PreviousAnnex 4 (Reference Chapter 6) - Fumigable warehouses
Conventional and traditional warehouses have frequently been fumigated, either by sealing gaps in the structure (Webley and Harris, 1979)' or by enveloping the entire building under gas-proof sheeting. However, such operations are never simple and are often fraught with difficulties. Bulk grain storage facilities are usually constructed with fumigation in mind and, unless they are structurally faulty, are sufficiently gas-tight for this purpose.
The fumigable warehouse briefly described here was developed in the sahelian zone of west Africa (Hayward, 1981), and is intended for long-term storage of reserve stocks of grain.
Much of what is written in Chapter 6 about the location, design and determination of size of standard warehouses applies equally to fumigable warehouses. Only the differences relating to sealing of the warehouses are highlighted in this Annex.
Walls: Constructed of hollow concrete blocks, these are rendered smooth with cement plaster and then covered on the inside with a special plastic paint.
Roof: The spaces between the aluminium roof sheets and the girders along the tops of the side walls are plugged with shaped wood pieces soaked with wood preservative and bitumen. A liberal coating of bitumen is then painted on and around the plugs.
Ventilators: These are fitted externally with tight fitting flanged metal covers, which can be locked and sealed with gas-proof sealing tape.
Doors: The hinged metal doors are tight-fitting, and have flanges overlapping the frame set in the wall so that the gap all round is not greater than 2 mm. When the doors are closed for a fumigation this gap is closed completely with gas-proof sealing tape.
