Space standardisation oflow-income housing units

in IndiaUttam Kumar Roy

Architecture and Planning Department,Indian Institute of Technology Roorkee, Roorkee, India, and

Madhumita RoyArchitecture Department, Jadavpur University, Kolkata, India

AbstractPurpose – This paper aims to develop a set of affordable space and dimensional standards formarket-driven low-income housing in Indian context for the purpose of mass production usingindustrialised building system.Design/methodology/approach – For this, the paper first explains the significance ofstandardisation from the literature and revisits the codes and contemporary practices in industrialisedbuilding system (IBS) in India. Next, it undertakes a market survey of ongoing/completed housingprojects to study the space/dimensions reflected in the market demand by the people. After consideringconditions like modular grid suitability and provisions of code, it identifies a set of dimensionalstandards of activity spaces, emerging from the market study. It also suggests a framework of modularunits showing the incremental attachment possibility for component-based construction using IBS.These standards and design frameworks will make the path for developing various products andcomponents towards an open system in India.Findings – The paper gives an insight of the market trends of low-income housing, focusing on unitdesigns and spatial elements.Research limitations/implications – Local contextualisation during the unit designs will berequired and that is not addressed in this paper.Practical implications – This will benefit developers, manufacturers, designers as well aspolicymakers towards a market-driven housing delivery using IBS.Social implications – As a result of this standardisation, housing delivery will be faster and therewill be more numbers of market-driven affordable housing in masses for low-income people, thussolving housing shortage.Originality/value – A developing country like India is a diversified country having manygeographical and social variations. Such standardisation for a space and design framework has neverbeen attempted before and will make a contribution for the public housing sector.

Keywords Housing market, Incremental housing, Industrialised building systems (IBS),Low-income-group (LIG) housing, Open system, Space standards

Paper type Research paper

Authors are thankful to the co-researcher of the Energy Efficient Built Environment at JadavpurUniversity for their support and also to Indian Institute of Technology Roorkee for allowingcontinuing the research at the institute.

The current issue and full text archive of this journal is available on Emerald Insight at:www.emeraldinsight.com/1753-8270.htm

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Received 12 December 2014Revised 4 March 2015Accepted 11 March 2015

International Journal of HousingMarkets and AnalysisVol. 9 No. 1, 2016pp. 88-107© Emerald Group Publishing Limited1753-8270DOI 10.1108/IJHMA-12-2014-0057

1. IntroductionProviding affordable housing for low-income people has been a challenge for all andIndia is no exception. Present estimated housing shortage, which has increased in pastdecades, is 2.47 million (one out of ten do not have liveable house) (National BuildingOrganisation (NBO), 2011 and Ministry of Housing and Urban Poverty Alleviation,2007). The problem is severe in urban areas where one out of six persons do not have aliveable house. In total, 96 per cent of this shortage caters to low-income category, whichhas been sub-categorised based on family income, in India, as lower-income group (LIG)and economically weaker section (EWS). EWS is considered to be the poorest among allcategories, except the pavement dwellers and homeless. In developing countries, likeIndia, a wide variety of design and dimensions is practiced concurrently in housingdelivery. Non-standard dimensions of physical spaces are common. Irrational andnon-modular physical planning, absence of modularity and dimension standard,involvement of non-technical persons in housing delivery are seen. However, due to lackof any standardisation, time and cost economy is not achieved. Advantage of repetitionstowards economy of scale is not utilised. As a result, the housing delivery is less incomparison with the increasing shortage of housing.

The government has been trying to bring various policy interventions for morehousing production. In the past couple of years, the policy reforms, like 100 per centforeign direct investment (FDI) in housing, repeal of ULCRA[1], Amendment of LandAcquisition Act, Regularisation of land title certification, enabled private developersand joint venture companies to develop “market driven affordable units” for LIG. Inmost of the cases, the units are sold without subsidy or marginal cross-subsidy.Considering the increase in and the importance of the housing shortage challenge,especially for low-income people, India requires a radical change in the housing deliverysystem to generate substantial housing stock in a faster speed. National Housing andHabitat Policy (1998) and National Urban Housing and Habitat Policy (2007) mentionedthe necessity of a faster housing supply system to fill up the demand–supply gap for thelow-income category housing. The recent trend of developing market-driven housingunit for low-income people is a mentionable improvement in India, though the quantityis not sufficient enough in comparison to the shortage. More supply of housing unitsusing industrialised building system (IBS)[2] is capable of mitigating the housingshortage for low-income people. Technologies for prefabrication of buildingcomponents are available, but they lack the linkages with the housing market.Therefore, to develop a linkage between such technology and the market demand, it isabsolutely necessary to develop some dimension standards and module based on themarket demand. To achieve such faster construction, standardisation is an inevitablestage.

The paper attempts to develop a set of affordable space and dimensional standardsfor market-driven low-income housing in Indian context for the purpose of massproduction using IBS. These standards and design frameworks will pave the path fordeveloping various products and components for an open system in India. For this, thepaper first explains the significance of standardisation from the literature and revisitsthe codes and contemporary practices in IBS in India. Next, it undertakes a marketsurvey of ongoing/completed housing projects to study the space/dimensions reflectedin the market demand by the people. After considering conditions like modular gridsuitability and provisions of code, it recommends a set of dimensional standards of

89

Low-incomehousing units

activity spaces, emerging from the market study. It also suggests a framework ofmodular units showing the incremental attachment possibility for component-basedconstruction using IBS.

2. Literature studyIBS, using prefabricated building components, has been shown to be effective inachieving speed, cost-effectiveness and quality in mass housing (Shaari and Ismail,2004). IBS is categorised into two categories based on its supply method: opensystem and closed system (Sarja, 1998; Thanoon et al., 2003). A closed system isbased on client’s design and pre-caster’s design. The first category is designed tomeet a spatial requirement of the client, that is, the spaces required for variousfunctions in the building as well as the specific architectural design. In this instance,the client’s needs are paramount and the pre-caster is always forced to produce aspecific component for a building. On the other hand, the production based onpre-caster’s design includes designing and producing a uniform type of building ora group of building variants, which can be produced with a common assortment ofcomponent (Thanoon et al., 2003). Closed system does not allow flexibility for theusers or the designers to develop many alternatives or add parts of components infuture. Open system involves the integration of many sub-systems from variousmanufacturers. Open system ensures flexibility for users as well as increasedsupply of housing units. In view of the limitations inherent in the closed system, anopen system allows the pre-caster to produce a limited number of elements with apredetermined range of product and, at the same time, maintaining architecturalaesthetic value (Thanoon et al., 2003). To achieve this, there are variousprerequisites. For example, positional and dimensional coordination (DC) ofbuilding parts and their interfaces are a tool and condition for industrialisation andprobably a leaner construction process (Cuperus, 2003). An illustration explainingsimplified stages of IBS is shown in Figure 1 (Sarja, 1998; Warszawski, 1999). Itshows that the standardisation is the essential and unavoidable stage followed bydimensional and modular coordination to achieve the prefabrication (partial/full)and mechanisation to reach industrialisation. The first two stages (1 and 2)essentially deal with the architectural design language where as the next stages (3and 4) deal with the delivery of that design through a faster mode of construction(Figure 1).

Dimensions of activity spaces are the outcome of the design process and aresubjected to satisfy user’s need which changes through time. To address this, changesan open building or skeletal system of design and construction using prefabricated

1.Standardiza�on

2. Dimensional and Modular Coordina�on

3. Prefabrica�on

4. Mechanisa�on

5. Industrialisa�on

Figure 1.Stages of IBS

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components has been suggested by Habraken (1961); Sarja (1998); Warszawski (1999)and Cuperus (2003). In order to accommodate unknown future changes, Habraken (1961)suggested different levels of decision making in the building process such as tissue,support and infill. Thus, open building is a multi-faceted concept, with technical,organisational and financial solutions for built environment that can adapt to thechanging needs (Cuperus, 2001). Thus, DC and standardisation have been identifiednotably by Sarja (1998) and Warszawski (1999) as an integral stage of industrialisationof the building process.

The standardisation and modularisation are the essential platforms on whichproducts for building components are developed using quality function deployment(QFD) (Akao, 1990), modular function deployment (MFD) (Erixon, 1998) and design forvariety (DFV) (Martin and Ishii, 2002). Standardisation means the establishment ofsystematic regulations to achieve optimal technical and economic solutions of recurringproblems. This is achieved by predetermined sizes, dimensions and interfaces as well asa limitation of variety, which ensures interchangeability and compatibility as well asflexibility. This is done by the use of standardised modules (Womack et al., 1990). Gibbstates that the standardisation of components and products is the foundation for furtherdevelopment of the house-building industry, achieved through continual improvementin the same way as in other industrial sectors (Gibb, 2001). Modularisation is a way ofdividing a structural system into limited and standardised elements, modules that areprovided with common interfaces. Modules with the same interfaces are given differentcontent, and with a limited set of different module types, unique end-products orstructures are designed (Johnson and Bröms, 2000). Dimensional standardisationfollowed by modular co-ordination suggests the following benefits for a designframework for open system:

• Variety generation: It creates a basis on which the variety of types and sizes ofbuilding components can be minimised. Through a rationalised method ofconstruction, each component is designed to be interchangeable with other similarones and, hence, provides a maximum degree of freedom and choice offered to thedesigner (Warszawski, 1999).

• Interchangeability: It allows for easy adoption of prefabricated components to anylayout and for their interchangeability within the building. This is achieved bydefining the location of each component in the building with reference to acommon modular grid rather than with a reference to other components(Warszawski, 1999).

A simple illustration in Figure 2 shows how a lack of supply of affordable qualityhousing and absence of dimension standards results in irrational designs and generatesthe need for dimension standards and a modular design framework. This frameworkeventually generates more housing stocks and can offer better utilisation of space,speedier construction, reduction of waste and more variety (Figure 2). Various scholarscategorised systematically the architectural elements for standardisation, includingHabraken (1961), Wikberg et al. (2009), etc.

Developed countries have experienced the DC followed by mechanisation andindustrialisation in the housing sector since the 1970s. The problem of joinery andinterconnection in building elements has resulted to research for management of joinery.Cuperus (2003) opined that changes in building process have resulted in an interesting

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Low-incomehousing units

change in thinking about modular co-ordination. Industrialised systems are able tosimplify the production and thereby achieve cost reduction and higher quality at thesame time. The present trend of industrialised housing system is towards offeringcustomised solution maintaining the cost reduction through the economy of scale. Thetrend is called as mass customised housing. Apart from the MCH, the recent debate andongoing deliberations are in the areas like energy efficient models of housing units usingIBS.

The categories and the stages of IBS can be traced back in the development modelgiven by Sarja (1998) as follows:

• local material � manual � in situ;• industrial materials � manual � in situ;• industrial material and equipment � manual assembly � in situ;• partial prefabrication;• closed building concept with prefabricated components and modules;• closed building concept � CAD design and production;• open building system with many suppliers � CAD (design and production); and• open building system from network of companies, total design thinking and

development of design, assembly and finishes.

India stands in Stages 3 and 4. Systemic change in the housing is a well-acceptedoption for faster delivery of housing. A shift from onsite conventional constructionto offsite manufacturing of buildings and/or its components can deliver speedierhousing. The myth that India, which has abundant unskilled labour, is not suitablefor prefabricated housing system continued till the 1990s. It has been shown by Royet al. (2008) that out of the various factors responsible for creating barriers for notachieving the housing target, a faster system of housing supply is the mostimportant one followed by lower affordability. It is mentioned by various authorslike Jain (2007), Chattopadhyay (2008), Adalakha and Puri (2003) and Roy et al.(2008) that for India, the mass production of housing by component-based partialprefabricated/IBS will be suitable to combat this increasing housing shortage. Jain

Irrational design configuration

Non-standardized design leading to

wastage of materials and time delay

Lack of supply of affordable quality

housing

Absence of dimensional standard

Formulation ofDimension Standards

Modular Designs of components and

building

• Faster construction. • Efficient spaces & lifestyle• Reduction of wastage and cost • Better finishing and User Satisfaction• More options for Developers

More housing stock

Figure 2.The reason whydimensionalstandard is required

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mentioned that India is a vast country with wide variation in its topography, livingpatterns and socio-economic conditions. The concept of industrialisation of housingin India should be decentralised and not the Western model of organisedcentralisation. With its diversity, India should adopt prefabrication by the massesrather than massive prefabrication (Jain, 2007).

Industrialised housing will address the major economic group falling in the EWSand LIG mainly. However, mainstream housing developed by owner/developer inthe conventional way will continue to exist in an inclusive manner with theindustrialised form of housing to cater all the cross-section of society. Thesocio-cultural and flexible needs of the people have to be satisfied through newdesign, new materials and new construction technology both in the owner-built andthe manufactured housing categories to make it an inclusive approach(Chattopadhyay, 2008). In spite of such deliberations by scholars, there are somesignificant research gap in the linkage between the space standards and theaffordable low-income housing market. The potential of offsite construction linkedwith the design standards has not been tested for low-income housing. Therefore,the mass production of housing through IBS is possible if appropriate study on thedimensional and modular coordination for housing in India is in place. The nextsection will discuss the methodology for the study and parameters.

3. Methodology, assumptions and parameters of the study3.1 Methodology of the study (Figure 3)The paper attempts to develop a set of affordable space and dimensional standardsfor market-driven low-income housing for the purpose of mass production usingIBS. The conventional approach to develop space standards has been centred on thedesigner. Deriving space standards based on the market demand has not beenfollowed in the predominant literature due to many reasons, including therobustness of volume of study, etc. However, here in this study, it basically adoptsa case study approach to link such design language (standards) with the marketanalysis of low-income housing. For this, it has already explained the significance ofstandardisation from the literature (Section 2). Next, it will revisit the codes andcontemporary practices in IBS in India (Section 4). Finally, it undertakes a marketsurvey of ongoing/completed housing projects to study the space/dimensions

Literature study

Check with the national Codes

Market study

Findings, analysis and development of

modular dimensions

Reference from Contemporary practices

Check with the Grid and basic

Module

Identified Modulardimension and module

Developing variety with expansion option within market range

Figure 3.Methodology

adopted for evolvingthe dimension

standards

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Low-incomehousing units

reflected in the market demand by the people (Section 5). After consideringconditions like modular grid suitability and provisions of code, it recommends a setof dimensional standards of activity spaces, emerging from the market study. It alsosuggests a framework of modular units showing the variety with expansionpossibility for component-based construction using IBS.

To enumerate the standards of functional space, a market survey was conductedduring the year 2011-2013. Total 17 projects have been selected, and out of those, morethan 25 types of one bed room layout having a saleable area of 400 � 100 sq.ft have beenanalysed. All functional room dimensions have been analysed as per the existingdimensions. The length and breadth have been considered separately (Appendix A1)and expressed as dimensions L and B. After compiling the range of dimensions of theparameters as mentioned in Table VII (and in Appendix A1, in details), the arithmeticaverage of all dimensions of activity spaces has been derived.

Naturally, the average shows “non-modular” dimensions. This has been roundedup to a standard modular dimension (e.g. if an average is 2,975 mm, then 3,000 mmhas been taken as the standard modular value). Standard deviations are calculatedto determine the range of variations. After this, a range of modular dimensions(maximum and minimum), considering the standard deviation of the rangesavailable, are identified.

An analysis for the appropriate grid sizes for the particular user group has been doneseparately. Following this, standard modular dimensions in the multiple of 3M aremarked as “Priority” standards. Proposed standard dimensions have been checked tocomply with the corresponding average and range (considering standard deviation) ofcarpet area and aspect ratio of length and breadth of each activity space. Recommendedstandard dimensions are clear dimensions in principle. The grid line refers to the typicalmodule assumed as the clear dimension excluding the wall thickness. Considering thesestandard dimensions (average, minimum and maximum of all activity spaces) as cleardimensions, the rentable/usable area has been calculated. Each corresponding size of thetotal unit is cross-checked with the other statutory standards/benchmarks as well asreference of users/social requirements from the literature, and finally, threesub-alternatives with their expansion/attachment options based on the open buildingprinciple are shown.

3.2 Assumptions and parameters• It is assumed here that the current practices of frame construction use components

in floors, columns, walls, etc., as the suitable option for low-income housing on thebasis of past works by M/S Siporex (Section 3.4). The use of AAC blocks aswalling and flooring elements is suitable.

• The LIG group refers to a wide range of economy group in several states of India.The Government of India adopts an area up to 300 sq.ft for EWS and 301-599 sq.ftfor LIG (MOHUPA, 2011). In this paper, a one bed room apartment having asaleable area of 400 � 100 sq.ft, which an LIG family having an income of Rs10,000 per month (as of 2012) can afford, has been considered.

• Recommended standard dimensions are clear dimensions in principle. The gridline refers to the clear dimension excluding the wall thickness.

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• Non-structural components such as fixtures, like electrical, plumbing, sanitaryand kitchen accessories, painting and other surface treatments, and furniture andmoveable components are not dealt with here.

• The present study considers the following parameters (Table I).

4. Codes and practices on IBS in India4.1 Provisions in the national codesInternationally, a modular dimension of 100 mm has been conceived as one module (1M).In India, considering the prevalent building code, National Building Code (NBC, 2005)has dealt with the prefabricated concrete elements in buildings. IS 15916-2010 providesthe basic rules for Dimensional and Modular Coordination and is given in Table II. Thenext section shows the major and relevant works conducted by the private sector andinstitutions in the areas of IBS in India.

4.2 Practices by Shirke group of company and Siporex India (source: company websiteand interviews)In India, M/s B.G. Shirke has been delivering housing using industrialised methods forseveral years, though it is confined only in some specific areas of India. BGSCTPL alsopioneered and patented the “3-S” system in India – a system using partial pre-caststructural components, such as dense-concrete hollow-core columns, dense concretepartially pre-cast beams, lintels, staircases, etc., and Siporex blocks and slabs to achievestrength, safety and speed (Table III).

The company has so far executed more than 200,000 dwelling units using “3 S”system, both in India and overseas, in all types of climatic conditions and heavy rainfallareas. At present, it executes very large housing, industrial and commercial projects inIndia on turnkey lump sum basis by the use of proven prefabricated products and/oralso by the conventional methods and materials. “3S” system of building constructionhas been used successfully for high-rise residential buildings up to 25 storeys. A typical

Table I.Parameters for the

market study

Category Spaces/elements Study parameters and its scope

Horizontal members Bed rooms 1 and 2, living cumdining, kitchen, toilet 1 and 2,verandah/balcony

Horizontal lengths and breadth of activityspace (i.e. interior dimensions)

Overall area Rentable/usable area in horizontal plane

Table II.Provisions for

dimension standardsin IS 15916-2010 code

Type of buildingsPlanning grids

Horizontal direction Vertical direction

Industrial buildings 15 M 2 MOther buildings 3 M M

Notes: In case of internal columns, the grid lines shall coincide with the centre lines of columns; in caseof external columns and columns near the lift and stair wells, the grid lines shall coincide with centrelines of the column in the topmost storey

95

Low-incomehousing units

housing project constructed using prefabricated components is shown in Figure 4, andthe standard prefabricated block sizes are given in Table IV.

4.3 The IIA–CCPS initiativesThe Confederation of Construction Products and Services (CCPS) has undertakenproduct standardisation initiatives with Indian Institute of Architects (IIA). It hasidentified doors and windows as important construction products, where industry isready to standardize. The collaboration has already done a nation-wide survey andrecommended a few dimensional standards as given in the table. It is visible from abovethat dimensions as marked in italics are not conforming to the recommendations of theIS codes (Table V).

Table III.Construction systemsadopted by M/S B GShirke

Building element ProductionErection andassembly Materials used

Foundation – Manual RCCFloor slabs Offsite mechanized

systemMix of manual andmechanized mode

RCC, AAC

Column and beam Do Do RCCWall blocks/panels Do Do Light-weight concreteFinishing and fixtures Onsite Manual Conventional

Notes: RCC � Reinforced Cement Concrete; AAC � Autoclaved Aerated Concrete

Figure 4.(a) Arrangement ofprefabricatedcomponents (extremetop left and centre);(b) General view of acompleted project(New Hindu Mills)(extreme top right);(c) Roof planshowing thearrangement ofprefabricatedcomponents (left); (d)Typical unit planand clusteringconfiguration in thefloor plan (top)

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Table IV.Standard dimensionof slabs and blocksadopted by Siporex

India

Slab

sB

lock

sW

allp

anel

sLe

ngth

Wid

thT

hick

ness

Leng

thW

idth

Thi

ckne

ssLe

ngth

Wid

thT

hick

ness

1to

4m

t60

0m

m12

5/15

0m

m65

0m

m24

0m

m75

/100

/125

/150

/200

mm

1to

3m

t60

0m

m75

/100

mm

Sou

rce:

Sipo

rex

Indi

a

97

Low-incomehousing units

5. Market study5.1 Profile of the study area (Kolkata)The market-based supply of low-income housing was facilitated after 2000 following theliberalisation and approval of 100 per cent FDI in housing by the Government of India.Thus, the public supply of housing for LIG first came as an outcome of joint venturecompanies in the city of Kolkata and around. Currently, the JV models have beenencouraged across the country among all the major cities. Housing projects already builtin Kolkata and around should be the best examples for the study. As mentioned inSection 3, total 17 projects have been studied (Table VI). Needless to say, the spacestandards and designed modules will be applicable to all geo-climatic regions of Indiawith appropriate alteration locally as per the geo-climatic condition and socio-economicprofile of the target population.

5.2 Findings from market studyResearch findings are based on the dimensional ranges/modularity for activity areas,quantity and composition activity areas and essential parameters like density/floorarea/FAR, efficiency of spatial plans from the floor plans, etc.

Table V.Dimensionalstandards of openingin residentialbuildings proposedby CCPS and IIA

Components Suggested standard dimensions (in mm)

Doors Width Height750, 900, 1,000, 1,200 2,100, 2,400

Windows Sill Width Height450, 900 750, 900, 1,050, 1,200, 1,350, 1,500, 1,650 1,200, 1,500, 1,650, 1,950

Source: IIA and CCPS

Table VI.List of the projectsstudied

Serial no. Name of project Developers

1 Sunrise Junction Bengal Park Chambers2 Anahita Bengal Peerless3 Animikha4 Avishikta5 Alaktika6 Punya Braja Dham7 Greenwood Elements Bengal Shrachi8 New Shrachi Garden9 Tinkanya, Neera Bengal Shelter

10 Malancha Bengal DCL11 Highland Willow Bengal Bellany12 Ambition Bengal Greenfields13 Sugam Park Sugam Homes14 Aponalaya Reside, Ritika15 Trinayani Merlin16 Green Gardens BGA Realtors17 Amra Kunja

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Generally, the size of units varies across the projects. Generally, LIG units have an areafrom 360 sq.ft to 500 sq.ft. Wide varieties of dimensions are seen across the projects andunit designs under study. Some projects show higher dimensional standards for livingand sleeping areas. Dimensions are non-modular and fragmented, leading to thewastage of materials and extra cost for the customer. It appears that dimensions haveevolved from the maximum use of the available land and buildable area (i.e. floor arearatio, FAR), and no rational modularity has been reflected even within the same projectsin some cases (Table VII and Appendix A1 for details).

The usable area (i.e. rentable area) is almost 69 per cent of the saleable areamentioned by the developers for each unit for LIG. This is higher than thecorresponding figure for middle-income group (MIG) (Roy et al., 2009). Within thedomain of the same developer, the dimensions vary from project to project, and evenwithin the same project, it differs within unit typologies. Modularity in arrangingthe space articulation or functional dimensions is not followed; rather, the spacearticulation has been driven by available land area or shape of the land instead ofspace usability in most of the cases.

The internal partitions between the activity spaces are rigid, and there is no scopefor personalisation during design or construction. Thus, the absence of flexibilityand interchangeability in the functional spaces (like kitchen, dining, living, etc.)

Table VII.Existing dimensions

of activity spaces

Serialnumber

Rooms/activityareas

Dimensions as per market trend (in mm)Dimensionrange L1(length) Average L1

Dimensionrange L2(breadth) Average L2

Average area(L1 � L2) in

Sq.m

Predominant configurations1 Living–Dining

(Hall)4,700-2,900 3,586 4,000-2,100 2,994 10.7

2 Bed room 1(larger)

3,910-2,700 3,261 3,300-2,700 2,913 9.5

3 Kitchen 3,000-1,200 2,165 2,080-900 1,576 3.44 Toilet 1 3,000-1,210 2,132 1,400-910 1,239 2.65 Verandah/balcony 2,850-900 1,525 1,250-800 1,094 1.7

Average useable/rentable area 28 (301 sq.ft)

Additional features (5 to 10% cases)6 Toilet 2 1,225 1,225 965 965 1.27 Bed Room 2

(smaller)2,650 2,650 2,400 2,400 6.4

Total usable/rentable area including additional features 35.5 (382 sq.ft)

Notes: Average is the arithmetic average of all dimensions available within all projects for a singleside. For living cum dining not having a single regular rectangular shape (i.e. separate living dining), theequivalent area summing up two or more rectangles considering average breadth of them is shown;generally, one bed room is larger than the other. Living and dining area is merged in a single rectangularspace except a few (10-15%) units

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Low-incomehousing units

limits the usability of the space in the fullest extent. Only 4 projects out of total 17show open kitchen as the only presence of flexibility in the design of the activityspaces.

Further, low-income families being larger than other economic groups need morethan one toilet space. This could be achieved by dividing the bath and water closetarea without increasing the saleable floor space. However, only a single projectshows such flexibility in design. Therefore, the opportunity to create more from theless has been lost in the design and construction. As a result, the low-income familiesare not getting the full value for their hard earned money. Nevertheless, they havevery few options, as the net supply of such houses through conventional system islimited.

5.3 Analysing grid and basic module sizesDimension standards for the basic module and grids have been analysed (Table VIII)based on the parameters like opening compatibility, modularity, multiplicity andconvenience.

Using the grids of 300, 600 and 900 is desirable as per the above table. However, tomake the grid system working in variable dimensions, it appears that 300 mm is the bestoption and is suitable for the basic module.

5.4 Identified modular dimensionConsidering the findings (Section 5.2) and base module size (Section 5.3) as mentionedabove, identified modular dimensions are illustrated in Table IX.

The priority standard expressed above denote the convenient aspect ratio expressedas a proportion of whole numbers (e.g. 3:2, 4:3, 6:5 etc.). LIG have maximum ranges ofdimensions due to larger standard deviation except for the living cum dining hall. Nextsection provides the configuration possibility and unit design options.

6. Discussion and recommendationsConsidering the priority dimensional standards in the preceding sub-section, theconfiguration possibility of activity spaces are shown in Figure 5. LIG people buildtheir houses gradually depending on their increasing income and affordabilitytowards housing. Many authors (Section 2) pointed that even in the formal housing,this feature may be embedded through a framework of open system. The startingpoint of an affordable house for low-income people can be basic and at the bareminimum. Following this, an increasing design framework is shown with theaddition of a single/double module of space standards of activity rooms. Suchframework is categorised into three categories named as “Starter Unit”, “ComfortUnit” and “Aspirant Unit”. The possible composition is shown in Table X, with theincremental options.

7. Conclusion and way forwardThe paper attempted to develop a linkage between the market responses based onthe affordability in housing for the low-income people and the improvedconstruction system (IBS) which is capable of delivering more in a given time. Thelinkage has been represented here through a design language based on basicmodular dimensions of interior space and overall unit size with its expansions

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Table VIII.Evaluation matrix ofvarious grid systems

Para

met

ers

Wei

ghta

geof

each

grid

mod

ule

optio

nA

ssum

ptio

ns1,

000

mm

900

mm

750

mm

600

mm

450

mm

300

mm

Ope

ning

com

patib

ility

(doo

r/w

indo

wet

c)1

32

12

3St

anda

rds

adop

ted

aspe

rII

A-C

CPS

(see

Sect

ion

4.2)

Doo

rsi

zes

1,20

0,90

0,75

0W

indo

wsi

zes

inth

em

ultip

leof

300

mm

Mod

ular

ity(M

�10

0m

m)

aspe

rN

BC

23

13

13

Mul

tiple

of3M

(as

per

ISco

de)�

3M

ultip

leof

M�

2N

on-m

ultip

leof

M�

1M

ultip

licity

for

mak

ing

mod

ular

activ

itysp

aces

12

13

23

Stan

dard

dim

ensi

ons

for

bed

room

:3,6

00/3

,300

,3,0

00Li

ving

dini

ng:3

,000

,4,

200/

4,50

0/4,

800/

5,10

0/5,

400/

5,70

0/6,

000

Kitc

hen:

2,70

0/2,

400,

1,80

0T

oile

t:2,

400/

2,10

0/1,

800,

1,50

0/1,

200

Con

veni

ence

inha

ndlin

g1

12

33

3H

ead

load

for

ansi

ngle

labo

uris

arou

nd24

-32

kgw

hich

iseq

uiva

lent

toR

CCco

mpo

nent

of60

0�

300

�75

Tot

alw

eigh

tage

(abs

olut

enu

mbe

rs)

59

610

812

Ran

king

53

52

41

Not

es:

3�

Com

plyi

ngm

ore

than

60%

;2�

com

plyi

ngm

ore

than

30%

tobe

low

60%

;1�

com

plyi

ngbe

low

30%

101

Low-incomehousing units

Table IX.Identified modulardimension of activityspaces

Func

tiona

lsp

aces

Dim

ensi

onL1

(leng

th)

Dim

ensi

onL2

(bre

adth

)A

vera

gem

odul

arR

ange

SDA

vera

gem

odul

arR

ange

SDPr

opos

edav

erag

e

Livi

ng-d

inin

g3,

600

3,00

0,3,

100,

3,20

0,3,

300,

3,40

0,3,

500,

3,60

0,3,

700,

3,80

0,3,

900,

4,00

0,4,

100,

4,20

0

600

3,00

02,

500,

2,60

0,2,

700,

2,80

0,2,

900,

3,00

0,3,

100,

3,20

0,3,

300,

3,40

0,3,

500

500

3,60

0�

3,00

0

Bed

room

1(la

rger

)3,

300

3,50

0,3,

400,

3,30

0,3,

200,

3,10

020

03,

000

3,20

0,3,

100,

3,00

0,2,

900,

2,80

020

03,

300

�3,

000

Bed

room

22,

700

2,60

0,2,

700

2,40

02,

400

2,60

0�

2,40

0K

itche

n2,

100

2,70

0,2,

600,

2,50

0,2,

400,

2,30

0,2,

200,

2,10

0,2,

000,

1,90

0,1,

800,

1,70

0

500

1,60

01,

900,

1,80

0,1,

700,

1,60

0,1,

500,

1,40

0,1,

300

300

2,10

0�

1,60

0

Toi

let1

(larg

er)

1,20

02,

600,

2,50

0,2,

400,

2,30

0,2,

200,

2,10

0,2,

000,

1,90

0,1,

800,

1,70

0,1,

600

500

1,20

01,

400,

1,30

0,1,

200,

1,10

0,1,

000

200

2,10

0�

1,20

0

Toi

let2

1,20

01,

200,

1,30

01,

000

1,00

0,90

01,

200

�90

0B

alco

ny1,

500

1,90

0,1,

800,

1,70

0,1,

600,

1,50

0,1,

400,

1,30

0,1,

200,

1,10

040

01,

100

1,30

0,1,

200,

1,10

0,1,

000,

900

200

1,50

0�

1,10

0

Not

es:

SD�

stan

dard

devi

atio

n;ita

licis

eddi

men

sion

sar

epr

iori

tyst

anda

rds

and

conf

orm

sba

sem

odul

e(3

M)

IJHMA9,1

102

options and variety. Therefore, it will bridge the gap between theory and practicealso. This design framework will benefit primarily the designers and developers torespond the low-income housing demand in a tested modular platform discussedhere, the prospective manufacturers of components who will get essential standardsfor manufacturing components and also policymakers to frame policy concerningthe supply of low-income housing units using IBS. Needless to mention, all thepossible design configurations within the standard domain, as discussed in thepreceding sections, may not be equally suitable for all cities and towns, andtherefore, they need suitable contextualisation. There can be a number of designoptions based on the frameworks discussed above.

This study is expected to give way for the further research in the following ways:• Connection and coordination between the units at the beginning and the

attachments. A multi-disciplinary research is required to evolve that. Structuraland architectural integration is the prime requirement to ensure that theconstruction is expanded and increased.

• The possibility of application of shape grammar to achieve at least some degree ofcustomisation for the low-income housing units. It is believed here that smallerunits as mentioned here need customisations, and the extent and typology of suchcustomisation might be a great area of study.

• The design framework presented here is based on the assumption that acomponent-based system containing frames will be applicable for a country likeIndia. However, the panel construction can be explored for low-income housing,and adequate research and development efforts may be provided.

Figure 5.Configuration

possibility of activityspaces with

standardised spaces

103

Low-incomehousing units

Table X.Composition ofhousing module

Cate

gory

ofdw

ellin

gac

tivity

Nam

esof

activ

itysp

aces

1H

K1

BH

K1�

BH

KSt

arte

run

it(2

1sq

.m/2

25sq

.ft)

Com

fort

unit

(28

sq.m

/300

sq.ft

)A

spir

antu

nit(

35sq

.m/3

75sq

.ft)

Livi

ngzo

neH

all

YE

SY

ES

YE

SSl

eepi

ngzo

neB

edro

om1

Att

acha

ble

YE

SY

ES

Bed

room

2–

Att

acha

ble

YE

SCo

okin

gzo

neK

itche

nPA

RT

LYY

ES

YE

SPr

ivat

ezo

neT

oile

t/W

C1

YE

SY

ES

YE

ST

oile

t/W

C2

––

Att

acha

ble

Sem

i-ope

nzo

neV

eran

dah

Att

acha

ble

Att

acha

ble

YE

SU

sabi

lity

atth

ebe

ginn

ing

Net

carp

etar

ea

Mul

ti-m

odul

e

Usa

bilit

yaf

ter

atta

chm

ento

fsu

itabl

em

odul

es(a

ssh

own

inth

efig

ure)

Net

carp

etar

ea

IJHMA9,1

104

Notes1. Urban Land Ceiling and Regulation Act (ULCRA), which is a state act, restricts individual

land ownership beyond 500 sq.m in urban areas of India.

2. Definition of IBS: An innovative process of construction that uses the concept ofmass-production of industrialised systems, produced at the factory or onsite within controlledenvironments; it includes the logistic and assembly aspect of it, done in proper coordinationwith thorough planning and integration (adopted from Kamar et al., 2011).

ReferencesAdalakha, P.K. and Puri, H.C. (2003), “Prefabrication building methodologies for low cost

housing”, IE (I) Journal, Vol. 84.Akao, Y. (1990), QFD: Quality Function Deployment – Integrating Customer Requirements into

Product Design, Productivity Press, Portland, OR.Chattopadhyay, S. (2008), New Essays on Inclusive Housing, Macmillan India, New Delhi, p. 151.Cuperus, Y. (2003), “Mass customization in housing an open building/lean construction”, Dense

Living Urban Structures International Conference on Open Building, 23-26 October, HongKong.

Cuperus, Y.J. (2001), “An introduction to open building”, The Ninth Conference of theInternational Group for Lean Construction, National University of Singapore, Singapore.

Erixon, G. (1998), “Modular function deployment – a method for product modularization”, PhDthesis, Royal Institute of Technology, Stockholm, Sweden.

Gibb, A.G.F. (2001), “Standardization and pre-assembly – distinguishing myth from reality usingcase study research”, Construction Management and Economics, Vol. 19 No. 3, pp. 307-315.

Habraken, N.J. (1961), Supports an Alternative to Mass Housing, London 1972, Amsterdam 1961(Dutch version).

Jain, A.K. (2007), “Building systems for housing”, Journal of Indian Institute of Architects, Vol. 72No. 11.

Johnson, T. and Bröms, A. (2000), Profit Beyond Measure, The Free Press, New York, NY.Kamar, M., Hamid, Z.A., Azman, A., Ahamad, S. (2011), “Industrialized Building System (IBS):

revisiting issues of definition and classification”, International Journal of EmergingScience, Vol. 1 No. 2, pp. 120-132.

Maharashtra Housing and Area Development Authority (MHADA) (2015), available at: https://mhada.maharashtra.gov.in

Martin, M.V. and Ishii, K. (2002), “Design for Variety: developing standardized and modularizedproduct platform architecttures”, Research in Engineering Design, Vol. 13 No. 4,pp. 213-235.

MOHUPA (2007), Government of India, Ministry of Housing and Urban Poverty Alleviation,National Urban Housing and Habitat Policy, National Housing and Habitat Policy 1998.

MOHUPA (2011), Government of India, Guidelines for Affordable Housing in Partnership,MOHUPA.

National Building Code (NBC) (2005), Government of India, New Delhi.National Building Organization (NBO) (2011), Government of India, Housing Data.Roy, U.K., Roy, M. and Saha, S. (2008), Mass-Industrialized Housing to Combat Consistent Housing

Shortage in Developing Countries: Towards an Appropriate System for India, IAHS WorldCongress on Housing, Kolkata, Vol. 36.

105

Low-incomehousing units

Roy, U.K., Roy, M. and Saha, S. (2009), “Space standardisation for dimensional coordination of aMIG housing unit based on market trend in India”, Journal of Institution of Engineers,Architectural Engineering Division, Kolkata, Vol. 9, pp. 1-7.

Sarja, A. (1998), Open and Industrialised Building, International Council for Building Research, EFN Spoon, London.

Shaari, S.N. and Ismail, E. (2004), Roadmap-Industrialised Building System (2003-2010), CIDBNews, Kuala Lumpur.

Thanoon, W.A., Peng, L.W., Kadir, M.R.A., Jaafar, M.S. and Salit, M.S. (2003), “The essentialcharacteristics of industrialized building system”, International Conference onIndustrialized Building Systems, 10-11 September, Kuala Lumpur.

Warszawski, A. (1999), Industrialized and Automated Building System, E&FN Spon,Technion-Israel Institute of Technology, US and Canada.

Wikberg, F., Ekholm, A. and Jensen, P. (2009), “Configuration with architectural objects inindustrialised house-building”, CIB W078 2009, available at: http://itc.scix.net/cgi-bin/works/Show?w78-2009-1-19

Womack, J., Jones, D. and Roos, D. (1990), The Machine that Changed the World– The Story ofLean Production, Harper Perennial, New York, NY.

Corresponding authorUttam Kumar Roy can be contacted at: uttamkroy@hotmail.com

IJHMA9,1

106

Appendix

Table AI.Details of existing

dimensions ofactivity spaces (LIG)

under study

Sl no.

Nam

e of p

rojec

t De

velo

pers

Livin

g zo

ne

Hall

Bed

Room

1 Be

d Ro

om 2

Kitc

hen

To

ilet 1

To

ilet 2

Ut

ility/

Lobb

y Ve

rand

ah

Carp

et*

Area

SB

A L

BAR

L

BAR

LB

ARL

BAR

L

BAR

L

BAR

L

BAR

L

BAR

1Su

nrise

Junc

tion

Beng

al Pa

rk Ch

ambe

rs 39

9033

001.2

3500

3300

1.124

9015

001.7

2390

1250

1.916

0091

01.8

353.6

2An

ahita

Be

ngal

Peer

less

3600

3065

1.231

5031

251

2250

1800

1.330

0012

002.5

1200

1075

1.132

0.544

0

3An

imikh

a 38

0028

001.4

3200

2900

1.121

0018

001.2

1875

1200

1.612

5010

001.3

292.4

4Av

ishikt

a 33

0029

251.1

3355

2750

1.220

0015

001.3

1800

1050

1.711

2510

501.1

1450

1250

1.228

7.7

5Al

aktik

a 33

0029

501.1

3350

2975

1.122

2520

801.1

2275

1260

1.814

9010

701.4

309.5

6Pu

nya B

raja

Dham

35

0035

001

2425

1500

1.624

0013

751.7

1500

900

1.714

0010

001.4

235.8

338

7Gr

eenw

ood E

lemen

ts Be

ngal

Shra

chi

2500

2400

127

0027

001

2400

1500

1.624

0013

001.8

900

900

112

0012

001

239.3

397

8Ne

w Sh

rach

i Gar

den

4475

2800

1.632

2529

001.1

2300

1500

1.524

0013

001.8

2000

1100

1.832

9.553

7

9Tin

kany

a, Ne

era

Beng

al Sh

elter

34

7527

751.3

3225

2450

1.326

5024

001.1

1675

1500

1.121

7512

001.8

2850

950

334

1.147

5

10

Malan

cha

Beng

al DC

L 30

5030

001

3200

2900

1.117

0014

501.2

2170

1200

1.812

0090

01.3

1100

1000

1.127

6.040

3

11

High

land W

illow

Beng

al Be

llany

41

4030

001.4

3275

2950

1.121

3015

251.4

2000

1400

1.430

2.436

2

12

Ambit

ion

Beng

al Gr

eenfi

elds

3225

3000

1.133

0030

001.1

2775

1800

1.527

7513

002.1

1825

1800

133

8.238

5

13

Suga

m Pa

rk Su

gam

Home

s 40

4040

001

3300

2700

1.225

1518

001.4

2080

1245

1.717

7512

501.4

369.9

496

14

Apon

alaya

Re

side,

Ritik

a 4,7

0030

501.5

3100

3075

12,1

7518

251.2

1250

965

1.312

2596

51.3

1550

1275

1.234

6.248

0

15

Trina

yani

Merlin

30

0030

001

3000

3000

124

0016

001.5

2300

1200

1.916

0011

001.5

283.4

425

16

Gree

n Gar

dens

BG

A Re

altor

s 29

0021

001.4

3000

3000

112

0090

01.3

1750

1513

1.290

080

01.1

210.0

17

Amra

Kun

ja 30

5024

251.3

3650

3050

1.212

1091

01.3

1210

910

1.312

1060

02

1525

900

1.724

5.440

7

18

Fortu

ne T

owns

hip

NA

4500

3800

1.239

1027

401.4

3000

1875

1.621

3014

251.5

1210

910

1.340

3.957

3

19

Stan

dard

Dev

iation

61

6.946

1.81.3

268.0

198.4

1.447

5.130

3.01.6

451.9

151.9

321

5.016

4.31.3

442.0

227.9

1.951

.369

.0

Aver

age

3586

2994

1.232

6129

131.1

2650

2400

1.121

6515

761.4

2132

1239

1.712

2596

51.3

1187

870

1.415

2510

941.4

304.7

439.8

Not

es: B

R =

bed

room

; Liv

-Din

= li

ving

cum

din

ing;

Kit

= ki

tche

n; B

al =

Bal

cony

; Dim

= d

imen

sion

s; C

r = c

arpe

t are

a (n

et a

rea

with

in th

e w

alls

); A

R =

asp

ect r

atio

bet

wee

n le

ngth

and

bre

adth

107

Low-incomehousing units