explosives testing (et) abl electrostatic discharge users

Explosives Testing (ET)

Users’ Group

Standards

ABL Electrostatic Discharge

Sensitivity Tester Operating Procedure

Approval of 19

R.T. Ford, Chair Revision: 2 Date: 5/6/2014

Procedure Number: A030-ETUG

1.0 SCOPE

1.1 This document describes the safety rules and procedures for electrostatic discharge (ESD) sensitivity testing of propellant and explosive materials using the Allegany Ballistics Laboratory (ABL) ESD tester. The ABL Electrostatic Discharge Test Apparatus uses 12 capacitors with varying capacitances, a variable voltage supply, and electrodes.

2.0 EXAMPLE APPLICABLE DOCUMENTS

2.1 TE-0000-S-609 Explosive Testing Standard Operating Procedure

2.2 6-7-10 Hazardous Waste Management Plan for the Test Site

2.3 Owner’s Manual ABL Electrostatic Discharge Test Apparatus

2.4 Test Sample MSDS

2.5 T1 Test Plan

2.6 TR1 Test Request

2.7 A030.1 Test Record Sheet

2.8 A100 Calibration Log

2.9 A101 Hand Cutting of Propellant Samples

2.10 A102 Operation and Maintenance of Microtome

2.11 A103.1 Operation and Maintenance of High-Speed Video camera

2.12 A104 Cleanup of Liquid Explosive Spills

2.13 A105 General Safety and Health Manual

NOTE: Please note that additional procedures have been included that may or may not be applicable to every test site. Applicability depends on each facility’s policies, procedures and equipment.

3.0 REQUIREMENTS

3.1 Only personnel thoroughly familiar with this document, the referenced documents, and the test equipment are authorized to perform the operations described in this procedure. To become authorized an individual must be approved by the Testing Director and personally instructed by a designated, trained operator to ensure that all safety and health precautions and operating instructions are completely understood. The new operator will then carry out the operation to


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the satisfaction of the designated, trained operator. Qualified personnel shall be recorded in the training log.

3.2 In addition to the safety rules and techniques outlined in these procedures, all applicable plant safety rules shall be followed.

3.3 All measuring devices that require calibration shall be inspected prior to an operation to verify that calibration intervals have not been exceeded. Calibration is done on the ESD machine at least annually or after a major repair.

3.4 High-speed video with GoDetect reaction detection software is available for use and can be used to give less subjective results. GoDetect-ESD results should not be directly compared with results that have been obtained by other methods including human detection. The high-speed video can be more sensitive than other methods. The sensitivity of the substance has not changed but the ability to detect reactions may have increased. In addition to testing the substance, it is required to also test a standard material using GoDetect-ESD. The high-speed video results are then indirectly compared to the results obtained from other methods by casting the results relative to the standard.

3.5 At least once every 6 months, determine the machine drift.

3.5.1 GoDetect-ESD Adv software gives the machine drift, if any, by plotting the background levels at various energies as a function of time from the test history.

3.5.2 Alternatively, a Threshold Initiation Level (TIL) test on a well characterized (by ESD) sample material can also be used to determine machine drift and operator variability. Check will be deemed successful if the material’s TIL is within ± 2 TIL standard test levels of the historical range. If the check fails then troubleshoot to determine the problem and consider the following: retraining the operator, performing a PROBIT to see if still within family, and/or performing the machine calibration found in the ABL Electrostatic Discharge Test Apparatus Owner’s Manual.

3.6 Calibration and verification of the ESD Machine shall be completed according to the ABL ESD Owner’s Manual and Section 6.1 below.

3.7 At least once every 6 months or after particularly messy testing, the machine should be evaluated for deep cleaning. This will consist of disassembly of movable parts in the test chamber and inspection of the capacitor bank and switches for build-up of any live materials.

3.8 Using a portable lamp or light, continuously evaluate for "hiding places" where material can accumulate.

3.9 Copies of this procedure shall be made available in the testing area control room.

3.10 Approved test plans are applicable when used in conjunction with this procedure


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4.0 MATERIALS AND EQUIPMENT

4.1 Material Description Test sample Granular solids, cured propellant, liquid explosives,

uncured propellants (~10 grams supplied by customer) Solvent Commercial grade acetone, methanol or equivalent

solvent Wiping tissues Kimwipes, Kleenex, or cheesecloth Sandpaper Grit No. 400A, or equivalent Bags Pink Polyethylene Antistatic or Conductive Velostat Gloves Compatible with test sample and cleaning solvent

Abrasive pad 3M Scotch-Brite™ General Purpose Hand Pad

Respirator As required, with proper cartridge Hearing protection Plugs or muffs as required Desensitizing Liquid Shingle oil Shoes Non-conductive Lab coat Flame resistant or coveralls Glasses With side-shields or mono-goggles Tape Teflon or equivalent, 1-2” wide Marker Black Felt Marker

4.2 Equipment Description 60000N86547 ABL Electrostatic Discharge Assembly 60000N86547-55-3 ABL ESD Electrode Needle 6000N86547-35-3_B ABL ESD Sample Holder 6000N86547-16 ABL ESD Insulating Ring 6000N86547-17 ABL ESD Liquid Insulating Ring Feeler gage 0.06 inch Feeler gage 0.02 inch


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Measuring spoon Conductive Eye dropper Glass or equivalent Spatula Conductive Video High speed with laptop running GoDetect reaction

detection software Kikusui 149-10A High Voltage Digital Voltmeter (0-10kv)

Craftsman Model 82139 Auto-Ranging MultiMeter Brush Natural hair, large (for cabinet) and small (for sample

holder)

Lamp or light, portable Electrically rated for area (illumination for cleaning) Containers Conductive with lid for sample and scrap, Qty. (2)

5.0 SAFETY

5.1 All applicable safety rules and practices established in TE-0000-S-609 shall be observed. NOTE: If at any time during this operation there should be an occurrence of a nature which would affect the safety of the operation, this operation shall be brought to a safe and orderly stop and supervision notified.

5.2 When testing, test samples and volatile solvents shall be kept in approved containers at least 3 feet from the test apparatus (including the high-speed video camera) or isolated (e.g., shield, barrier).

5.3 Personnel shall wear, as a minimum, the following equipment while performing operations described in this document:

a. Safety glasses with side-shields or mono-goggles (polarized)

b. Flame resistant lab coat or coveralls

c. Safety shoes (non-conductive) d. Gloves as specified for the material being tested and compatible with solvents

used for cleaning e. Hearing protection (as required in noise hazards areas) f. Respirator (as required by planning)


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WARNING: These tests involve high voltage and conductive shoes shall not be worn. Wearing conductive shoes increases the hazard of an electrical shock to the operator by grounding high voltage through his/her body.

5.4 Explosive and personnel limits established in TE-0000-S-609 shall be followed.

NOTE: All tests requiring samples greater than normal test limits shall be run remotely using the remote firing switch that connects to the remote switch port on the front of the ESD machine.

5.5 Prior to testing, personnel shall ensure that anticipated sensitivity and toxicity of the material/propellant is known so that proper handling, cutting, storage, and disposal can be completed. Special precautions and planning shall be provided by the requestor and test engineer.

NOTE: You are not required to do anything that is deemed unsafe. If you feel that you have been asked to do something that would jeopardize your safety or the safety of others or facilities, stop and contact supervision. If anything unusual should occur during the normal operation of this test, stop and notify supervision immediately.

5.6 All personnel using respirators must have completed and be current in all respirator training, and must complete cleaning, inspecting, and recording requirements.

5.7 Use appropriate ventilation as needed to remove reactants (e.g. smoke, combustion products) resulting from the ESD test.

5.8 In case of an unexpected fire (beyond test expectations) evacuate to the assembly area.


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6.0 OPERATIONS

Figure 1: ABL ESD machine

6.1 CALIBRATION & VERIFICATION

DANGER: ELECTROCUTION HAZARD! VERIFY THAT THE POWER TO THE MACHINE IS TURNED OFF AND THERE IS NO STRAY VOLTAGE ON THE ELECTRODE BEFORE APPROACHING THE DISCHARGE NEEDLE.

6.1.1 DE-ENERGIZE Pneumatics: De-energize the pneumatic supply line to the back of the ESD machine (e.g. disconnect line or LOTO) prior to performance of the following calibration & checkout procedures, disconnect the pneumatic supply line from the back of the ESD machine. Reconnect the supply line upon completion.

DANGER: PUNCTURE HAZARD! IF THE PNEUMATIC SUPPLY LINE IS NOT DE-ENGERIZED, INJURY MAY RESULT WHEN THE “FIRE” BUTTON IS PRESSED (LOWERING THE NEEDLE) WITH HANDS ARE PRESENT INSIDE THE MACHINE!

6.1.2 TRY Pneumatics: Turn the “FUNCTION” switch to “ready”, the “CAPACITORS” switch to “ready”, the “POWER” switch to “on” and try the “FIRE” button. If the needle lowers, STOP and consult supervision or the test engineer.

6.1.3 Function of Safety Interlocks

6.1.3.1 Turn the “FUNCTION” switch to “ground”, the “CAPACITORS” switch to “charge”, and the “POWER” switch to “on”.


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6.1.3.2 Wait until the red indicator light next to the “POWER” switch turns ON.

6.1.3.3 Opening an interlocked door should de-energize the safety switch, shutting off electrical power, grounding the needle, and turning OFF the red indicator light next to the “POWER” switch. When the interlocked door is closed, the safety switch should re-energize, restoring power and turning ON the red indicator light. If this functionality is NOT observed, STOP and consult supervision or the test engineer.

6.1.3.4 To test the safety interlocks on the front access door of the cabinet, open the door and verify that electrical power is shut off to the machine. Close the door and verify that electrical power is restored as indicated by the power indicator light.

6.1.3.5 To test the safety interlock on the side access door of the cabinet, open the door and verify that electrical power is shut off to the machine. Close the door and verify that electrical power is restored as indicated by the power indicator light.

6.1.3.6 To test the safety interlock on the capacitor access hatch of the cabinet (if equipped), open the hatch and verify that electrical power is shut off to the machine. Close the hatch and verify that electrical power is restored as indicated by the power indicator light.

6.1.4 Grounding the Capacitors

6.1.4.1 Turn the “FUNCTION” switch to “ground”, the “CAPACITORS” switch to “charge”, and the “POWER” switch to “off”.

6.1.4.2 Turn “ROTARY SWITCH A” to the 0.0001 µF position and “ROTARY SWITCH B” to the open (none) position.

6.1.4.3 Rotate through each of the capacitors, briefly pausing on each one to allow for removal of charge from the grounded capacitor.

6.1.5 Function of Variable High-Voltage Power Supply and Voltage Dissipation



6.1.5.3 Insert the insulated leads of the Kikusui High Voltage Digital Voltmeter 149-10A (or equivalent) into the test chamber (e.g. through the overhead vent tube), NOTE: Can place the multimeter on top of the cabinet for convenience.

6.1.5.4 Open the front access door of the cabinet and attach the INPUT high-voltage lead to the needle (a bare wire may be wrapped around the needle).


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6.1.5.5 Attach the low-voltage lead to the grounded pedestal (alligator clip may be attached to the bolt on the pedestal connecting the ground wire).

6.1.5.6 Close the front access door of the cabinet.

6.1.5.7 Turn the “POWER” switch to “on”, the “FUNCTION” switch to “ready”, and the “CAPACITORS” switch to “charge”,

6.1.5.8 Verify that the “SUPPLY VOLTAGE” display on the ESD machine and the readout on the high voltage digital meter are reporting similar values (within 1%). If this functionality is NOT observed, STOP and consult supervision or the test engineer.

6.1.5.9 Rotate the “VOLTAGE ADJUST” knob and verify that the supply voltage proportionately increases or decreases. Set the supply voltage to the desired value (standard value is 5000 V ± 1%)

6.1.5.10 Switch the “CAPACITORS” switch to “ready”, opening the charging circuit. The capacitor should hold its charge. If this functionality is NOT observed, STOP and consult supervision or the test engineer.

6.1.5.11 Switch the “CAPACITORS” switch to “charge”, the “FUNCTION” switch to “ground”

6.1.5.12 Select the next capacitor from “ROTARY SWITCH A” and repeat from step 6.1.5.7 until the functionality of all capacitors has been tested.


6.1.5.14 Verify that the readout on the high voltage digital meter shows 0 volts. If this functionality is NOT observed, STOP and consult supervision or the test engineer.

6.1.5.15 Open the front access door of the cabinet and detach the meter leads. Remove the meter leads from the cabinet and close the front access door of the cabinet.

6.1.6 Measurement of Actual Capacitance

NOTE: Ensure meter is calibrated for the range being tested

6.1.6.1 Generate or obtain the matrix for recording theoretical vs. measured capacitance to be posted near the machine for quantitative analysis (as needed). An example matrix is as follows:

Capacitance (µF)

Left Capacitor

Right Capacitor

Theoretical Value

Measured (Actual) Value

OCT 2012 OCT 2013 OCT 2014 OCT 2015

0.5 - 0.5 0.488

0.25 - 0.25 0.200

0.1 - 0.1 0.106

0.05 - 0.05 0.055


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0.02 - 0.02 0.022

0.01 - 0.01 0.011

0.005 - 0.005 0.0061

0.002 - 0.002 0.0025

0.001 - 0.001 0.0014

0.0005 - 0.0005 0.00090

0.0002 - 0.0002 0.00060

0.0001 - 0.0001 0.00051



6.1.6.4 Configure a Craftsman Model 82139 Auto-Ranging MultiMeter to measure capacitance. NOTE: Other multimeters of varying complexity have been used with mixed results due to the nature of this measurement. This specific multimeter was found to produce reasonable values and consistent results for this specific application.

6.1.6.5 Open the front access door of the cabinet.

6.1.6.6 Attach the positive (red) lead of the multimeter to the needle (alligator clip may be attached to the bolt on the approaching needle connecting the live wire).

6.1.6.7 Attach the negative (black) lead of the multimeter to the ground electrode/ base (alligator clip may be attached to the bolt on the pedestal connecting the ground wire).

6.1.6.8 Measure and record the total capacitance (capacitor and internal wiring) in microfarads from the needle to the ground electrode (base).

6.1.6.9 Select the next capacitor from “ROTARY SWITCH A” and repeat from step 6.1.6.8 until the value of each desired capacitor combination has been tested.

6.1.6.10 Detach the meter leads, remove the meter leads from the cabinet, and close the front access door of the cabinet.

6.1.7 Adjustment of Needle Gap

6.1.7.1 Open the front access door of the cabinet.

6.1.7.2 Loosen the collet securing the electrode needle and remove the electrode needle.

6.1.7.3 Examine the electrode needle for damage. Buff with a Scotch Brite pad or fine grit sandpaper as necessary. Replace the needle if damage is present.

NOTE: The needle should be of standard thickness as specified in the parts list. Changing the diameter of the needle can affect test results.


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6.1.7.4 Replace the electrode needle into the collet and tighten to secure.

6.1.7.5 Place a sample holder on the base electrode and twist to lock into place.

6.1.7.6 Manually extend the pneumatic cylinder, lowering the approaching needle.

6.1.7.7 Fit the pneumatic insert block into position to lock the approaching needle in the down position.

6.1.7.8 Adjust the approaching needle gap by dropping the needle out of the collet and/or twisting the base electrode to raise/lower the pedestal. Adjust the needle gap so that (1) the needle will not impact the sample, and (2) there is no apparent delay in the electrostatic discharge once the needle reaches the bottom of the its travel. A typical gap between needle and sample holder is 0.020 - 0.060 inches.

6.1.7.9 Remove the pneumatic insert block and raise the approaching needle to the up position.

6.1.7.10 RE-ENERGIZE Pneumatics: After verifying that the pneumatic insert block is removed, energize the pneumatic supply line to the back of the ESD machine.

6.1.8 TRY Pneumatics: Turn the “FUNCTION” switch to “ready”, the “CAPACITORS” switch to “ready”, the “POWER” switch to “on” and try the “FIRE” button. If the needle does not lower, STOP and consult supervision or the test engineer.

6.2 TEST SETUP

6.2.1 Place a non-conductive rubber mat on the floor in front of the ESD tester.

6.2.2 Ensure that all calibrated equipment has a valid calibration.

6.2.3 Examine the sample holder and insulating ring for damage. Clean with solvent or buff with a Scotch Brite pad or fine grit sandpaper as necessary. Replace the sample holder if burrs or divots are present.

6.2.4 Turn on the exhaust fan as needed to ventilate sample chamber.

6.2.5 Before turning the power on verify that the "FUNCTION" switch is turned to "ground" and the "CAPACITOR" switch is turned to "charge".

6.2.6 Turn the power switch to ON.

6.2.7 Check the line voltage. Use the voltage necessary to obtain the energy levels required (standard is 5000 V).

NOTE: The ABL ESD Machine is capable of running at up to 10000 volts. However, this is not the standard configuration and should be used only upon request. Using the machine at voltages other than 5000 volts will change the ignition characteristics of the material being tested. Always note on the data sheet if a voltage other than 5000 volts is used.


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6.2.8 Ensure that the "Test Type" switch is in the "Lowering" mode. This is the standard mode for this test. Use the fixed mode only upon request.

6.3 GODETECT SETUP

6.3.1 Setup the high-speed video camera and GoDetect reaction detection software per the GoDetect Owner’s Manual, calibration certificate or user best practice. Highlights of this process are as follows.

6.3.2 Place a sample holder on the base electrode and twist to lock into place. Manually extend the pneumatic cylinder, lowering the approaching needle. Fit the pneumatic insert block into position to lock the approaching needle in the down position.

6.3.3 Fit the high-speed video with the necessary extension tubes (to shorten the focal length) and lens with adjustable focus and f/stop.

6.3.4 Secure the high-speed video camera on the GoDetect camera mount.

6.3.5 Set the f/stop to the value listed on the calibration certificate (e.g. f/4), or based on user best practice.

6.3.6 Launch the GoDetect software and select the option to setup the camera.

6.3.7 Click on the button to change camera settings for focusing, slowing the frame rate and increasing the frame exposure time. Focus the camera until the tip of the needle electrode is in sharp focus.

6.3.8 Set the acquisition rate to 20,000 frames per second for fast reacting materials and lower frame rates for slow burning materials.

6.3.9 Cover the lens and click the button to set the Current Session Reference (CSR) to establish the black level.

6.3.10 Setup the triggering by adjusting the trigger area, area %, threshold, and frames between update values as specified on the calibration certificate.

6.3.11 Check that the trigger is fully functioning; motion should NOT trigger the camera, but the lowest energy spark should.

6.4 SAMPLE PREPARATION

NOTE: Instructions in this section dictate the standard method for preparing samples. Samples should generally come ready to test from the test requestor. However, a test requestor may supply special conditioning and preparation requirements. If a test sample has a non-standard morphology (i.e. hygroscopic or nanometallic powder, non-standard cured or uncured propellants, compatibility samples, etc.) then special testing instructions from the test engineer or test requestor MUST accompany the sample.


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6.4.1 All samples whose condition will not change with exposure to the normal atmosphere, such as ingredients, casting powders, or cured propellants, shall be conditioned to the building temperature and humidity.

6.4.2 The actual temperature and humidity shall be recorded on the test record sheet (A030.1).

6.4.3 Ensure samples are tested in the condition specified by the requestor.

6.4.4 Samples whose condition is subject to change shall be tested immediately after delivery (e.g., uncured propellants). If this is not possible contact the test requestor for instructions.

6.4.5 Hygroscopic powders or granular mixtures should be dried in an oven or vacuum desiccator to remove any moisture before testing and verified to be dry.

NOTE: Hygroscopic powders or granular mixtures have typically been dried for approximately 24 hours at 120°F. Sample dryness is determined by weighing the sample: prior to dying, during the drying process and after drying. To be considered dry, the sample during the process and after drying must be the same. If not, then further drying is required until there is agreement between the last two sample weights. Cooling the sample while under vacuum can help mitigate the sample picking up moisture from the atmosphere prior to testing.

6.4.6 Granular solids should have a smooth, flat, monolayer of material on the sample holder to ensure the spark travels through the sample.

6.4.7 For liquids, use the liquid sample retaining ring, part number 60000N86547-17. Use enough sample to ensure spark travels through the sample while minimizing the amount of sample on the holder.

NOTE: NG should rest for a minimum of 16 hours to allow moisture to rise to the surface, and then removed by blotting with filter paper.

6.4.8 For slurry testing, use the liquid sample retaining ring, part number 60000N86547-17. Use enough sample to ensure spark travels through the sample, while minimizing the amount of sample on the holder.

NOTE: For unusual or very large particles consult with Hazards Analysis and Test Requester prior to performing test.

6.4.9 Propellant (cured) and solid samples should be cut to a minimum dimension of 5/8 inch square or 5/8 diameter and having a thickness of 0.033 ± 0.004 inch. Record the sample thickness on the test record.

6.4.10 A note on the sample’s condition, appearance, and/or any unusual characteristics shall be made on the test record sheet (A030.1) even if the sample does not contain any abnormal or irregular qualities.

6.5 TEST OPERATION


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NOTE: The high-speed video camera and GoDetect reaction detection software should have already been set up in accordance with the owner’s manual, calibration certificate and/ or user best practice.

6.5.1 Place an inert material on the sample holder to simulate the test material.

6.5.2 Place the sample holder in position on the lower electrode. Close the door of the cabinet and listen for energizing of the safety switch.

6.5.3 Set the GoDetect software to baseline acquisition mode.

6.5.4 Switch the "FUNCTION" from "ground" to "ready" and wait for the voltage to climb to the correct voltage (standard is 5000 V ± 1%). Switch the “CHARGE” switch from “charge” to “ready”; press and briefly hold the red “FIRE” button and watch/ listen for the spark. Return the “CHARGE” switch to “charge”.

6.5.5 Repeat step 6.5.4, collecting at least 25 baseline trials at the chosen energy level, pausing briefly between each trial to allow the capacitor(s) to charge. NOTE: For the baseline ONLY, the inert sample and sample holder can be reused repeatedly (does NOT need to be changed out every trial).

6.5.6 Remove the inert material and replace with a sample holder loaded with the live material. Close the door of the cabinet and listen for energizing of the safety switch.

6.5.7 Set the GoDetect software to reaction detection / trial acquisition mode.

6.5.8 Switch the "FUNCTION" switch from "ground" to "ready" and wait for the voltage to climb to the correct voltage (standard is 5000 V ± 1%).

6.5.9 Switch the “CHARGE” switch from “charge” to “ready” and observe the sample.

6.5.10 Press and briefly hold the red "FIRE" button and watch for the spark and observe any sample reaction.

NOTE: The trial is invalid if two discharges occur and the machine should not be used for testing until the source of the issue is resolved. NOTE: If after pressing the fire button no spark was present, move the FUNCTION switch to GROUND and verify that the supply voltage has bled off by looking at the voltage display dial. Remove the energetic sample and check the spark gap; clean off any carbon or residue from the needle and the sample holder. If the gap is out of tolerance readjust the gap and run the test again. If no spark is still evident, again move the FUNCTION switch to GROUND and verify that the supply voltage is bled off. Check that the material thickness is within tolerances. If all parameters are still nominal contact the test engineer.

6.5.11 Record the reactions of the sample and the GoDetect reaction detection result (if used).

6.5.12 Remove and clean the sample holder.


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6.5.13 Repeat Steps 6.5.7 through 6.5.12 with a fresh sample.

6.5.14 To change energy levels, switch the “FUNCTION” switch to “ground” and repeat steps 6.5.1 through 6.5.6 for each new energy level.

DANGER: ELEVATED FIRE OR EXPLOSION HAZARD! DO NOT ALLOW RESIDUAL MATERIAL TO BUILD UP INSIDE THE DARKENED TEST CHAMBER. UTILIZE AN APPROVED LIGHT SOURCE TO ILLUMINATE THE RECESSES OF THE CABINET AND REMOVE EXCESS MATERIAL TO PREVENT BUILD UP.

6.5.15 Upon completion of testing, clean the apparatus thoroughly with an approved solvent and dispose of all remaining residue, cleaning solvents, and contaminated wipes.

6.6 SHOT DIFFERENTIATION

6.6.1 A “shot”, “go”, or reaction is defined as a detectable reaction ranging from a barely detectable decomposition to a violent reaction.

6.6.2 Differentiation between a go reaction and a no-go reaction can be completed with the GoDetect-ESD software program, review of high-speed video, review of camera evidence, gas analysis or human observation. Instrumentation that records the test outcome for review is preferred. Instrumentation is preferred over human observation to limit test subjectivity.

6.6.2.1 High-speed video detection includes the high-speed camera, camera mounts and brackets, lens and extension tubes, and computer hardware/ software to review the data. GoDetect

TM

automatically indicates a go or no-go based on the comparison of baseline data with inert material that is similar to the sample and compares that with the brightness, buoyancy, shape, and uniformity data from a trial. The frame collection rate should be approximately 2000 frames per second. Baseline and trial video is systematically stored to facilitate future review.

6.6.2.2 Gas analyzer instrumentation includes the gas analyzer, vacuum pump, flow meters, filters, associated valves and flow lines, and ESD sample chamber. The analyzer shall not be used with samples containing volatile solvents or samples whose decomposition gases do not include CO, CO2, N2O, or NO2. In the case of volatile solvents, the vapors are recorded by the gas analyzer, thus blocking detection of any decomposition gases. On the other hand, the gas analyzer does not record sparks and flashes of zirconium and aluminum which do not produce the gases for which the gas analyzer is calibrated

6.6.2.3 When tests are run in which shot differentiation must rely on operator senses rather than high-speed video with GoDetect reaction detection software, a "shot" is defined as any reaction evidenced by the following:

a. Noise level greater than that normally produced by an ESD spark when no test material sample is present. b. Visible burning, smoke, flash greater than that produced by the discharge alone.

c. Smoke (be careful not to interpret mist as smoke).


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NOTE: For materials with limited conductivity ensure the spark travels through the sample and not simply around the sample. A reaction may not have occurred if a noise is heard. Non-conductive materials may block the spark altogether. NOTE: For pyrotechnic materials only “sparkling” may be used as a “shot” or “go” reaction.

6.6.2.4 Following descriptions shall be used to document a “shot”, “go”, or reaction. Also indicate the method used for detection. Record these on the test record as:

T = flame trace M = smoke Z = spark A = flame B = flash X = sample consumed, propagating fire or mass ignition L = loud noise or explosion H = hardware damage P = pop or small explosion HV = high-speed video determination GA = gas analysis determination

6.7 DATA REDUCTION

6.7.1 Threshold Initiation Level (TIL) Test Method

6.7.2 The ESD Threshold Initiation Level (TIL) is the highest energy at which no reaction is obtained in 20 trials. Commence testing by using an initial test level based on past experience or by ESD information supplied by the requester. Using successively higher predetermined levels, obtain an initial "shot", then continue at successively lower energies until a "shot" is observed or 20 "failures" are obtained.

6.7.2.1 ESD TIL is reported as the final energy (J) at which 20 “failures” are obtained with at least one reaction at the next highest energy level. Energy increments as used for the ESD machine are shown in Table 1. Standard test levels are listed in boldface type.

6.7.2.2 Record the data on the test record.

NOTE: An ideal initial test trial results in a reaction after a few trials and thus would result in a reaction occurring ~50% of the time.

Table 1. ESD capacitance and theoretical energy levels with a charge of 5kV

Switch B

Position 2 3 4 5 6 7 8 9 10 11 12 1

Sw

itch A

Position Capacitor 0.25 0.1 0.05 0.02 0.01 0.005 0.002 0.001 0.0005 0.0002 0.0001 0

1 0.5 9.4 7.5 6.9 6.50 6.4 6.3 6.3 6.3 6.3 6.3 6.3 6.3

2 0.25 4.4 3.8 3.4 3.3 3.2 3.2 3.1 3.1 3.1 3.1 3.1

3 0.1 1.9 1.5 1.4 1.3 1.3 1.3 1.3 1.3 1.3 1.3

4 0.05 0.88 0.75 0.69 0.65 0.64 0.63 0.63 0.63 0.63


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5 0.02 0.38 0.31 0.28 0.26 0.26 0.25 0.25 0.25

6 0.01 0.19 0.15 0.14 0.13 0.13 0.13 0.13

7 0.005 0.088 0.075 0.069 0.065 0.064 0.063

8 0.002 0.038 0.031 0.028 0.026 0.025

9 0.001 0.019 0.015 0.014 0.013

10 0.0005 0.0088 0.0075 0.0063

11 0.0002 0.0038 0.0025

12 0.0001 0.0013

6.7.3 PROBIT Analysis Test Method

6.7.3.1 Obtain the TIL by performing step 6.7.1.

6.7.3.2 If more than five levels were used to reach the TIL, select the four standard test levels immediately above the TIL level.

6.7.3.3 At each of the four levels, perform additional tests such that a total of ten tests per level are obtained regardless of the shots/tests ratio.

6.7.3.4 Probit analysis is then completed via the standardized Excel sheet available upon request.

NOTE: If possible, split levels if you reach 100% (10/10) before you have the minimum 4 levels and add additional levels at higher energy if needed so that the highest level has at least 50% reactions (5/10). If ESD TILs are below minimum level of the test machine, obtain 10 trials at the lowest level and up to 4 levels above that are not 10/10. This data can still be used in PROBIT plotting. NOTE: If one obtains 10 of 10 or a high probability of obtaining 10 of 10 at the next higher level then adjust the originally planned test levels by choosing a level between the standard levels found in Table 1, as necessary to obtain a good distribution of levels as stated above.

6.7.4 Bruceton Test Method (Logarithmic)

6.7.4.1 As with Probit testing, Bruceton tests can be used to obtain a response curve that shows the transition from low probability to higher probabilities of observing a reaction as a function of insult energy. Bruceton tests can also be used to compare the relative sensitivity between two substances. Two parameters are obtained: the 50% ignition value and an estimate of the standard deviation. Typically Bruceton tests are completed with equal spacing between levels. Completing the test with equal spacing logarithmically can yield better resolution near lower energy levels where typical reference samples show transitions from no reactions to reactions. Methods such as SEQ and Neyer that adaptively change the spacing according to the material’s response are preferred.

6.7.4.2 ESD capacitance with a 5kV potential that give energy levels with equal spacing (~10%) logarithmically are: 0.0002, 0.0003, 0.0007, 0.0012, 0.0025, 0.005, 0.01, 0.015, 0.03, 0.06, 0.12, 0.2, 0.35, 0.75 microFarads.


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6.7.4.3 Begin testing at the energy closest to the level of 50% probability of initiation, if known. Thirty trials are completed where if a reaction is observed the next test is completed at a lower level and if a reaction isn’t observed, the energy is increased up one level.

6.7.4.4 Once testing is completed, the two parameters defining the transition curve are found with the following equations (reproduced here from W.J. Dixon and F.V. Massey, Jr. “Introduction to Statistical Analysis, McGraw-Hill Book Co., Toronto, 1969): (Eq. 1a)

{

} (Eq. 1b)

where E50 is the 50% energy level in log units, Sln is the log logistic sigma value, Ns is the sum of the negative (or positive, whichever sum is smaller) results, A is the sum of the product of the log level and the number of negative (or positive) results at that level, c is the lowest energy level tested (in log units) and d is the energy interval (in log units). B = Ʃ(i

2∙ni) where n is the

number of negative (or positive)results at that level. As parenthetically called out above, only the positive or only the negative results are used depending on which has the smaller total. If negative results are used, the sign is positive or if positive results are used, the sign is negative in Eq. 1a. Note that the sigma value result in Equation 1b includes a factor of 0.551 to convert the normal standard deviation (S) to a logistic value.

6.7.4.5 Example results of a Logarithmic Bruceton test are contained in Tables 2 and 3 below. According to the example results and using Equations 1a and 1b with c equal to -4.7387 and d equal to 0.665, E50 is equal to -3.41 (ln J) or 0.033 J and S is equal to 0.716. The transition curve is plotted using these two parameters below in Figure 2. According to the logistic distribution, the probability of a reaction can be found by the following: { [ ]} Eq. 2 where ln x is the natural log of the energy. The other symbols are defined as part of Eq. 1.

Table 2

Example of Bruceton with 15 Trials Energy

(J)

Energy

(ln J) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 + Frequency - Frequency

0.125 -2.07944 + 1 0

0.0625 -2.77259 + + - 2 1

0.03125 -3.46574 + - + - - 2 3

0.015 -4.19971 + - - - 1 3

0.00875 -4.7387 - - 0 2

Table 3 Summary of Example of Bruceton with 15 Trials (Used only positive results due to smaller total) Energy (J) Energy (ln J) i(+) n(+) i(+)∙n(+) i2(+)∙n(+)

0.125 -2.07944 4 1 4 16

0.0625 -2.77259 3 2 6 18


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0.03125 -3.46574 2 2 4 8

0.015 -4.19971 1 1 1 1

0.00875 -4.7387 0 0 0 0

Total Ns = 6 A=15 B=43

Figure 2: Plot of the transition probability with the example results from a Bruceton (logarithmic) test.

6.7.5 SEQ or Neyer Test Method

6.8 The SEQ or Neyer methods are both software programs that the user interfaces with to determine the two parameters that define the transition curve. Either program outputs the values at which the test should be run; the user then records the result of each trial.

6.9 CLEANUP AND DISPOSAL

6.9.1 Upon completion of the test, deposit all sample residue and contaminated trash in the appropriate waste container and dispose of this material per the Hazardous Waste Management Plan for the Test Site.

6.9.2 After testing is completed on each individual sample, and at the end of each work day, the ESD machine and surrounding test area shall be cleaned using methanol or equivalent solvent and disposable wipes.

6.9.3 Store unused samples in the appropriate area.

WARNING: Reactive metal powders such as aluminum, magnesium, iron, zirconium, hafnium, etc can exothermically react with water or alcohol to form flammable hydrogen. This would


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be an issue in covered locations where the hydrogen could accumulate, or where a bulk quantity could generate heat. Always verify that the exhaust fan is connected and functioning, and containers are tightly sealed when working with such metals. If there is any question, stop and consult supervision or the test engineer.

6.10 TROUBLESHOOTING

6.11 A troubleshooting guide is provided in the ABL Electrostatic Discharge Test Apparatus Owner’s Manual. The troubleshooting guide provides methods for isolating defective component parts. It is written under the premise that the ESD machine has been correctly verified as detailed in the ABL Electrostatic Discharge Test Apparatus Owner’s Manual. It is also assumed that the cause of difficulty is not the test specimen, sample preparation, or operator error in judging initiations.

7.0 REVISION NOTES

7.1 REVISION 1 TO 2

7.1.1 The following revisions were incorporated into Revision 2 working from Revision 1:

Section 6.1.3.4, 6.1.3.5, and 6.1.3.6: added “as indicated by the power indicator light”.

Section 6.1.5.8: added “(within 1%)”.

Section 6.3.1 and 6.3.5: Added “or user best practice”.

Section 6.5.1: Removed instruction to arrange inert substance in donut shape as this is unnecessary as it occurs with the baseline testing.

Section 6.6.2: Added greater detail on high-speed video, gas analysis and reaction detection details.

Section 6.7.2.2: Replaced theoretical energy chart with one that is clearer. Removed example ESD Data Record Sheet to be consistent with the other ETUG test procedueres.

Section 6.7.3.4: Added “Probit analysis is then completed via the standardized Excel sheet available upon request”

Section 6.7.4: Added section on Bruceton Test Method (Logarithmic)

Section 6.7.5: Added reference to the SEQ or Neyer Test Methods

Added Section 7.0: Revision Notes

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