Safety Cautions And Warnings - Blue Bird D3RE 2014 Driver's Handbook Manual

Do not uncouple fittings until all tanks are closed and pressure has been purged
from the line. The lines are high pressure rated 3/8 stainless steel seamless tubing
which carries the fuel to the high pressure regulator.
In refilling, the fuel enters the fill valve on the entrance side of the bus and then
flows through a check valve into the common tubing before reaching the tanks.
From the high pressure regulator, the fuel flows to the shutoff solenoid. The igni-
tion switch, engine operation, and the fire suppression system activate the shutoff
solenoid. The loss of any of these will shut off fuel supply to the low pressure regula-
tor (LPR).
The fuel gauge is proportional to the pressure when corrected to 70° F. Fuel level
is only accurate for the tanks that are open.

Safety Cautions And Warnings

Both gasoline and CNG are volatile, flammable fuels, yet they are safe to work around
when necessary precautions are taken. As on a gasoline fueled system, carelessness
with CNG can lead to a fire or explosion when a leak occurs. CNG will not pool and
spread like gasoline. It has a narrower range of flammability than gasoline, as well as
a higher ignition temperature. Despite these relative safety advantages, fire poten-
tial does exist. CNG is lighter than air, so it can collect in the higher regions of a room
and possibly go undetected, creating fire potential.
Since the fuel system is a very high pressure system employing a flammable gas,
all safety issues normally considered in these situations should be applied. Some of
the more obvious precautions are listed below. This list is not necessarily intended to
be complete, and responsibility for assuring full safety is that of the person(s) doing
the work or operating the system.
[WARNING] Handle natural gas with care. Compressed natural gas is a
volatile fuel stored under high pressure. If fuel storage or delivery components
are installed, serviced, or operated improperly, fire, explosion, and/or serious
injury could result. Do NOT smoke while working on or around natural gas
equipment. Avoid flames, sparks, and operation of electrical devices in or
around a vehicle with a possible natural gas leak. Properly tighten all connec-
tions and thoroughly check for leaks after servicing fuel system. Natural gas
fumes may cause sickness or death. Work in a well ventilated area.
[WARNING] Protect against high pressure CNG. Compressed natural gas is
stored and routed to the engine at a pressure up to 3,600 psi. Do NOT attempt
to remove or disassemble any fuel system component while it is pressurized.
Explosive separation of components and escaping natural gas can cause seri-
ous injury. Avoid the hazard by relieving pressure before disconnecting any
CNG fitting or line. Properly tighten all connections and thoroughly check for
leaks before applying pressure. Never attempt to over pressurize the system.
ROUTINE OPERATION
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