Storage and handling:
Cylinders should be stored in an upright position. They should be secured to prevent from falling over. Full and empty cylinders should not be stored together. Two containers should be stored on their sides. They should not be stacked or racked more than one high
Storage areas should be remote from elevators gangways or ventilating system because, in the event of a chlorine leak, dangerous concentrations of chlorine may spread rapidly.
The storage area should be separate from that in which other compressed gas containers are stored, and should contain no turpentine, ether, anhydrous ammonia, finely divided metals or other inflammable materials. The storage area should be dry, well ventilated clean of trash, and protected from external heat source (steam pipes etc). Sub surface areas should be avoided for storing chlorine cylinders.
The valves on cylinders and on containers should be protected by a stout metal cap securely attached to the cylinder body. This cap should always be kept in place on all containers in storage and at all times except during evacuation of chlorine.
Cylinders should never be lifted by means of the metal cap, nor should rope slings, chains or magnetic devices be used. Unloading platforms should preferable be at truck or car bed level. The ton container should be handled with a suitable cradle with chain slings in combination with a hoist or crane having at least 2 metric tons capacity.
Cylinders and ton containers being trucked should be carefully checked, clamped or otherwise suitably supported to prevent shifting and rolling. They should not be permitted to drop, and no object should be allowed to strike them with force. They should not project beyond the sides or ends of the vehicles in with they are transported.
Using Chlorine From Cylinders – Cylinders normally should be emptied in the gas phase, standing secured in an upright position. If it is necessary to empty them in the liquid phase, they should be partially inverted and clamped securely on a rack set at an angle of above 600 to the horizontal. Connection of containers discharging liquid to manifold is not recommended.
Ton containers set in a horizontal position, with the valves in a vertical plane, deliver gas from the upper valve and liquid from the lower valve. When emptied in the liquid phase, a vaporizer should normally be used.
The flow of chlorine gas form any chlorine container depends on the internal pressure which in turn depends on the temperature of the liquid chlorine. Discharge rates may, however be increased by forced circulation of room temperature air around the container.
If the gas discharge rate from a single container will not meet demand requirements, two or more may be connected to a manifold and discharged simultaneously or a vaporizer may be used. When discharging through a manifold, care shall be taken that all containers are at the same temperature, particularly when connecting a new container to the manifold if there is a difference in the temperature of the liquid chlorine, it will be transferred by distillation from the warm to the cool container, and the cooler container may become completely filled with liquid. If this should occur and the container valve remains closed, hydrostatic pressure may cause bursting. For this reason, extra precautions shall be observed when closing valves of containers connected to a manifold. Connection of cylinders or ton containers discharging liquid chlorine to a manifold is not recommended.
A flexible connection between the container and the piping should be used; annealed copper tubing (9.5 mm outside diameter x 0. 889 mm wall), suitable for 35.2 kg/cm2 service is recommended. A clamp and adapter connecter is preferred; if a union connector is used, the threads on the connector shall match the valve outlet thread. (Valve outlet threads are straight threads, not standard taper pipe threads). A new gasket (lead) should be used when making a connection.
Valves should be opened counter clockwise with a 9.5 mm square box wrench not over 152 mm long. If the valve is difficult to open, the packing nut may be struck with the heel and no other implements ought to be used.
When chlorine is being absorbed in a liquid, proper precautions shall be taken to prevent flow back of the liquid into the container when it becomes empty (due to a partial vacuum created); a barometric leg or vacuum breaking device or both should be used.
General Preventive Measures:
The fundamental steps for safe working conditions in a plant or area where chlorine is produced, stored or processed are:
1) Designing of layout of area with due consideration for adequate natural or mechanical ventilation.
2) Use of properly selected material for construction of plant and equipment for handling of chlorine.
3) Preventive maintenance of all equipment in proper working condition, and
4) Availability and use of adequate and suitable personal protective equipment at all times.