Bridging The Housing Deficit In Nigeria: Energy And Co2 Emissions Implications

Affordable and decent housing constitute an important component of the urban infrastructure of any nation. In Nigeria, the housing deficit was estimated in the year 2012 to be about 17 million. Understandably, the huge financial and complex logistical implications of bridging the deficit appear to have dominated academic discussions on the subject matter. This paper attempts to address the energy and CO2 emissions implications of mitigating the huge housing deficit. Using a predominant urban social housing typology in the highly urbanized city of Lagos as a basis, the paper estimated the embodied energy and CO2 emissions associated with providing the additional housing units needed to bridge the deficit. The life cycle energy analysis framework was adopted for the study with the Inventory of Carbon and Energy (ICE) as the main source of embodied energy and CO2 coefficients. It was found that given a housing unit footprint of 120m2 and a building life span of 50 years, the embodied energy and CO2 emissions intensities for the prototype were 7378MJ/m2 and 589kg/m2 respectively. For the additional housing units, the above intensities translated to about 15.x 1012 MJ of embodied energy and 1.2 x 1012kg of CO2. With respect to the building components, the largest contributors to the embodied energy and carbon profile were the substructure, frame and upper floors as well as internal and external walls and the key materials for the components were cement and steel reinforcement. In order to reduce the estimated embodied energy and carbon impact of providing the additional housing needs, the targets for mitigation should be the concrete, steel reinforcement and envelope/partition materials of the building

Implementation of lean practices in the construction industry: A systematic review

The implementation of lean principles and approaches is gaining grounds in the construction industry globally. However, there is no clear understanding of the number and categories of lean practices implemented and the benefits associated with it in the planning, design and construction of building and infrastructure projects. This paper relied on a systematic review of published literature in Scopus, Science Direct and Google Scholar to identify and categorize the different lean practices implemented in the construction industry and the benefits derivable from them. Totally, 102 documents published between 1996 and 2018 were reviewed and their contents analyzed using descriptive statistics and content analysis. A total of 32 different lean practices categorised into design and engineering; planning and control; construction and site management; and health and safety management were identified. The review also found that the last planner system and just-in-time were the top two most implemented lean practices and about 20 different economic, social and environmental benefits were linked to the implementation of lean practices in the construction industry. This review is instructive that lean practices have good prospects for enhancing the productivity of the construction industry and achieving sustainable built environment, but a critical mass uptake and sustained implementation are required to attain these goal

Lean construction: an approach to achieving sustainable built environment in Nigeria

The Nigerian building industry (NIB) is faced with numerous challenges. Chief among these is how best to manage the different kinds of wastes generated during the building procurement process and by so doing improve the sustainability record of the industry. Cost overrun, time overrun, and waste of building materials are the major problems crippling the industry. However, lean approach has been established in western world such as the USA, UK and others as an approach that helps in attaining sustainability in the building projects. This paper presents result of a study conducted to identify benefits derivable from the adoption of lean practices (LPs) by firms in the NIB. The approach adopted for this study was the review of literature to identify the benefits of Lean Practices (LPs) adoption and a questionnaire survey of architecture, building consulting and contracting and quantity surveying firms in Abuja, Lagos, Port-Harcourt, Enugu and Kaduna. In all, 446 valid responses were obtained and the data analyzed using descriptive statistics. The result revealed that stakeholders in the Nigerian building industry perceived LPs adoption as very helpful in the reduction of time and cost overrun on projects. Thus, the study has established that the adoption of LPs is one of the ways stakeholders in the industry are using to achieve economic sustainability in the procurement of building projects and ensuring that clients and end-users get value for money in such projects

De-carbonizing the Nigerian Housing Sector: The Role of Life Cycle CO2 Assessment

Carbon in the form of carbon dioxide (CO2) is the most important chemical compound in the climate change process as it is the main causative agent of global warming and climate change. International efforts aimed at arresting climate change are all directed at carbon elimination or reduction. Buildings especially residential buildings have been found to contribute substantially to climate change through the carbon emitted to the environment in the process of building procurement and use. This paper aims at tracking the CO2 content of the various activities and processes involved in building procurement and use in a Nigerian context with a view to indentifying the target areas for decarbonization. This is done by applying the life cycle CO2 assessment (LCCO2A) approach to a typical urban residential apartment building in Lagos, Nigeria’s most populous and urbanized city. In this respect, the ICE database and the activity based method were used to estimate the embodied and operational CO2 emissions associated with the case building. The study found that the embodied and operational emissions were significant when compared with baseline scenarios in other countries. Hence the paper concluded that de-carbonization strategies should be targeted at both the embodied and operational carbon emissions of buildings. The best result will be achieved if the de-carbonization efforts are combined with natural and active carbon sinks that exist in the study contex

Implementation of Quality-Management Procedures in the Production and Utilization of Cement Stabilized Laterite Interlocking Blocks in Nigeria

The challenges associated with building materials in Nigeria have been largely blamed for the high cost of housing delivery in the country. As a result, there has been a clarion call for the introduction of cheaper building materials into the Nigerian building construction market. Consequently, various research and development efforts have resulted in the introduction of alternative building materials and their associated technologies. Building materials are expected to meet stipulated standards which will ensure not only their aesthetics but also their appropriateness for their intended uses including structural stability, safety and health of building occupants. A major criticism of alternative building materials in the country has been their non- compliance to quality management procedures in their production and use. This study explores the extent to which quality control measures have been implemented in the production and use of alternative building materials and challenges encountered. The study has been motivated by series of building collapse in the country. Qualitative research method was adopted for the study and involved interviews with purposively selected persons involved in the production and use of alternative building materials in the Lagos area. Findings indicate a low level adoption of quality management procedures due to insufficient training, non-optimum performance of equipment, lack of manuals, time constraints, low education and motivation of workers involved in the production and use of alternative building materials. The paper concludes that in order for the potentials of alternative building materials to be realized in the country, there is a dire need for quality control procedures

EMPLOYEE PARTICIPATION IN DECISION-MAKING IN ARCHITECTURAL FIRMS

In this study, the participation of employee architects in decision making in architectural firms is investigated. This is with a view to identifying the organisational contexts that enhance employee participation in decision making. The impact of such participation on the performances of the firms was also assessed. This study was carried out through a questionnaire survey of employers of architects in Nigeria. In agreement with findings of previous studies, participation of the employees of the architectural firms in the study in decision making is low. Employee participation in decision making in the firms was dependent on the staffing strategy and proportion of junior staff in many cases. The positive impact of employee participation in decision making on firm performance varied with the nature of the decision. This study concludes that there is need for employers in architectural firms to identify the categories of decision that employees should be involved in and to modify their firm contexts to encourage participation where desired

BRIDGING THE HOUSING DEFICIT IN NIGERIA: ENERGY AND CO2 EMISSIONS IMPLICATIONS

Affordable and decent housing constitute an important component of the urban infrastructure of any nation. In Nigeria, the housing deficit was estimated in the year 2012 to be about 17 million. Understandably, the huge financial and complex logistical implications of bridging the deficit appear to have dominated academic discussions on the subject matter. This paper attempts to address the energy and CO2 emission implications of mitigating the huge housing deficit. Using a predominant urban social housing typology in the highly urbanized city of Lagos as a basis, the paper estimated the embodied energy and CO2 emissions associated with providing the additional housing units needed to bridge the deficit. The life cycle energy analysis framework was adopted for the study with the Inventory of Carbon and Energy (ICE) as the main source of embodied energy and CO2 coefficients. It was found that given a housing unit footprint of 120m2 and a building life span of 50 years, the embodied energy and CO2 emissions intensities for the prototype were 7378MJ/m2 and 589kg/m2 respectively. For the additional housing units, the above intensities translated to about 15.x 1012 MJ of embodied energy and 1.2 x 1012kg of CO2. With respect to the building components, the largest contributors to the embodied energy and carbon profile were the substructure, frame and upper floors as well as internal and external walls and the key materials for the components were cement and steel reinforcement. In order to reduce the estimated embodied energy and carbon impact of providing the additional housing needs, the targets for mitigation should be the concrete, steel reinforcement and envelope/partition materials of the building

Mitigating the environmental impact of residential buildings through the use of alternative building materials: A review.

Buildings in general and residential buildings in particular impact on the environment through the energy and carbon embodied in the production and use of building materials. A number of studies have identified portland cement, portland cement cement-based products and steel reinforcement as major contributors to the embodied impact of residential buildings. Incidentally, these high impact materials constitute the bulk of the materials used in urban residential building construction in Nigeria. Also, there is considerable literature on alternative building materials which can be used to substitute high impact materials in Nigeria. Using the literature review approach, this paper examines the alternative materials that can be used to substitute the prevalent high impact materials with a view to making the buildings more sustainable by reducing their embodied energy. Relevant journal articles published between 2000 and 2015 and sourced from several databases were selected and studied. The materials were examined under the following headings: cement substitutes, mortar substitutes, concrete substitutes, steel reinforcement substitutes and substitutes for external and internal walls. The study found that in as much as substitutes exist for some high impact materials, there is the need to undertake further research especially for the purpose of codifying the materials for unhindered use in the building construction industry. In addition, adequate research-industry partnership is necessary for speedy adaptation, dissemination and use of research findings on alternative building material

Prospects, Barriers and Development Control Implications in the use of Green Roofs in Lagos State, Nigeria

Green roofs are gaining importance as “soft” engineering approach to urban environmental management and have been found to be beneficial in stormwater management, noise and thermal insulation, mitigation of the urban heat island effect, carbon sequestration and ultimately climate change mitigation. Lagos, a fast growing megacity is characterized by a rapidly growing population within a very limited land area. The resultant development pressure on land has given rise to dense urban fabric with associated loss of green cover especially within the inner city thereby eliciting suggestions for the adoption of green roofs. The present paper examined the prospects and the barriers to the adoption of green roofs as well as the attendant development control implications in Lagos, Nigeria. A combined quantitative and qualitative research strategy was adopted for the study. For quantitative data, pre-tested questionnaire was administered to 60 purposively selected built environment professionals in academics, consultancy and in government while qualitative data were obtained from interview of four key stakeholders. Secondary data were obtained from literature. Analysis of primary data was by the use of descriptive statistics and relative importance index while content analysis was used for the analysis of qualitative data. The study found that while opportunities for adoption of green roofs exist, they were not popular in the study area because of cost, technical challenges, poor knowledge as well as limitations imposed by the interpretation of planning laws. The paper proposed context-relevant application of green roofs as a complement to ongoing green infrastructure programme in the study area