Thermal Conditions in Sheet Metal Clad Residential Buildings A Case Study of Kiambu County, Kenya

Overview
Overview

The high demand for affordable sustainable residential buildings in Kenya is not being met,

and thus the use of galvanized sheet metal houses by local developers for site accommodation, cheap

rental housing and private homes has increased.Sheet metal building structures come in different

forms in Kenya; first, there is the simplest form constructed of a light wooden frame covered

with light gauge galvanized sheet metal; secondly, there is the ‘uni-hut’ type made of heavy gauge

galvanized structural sheet metal; and lastly, there is the shipping container building structure

(Republic of Kenya (ROK), 2016). During a sunny day the metal structures transmit a lot of heat

internally and during chilly nights they lose heat fast to the external environment (Abrasheva, Senk

& Häußling, 2012).

Simple sheet metal clad buildings are used as sheds and barns in the temperate countries and

are not considered as shelter for human habitation due to their poor insulation capacity. The simple

sheet metal clad building is the most popular in tropical Africa and Kenya in particular where

they are used for accommodation in the informal settlements. Studies have shown that in Nairobi

alone, 60% of the population lives in the informal settlements (ROK, 2016).

Principle Instigator
Peter M. Gathirimu*, Charles Kabubo and Patrick Ajwang
Abstract

This research aimed to conduct a field study on sheet metal clad residential buildings with an aim to gather data to determine their thermal comfort, condensation risk, and develop a micro-climate predicting model. The geographical area for the study was Uthiru in Kiambu County. The findings of this research document the thermal comfort (and living conditions) of sheet metal clad buildings under normal residential use which are exposed to the same climatic conditions simultaneously. A web-based application software (Thermal Comfort Tool for ASHRAE-55) based on the adoptive method of ASHRAE Standard 55-2017 was used to check the compliance on the thermal comfort of the case study buildings. From the temperature and relative humidity data, absolute humidity values, and dew point temperatures were calculated thereby determining the level of condensation risk on the buildings. Use was made of Microsoft Windows Excel application to analyze the collected data and to develop a microclimate predicting model. The recommendations are specific to the case study buildings’ design adjustments that could be required and recognition for acceptability of the sheet metal clad buildings as worthy to be included in the Kenya Building Code.