CHAPTER 4 BLUEPRINT READING AND TECHNICAL DRAWINGS

Blueprints, sometimes called prints, are reproduced copies of mechanical or technical drawings. Drawing or sketching is the universal language used by engineers, technicians, and skilled tradesmen.

The term reading print is defined as the ability to interpret the ideas of others expressed on drawings and sketches. This chapter has been developed to give you some insight into the preparation and use of blueprints.

DEVELOPMENT OF CONSTRUCTION DRAWINGS

Drawings are generally categorized according to their intended purposes as follows:

Preliminary drawings

Presentation drawings

Shop drawings

Working drawings

PRELIMINARY DRAWINGS

A building project may be broadly divided into two major phases: the design phase and the construction phase. Preliminary drawings are prepared by the A and E (architects' and engineers') firm during the design phase to promote building development. These drawings are used for exploring design concepts between the designer and the user (customer), making material selection, determining preliminary cost estimates, and as a basis for preparing the finished working drawings.

PRESENTATION DRAWINGS

Presentation drawings show the proposed building or facility in an attractive setting in its natural surroundings at the proposed site. Since presentation drawings are actually used to sell an idea or a design, your only contact with such drawings will be as a cover sheet for a set of construction drawings.

SHOP/WORKING DRAWINGS

After approval has been given for construction, the shop and working drawings are developed. Throughout your career, you will hear these drawings referred to as construction drawings, prints, or plans. Basically, these terms are all correct; they can be used interchangeably.

As mentioned earlier, the construction drawings are developed from the preliminary drawings. With the collaboration of the designer or the architect and the engineer, both the materials to be used and the construction methods to be followed are decided. The engineer determines the loads that the supporting (structural) members will be required to bear and then designs the mechanical systems for the structure; for example, heating, power, lighting, and plumbing.

You will find the construction drawings, the specifications, and the bill of material (BM) your chief source of information during the construction phase of the project.

BLUEPRINT READING

There are several reasons for having construction drawings and why you need