. The second  are  various references at Wikipedia.org.  The  wiki references  lead to  a whole string of varied definition. See/go wiki :- http://en.wikipedia.org/wiki/Modularity , http://en.wikipedia.org/wiki/Modular_process_skid
The  wiki references  lead to  a whole string of varied definition.

Reading  between the first and second definitions  shows that there  are very varied understandings. For the sake of this presentation the simplistic definition is taken “as the bringing together of various items to create a part of a whole which may be as itself or combined with others into a single entity . The other factor is that these acts are related  to the  petro Chem, Oil and gas Industries.

Where do we use Modules in the Petro Chem, Oil and Gas Industries? The two main areas they are used are at Onshore or Offshore locations.

Onshore examples cover the development of refineries, gas plants, pipeline terminals, midline pumping stations etc. Such facilities as these are often in remote locations, to build them at the place of operation demands a complexity since there is invaribly a lack of manufacturing facilities, accomodation for labour. It is often the case to pre build at a more suitable location and then move theunits (modules) to site. A major difference between on shore and offshore locations is that onshore more real estate is available to better space units. This may be a disadvantage to the need to modularise which looks to more compact equipment arrangements.

Offshore examples cover  the means of drilling or production both as topsides on jackets, floaters or as subsea units. These usually are more dense (lack of real estate), complex than onshore facilities and usually require more rigorous laylouts, understanding of codes, complex solutions for structures.

Both On and Offshore Locations present particular problems for Modules. If we have a problem in defining what a Module is, we have an equal problem in defining how they will be used. Both Locations are subjects  to Codes Laws and Standards and this conditions how we conceive the design of any Module. A Module for use on an FPSO  needs to comply with its physical Location on the  Floater, the Floater itself must be to Class eg Lloyds, DNV GL, ABS etc, the layout must comply with requirements of Standards for the Equipment, the Process Area restraints, its hazards spacing, economic requirements etc, etc the list goes on. The only way to address these requirents is to competantly and methodically engineer all of the requirements to ensure compliance. It also means finding solutions that take in the impact of any Restraints.     
HMV Statpipe Module Loadout
HMV Statpipe Module Loadout
Is this a Module or not ?
a general understanding of Modules 
Section 1, Introduction which follows the Preamble addresses some of the Major Aspects, Restrictions, Restraints etc  that can condition "what is a Module"  and where it can be used and shows how the design is executed to meet these requirements. These Aspects are often dominant and cover  the limits set by such things as 1a, Generalities, 1b, Real Estate Availble and Applicable Codes etc, 1c, Schedule, 1d, Location (WorldWide), 1e, Space (Area available)  and 1d, Demands (specific). These Aspects can apply for both Offshore  and Onshore.

To commence GO

Although not the main subject of the site associate sites give some information to provide an understanding of materials handling and transportation as they apply to modules and the equipment they contain.
To follow......

The definition of the word Module has ment different things to different people. It is therefore interesting to look at some definitions

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The first is the Collins Concise Oxford Dictionary which has a simple definition.  “module a standard measure, esp. one used to cc dimensions of buildings and campons standard, self-contained unit or item, such as assembly of electronic components/that used in combination with other.  Astronautics. any of several separable units making up a spacecraft or vehicle, each of which has one or more tasks”.
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