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Storage/Loading/Unloading - Tank Car Loading
April 2, 2008
Introduction
The following procedure is applicable to loading of tank cars.
The procedure is general in nature and must be adapted to the specifics of
each loading facility and to the owners own procedures and rules.
Personnel
Attendance by a qualified person during the entire unloading procedure should
be required. This person must be thoroughly familiar with the hazards of sulphuric
acid and all operating, emergency, safety and first aid procedures recommended for its
safe handling.
Safety and Preparation
Water in large quantities should be immediately available at the unloading
site to wash down any acid that may be spilled.
A safety shower is recommended along with a signal system designed to get
assistance if an emergency should arise. The signal system and safety showers should
be tested routinely.
Signs restricting access to the area should be used.
The slow attack of sulphuric acid on mild steel results in the formation of
hydrogen sulphide gas which is flammable and can form explosive mixtures with air.
Smoking or other sources of ignition should not be permitted near acid tank cars, and cars
fittings should never be hammered or chiseled.
Tank Car Loading
Locating the Container
The tank car must be accurately spotted at the loading platform so that the
loading ramp lines up with the opening on the tank car platform.
Setting Brakes
Firmly apply the tank car handbrake and block the wheels using standard wheel
clamps.
The loading ramp can be lowered into place once the tank car has been spotted
and secured.
Setting Safety Flags
Blue warning flags and derails should be placed at least 1 1/2 car-lengths
away.
Inspect Shipping
Container
Inspect the shipping container for leaks or damage which could interfere with
safe loading.
Venting
Shipping containers as received will frequently be under pressure either
because of thermal expansion of the acid or slow hydrogen generation.
Carefully open the air connection valve if the truck is so equipped and vent
any pressure in the container. If there is no air connection, the safety vent should
be removed.
If no venting occurs, check to make sure the air connection and valve are
unobstructed. Carefully loosen the fill hole cover bolt (do not disengage), and pry
up slightly. If any pressure is present, let it bleed off slowly until no pressure
is in the tank, then open the fill hole cover.
Caution: All pressure must be vented before any container
fittings are removed because of the danger of acid spray. Do not remove the cap from
the liquid eduction pipe until it is definitely known that all pressure has been vented
from the container, and that the valve is closed (if so equipped).
Determine the Tank
Contents
Check to see if the tank car is completely empty. If the car is not
empty, the amount of acid left should be measured. Any acid remaining in the tank
car must be accounted for in terms of the amount of acid to be loaded to avoid overfilling
the tank car.
Loading System
Ensure that the loading system is ready to deliver acid to the tank
truck. The tank vent should be checked to ensure that it is open. Ensure all
valves are properly set for the loading operation.
Place the loading nozzle in hatch and chained the loading line into a secure
position.
Final Check
Inspect the system to be sure and all valves are properly positioned to
deliver acid.
Loading
Start the loading pump to begin loading acid into the tank car.
Check that acid is flowing into the tank car without
approaching the top of
the tank car. This can be done by watching for movement of the fill pipe or
listening from the bottom of the car for acid flowing into the car. If acid is not
flowing into the car, stop the pump. Recheck all the valves and ensure the pump is
operating properly.
If leaks develop or acid is spilled, promptly wash down any surface where
acid has spilled with an excess of water being extremely careful to avoid getting water
into the container, piping or into large accumulations of acid in holes or trenches.
While the car is loading the pump must be shut off before climbing onto the
loading platform. This is to minimize hazards to the loader due to overflowing as it
is being approached. The pump can be restarted on the platform after it has been
determined there is acid required to fill the tank truck.
Termination of Loading
When the acid reaches the required outage shut off the loading pump and close
valve on loading line. Remove the loading line from the fill hole.
Sampling
If a sample of the acid is required, it
should be taken after loading is
complete and the loading nozzle removed from the hatch.
Sealing of Container
Close the fill hole cover tightly and replace the caps on the air connection
valve and liquid eduction line. Replace the valve covers. Inspect the
container and place proper DOT required placards on the container for the return shipment.
Wash down any acid spills from the top of the tank car and raise the loading
platform.
Documentation
Obtain the necessary bills of lading signed as required and check to see that
the safety data sheet and driver instruction sheet are attached.
Departing
Check that the truck for signs of leaks and ensure that the placards are in
place. If the truck is not in satisfactory condition or there is a problem the truck
should not be allowed to leave until the problem is corrected.
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