishing, to achieve the desired surface characteristics.

The main inputs required for the production of float glass include high-quality raw materials like silica sand, limestone, and soda ash. Additionally, the manufacturing process requires specialized equipment such as furnaces, float baths, and annealing ovens. Energy sources, such as natural gas or electricity, are also essential for the high-temperature melting and cooling processes involved in float glass production.

The primary output of HS code 700521 is float glass in sheets, which can be used in a variety of applications. This type of glass is commonly used in the construction industry for windows, doors, and facades. It is also used in the automotive industry for windshields, side windows, and rear windows. Additionally, float glass is utilized in the furniture and home appliance sectors, as well as in the production of mirrors and other decorative glass products. Other HS codes that may consume the output of 700521 include 700600 Glass; glass of heading 7003, 7004 or 7005, bent, edge-worked, engraved, drilled, enamelled or otherwise worked, but not framed or fitted with other materials, 701910 (Glass fibres (including glass wool) and articles thereof (for example, yarn, woven fabrics)) and 701990 (Glass fibres (including glass wool) and articles thereof (for example, woven fabrics, other than narrow fabrics of heading 5806; mechanical wool)).