Bricks are one of the oldest manufactured materials in the world. They have been used in building houses, factories, tunnels and bridges for centuries. They are made from clay, usually with sand and water added to form the mix that goes into moulds to be pressed before being fired in a kiln.
Manufacturing of bricks takes place at a wide variety of factories around the world. Some use machinery while others use traditional hand labour to produce the bricks. The factory may be part of a larger, multi-national company, or it may be a single-site business.
There are a number of methods for producing bricks, including extrusion, wirecut and dry press. Some factories make both soft mud and dry-press bricks, while others make only one of the two types. In either case, the bricks are produced by mixing a combination of clay, sand and water with some type of additive to achieve the desired properties such as strength, colour and a certain thickness.
Typically the brick mixture is poured into moulds and pressed, but some firms use hydraulic power to compress the clay into the moulds. This produces a thicker mix and the edges are defined more crisply, although it increases the cost of production. The bricks are then fired in a kiln to harden them and give them the desired properties.
In some cases, the bricks can be cut into smaller pieces allowing them to be easily laid out in a wall. This is useful for larger structures, such as house walls or large outdoor storage buildings, where the wall assembly can be constructed in stages.
These types of bricks have a low thermal emissivity and are highly insulated. These properties mean that they are a good choice for use in cold climates where it is important to keep interior spaces warm enough to prevent freezing. They are also a good choice for lining exterior walls, especially in areas where there is an opportunity for rain to fall on the wall.
When choosing a brick for use, it is important to consider the design of the building, the site conditions and the desired look and feel. This is because there are many different types of bricks with different properties and different aesthetic effects, and some have more specific uses.
The bricks are usually arranged in rows, which are then held together by their mortar joints. The mortar joint is often made using a trowel or similar implement with a hole drilled in it to allow the bricks to be laid. This method is very efficient and enables the bricklayer to lay the wall more quickly, however, it is difficult for the bricklayer to ensure that the entire wall is level and in the correct orientation.
Another consideration is the size of the bricks. These are normally 215 mm long, 102.5 mm wide and 65 mm high with a mortar joint of 10 mm in the United Kingdom (and 225 mm in most other countries), giving a unit size of 6:3:2.
The brick manufacturing industry is a growing sector in Nepal, with around 300,000 people engaged in the brick production in 2019. They make up an increasingly large part of the economy, with many workers migrant from marginalized social groups. There are also concerns about the health and safety of the workers and their families. The FNBI has implemented a series of policies to regulate its member factories, including a social code of conduct. These regulations aim to improve the working and living conditions of the workers. They have focused on the following issues: occupational health and safety, childcare, basic services, living conditions and social benefits.