Analysis of the rainwater tank sizing methods suggested by NBR 15527/07 through daily simulation

ABSTRACT To overcome the problem of water availability and to preserve water resources, there have been sought alternative sources of water to supply human activities. Among the available solutions, there is rainwater harvesting. This technique is based on capturing rainfall from impermeable areas and storing it in tanks to enable its use. The tank is, usually, the most expensive part of such a system. This structure design is possible through different methods, hence the need to evaluate which of those is the most appropriate one. Therefore, this paper analyzed the sizing methods suggested by the Brazilian Association of Technical Standards (Associação Brasileira de Normas Técnicas - ABNT), presented in the technical standard NBR 15527/07, concerning their performance levels. The analysis was based on the guarantee levels of supply achieved according to the method used. From the results obtained, the Daily and Monthly Rippl methods for producing tank capacities associated with the higher supply reliability (98 to 100%).