Burnt-Pot Roof Insulation” (BPRI): Its Application and Efficiency in Bangladesh
Summary
The uppermost roof of the building needs insulation for thermal and humidity purposes. In Bangladesh Lime-terracing is used for this purpose. Mortar made of slaked Lime and powdered Brick (local name : surki) is applied on the r.c.c. roof in 100 mm layer. It works fairly well in the situation where the variation of internal and external temperatures is low. In Bangladesh this variation in the naturally ventilated rooms is not over 30 Celsius and lime terracing shows a time lag of about 5 hours at this range.
Some of the problems of the conventional Lime terracing are : (a) It is costly, (b) It allows heat leakage when atmospheric temperature rises above 350 Celsius and also when there is wide variation in internal and external temperatures due to air-conditioning of the room. The authors of this paper devised an alternate system. In this system air pockets were provided inside the layer such that it became lighter, consumed less material and had more insulating properties. The air pockets were provided by using burnt clay pots available in the market. The system was named Burnt-Pot Roof Insulation, abbreviated as BPRI. BPRI was first applied in Khulna, Bangladesh in 2002. The cost of constructed was only 10% cost of the conventional lime terracing. Now BPRI is being used in various regions of the country.
References
Sarma, 2005 : Book “A TEXT BOOK OF CLIMATE AND DESIGN FOR THE BUILT-FORM DESIGNERS”, ISBN 984-8684-02-6, Authors Bijon B. Sarma and Falguni Malick, Published by Bangladesh Publishers, Dhaka, Bangladesh P. 104.
Sarma, 2002 : Unpublished M. Arch Thesis “A STUDY OF THE FACTORS FOR THERMAL COMFORT IN RESIDENTIAL HIGH-RISE IN DHAKA CITY” done in Architecture Department, Bangladesh University of Engineering and Technology, Dhaka, Bangladesh in 2002.
Sarma, 1997 : Paper “SOLAR ARCHITECTURE AND THE UTILIZATION OF SOLAR ENERGY IN BANGLADESH”, published in the ARCHI TIMES, November 1997, Vo. 12, No. 11, Published from Gafoor Chamber, Karachi, Pakistan.
Alam and Ullah, 1994 : Paper “REDUCTION OF HEAT TRANSMISSION THROUGH BUILDING ENVELOPE : STRATEGY FOR REPLACEMENT OF BUILDING ELEMENTS”. Published in the Report of the Technical Conference on Tropical Urban Climates. WCASP – 30. WMO/TD-No. 617, World Meteorological Organization 1994. Page 395- 412.