Small-Scale Postharvest Handling Practices PDF

CHAPTER 7: STORAGE OF HORTICULTURAL CROPS - 3 Storage structures A yam barn is a traditional structure used in West Africa to store yams after curing. Fast-growing, live trees are used to create a rectangular structure, and form the framework of the barn as well as provide shade....

CHAPTER 7: STORAGE OF HORTICULTURAL CROPS - 3 Storage structures A yam barn is a traditional structure used in West Africa to store yams after curing. Fast-growing, live trees are used to create a rectangular structure, and form the framework of the barn as well as provide shade. Outside view of barn with 'live' shade Trunks of fast growing trees planted in situ Source: Wilson , J. No date. Careful Storage of Yams: Some Basic Principles to Reduce Losses. London , England : Commonwealth Secretariat/International Institute of Tropical Agriculture. Storage facilities require adequate ventilation in order to help extend shelf life and maintain produce quality. The following are three types of fans found in common use. Centrifugal: Axial flow: Propeller/expeller: Source: Potato Marketing Board. No date. Control of Environment. Part 2. London : Sutton Bridge Experiment Station, Report No. 6 Ventilation in storage structures is improved if air inlets are located at the bottom of the store, while air outlets are at the top. A simple, light-proof exhaust vent is a pressure-relief flap.  Source: Potato Marketing Board. No date. Control of Environment. Part 2. London : Sutton Bridge Experiment Station, Report No. 6 Any type of building or facility used for storage of horticultural crops should be insulated for maximum effectiveness. A well insulated refrigerated building will require less electricity to keep produce cool. If the structure is to be cooled by evaporative or night air ventilation, a well insulated building will hold the cooled air longer. Insulation R-values are listed below for some common building materials. R refers to resistance, and the higher the R-value, the higher the material's resistance to heat conduction and the better the insulating property of the material. R – Value Material 1 inch thick Batt and Blanket Insulation Glass wool, mineral wool, or fiberglass 3.50 Fill-Type Insulation  Cellulose 3.50 Glass or mineral wool 2.50-3.00 Vermiculite 2.20 Wood shavings or sawdust 2.22 Rigid Insulation Plain expanded extruded polystyrene 5.00 Expanded rubber 4.55 Expanded polystyrene molded beads 3.57 Aged expanded polyurethane 6.25 Glass fiber 4.00 Polyisocyranuate 8.00 Wood or cane fiber board 2.50 Foamed-in-Place Insulation Sprayed expanded urethane 6.25 Building Materials Full thickness of material Solid concrete 0.08 8-inch concrete block, open core 1.11 8-inch lightweight concrete block open core 2.00 8-inch concrete block with vermiculite in core 5.03 Lumber, fir or pine 1.25 Metal siding