Contract conditions (general and supplementary). These include general conditions of the contract such as AIA Form 201 or similar preprinted forms. Supplementary conditions include anything that is not covered in the general conditions, such as addenda (changes made before contract signing) and change orders (changes made after contract signing).
Technical specifications. These provide technical information concerning the building materials, components, systems, and equipment shown on the drawings with regard to quality, performance characteristics, and stipulated results to be achieved by application of construction methods (Figure 10.2).
Writing and Coordination Guidelines
As mentioned earlier, specifications are legal documents, and their language must be precise. If the written text is ambiguous or inadequate, the specification will not communicate. Moreover, a convention has developed over the years as to the information that should be shown on the drawings and that which should be indicated in the specifications. This is essentially based on a number of broad general principles, which include:
Drawings should convey information that can be most readily and effectively expressed graphically by means of drawings and diagrams. This would include data such as dimensions, sizes, gauges, proportions, arrangements, locations, and interrelationships.
Specifications should convey information that is easier to convey through the written word,such as descriptions, standards, procedures, guarantees, and names.
Drawings are used to express quantity, whereas specifications should describe quality.
Drawings should denote type (for example, wood), while specifications will clarify the species (for example, oak).
Some exceptions to these understandings can create confusion. For example, building departments of the majority of municipalities will only accept drawings with applications for building permits and will not accept a project manual with specifications. Furthermore, all data demonstrating compliance with the building code must be indicated on the drawings.
This stipulated repetition of identical data on both the specifications and the drawings exposes the documents to errors and inconsistency. Nevertheless, this aside, to achieve better communication, the specifier should:
Have a good understanding of the most current standards and test methods referred to and the sections that are applicable to the project. Use accepted standards to specify quality of materials or workmanship required, such as “Lightweight concrete masonry units: ASTM C-90-85; Grade N. Type 1.”
Avoid specifications that are impossible for the contractor to carry out. Also refrain from specifying the results and the methods proposed to achieve those results, as the two may conflict. For example, if you specify that a fabric should meet certain ASTM standards and then specify a specific fabric that fails to meet the stated requirements, the specification will be impossible to comply with.
Do not specify standards that cannot be measured. Using phrases such as “a workmanlike job,” for example, should be avoided, as they are subject to wide interpretation.