In Nepal, brick is one of the most widely used building materials, with over 3.2 billion bricks made and consumed each year according to a study in 2015. According to the Federation of Nepal Brick Industries, there are 800-850 brick kilns in operation across the country. The brick-making industry is a significant element of Nepal’s economy, with an estimated investment of USD 36 million. The Kathmandu Valley and the Terai’s flat plains are home to the majority of brick kilns. Within the Kathmandu Valley alone, there are roughly 110 brick kilns in operation.
When compared to other classes, first class bricks are of higher quality. Table-moulding is used to shape them, and they are fired in enormous kilns. As a result, these bricks have a consistent shape, sharp edges, and smooth surfaces. They are more long-lasting and powerful. They can be utilised to build long-term constructions. However, due to their superior qualities, they are more expensive than other classes.
Second-class bricks are of moderate quality and are manufactured using the ground-moulding method. Kilns are also used to burn these bricks. However, due to the ground moulding, they lack smooth surfaces and sharp edges. Because of the unevenness of the ground, the shape of the bricks is similarly irregular. These will also produce the best outcomes in terms of strength and durability. On the brick construction, smooth plastering is essential.
Third-class bricks, also known as unburnt bricks, are low-quality bricks that are typically used for temporary buildings. These are not suitable for use in wet environments. They are ground-moulded bricks that have been burned in clamps. The surface of these bricks is rough, and the edges are uneven.
Fourth-class bricks are of poor quality and are not used in the construction of the project. They are crushed and used as aggregates in concrete production. They are made by over-burning them, which causes them to become hot and brittle. As a result, they are prone to breaking and are unsuitable for building.
Concrete bricks are made with cement, sand, coarse aggregates, and water as the main materials. These bricks can be made in whatever size you choose.Concrete bricks have several advantages over clay bricks, including the ability to be created on-site, a reduction in the amount of mortar required, and the ability to be manufactured in a variety of colours as pigmented during the manufacturing process. Concrete bricks are used to make masonry and framed buildings, facades, and fences, and they have a great aesthetic appeal. In Nepal, Asian Bricks are high quality concrete bricks available in red and grey colour.
The typical brick must be 240 mm long, 115 mm broad, and 57 mm thick, with a tolerance of +/-10 mm on length, +/-5 mm on width, and +/-3 mm on thickness, according to the Nepal National Building Code (NBC 109: 1994). However, the size of clay bricks produced varies greatly across the country in practice. The Terai region produces clay bricks that are often larger in size than those manufactured in the Kathmandu valley.
For a brick of 240X115X57 mm3 , 1 cubic metre of volume holds about 636 standard bricks
The Nepal Building Code (NBC) specifies a Crushing Strength criterion of 35 kg/cm2 for bricks.
However, in practice, crushing strength is usually higher. The water absorption of bricks should be 15% for machine manufactured bricks, while it could be up to 25% for hand moulded bricks, according to the Nepal Building Code.
The price of clay bricks varies according to the geographical location in Nepal where the size of the brick is larger in terai compared to the hilly regions. The average price of a standard clay brick in Nepal is Rs 17. Chinese clay bricks are expensive compared to local clay bricks at about Rs 22. Concrete bricks are a cheaper option with respect to clay bricks in Nepal which come at an average price of Rs 14 for grey bricks and Rs 15 for red bricks.