Southern Inspection Services
HALOGEN DIODE DETECTOR LEAK TESTING
LEVEL I – QUESTIONNAIRE
1. Good operating practices that the period of time to allow for warm up of
the Halogen Diode Detector prior to calibrating is.
a. 30 minutes
b. 15 minutes
c. one hour
d. as recommended by the manufacturer
2. An operator smoking a cigarette while performing a Halogen diode leak
detector test in a confined area discovers repeated erratic signals on the
instrument meter. Which of the following is most likely the cause of the
signals
a. A dirty instrument sensing element
b. High back ground caused by the halogen rich cigarette smoke
c. Low line voltage to the instrument control unit air pump
d. Low line voltage to the instrument.
3. When preparing objects for halogen diode leak testing the areas to be
tested must be free of
a. dirt
b. grease
c. moisture
d. all of the above
4. For accurate leak location during halogen leak testing if air movements is
encountered which doesn’t reduce the required sensitivity of test, the
probing operation should begin at:
a. The first located leak and proceed in a clock wise direction
b. The down stream side of the draft
c. The upstream side of the draft
d. The test should be stopped and the detector re-calibrated
5. When performing a halogen stiffer test of a large object, in the absence of
significant air movement, sniff ring or scanning should normally proceed
from the
a. weld furthermost from the test manifold
b. Highest to the lowest point in the test system
c. leeward to the windward side of the test system
d. lowest to the highest point in the system
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6. Halogen diode type leak detectors should never be used in an explosive
atmosphere because;
a. This is a violation of good safety practices and OSHA Standards
b. The sensing element of the instrument which operates at a very high
temperature could ignite the explosive mixture
c. The instrument contains electrical circuits which could ignite the explosive
mixture
d. All of the above are applicable
7. As the surrounding temperature increases the maximum pressure
attainable from a bottle of halogen rich refrigerant gas
a. Increases
b. remains the same
c. Decreases
d. Varies with the squire of the temperature
8. When recharging the reservoir type halogen standard leak with refrigerant,
personnel should
a. always use “ Freon “ band of refrigerant
b. for economy use any brand as R11, R12 and or R22
c. always use safety goggles with side shields to protect eyes
d. Always use asbestos gloves to keep from R12 , cold burning the hands
9. A Halogen Diode Detector Test procedure requires 5 psig of refrigerant 12
and a total pressure of 45 psig for the test. From the table, the percent by
volume halogen mixture at test pressure is:
a. 6.7
b. 8.3
c. 40
d. 75
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10. A Halogen Diode Detector Test is to be performed at a test sensitivity of 1 x
10-4 std. cc/sec with a 5% by volume halogen mixture in the test object.
From the table, the approximate size standard leak setting that should be
used to calibrate the halogen leak detector for the test is:
a. 2 x 10-4 std cc/sec
b. 5 x 10-5 std cc/sec
c. 5 x 10-6 std cc/sec
d. 2 x 10-7 std cc/sec
11. When erratic signals are indicated during a halogen diode sniffer test, one
cause of the problem could most likely be:
a. Erratic sniffing technique by the operator
b. Halogen background from a large leak
c. A downstream virtual leak
d. Inadequate instrument sensitivity
12. Good operating practice dictates that the sensitivity of the Halogen Diode
Detector should be determined before and after testing and at intervals of
_______________ minimum while scanning.
a. 2 hours
b. 1 hour
c. ½ hour
d. 3 hours
13. While increasing the leak rate setting on reservoir type variable halogen
standard leak, if the instrument pointer continues to go up the scale after
the INCREASE valve is closed, this is an indication that the:
a. DECREASE valve is not firmly closed
b. Gas reservoir is over pressurized
c. Liquid tank is too full
d. INCREASE valve is not firmly closed
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14. When adjusting a reservoir type variable halogen standard leak, if the
DECREASE valve is opened when the INCREASE valve is not fully closed,
the:
a. Valve between the liquid tank and gas reservoir will close
b. Instrument pointer will rapidly go to the top of the scale
c. Refrigerant will vent from the standard leak reservoir and refilling will most
likely be necessary
d. Instrument pointer will slowly decrease to halt scale
15. The basis for the scanning or sniffing direction during a halogen sniffer
test is that refrigerator gas:
a. is heavier that air and will settle to the lowest point
b. is lighter that air and will rise during testing
c. is the same weight as air and will stay in the immediate area of the leak or
leaks from which it is escaping
d. will rapidly change chemical composition as it escapes in the surrounding
air
16. Which of the listed items could temporarily plug leaks in a test object?
a. Water
b. cleaning solvent
c. paint
d. all of the above
17. A halogen diode detector test procedure specifies the use of refrigerator
R – 12 as the source of tracer gas, which of the following refrigerants
would it be permissible to use?
a. Genetron 12
b. Freon 12
c. Ucon 12
d. Any of the above
18. Materials that contain halogens are usually called:
a. Fluorines
b. Inert
c. Halides
d. Ozone
19. While adjusting a reservoir type variable Halogen Standard Leak, the
operator accidentally events the gas from the only standard leak available.
Which of the following actions would quickly resolve the problem?
a. Replace the standard leak
b. Replace the cylinders in the standard leak
c. Recharge the standard leak
d. Send the standard leak to the manufacturer for recharging
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20. The test connections used for pressuring a halogen sniffer test system
should be halogen leak tested prior to performing the halogen sniffer test
of the system, in order to:
a. Complete the training of the operator and qualify that individual in this test
method
b. Check the ad4equacy of the instrument calibration
c. Detect and eliminate leakage that could create background contamination
d. Verify the adequacy of the soak time
21. Placing the sniffer probe or gun of halogen diode leak detector in stream of
pure refrigerant:
a. is a rough method of checking instrument sensitivity in the absence of a
standard leak
b. will temporarily or permanently contaminate and shorten or end the life of
the instrument sensing element
c. Is a method of determining the percentage of halogen compound in
refrigerant
d. Enable the operator to simulate background contamination
22. One purpose of a built-in automatic zeroing circuit in a halogen diode leak
detector is to:
a. Enable the operator to use a faster scanning speed
b. Eliminate the steady background signal caused by local atmospheric
halogen content
c. Ensure that the operator will not miss a leak
d. Make it easier to more rapidly pinpoint very small leaks
23. The size of the smallest leakage detectable with a halogen leak detector is
known as:
a. Total leakage rate
b. Leak indicator range
c. Response time
d. Sensitivity
24. When pressurizing a vessel or component with a mixture of compressed
air and halide refrigerant, adding the refrigerant to the system first:
a. Reduce the total quantity of refrigerant required for the test
b. Aid in the dispersion and mixing of the refrigerant throughout the system
c. Minimizes the possibility of the operator missing leak due top the higher
concentration of tracer gas at the st scanning
d. Speeds the stratification of refrigerant within the test system which
increases the reliability of the results
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25. While performing a Halogen Detector test, the leak detector becomes
difficult to zero and the pointer on the rate meter repeatedly swings up
scale. The most likely cause of the problem could be the use of too high a
sensitive range, shorted element, excessive heater voltage, of:
a. Poor air flow
b. Sensing element is too new
c. High halogen background
d. Faulty leak rate meter
26. When venting a halogen mixture from a vessel or component in order to
repair detected leaks, the location of the vent or exhaust line:
a. Is dependent on the percent by volume mixture.
b. Is unimportant since the initial test is already complete
c. Must be down wind and far enough away to prevent the halogen mixtue
form re-entering the test are
d. Is not important at this stage of the test since the repairs can be made
without releasing the pressure from the system
27. Which of the following leak rate values does not match any of the halogen
standard leak settings shown?
a. 5.3 x 10-2 oz. per year
b. 1.2 x 10-6 std. cc/sec
c. 2.6 x 10-5 std. cc/sec
d. 1.2 x 10-1 oz. per year
28. One of the better methods of assuring that the distance between the sniffer
probe tip and the test surface does not ex the maximum allowed by the
code and/or test procedure is to:
a. Fit the end of the sniffer with a notched piece of plastic that projects no
more than the allowed maximum distance beyond the tip of the sniffer
b. Time the tip of the sniffer by the mount of allowed maximum distance
c. Tape a wire rod to the sniffer with the end projecting beyond the tip of the
sniffer by twice the required maximum distance
d. Estimate the distance between the sniffer and the test surface during
scanning
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29. A leak test procedure for a halogen diode sniffer test requires a mixture of
halogen and air or inert gas. If compressed air is not available, which of the
following tyupe of available bottled gases could be used to safely complete
the pressurization?
a. Oxygen
b. Carbon dioxide
c. Butane
d. Propane
30. Refrigerant 12 in the presence of high temperature (such as a weld
puddle)will break down into hydrogen chloride hydrogen fluoride, chlorine
and:
a. carbon monoxide
b. sulfur dioxide
c. phosgene (mustard gas)
d. sodium sulfate
31. From the graph, what would be the minimum ambient temperature needed
for refrigerant 12 to required halogen pressure of 40 psig in a system
pressurized to a test pressure of 60 psig?
a. 15 ºF
b. 35 ºF
c. 45 ºF
d. 65 ºF
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HALOGEN DIODE DETECTOR LEAK TESTING
LEVEL I – QUESTIONNAIRE ANSWERS
Q.NO. ANS Q.NO. ANS
1 D 17 D
2 B 18 C
3 D 19 C
4 C 20 C
5 B 21 B
6 D 22 B
7 A 23 D
8 C 24 B
9 B 25 C
10 C 26 C
11 B 27 A
12 A 28 A
13 D 29 B
14 C 30 C
15 A 31 C
16 D
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