Post 615 –by Gautam Shah


Primary instinct for a human effort is to create a Recipe or Process. We tend to perceive an item by hypothetically enacting its process. First step is compilation of a list of physical inputs (ingredients). Second step is forming lists of things to do, how to do and not to do (human interventions). Third step is planning the sequences in time. Fourth step is readying tools required for various processes. A fair mix of all FOUR steps can offer an object, but not a desired entity. The end result is conjectural. In real design work intentions are additionally transmitted through drawing documents and other forms of surrogates.


Oven Cooking > ART by Jean-Francois Miller (1814-1875)

Item or design specifications have been used for execution, manufacturing, fabricating, erecting, for procuring ready-made objects, and also for effecting various services. The term Design here means any scheme, as such orally conveyed, written, drawn, or otherwise implied.

A Design or Scheme specifies aspects like : constituents, processes of combining, synthesizing a coherent entity or system, method of care and handling the men, materials, tools, equipments and the entity itself as it is being created.


Elevator Design by German Engineer Konrad Kyeser (1405) Wikipedia image

When a design (recipe) is specified for a product, and once readied (with reasonable sincerity), a client has to pay even if it fails on acceptability count. As a result, writing Item or Design Requirements is not an assuring process, unless the specifiers have had recent experience, at designing nearly Identical Items, and fully comprehends all aspects of the design problem.


Design confusions > Image attribution: Wiki4des at English Wikipedia

Specifications for a Designed Object

A Designer prepares design specifications, (materials + procedures + conditions of origin), so that the contractor or vendor can provide the stated item. The contractor or vendor gets very exact data, but little freedom to use alternative materials or execute it differently. If there is an uncommon item, the contractor will invariably charge more for the extraordinary effort or customization. This process does not assure that in spite of a sincere execution and diligent supervision a functional product will be delivered. The Item specifications specify ‘physical adequacy of the item while seeking a hypothetical performance’.

A contractor or vendor is better aware of latest materials, processes, technologies and their costing as available in the market, In comparison to any specification formulator like a designer. A contractor or vendor, if allowed to provide, can offer an item that surpasses the one conceived in the ‘item or design specifications’. This cause was identified by US Air-force and made it mandatory to procure entities by PERFORMANCE SPECIFICATIONS, through the ITEM or DESIGN SPECIFICATIONS. A performance specification states the exact requirements of performance of an entity, and no materials + procedures + conditions of origin are given. This is an appreciable method but very difficult to implement. Performance of some of entities cannot be checked-validated over a longer time span (e.g. Operative suitability of a submarine beyond 20 years).

Performance specifications are partially used in many works with item specifications. For example, 6/7 decades back many builders were asked to refer to Standards for Cement, Sand, Aggregates, Water, Mixing procedures and testing methods for quality to be achieved. This is now replaced by pre-mix cement concretes of assured quality. This a way of relying on the performance, than Materials+Processes methods.


Ready-mix Concrete > Wikipedia image by High Contrast

Specifications for acquiring some ready-made objects can be Performance specifications but tend to be even more restrictive. A specifier (buyer-acquirer) of a ready-made item of the market shelves has no way of verifying a product, so relies on average standards followed by the Industry, or match with some ‘super’ supplier’s (top product in the market) specifications. Failing either of the conditions, one, has to pay the extra cost of customizing a regular or standard item. In the later case the assurance nominally available for the regular or standard item are unlikely to be offered for the altered form.