Plants cannot be laid out once for all. Howsoever detailed and careful may be the planning on the part of engineers and management, with changes in the situation changes in layout are bound to become necessary. The modernization of an obsolete plant calls for re-layout as carefully planned and executed as the original layout.
Re-layout becomes necessary for one or more of the following reasons inaccuracies in original planning, mushroom growth into improper layouts, lack of efforts towards work simplification , the development of new products or equipment, and improvements in the techniques of plant layout engineering. The procedure involved in the re-layout of an obsolete plant is essentially the same as that for original layout in that it calls for a careful appraisal of objectives and the collection and compilation of the necessary data including floor plan and plot plan drawings and the original building specifications.
Templates of new machinery proposed to be ‘laid down’ should be got prepared.
For an efficient layout certain basic information are required for proper planning. These can be listed as :
(i) Type and quantity of labor required.
(ii) dimensional plan of the space to be laid out.
(iii) volume of work to be taken from the space at present and in future.
(iv) description of the operations, their sequence and standard times in the production process.
(v) nature of machines and equipment needed to perform the operations.
(vi) amount of material, buffer stock required at each work station.
(vii) size of finished and semi-finished products inventory.
(viii) kinds of communications and fire-exits necessary for the plant.
(ix) special requirements if any to fulfill the local bye-laws.
(x) special geographical and inspection requirements.
On the basis of above information, one can select appropriate method to plan the desirable layout. Planning a layout is not an operation to which some rigid technique can be applied. The process is mainly of trial and error i.e. laying out, modifying and relaying out.