Appendix III to Part 150 - Testing Procedures for Determining Exceptions to the Chart
46:5.0.1.3.11.0.6.10.6 : Appendix III
Appendix III to Part 150 - Testing Procedures for Determining
Exceptions to the Chart experimental procedure for evaluating
binary chemical reactivity
General safety precautions - Chemical reactivity tests
have, by their nature, serious potential for injuring the
experimenter or destroying equipment. The experimenter should 1)
have knowledge of the magnitude of the reactivity to be expected,
2) use adequate facilities and protective equipment to prevent
injury from splatter of materials or release of fumes, and 3) start
on a small scale so that unexpected reactions can be safely
contained. All tests should be performed in a well-ventilated
laboratory hood provided with shields.
Testing chemicals other than liquids - The procedure
outlined below was developed for chemicals which are liquids at
ambient temperatures. If one or both chemicals are normally shipped
at elevated temperatures, the same procedure may be followed except
the chemicals are tested at their respective shipping temperatures
and the oil bath in Step 3 is maintained at a level 25 °C above the
higher temperature. This information is then indicated on the data
sheet. If one of the chemicals is a gas at ambient temperatures,
consult the Coast Guard for additional instructions before
proceeding with the compatibility test.
Step 1
Objective - To determine if the test chemicals react violently
and present a safety hazard in further tests.
Procedure - Place 0.5ml of one (A) of the test chemicals in a 25
× 150mm test tube. Clamp the test tube to a stand behind a safety
shield (in a hood). Carefully add from a dropper 0.5ml of the other
substance (B). Shake to induce mixing. If no immediate reaction
occurs, retain the mixture for at least 10 minutes to check for a
delayed reaction.
Results - If a violent reaction occurs, such as sputtering,
boiling of reactants or release of fumes, record the results on the
Data Sheet (appendix IV) and do not proceed to Step 2. If no
reaction or a minor reaction occurs, proceed to Step 2.
Step 2
Objective - To determine the heat of reaction of two chemicals
on mixing under specified conditions.
Procedure - These separate mixes of the proposed binary
combination will be tested. These are 2 ml : 18 ml, 10 ml : 10 ml,
and 18 ml : 2 ml, respectively, to result in a final mixture of
about 20 ml in each case.
A reference-junctioned thermocouple is prepared by inserting two
lengths of 20 gauge or finer iron-constantan or chromelalumel
duplex thermocouple wire into glass capilary sheaths. The common
wire of each probe is joined, while the other wire of each is
connected to a strip-chart recorder. The thermocouple probe which
produces a negative pen deflection upon warming is the reference
junction and is placed in a test tube of water at ambient
laboratory temperature. The other probe is placed near the bottom
of a Dewar flask of about 300ml capacity, such that the
thermocouple will be below the surface of the test mixture. The
Dewar flask is equipped with a magnetic stirrer having a stirring
bar coated with an inert material such as a fluorinated
hydrocarbon.
Start the temperature recorder and stirrer. Deliver the test
chemicals to the Dewar Flask simultaneously from separate graduated
syringes. If an exothermic reaction occurs, continue the test until
the maximum temperature is reached and begins to subside. If no
apparent reaction occurs, continue the test for at least 30 minutes
to check for a delayed reaction. Stop agitation and observe the
mixture at five-minute intervals to determine if the mixture is
miscible, if gases are evolved, or if other visible changes occur.
In the interest of safety, a mirror can be used for these
observations. Repeat the above test for the other mixture
combinations.
Results - Record the results in the appropriate places on the
Data Sheet. If no reaction occurs or if the temperature rise is
less than 25 °C, proceed to Step 3. If the observed temperature
rise exceeds 25 °C or gases are evolved, do not proceed to Step
3.
Step 3
Objective - To determine if exothermic reactions occur at
temperatures up to 50 °C.
Procedure - If a non-hazardous reaction occurred in Step 2, the
ratio of chemicals which resulted in the greatest temperature rise
will be tested. Fresh chemicals will be used with a total volume
for this test of about 10ml (a ratio of 1ml:9ml, 5ml:5ml, or
9ml:1ml). If no reaction was observed in Step 2, use a ratio of
5ml:5ml. Using the thermocouple prepared for Step 2, insert the
reference probe into a 25 × 150mm test tube containing 10ml of
water. Place the other probe into an empty test tube. Start the
temperature recorder and add the two chemicals of the combination,
one at a time, to the empty test tube. Lower the two test tubes
into an oil bath maintained at 50 ±2 °C. Hold the samples in the
oil bath until the maximum temperature differential is recorded,
and in all cases at least 15 minutes. Observe the test mixture to
determine if gases are evolved or if other visible changes occur.
Follow prescribed safety precautions.
Results - Record the maximum differential temperature measured,
the time required to reach this temperature, and any other
observations in the proper space on the Data Sheet.
Send a copy of the Data Sheet for each binary chemical mixture
tested to: Commandant (CG-ENG-5), Attn: Hazardous Materials
Division, U.S. Coast Guard Stop 7509, 2703 Martin Luther King Jr.
Avenue SE., Washington, DC 20593-7509.
[CGD 75-59, 45 FR 70263, Oct. 23, 1980, as amended by CGD 82-063b,
48 FR 4782, Feb. 3, 1983; CGD 83-047, 50 FR 33046, Aug. 16, 1985;
CGD 88-070, 53 FR 34535, Sept. 7, 19885; CGD 96-041, 61 FR 50731,
Sept. 27, 1996; USCG-2012-0832, 77 FR 59783, Oct. 1, 2012;
USCG-2013-0671, 78 FR 60155, Sept. 30, 2013; USCG-2014-0688, 79 FR
58284, Sept. 29, 2014]