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Californ ia Test 685S

TATE OF CALIFORNIABUSINESS, TRANSPORTATION AND HOUSING AGENCY December 2002

DEPARTMENT OF TRANSPORTATIONDIVISION OF ENGINEERING SERVICESTransportation Laboratory5900 Folsom BoulevardSacramento, California 95819-4612

METHOD FOR HOLIDAY DETECTION IN EPOXY-COATED REINFORCING STEEL

CAUTION: Prior to handling test materials, performing equipment setups, and/or conductingthis method, testers are required to read " SAFETY AND HEALTH " in Section F ofthis method. It is the responsibility of the user of this method to consult and usedepartmental safety and health practices and determine the applicability ofregulatory limitations before any testing is performed .

A. SCOPE

The procedures to be used fordetermining holidays in epoxy coatings onferrous materials are described in thismethod. This method uses an electricalcurrent flow through a low resistancepath to trigger an alarm (buzzer) toindicate to the operator the presence of aholiday.

Holidays are defined as pinholes andvoids in non-conductive coatings that

allow current to pass through theprotective coating to the metal basematerial. These discontinuities are suchthat they may not be visible to a personwith normal or corrected vision.

B. APPARATUS

1. A low voltage holiday detector testerhaving an electrical source of 67.5 to100 V DC that meets the requirementof ASTM G 62 Section 1.2, Method A.Example: Tinker & Rasor, Model M/1

Holiday Detector.2. A cellulose sponge with an insulated

handle. The sponge is wired to thepositive contact electrode.

3. A grounding clamp/magnet and wireto the negative (ground) terminal.

This provides the system connectionto the low resistance base metal.

4. Tap water. Plain, if measuring pinholes and voids in coating thicknessup to 10 mils.

5. A non-sudsing type wetting agent.Use the following dilution factor formeasuring pin holes and voids incoating thickness up to 20 mils: Oneounce agent to one gallon of tapwater. Reference: Tinker & RasorWater-Wetter.

6. A 80,000 ohm, watt resistormounted on an insulated terminalboard for checking proper audioindication and the drop in batteryvoltage with this resistance load. (Thistest resistance may be built in tonewer models of the holiday tester.)

C. TEST PROCEDURE

Wet the sponge with sufficient wettingsolution to assure moisture penetration ofany defect in the surface coating.

Squeeze out any excess.1. Before starting the testing process,

place the moist sponge on one end ofthe 80,000 ohm resistor and place themagnet contact on the other end.Verify that an audible alarm is given.Weekly, check the voltage (with a highimpedance volt/ohm meter) acrossthe tester terminals when the system

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is loaded with the 80,000 ohmresistor. If the voltage less than 90 %of required voltage, replace the systembattery.

2. If the sample bar ends are coated,grind the coating off one end of thebar being tested. This is for theground contact .

3. Place the magnet with the attachedground wire on the bare end of thebar. The magnet should be in directcontact with the base metal.

4. Test the connections by contactingthe bare end with the sponge. Theaudible alarm should be triggered.

5. Test the coated metal sample bysweeping the moist cellulosesponge up and down the deformationsides and the ribbed sides of thesample. The sweep rate shall notexceed 60 mm/s. Count the alarmindications, mark the spots (SeeNote 3) and record the total numberdetected.

D. NOTES

1. Sample coating shall be dry and free

from contamination before holidaytesting.

2. Insure that sponge contact covers theentire surface of the bar to accuratelydetect all holidays.

3. Mark all detected holidays on the barwith an indelible marker to insure anaccurate count.

4. Obvious shipping and handlingcaused skinned or damaged spots are

not to be counted as holidays.

5. Follow manufacturers instructions foradjusting the electronic circuit tosound at 80,000 ohms across theterminals.

E. REPORTING RESULTS

Document results of tests withappropriate comments and notations on atest form (example of an appropriate formis shown in Figure 1). Report results informal form (as complying or notcomplying with specifications) on asample testing form (sample of anexample is shown in Figure 2). Thesample will be documented with theinspectors or the coaters name and lotnumber, the date sampled, the requiredspecification, and the number of holidaysfound.

F. SAFETY AND HEALTH

Prior to handling, testing or disposing ofany waste materials, testers are requiredto read: Part A (Section 5.0), Part B(Sections: 5.0, 6.0 and 10.0) and Part C(Section 1.0) of Caltrans LaboratorySafety Manual. Users of this method doso at their own risk.

REFERENCECalifornia Standard Specifications,

ASTM A 775/775M, A 884/884M, A 934/934M, G 62

End of Text(Califo rnia Test 685 contains 4 pages)

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Figure 1 Test Form for Recording Holiday Detection Results

Standard Specs: 52-1.02BASTM: A775/A934Holiday Detection:Criterion for passing =less than 1 holiday perfoot.

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Figure 2 Sample Testing Report

52-1.02B

TL-101 No.