General Remarks

Compared to other energy efficient technologies, such as Tunnel Kilns, the Third Generation VSBK is a low tech brick kiln which can be built with locally available building materials and operated with accurately working, but normal skilled labour. However deficient construction quality can affect the production flow and generate higher maintenance costs.

Investment Capital

For establishing a brickyard from the scratch, costs of land and hardware (kiln, labour quarters and equipment) determine the required capital investment. If no very advantageous leasing contract can be made, land is the most important cost factor for a new brick venture, especially in the peri-urban areas of Kabul.

A BTK covers an area of 3200-4000m2, while a four-shaft VSBK requires only 400-500m2 land. With the actual land price in the per-urban area of Kabul (60USD/m2), a VSBK requires about 180’000USD or 8 million Afghani less investment capital for land (3000m2 x 60USD/m2), than a BTK, only considering the land for the kiln without counting the usually leased moulding and mining area.

The land related cost savings of a VSBK brickyard are partly absorbed by the higher kiln costs (about 40-70.000 USD higher, depending on the site characteristics and the degree of mechanisation selected).

As for every new venture, additional capital (approximately the 40’000 USD) must be kept available for the initial operation tuning and for optimising the production process, so that the business can become profitable.

However, the actual investment costs are different for each site and each production set-up and have to be calculated carefully before comparing them with other options.

Rough calculations show that in areas where land costs about 20 USD/m2, establishing a VSBK or a BTK venture requires the same amount of approximately 120.000USD or 5.4 million Afghani, (land for the kiln included, but without initial operation costs). With increasing land prices, VSBK becomes the more economic solutions, whereas in cheaper areas, establishing a BTK brickyard may be less capital intensive than a VSBK.

Site Selection

A VSBK with 3-4 shafts can be established on roughly one-sixth of the area needed by an equivalent BTK. However, for soil mining and green brick production, that land area required is no different to a BTK. A VSBK can be built either in flat or sloping terrain. Sloping terrain offers more benefits during operation because it eases the green brick transportation to the VSBK platform. Some important factors to be considered while selecting site for a VSBK includes the availability of raw materials (clay), access to road and electricity (for mechanized VSBK), availability of water and country specific legal compliances. Soil selection forms an integral part of VSBK site selection. VSBK requires good soil quality to cope with its rapid firing system.

Building Material

Except fire resisting refractory bricks for shaft construction, VSBK can be built with commonly available building materials such as normal brick, sand, cement, aggregates and iron bars. Some metal parts such as I beam and C channels are used to support unloading system and shaft wall. Fired clay dust is used as insulation material. Screw jack or hydraulic systems are the only mechanized devices required for operation, along with some iron bars.

Construction Management and Supervision and required Skills of the Construction Labour

A well planned and managed VSBK construction site can be completed within 80 days. Timely availability of building materials and an adequate number of masons and labourers are essential to complete a VSBK within the planned time period. Equally, the quality of building materials is important, especially for foundation work and shaft construction. Use of second-hand or low grade materials may reduce up front investment but it will increase the maintenance cost and also creates operational problems. It is advised to construct a VSBK under the supervision of experience engineer/overseer and with well trained masons and labourers. A well built VSBK will have a life span of at least 15 years.

Critical Elements

The most critical element in VSBK construction is the shaft. It requires special skills with refractory masonry, since only +/- 2mm tolerance is allowed in shaft construction. Hence it requires refractory bricks with uniform shape and size and masons with specialised skills.

The foundation is another critical element. A VSBK with two shafts weighs about 1000 t, including weight of green bricks on top of its platform. Hence strong foundation has to be laid to withstand this load and the horizontal movement during earth quakes. It is always advisable to consult a structural engineers in case of poor sub soil condition.