Module 9: Control Techniques - International Association of Fire ...

IAFF Training for Hazardous Materials: Technician©
Student Text
Corrective Actions for Tank Car Fittings
Pressure/Vacuum Fittings
Location of Leak Probable Cause Basic Repair Method
Safety Relief Valve—External, Internal, or Combination
Liquid or vapor leak Loose flange nuts Tighten flange nuts
from joint between base of
valve and manway cover
Liquid or vapor leak “O’’ ring or washer installed To be handled by a tank car
from valve seat incorrectly or damaged from specialist; do not remove the
normal wear. safety relief valve
Caution: Spring may be
broken and is not repairable
in the field.
Liquid or vapor leak Valve stem bent or broken To be handled by a tank car
from valve seat specialist
Safety Vent
Overloaded tank Unload; to be handled by a
tank car specialist
Liquid or vapor leak Ruptured frangible Replace frangible disk with
from opening in center (rupture disk). Liquid new disk identical to the
of safety vent indicates overload or splash ruptured disk
without overload
Vacuum Relief Valve
Liquid or vapor leak “O” ring off seat or valve To be handled by a tank car
from under deflector stem bent specialist
cap
Solidified product To be handled by a tank car
specialist
9-48 Module 9: Control Techniques