Third Edition

Breather Vent — a device having an operating part that
is a permeable disc or a disc having a breather hole or slit.
Breather vents are typically applied to tank cars
transporting hydrogen peroxide to allow vapors created
by the decomposition of the commodity to be vented
from the tank.
Burst Pressure — the value of the inlet static pressure
at which a rupture disc device or breaking-pin device
functions.
Burst Pressure (Tank) — the internal pressure at
which a tank will theoretically burst. For a tank car tank,
the minimum burst pressure is based on the tank’s inside
diameter, welding joint efficiency, minimum tensile
strength of the plate material, and the minimum
thickness of the plate after forming.
CANUTEC — acronym for the Canadian Transport
Emergency Centre. CANUTEC is operated by the
Transport of Dangerous Goods Directorate of
Transport Canada and provides a national bilingual
(English and French) advisory service, including
emergency response advice for incidents involving
dangerous goods. Call collect at 613-996-6666 (24
hours) or *666 cellular (Canada only). Call 613-992-4624
(24 hours) for nonemergency inquiries.
Capacity/CAPY — the volumetric capacity (stenciled
in gallons and liters) of a tank car’s tank. The capacity
may also be shown in imperial gallons.
Center Sill — the center longitudinal structural member
of a car underframe that forms the backbone of the
underframe and transmits most of the buffering shocks
from one end of the car to the other (also see Stub Sill
Tank Car).
Check Valve — a valve that automatically closes to stop
the flow of liquid or vapor in one direction. A springloaded
check valve has its valve maintained in the closed
position by a spring and is opened by the valve above it.
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