PREFABRICATION AND MODULAR
Prefabricationis the practice of assembling components of a structure in
a factory or other manufacturing site, and transporting complete assemblies or sub-
assemblies to the construction site where the structure is to be located.
1.2METHODS OF CONSTRUCTION
CONVENTIONAL METHOD PREFABRICATION
The conventional method of building
is to transport bricks, timber ,cement,
sand ,steel and construction
aggregate, etc. to the site and to
constructthe house onsite from these
Prefabrication is the practice of
assembling components of a structure
in a factory or other manufacturing site,
and transporting complete assemblies
or sub-assemblies to the construction
site where the structure is to be located.
The term is used to distinguish this
process from the more conventional
construction practice of transporting the
basic materials to the construction site
where all assembly is carried out.
1.3STAGES INVOLVED IN PREFABRICATION
1. The structure is divided into number of units.
2. The different units are precast in permanent factories(plant fabrication) or
temporary plants (site prefabrication).
3. Transported to the site.
4. Hoisted set into their final places and assembled to form a complete
1.4PLANS AND SPECIFICATIONS (IS15916)
• Drawings shall describe the elements and structures and assembly including
all required data of physical properties of componentmaterials (material
• Details of connection joints
• Site or shop location of services (installation of piping, wiring and other
• Location of inserts (doors, windows and ventilators)
• Handling arrangements to avoid failure
• Modular coordination is a conceptof coordination of dimension and space in
which buildings and components are dimensioned and positioned in terms of
basic unit or module.
• The basic module is known as 1M which is equivalent to 100mm.
• It is internationally accepted by the International Standard Organisation and
many other countries including Malaysia.
• Modular coordination was first explored as an aid to design shortly after the
introduction of prefabrication in the construction industry in the
industrialization. It was conceived as a further step in the development of
systematic design and construction of the building.
• This subject has been discussed and attempted in an actual building
experiment in practically every developed country.
• Modular coordination was first studied in Singapore in the early seventies.
The housing and development board implemented the conceptin 1973 in the
new generation flats.
Prefabrication and standard components were subsequently introduced.
Modular blocks and bricks were introduced in 1983. There are merits to
extend the use of modular coordination in other components as well.
1.7AIMS AND OBJECTIVES OF MODULAR COORDINATION
The principle objectives of modular system are to provide practical and
coherent solutions for coordination of the position and dimensions of
elements, components and space in building design.
This process can contribute to increase design freedom and improved
balance between quality and cost in manufacture and construction.
1.8BASIC PRINCIPLE OF MODULAR COORDINATION
The main purpose of Modular Coordination is to achieve the Dimensional
Compatibility between the Building Dimensions, Span or Spaces and the
Size of Components and Equipments by using related Modular Dimensions.
Modular Coordination generally provides the easy grasped layout of the
positioning of the building components in relation to each other and to the
building and facilitates collaboration between planners, manufactures,
distributors and contractors.
1.9STANDARD RULES IN MODULAR COORDINATION
Modular Coordination is essentially based on the use of modules (basic
module and multi-modules) and a reference system to define coordinating
spaces and zones for building elements and for the components which form
There are standard rules to abide by
- Rules for locating building elements within the reference system;
- Rules for sizing building components in order to determine their work sizes;
- Rules for defining preferred sizes for building components and coordinating
dimensions for buildings.
• IS:7922-1987: Recommendations for Modular coordination in Building
1.10PURPOSE OF MODULAR COORDINATION:
• To reduce the component size produced;
• To allow the building designer of greater flexibility in the arrangement of
SQUARE GRID RECTANGULAR GRID
BASIC MODULAR GRID
The fundamental modular grid, is that in which the intervals between consecutive
parallel lines is equal to the basic module, smallest planning grid.
Fig 1.1BASIC MODULAR GRID
MULTI – MODULAR PLANNING GRID :
In addition to the basic modular grid, multi-modular grids in which the intervals
between consecutive lines are a multi-modular may be used.
• Interrupted modular planning grid
• Intervals or bands of interruption are regularly spaced in both
• Pattern may be used in very regular plans like those with columns
at constant intervals throughout the floor
Fig 1.2 SQUARE AND RECTANGULAR MULTI MODULAR GRID
Fig1.4TYPICAL WORKING DRAWING
Fig1.5MODULAR COORDINATION WORKING DRAWING
Basic modules Multi modules Sub-modular module
1.13Module- It is a standard unit of size to coordinate the
dimensions of buildings and components.
a.) Basic module-
It is the fundamental unit of size ‘n’ modular coordination. The basic module is
represented by letter M while its international standard value is:
They are standardized by selected whole multiples of the basic module. The
international standard values of multi-modules for horizontal coordinating
3M, 6M, 12M, 30M and 60M
Multi-module of 15M is used for special applications.
Fig1.6 MULTI MODULE
The standardized dimension of horizontal coordination is
MH =3M (300mm)
Mv =M (100mm)
- Floors are placed within a modular floor zone of nxM increments
- Floor to Floor heights are vertically placed nxM increments
Fig.1.7 VERTICAL COORDINATION
SUB –MODULAR INCREMENT
Sub-modular increment is an increment of size, the value of which is a selected
fraction of the basic module.
The international standardized value of the sub-modular increment is M/2 =
It is to be used where there is a need for an increment smaller than the basic
module. Determining the displacements of different modular grids
Modular coordination is the basis for a Standardization of a mass production
Fig 1.8 COMPONETS OF WALL
1.14ADVANTAGES OF MC
Facilitate collaboration between buildingdesigners, manufactures,
distributors and contractors
Standard size- building components different types of buildings
Speed of construction
Minimize the wastage of materials, time and manpower in cutting and
trimming on site
Balance between Quality and Cost
1.15DISADVANTAGES OF MODULAR COORDINATION
Can lead to problems when modules are linked because link must thoroughly
It is difficult to manufacture to producecomponents based on mm tolerance.