General and Particular Specification

Introduction
Shorter Oxford English Dictionary refers a specification is "a detailed description of the dimensions, construction, workmanship, materials etc., of work done or to be done, prepared by an architect, engineer, etc."
The followings are included in the specification
A specification is a document that describes in words what cannot be visualised or explained on a drawing or model. This document can be incredibly wide-ranging - covering the establishment of the site, the type of contract to be used, the performance criteria of the asset, the quality of the systems and products, which standards are applicable and how they should be executed, and even the products to be used.

Specifications do not include information on cost, quantity or drawn / visualised information so need to be read in conjunction with documents detailing quantities, schedules and drawings.
Specifications are not only used in construction - they are also used in a range of other industries; from the aerospace, oil and gas and automotive industries to manufacturing.
The type of specification can relate to the project or the procurement route.
Specifications will vary depending on the stage to which the design has been developed: performance (open) specifications will require further design work, while prescriptive (closed) specifications draw on an already complete design.
A specification is a document that describes in words what cannot be visualised or explained on a drawing or model.

A very prescriptive specification at tender stage will ensure the client has a high degree of certainty about what will be delivered.
A performance specification gives suppliers more discretion, for example, to suggest innovative solutions and more cost-effective ways of working, potentially saving money in the long run.

Performance specifications tend to be used on projects where typical, straight forward kinds of buildings are required.
Prescriptive specifications are typically used to deliver more complex buildings or where a client's requirements may not be known or assumed by suppliers and therefore the extra certainty will be important. Prescriptive specifications are also used where a very specific end result is required (for example, a supermarket chain will require a branded, uniform, kind of building - here the building type is likely to be straightforward but the client likely to insist on a prescriptive specification).

In reality, many projects will use a combination of specifications - both performance and prescriptive. Design aspects are likely to be specified prescriptively, less critical items (such as lifts) by performance only.
Deciding which approach to take involves weighing up who is likely to achieve best value for each particular element on the project - the client, designer or contractor.

Structure of specification
The structuring of specifications will vary from project to project but should reflect the work packages on a particular project and any sub-contracts. This structuring should make it easier for contractors to price a job and give a more accurate tender.

The use of a standard classification system, such as Uniclass 2015, is encouraged as it should remove any potential for confusion or ambiguity.

Production of specification
The production of specification documents should happen in tandem with design work - with ever greater level of detail added as the design progresses. At tender stage, the specification serves as an essential reference.

Examples of specifications
Specification is usually grouped together in construction project such as : .

Section 1 General Conditions
Section 2 Excavation & Earthworks
Section 3 Form work for Concrete Works
Section 4 Reinforcement for Concrete Works
Section 5 Cast in Place Concrete
Section 6 Concrete Curing
Section 7 Mortar
Section 8 Concrete Unit Masonry
Section 9 Portland Cement Plaster
Section 10 Bituminous Membrane Waterproofing
Section 11 Fluid Applied Waterproofing
Section 12 Expansion and Construction Joints

Section 13 Stone Work
Section 14 Floor Tile Work
Section 15 Wall Tile Work
Section 16 Metal Fabrication
Section 17 Fire Rated Doors
Section 18 Joinery And Ironmongery
Section 19 Glazing
Section 20 Painting Works
Section 21 Drainage
Section 22 Electrical Installations
Section 23 Plumbing and sanitary Installations

Particular Specification
Particular specification gives specific requirements such as

Strength and other properties of steel
Strength of concrete
Specification of bricks
Specification of electrical items
Or equipment to be produced and assembled in certain countries.