Figure 2-11.--Coordinated phosphate curve (waste heat boilers).
plan. In the following paragraphs, we will discuss
2. Periodically check the dates of the chemicals
how to control contamination under normal and
you have in stock.
abnormal situations. We will also describe some key
symptoms and factors you must be able to interpret
3. Dispose of the outdated stock and rotate the
so you can determine what type of contamination has
rest to get optimum use of the good stock.
occurred.
Another precaution you should take is to test your
CONTAMINATION CONTROL
samples within a reasonable amount of time. Do not
allow your samples to sit for long periods of time
To monitor your ship's water for contaminants,
before you test them.
you must first be able to recognize the standards for
normal operating conditions for both the boiler water
Chloride Test.-- The chloride test will be the last
and the feedwater systems. Next, you must be able to
test you will perform. Although this test is not
recognize when contaminant levels start to exceed
difficult to perform, you must take care to avoid two
normal control limits and threaten to become a
things: (1) adding reagents too quickly during
hazard to your ship's engineering equipment and
titration and (2) attempting to test discolored water.
systems. First, let's talk about the contamination
Adding the reagents too quickly will cause a high
control procedures you will use for boiler water.
chloride reading. Many of the color changes in this
test are very subtle. If you are not careful, you may
Boiler Water
add too much reagent before you notice the color
change.
In monitoring and maintaining the quality of your
ship's boiler water, you will follow routine procedures
Now that the testing is complete, we need to know
how to interpret our results and develop a treatment