Hazards of Chemicals and Gases
FLAMMABLE AND COMBUSTIBLE LIQUIDS
Avoid accidental mixture of flammable and combustible liquids. A small amount of a highly
volatile substance may lower the flash point of a less volatile substance and form a more
flammable mixture. In addition, the lower flash point liquid can act as a fuse to ignite the higher
flash point material in the same manner as if it were a flammable mixture.
Fill and discharge lines and openings, as well as control valves associated with flammable and
combustible systems, shall be identified by labels, color coding, or both, to prevent mixing
different substances. All storage tanks shall be clearly labeled with the name of its contents, and
products stored within shall not be intermixed. Transfer lines from different types and classes
of flammable products should be kept separate, and preferably, different pumps should be
provided for individual products.
For handling quantities of flammable liquids up to five gallons, a portable FM (Factory Mutual
Engineering Corp.) or UL (Underwriters Laboratory) approved container should be used. The
container should be clearly identified by lettering or color code.
Smoking, the carrying of strike-anywhere matches, lighters, and other spark-producing devices
should not be permitted in a building or area where flammable liquids are stored, handled, or
used. The extent of the restricted area will depend on the type of products handled, the design
of the building, local codes, and local conditions.
Suitable NO SMOKING signs should be posted conspicuously in those buildings and areas
where smoking is prohibited.
Static electricity is generated by the contact and separation of dissimilar material. For example,
static electricity is generated when a fluid flows through a pipe or from an orifice into a tank.
Examples of several methods of generating static electricity are shown in Figure 5. The principal
hazards created by static electricity are fire and explosion, which are caused by spark discharges.
A point of great danger from a static spark is where a flammable vapor is present in the air, such
as the outlet of a flammable liquid fill pipe, at a delivery hose nozzle, near an open flammable
liquid container, and around a tank truck fill opening. In the presence of a mechanism for
generating a static charge, a spark between two bodies occurs when there is a poor electrical
conductive path between them. Hence, grounding or bonding of flammable liquid containers
is necessary to prevent static electricity from causing a spark.