marked with an arrow to show direction of flow and
uses the standard symbols shown in figure 5-9, and
hazard marking, as you will see later in this chapter.
that it includes a symbol list. Some small piping
The following paragraphs contain markings for the
diagrams do not include a symbol list; therefore, you
four general classes of hazards, and figure 5-12 shows
must be familiar with the standard symbols to
examples of the hazards in each class.
interpret these diagrams.
FLAM — This marking identifies all materials
ordinarily known as flammable or combustible.
TOXIC — This marking identifies materials that
are extremely hazardous to life or health.
AAHM — This marking identifies anesthetics
and harmful materials. These include all materials
that produce anesthetic vapors. They also include
those that do not normally produce dangerous fumes
or vapors, but are hazardous to life and property.
PHDAN — This marking identifies a line that
carries material that is not dangerous in itself, but is
asphyxiating in confined areas. These materials are
generally handled in a dangerous physical state of
pressure or temperature.
SHIPBOARD PIPING PRINTS
There are various types of shipboard piping
systems. Figure 5-13 shows a section of a piping
diagram for a heavy cruiser. Note that the drawing
Standard symbols are generally not used in
drawings of shipboard piping systems found in
operation and maintenance manuals. Each fitting in
those systems may be drawn in detail (pictorially), as
shown in figure 5-14, or a block diagram arrangement
(fig. 5-15) may be used.
HYDRAULIC PRINTS
The Navy has increased its use of hydraulic sys-
tems, tools, and machines in recent years. Hydraulic
systems are used on aircraft and aboard ship to
activate weapons, navigational equipment, and
remote controls of numerous mechanical devices.
Shore stations use hydraulically operated main-
tenance and repair shop equipment. Hydraulic
systems are also used in construction, automotive, and
weight-handling equipment. Basic hydraulic
principles are discussed in the basic training course
Fluid Power, NAVEDTRA 12064.
To help you distinguish one hydraulic line from
another, the draftsman designates each line according
FLUID
Air (under pressure)
Alcohol
Carbon dioxide
FREON
Gaseous oxygen
Liquid nitrogen
LPG (liquid petroleum gas)
Nitrogen gas
Oils and greases
JP-5
Trichloroethylene
HAZARD
PHDAN
FLAM
PHDAN
PHDAN
PHDAN
PHDAN
FLAM
PHDAN
FLAM
FLAM
AAHM
Figure 5-12.—Hazards associated with various fluids.
5-8
