Module is a set of separated parts from a complete unit or plant.
Modular design is an engineering technique that a design of complete unit or plant divide into smaller units (system or subsystem) with tie-in provisions
Modularization is for difficulties in a skilled labour mobilization at the site or remote areas and significantly disadvantages in economics for a traditional stick built construction method, requires large number of labour, construction equipment and supporting infrastructures, modularization method is applicable. Modules are self contained and operated with essential utility supply. Module design and engineering is slightly different form a normal engineering, reinforcement of structures for transportations and minimize ground spaces are executed, modules are fabricated (pre-fabricated) or manufactured at the module shop yard, tested, pre-commissioned, preserved and transported to the site for installation and connection (tie-ins) to other module or existing facility to complete a unit or plant. Modularization plan develops in the beginning of the project, and perform a module design and engineering, procurement and construction. Optimum module size and inclusions are depend on a transportation ability for inland and ocean, module erection and handling capacity at the site, module fabrication yard capacity as well as ability of skilled labour mobilization and level of direct cost at the site, and a severity of project such as project duration, quality, safety and environmental requirement.
In general, a Modularization project is shorter project schedule but cost is dependent.