12.2.1 Basic shape
12.2.2 Floors
12.2.3 Drains
12.2.4 Walls, ceilings and fittings
12.2.5 Plant and equipment
12.2.6 Area requirements
Perhaps the most important decision in the planning of a new processing plant or fish market is the selection of location. which is often critical to the success or otherwise of the venture. Once established it is most disruptive an costly to move site.
In evaluation of a site the following factors should be considered:
The initial cost of a building is only the first of a series of costs which will arise throughout its life. The building will require regular maintenance, heating and lighting, and cleaning and servicing rates and insurance will be incurred. Over the life of a building these running expenses will amount to two or three times its cost of construction and their incidence will depend on its planning and design.
The inclusion of running costs as well as initial costs within the costing concept considerably increases the value of cost analysis of the building design. There is often conflict between the effects of a design feature on capital and running costs, but the long-term nature of the investment necessitates a long-term evaluation of the effect of design on costs. As examples the amount of insulation specified will effect the heat gains or losses to or from a building, the use of natural lighting will influence power consumption and materials of construction will effect life, cost of insurance and the cost of maintenance and cleaning.
It is often helpful at the planning stage to draw up a process flow diagram showing the sequence of operations, proposed equipment, service requirements (water, electricity, steam) and the need for removal of wastes. This will assist in planning of layout and in assessment of total service requirements. Modelling techniques can also be usefully employed in planning layout.
The very diverse nature of fish processing operations, local practices and material availability make it impossible to describe within this text universal detail designs of fish working premises but the following notes relating to the principles of design, construction and materials are relevant.
The basic shape or configuration of a building will be influenced by the nature of the process, the installed equipment and cost considerations. It may also be influenced by site restrictions or planning regulations. Most fish processing buildings and markets are single story or of a hybrid configuration with offices or stores above part of the processing area. In the design of a floor plan particular attention should be paid to product and materials handling; a through-flow design often being the simplest and most economical to operate.
Wholesale fish markets for example are often long narrow structures running the length of and a short distance from, the landing quay. Such a shape enables the maximum number of vessels to simultaneously unload at the market with the minimum handling of fish along the quay for market display. It also enables the maximum number of road vehicles access to the rear of the market for loading. The narrow width of building means reduced handling from vessel to road transport.
Floors should be hard-wearing, non-porous, washable, well-drained, non-slip and resistant to possible attack from brine, weak ammonia, fish oil and offal. Granolithic concrete is attacked by the continued action of strong brine and acids and accelerated by wear or damage of the surface. Nonetheless it is a popular and reasonably cheap surface for fish working premises. Clay tiles are more expensive than concrete but are harder wearing and less susceptible to attack by brine or acid. Care should be taken that they are layed level. Asphalt is not resistant to oils and is rather soft but is waterproof, fairly hard-wearing and less slippery when wet.
Areas subject to extra traffic may require metal tiles and the exposed edges of loading bays or steps may require some form of metal protection to the edge.
Fish working floor surfaces should be well drained and not allow the formation of water pools. A slope of 1:100 is usually sufficient for drainage but should not be greater than 1:40 which can be dangerous.
Where possible three drainage systems should be provided, one for domestic foul sewage, for storm water and surface drains, and the main drainage system for handling liquid wastes. Main drains should not connect directly to a sewer without an intermediate trap, and should be sufficiently barge to carry away all waste water without backing up or flooding. Floor drainage channels should have easily removable gratings which can be simply cleaned. It should not be possible for rodents to enter the building via the drainage system.
The prime requirement of walls, ceilings and fittings in general is that they are easily cleanable. Walls should be smooth and waterproof and ideally surfaced with ceramic tiles to a height of at least 1 m. Pipe runs and electrical cables should be recessed into the wall or boxed in. If brine, salt or acids are used in processing special attention should be paid to protection of the steelwork or use of alternative materials.
Again a prime requirement of plant and equipment is that it is readily accessible for easy cleaning. Preferably all plant should be raised off the floor on plinths. Electric motors and starters should be water (pressure) proof and good lighting should be provided where cutting, strapping or similar operations are undertaken. Copper and bronze are not suitable metals when in direct contact with food products; stainless steel or aluminium being preferable.
The floor area requirements for fish handling operations depend on the throughput, the nature of the operation and methods of handling and storage. Within the building adequate space must be left for access and movement of fish, offal, ice, packaging materials, etc. Area requirements for ice and chill stores are given in Sections 5 and 7 and fish box dimensions and capacities in Section 8. Careful consideration should also be given in the planning stage as to the requirements of access to the building and parking in its vicinity particularly in the case of fish markets. As an example, Figure 41 shows the plan of a wet fish (filleting) operation designed for a maximum throughput of 5t (whole gutted fish input) per day. It is typical of many small concerns operating on or near wholesale fish markets supplying a wet fish trade. It is assumed in this cage that centralised facilities of canteen, toilets, etc.,are available to staff.
The second example shown in Figure 42 is of a wholesale fish market designed for a maximum landing (mostly by vessel) of 200 t per day. The design assumes that a11 fish is laid out for display and that only one auction round is conducted each day. A boxed display is assumed with no stacking of boxes. The design makes allowance for storage of unloading and grading equipment, box cleaning and storage, and washroom facilities. Other facilities such as canteen, ice supply, banking and other offices are assumed to be available.
The capital cost of buildings suitable for fish processing or handling will vary enormously depending on location, design, materials of construction and size but as an indication of UK cost levels the following table gives the cost per square metre for three classes of building (excluding ground cost) .
Table 24 Building costs
| US$/m� | |
| First class processing building including offices, storage, washrooms, etc. | 250-350 |
| Auction hall with washrooms and limited office facility | 150-250 |
| Sheds and open building of a simple nature | 100-175 |
Figure 41. Wet fish processing unit -5 t/d
Figure 42. Wholesale fish market - 200 t/d
