interfaces and problems your crew may encounter during the job.

The working sketch is something a crew should have with them while working. It can show them how, what, when, and where things happen in the sequence of a job. Your first step in making a working sketch is to draw the symbols that represent all the fixtures to be installed and locate them within the room. Try to draw them in the sequence of installation and include measurements. Now draw the piping for hot and cold water, show where it comes from and where it is going. Include pipe sizes, fittings, hanging requirements, and rough-in measurements. Do the same for the sanitary and vent systems.

The amount of detail you should use in a working sketch is determined by the crew's experience, the complexity of the system involved, and the need for interface with other trades working on the jobsite.

Working sketches are also useful to simplify complicated electrical schematics when you are installing or servicing mechanical equipment, such as air conditioners and boilers. Figure 4-10 shows electrical symbols commonly found on electrical schematics. By understanding what these electrical symbols represent, you will be able to translate the manufacturer's schematics.. By drawing a simplified working sketch of this information, you are aiding your crew in installing and troubleshooting the equipment.

Figure 4-10. - Electrical symbols.