Top Ten Chlorine Questions

The Water Treatment Operator certification exam will be three weeks from tomorrow here in California.  Chlorination is probably the topic with the most questions on the exam.  So I am posting a repeat blog for you from about this time last year, to help you get ready.  And don’t forget that we have a number of great courses — for only $10 each — here at MOST.  And they will help even more than my top ten chlorine questions below:
1.  How do we detect chlorine leaks?  While no help is needed to detect a large leak, ammonia will form a white mist when it reacts with a small chlorine leak.
2.  Chlorine attacks rubber, so we use lead gaskets instead of rubber.  Since the lead will develop grooves when tightened, a new lead gasket must be used for each connection.
3.  Liquid chlorine leaks are about 400 times more rapid than gaseous leaks, so leaking containers should be rotated to place the leak on top, thus making it a gas leak.
4.  Special repair kits are available to address container leaks.  The “A” kit is for 100/150 pound cylinders; the “B” kit is for ton containers; and the “C” kit is for larger tank and rail cars.
5.  Since chlorine gas will displace all of the air in an enclosed storage room, the only viable respiratory protection is an SCBA — Self-Contained Breathing Apparatus.
6.  The SCBA should not be stored in the same room as the chlorine, but should be removed by a moderate distance so that it is accessible during a leak event.
7.  There is one fusible plug on a 100/150 pound cylinder, and 6 or 8 on a ton container.  These will melt at about 160 degrees F, to prevent the explosion of the pressurized storage vessels during a fire.  They should never be removed or tampered with by the Operator.
8.  There is one outlet valve on a 100/150 pound cylinder, and there are two on a ton container.  Of these, the top will provide gaseous chlorine, while the bottom will provide liquid.
9.  Because chlorine gas is more dense than air, chlorine leak detectors are mounted near the floor in chlorine storage and feed areas.
10. The maximum withdrawal rate of chlorine gas from a 100/150 pound cylinder is 40 pounds per day; for a ton container, this rate is 400 pounds per day.
Make sure you know my top ten.  There’s a good chance you will see at least half of them on the exam on Saturday.

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