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TM 9-254
8-9.
General Information - Continued
Table 8-7. Means of Static Charge Generation and the Associated Voltages - Continued
MEANS OF STATIC GENERATION
ELECTROSTATIC VOLTAGES WITH
AND
10 - 20 %
65 - 90 %
PERCENTAGE OF RELATIVE HUMIDITY
RELATIVE
RELATIVE
HUMIDITY
HUMIDITY
VINYL ENVELOPES FOR WORK
7,000
600
INSTRUCTIONS
COMMON POLY BAG PICKED UP
20,000
1,200
FROM BENCH
WORK CHAIR PADDED WITH
18,000
1,500
POLYUREATHANE FOAM
d.
Prime Charge Carriers. Personnel are the prime charge carriers, with the greatest potential of damaging
ESD items. Activities such as walking, working at a table or bench, sliding on a chair, or simply combing one’s hair can
generate static charges of thousands of volts with high potential for damage to sensitive devices.
e.
Items to Avoid. The following items will generate sufficient charges to damage sensitive items: All common
plastics, spray cans, tape dispensers, heating guns, bubble pack, polystyrene cups, cigarette papers and wrappers, paint
cans, stencil ink applicators, common poly bags and sheets, and plastic tape.
8-10.
ESD Handling, Labeling and Packaging.
a.
Handling Unpackaged ESD Sensitive Items. Never store or transport ESD sensitive components or
assemblies outside of the protective packaging. The protective packaging should not be opened or removed until the item
is to be installed in the next higher assembly. At this time, the technician should be grounded in an approved work station.
Avoid touching bare leads and contacts on sensitive material. Never use plastic solder suckers to remove soldered
components from ESD sensitive assemblies. Use metallic or antistatic solder removal means.
b.
Packaging and Labeling ESD Sensitive Items/Assemblies. After replacement of a sensitive circuit card
assembly (CCA) or other subassembly into instrument, a CCA/sensitive item that is to be returned for repair must be
Change 3 8-27
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