 |
| ||||||||||||||||||||||||||||||||||||||||||||||||||
PRODUCTION SITE
Production requires quite a lot of space, because of the different stock requirements (raw materials and blocks). Depending on the type of project, production will be carried out either directly on site or in a workshop which is not directly linked to the site, and this needs to be decided at the outset. The choice will be influenced by parameters which include the duration and volume of production, and transport distances, which should be kept to a minimum.
Access to the site must be good for supplies and for removing stocks of blocks. The site should preferably have a water supply and electricity if motorized equipment is being used.
PRODUCTION CYCLE
All the operations which the manufacture of the blocks requires must be defined. The need for various processing operations should be evaluated in context. There will be no need to allow for drying out the earth in a very dry region for example, nor to screen it if the earth naturally has a good grain size distribution.
Any intermediate operations which take up space and manpower then have to be assessed - transporting, stocking, removing the blocks. Once this has been done, the quality standards of the products have to be defined in order to decide on the target objectives to be reached at each stage of processing, based on general and local technical data. Thus the influence of each operation on the ultimate quality of the product can be assessed.
SCALE OF THE OPERATION
Target productivity must first be set in the light of product demand. High productivity is not necessary if the rate of demand for the blocks is low, as this will only lead to the storage area becoming congested.
Low productivity is harmful if demand for the blocks is high. There is a risk that blocks will be put into use without having had the complete curing time which is indispensable. If CEBs run out of stock, either site work will stop, or there is a risk that the client will change the supplier.
Once the productivity target has been set, calculating consumption is easy. This in turn defines the sizes of the various storage areas needed.
METHODS AND MEANS OF PRODUCTION
Once the broad principles have been determined, each work station must be refined in more detail. It should be possible to apply a precise output figure for each. This means comparing the options and working out what each implies in terms of labour. There may, for example, be a choice between a labour-intensive operation using simple equipment, or sophisticated equipment requiring very little labour. For example, in one hour a bulldozer and one person can do what it would take forty people two days to do without machines. This therefore defines the equipment, the materials, and the labour-force required.
ORGANIGRAMME AND ORGANISATION
The methods and means of production are determined by allocating tasks between the various work-stations, thus setting the ideal output of each and the general coordination of the inputs and outputs of each operation. To avoid having to close down production because of a fall in output of one work station, buffer stocks should be allowed between each. These absorb variations in rhythm between various work stations and should not be excessive. This enables one to work out the surface area required for each work station.
INFRASTRUCTURE
The manufacturing line needs to have the benefit of a certain environment to be operational. The scale of these various arrangements will vary with the type of unit and with productivity, but should be flexible enough to allow for growth without too many additions.
In dry, warm areas, measures will have to be taken to protect workers from the sun and from dust.
Built areas
A depot to store tools and raw materials, including any stabilizer used, will be needed. It may also be necessary to provide sanitary and cloakroom facilities for staff, an office for administrative tasks and a laboratory for quality control testing.
Sheltered areas
Certain operations will need to be protected from direct sun and/or from rain: earth preparation and mixing, compression and initial curing. A small structure of posts roofed over with straw, canvas, tiles etc. and a hard, flat ground surface will be required.
Flat surfaces
Blocks need not necessarily be stocked under a roof as such: canvas can suffice. A hard, flat ground surface (such as rammed stabilized earth or a concrete slabs) is, however, essential for the piles of blocks to be stable.
FIGURE
The following table is intended to help define the production line. It allows accounting considerations between the various possible approaches and equipment to be defined and at the same time gives an idea of the scale of investment each represents. Prices given are indicative, as are output figures, to which we return in more detail in the chapter on PRODUCTION. Reading the table from top to bottom gives an idea of the different means available for each operation. From left to right, the table illustrates the various possible production lines, providing that there is sufficient consistency between the levels of investment and of output for each work station. The high degree of flexibility in terms of growth of a CEB production unit is also apparent.
FIGURE
Note
Output figures reflect the normal use potential of equipment, but are purely indicative, as are the prices quoted. The organization and the staffing of the production unit, however, will be of paramount importance in determining outputs.
FIGURE
This table illustrates the various types of production unit presented in the INTRODUCTION chapter. Other types are possible but the range shown here follows progressive increases in productivity, investment and mechanization.
These increases will be dictated by the need to improve product quality from types 1 to 3, and then to improve productivity through greater mechanization from types 4 to 6. The table lists only equipment specifically for CEB production. For intermediate transportation, see the tables on the preceding pages.
FIGURE
A production unit does not begin and end with the acquisition of a press.
Detailed comments on investments are given in the INTRODUCTION chapter. Here, however, investment is shown in terms of particular pieces of equipment or tools. The relationship between one and the other deserves careful attention, particularly for type 5 where there is a very high investment in equipment because of the mechanization of all transport. It is also clear that purchasing processing equipment alone does not constitute setting up a brickworks: investment in tools and transport ranges between 9 and 52% of the total equipment investment, which is in the order of 80% of the total investment. The remaining 20% consist in investment in infrastructure, not counting the cost of land for the production site.
FIGURE
FIGURE
FIGURE
General remarks
Here, our intention is mainly to show a type of layout and its infrastructure; from that point onwards, there is great flexibility in the type of machines chosen, depending on the investment potential.
This plan can be adapted to suit a manual workshop (preparing and mixing the earth, and compressing and transporting the blocks by hand) with 2 or 3 manually operated presses (type 2), but also a brickworks where preparation, mixing, compressing and transportation are mechanized, such as for types 4 and 5, provided daily production does not exceed 2 000 blocks, in which case larger areas will need to be set aside for stocks.
FIGURE
FIGURE
FIGURE
Comments
The brickworks shown below is one which is in operation in N'djamena (Chad) and which is mainly geared to the sale of blocks, and therefore to irregular demand, which explains the large size of the areas set aside for stocking soil and blocks.
The presses used (Terstaram, etc.) are easy to move around, relatively light and equipped with wheels. Using them in different places reduces the distance blocks need to be transported to the curing area and risk damage. On the other hand, this approach requires more transportation of the soil-cement mix.
The shelters for the presses are made from steel tubes with a canvas covering: they have to be light-weigh/in order to be easily moved around.
This type of layout can also be used for manual operations, preparation and mixing (type 2).
FIGURE
FIGURE
FIGURE
Comments
The brickworks shown is below one which is in operation in Thoronet (France). It is located close to the site for which it was intended, but is also open for external sales of blocks. Demand for its blocks is therefore regular and high, which explains why the areas set aside for stocking blocks is fairly limited. This type of brickworks mainly suits situations where the cost of labour is high and where maintenance staff are highly skilled.
FIGURE
FIGURE
 |
 |
