Prospects of green plot ratio in residential buildings in context of Dhaka

Abstract

Green plot Ratio (GPR) is a concept that helps to determine amount of green of a particular site.GPR is presented as a ratio that is similar to the Floor area ratio (FAR), currently in use in building regulations of Bangladesh, to control maximum allowable built-up floor area in a building development. In context of Dhaka apartment building development has been growing rapidly since 1999 because of huge household demand, lack of enough land, rapid urbanization etc. Real estate sector has already supplied approximately 60,000 units to housing market in past 20 years. Transition of single family dwellings to multistoried apartments has led to alteration of green to grey area increasing built-up areas at the cost of green /unpaved areas ( example: Dhanmondi). From operational phase of these apartment buildings there is significant amount of CO2 emission. However there is no specific clause to provide green in a plot according to Building construction rule (BCR) 1996 and 2006, as vegetation absorbs CO2 and heat, carbon sequestration is reduced by this change. This study intended to find out the amount of CO2 emissions from residential areas and the sequestration capacities of plant species present in that building. Three kinds of data have been collected: one in terms of CO2 emission from the selected buildings, second is CO2 absorption capacity of the plant species and the third one is regarding design attributes of the buildings (FAR, Ground coverage, height etc). The study has included field survey and plan analysis of selected buildings. CO2 emission of the building has been estimated with the collected data. Therefore, the study used green plot ratio (GPR) as a method in measuring the greenery in the case studies. A blending of correlation and regression method has been used see the influence of building design attributes, CO2 emission and sequestration on GPR. The study reveals that FAR, GC and CO2 sequestration have the strongest correlations with GPR regarding the case studies. An equation is derived from the regression to account GPR with the known value of FAR, GC and CO2 sequestration based on the eight case studies. The chapter proposes guidelines to facilitate CO2 emission control with building integrated green by using GPR to create a balance of urban green and built-up area based on the study buildings.