All Building Services symbols are drawn
at relative sizes in accordance with common industry usage and
accepted practice for architectural drawings.
The electrical wiring symbols conform
with Y32.9-1972 and common industry usage, the HVAC symbols
conform with ANSI Y32.2.4-1949 (R1998), and the pipe fittings
and valves conform with Y32.2.3-1949 (R1999).