ESD CONTROL - SURVEY REPORT

SURVEY DATA

 

Equipment Used:  Desco EMIT 50550 ESD Survey Kit

 

S/N:  242650851001

 

Note: Environment during this ESD Control Survey was measured as 69ºF / 41%RH.

 

Electrostatic charges measured on insulators and resistance measured on hygroscopic materials may be lower than in times of low relative humidity (<30% RH).  You can expect charge measurements on insulators and resistance on hygroscopic materials to be higher during periods of low RH.  It is recommended that the static field meter and surface resistance measurements also be taken during those periods of low RH in order to establish your “Worst Case” conditions.  Your ESD Control Program must be established to perform in those conditions.

 

1.         GROUNDING

 

1.1        Check Ground, three-wire AC electrical outlets properly wired.

            

Observation:

·         There is a defined grounding system.

·         Grounding system is via equipment ground / 3rd-wire electrical.

 

Measurement:

·         Using AC Outlet Analyzer, outlets checked were properly wired.

 

Recommendation: 

·         No corrective action required.

 

1.2               Wrist Straps worn and grounded when seated, with the resistance of operator-to-ground Required Limit measured at <3.5 X 10^7 ohms.  This is the upper limit if ESD Garment is used as part of the path to ground.

 

Observation:  

·         Wrist straps are part of the ESD Control Program.

·         All seated operators are wearing properly grounded wrist straps. 

 

Measurement:  

·         Tested Operators, all RTG tests measured <3.5 X 10^7 ohms – in spec.

 

Estimated number of seated operators:  5

 

Recommendation:  

·         No corrective action required.

 

 

1.3        ESD Footwear on each foot for mobile personnel.  When foot grounders are used in conjunction with an ESD Floor for grounding of standing and/or mobile personnel, the RTG of the operator/ footwear floor circuit (Flooring / Footwear System) Required Limit is: 

·         Method 1 - Measure less than 3.5 x 10^7 ohms or 

·         Method 2 - Measure both < 1 X 10^9 ohms AND charge generation to be less than 100 volts.

 

Observation:

·         Foot grounders are part of the current ESD Control Program.

·         Operators wear foot grounders on both feet.

 

Measurement:  

·         Method 1

·         Tested Operators, RTG measured <3.5 X 10^7 ohms – in spec.

 

Estimated number of standing/mobile operators:  5

 

            Recommendation:  

·         No corrective action required.

 

1.4      ESD Floor (and/or mat) grounded & clean.  Flooring must be <1 X 10^9 ohms RTG to be considered “ESD Protective”.

·         Method 1 Required Limit< 3.5 X 10^7 ohms RTG.

·         Method 2 (must be used when operator RTG is >3.5 X 10^7 ohms)) Required Limit < 1.0 X 10^9 ohms RTG for Flooring-Footwear System AND less than 100 volt charge generation.

 

Observation:

·         ESD Floor is part of the current ESD Control Program.

·         ESD Floor is:

·         ESD Floor Finish

·         Floor is clean

 

Measurement:

·         Floor is NOT used to ground mobile or standing operators (no foot grounders) but is meant to be “ESD Protective”.

·         Floor measured <1 X 10^9 ohm RTG – In spec.

 

Estimated number of sq. feet of ESD Floor:  600

 

Recommendation:

·         No corrective action required.

 

1.5        Personal grounding devices (Wrist Straps, Footwear, and Groundable Static Control Garment Systems) tested with results logged.

 

Observation:  

·         Operator touch-testing of personnel grounding devices is required – daily

·         Touch-test results are logged, via honor system.

·         Calibration date is within one-year / current on all touch-testers.

 

Number of “touch-testers” currently in place: 1

Number of operators currently wearing:

·         Wrist Straps ~ 5

·         Foot Grounders ~ 5

·         Groundable Static Control Garment System Smocks ~ 5

 

Recommendation:

·         No corrective action required

 

2.         ESD Protected Area – TECHNICAL ELEMENTS

 

2.1               ESD Protected Area (EPA) Clearly Identified and access to ESD Protected Area controlled. Caution signs indicating the existence of the EPA shall be posted and clearly visible to personnel prior to entry to the ESD protected area.

 

Observation:

·         ESD Protected Areas are identified using signs, but not aisle tape.

·         Access is controlled, only persons that have received ESD Training are allowed to enter the ESD protected area, visitors escorted, and personnel grounding items tested and results logged.

 

Recommendation:

·         No corrective action required.

·         All people entering and working in the ESD protected areas should have been ESD Trained.  All people entering the ESD protected area (including visitors) shall wear and test all ESD precautions as defined by the company.  Persons that have received ESD training should escort visitors.

 

2.2        ESD Protected Area Worksurfaces >1 X 10^6 – <1 X 10^9 ohm RTG.  Properly grounded to common point ground, using ESD Mat Cleaner.

 

Observation:

·         ESD worksurfaces are:

·         2-layer rubber mat

·         ESD worksurfaces are clean.

·         Worksurfaces are grounded via common point.

·         Continuous Monitors used at some workstations, all continuous monitors observed indicated mats properly grounded.

 

Measurement:

·         All ESD worksurfaces measured <1.0 X 10^9 ohms RTG – In spec.

 

Estimated number of ESD worksurfaces:  4

 

Recommendation:

·         No corrective action required.

 

2.3        Packaging (including Material Handling Devices and storage containers)

 

2.3.1   Inside the ESD protected area – Low Charging, Dissipative, or Conductive Materials (RTT >1 X 10^5 to <1 X 10^11) are to be used.

 

Observation:

·         Some packaging used for ESD susceptible items is high charging and not ESD Protective.

·         Insulative packaging observed within 12” of ESD susceptible.

            

            Measurement:

·         Measured >1 X 10^11 ohms RTT on the following material handling devices and storage containers for ESD susceptible devices/assemblies:

·         -  Clear plastic bags

·         -  Cardboard cutting station

 

Recommendation:

·         Replace all non-ESD packaging materials with the proper ESD equivalents.

 

 

 

2.3.2     Outside the ESD Protected Area - Shielding bags or other shielding containers with covered lid (Faraday Cage) are to be used to transport or store ESD susceptible items outside the ESD protected area.  All packaging materials used for outside the ESD protected area must measure >1 X 10^4 to <1 X 10^11 RTT AND provide ESD shielding.

 

Observation:

·         Packaging for ESD susceptible items that moved outside the ESD protected area does provide ESD shielding.

·         ESD shielding containers are used properly and are closed when containing ESD susceptible items.

·         Shielding bags are re-used.

 

Recommendation:

·         No corrective action required.

·         When moving ESD susceptible items outside an ESD protected area, it is necessary for the product to be packaged in closed ESD Shielding Packaging.  

·         Specify material handling, totes, and/or packaging ESD protective packaging marked with the ESD Protective Symbol.

 

Information:

·         A basic principle is that ESD susceptible items should only be out of their ESD Protective packaging when they are in an ESD protected area.  Un-packaged ESDS items should only be handled by a grounded operator in an ESD protected area.

 

2.4        ESD Workstation Clear of Insulators such as regular high charging bags, packaging, document holders, binders & tape.

 

Observation:

·         Insulators are present.

 

Measurement:

·         The following items were measured at (estimated voltage):

·         -  Scotch Tape ~ 2000v

·         -  Serial Number stickers ~ 2000v

·         -  Cardboard platform for packaging ~ 1000v

 

Recommendation:

·         Insulators can be controlled in several methods:

·         Keep insulators a minimum of 12” from ESD susceptible items, or

·         Replace insulators with an ESD protective version or move them more than 12” from ESDS devices.

·         Periodically treat with a topical anti-stat.

·         Use ionization to neutralize insulators that are considered process essential.

·         Paper may isolate ESD susceptible items from being grounded via the ESD mat.  All paper should be removed from the immediate ESD work area or placed in dissipative document holders.

·         Ionization should be considered for those areas where process essential insulators are capable of being charged to >2,000 volts.

 

 

2.5        Ionization -   Out of balance to be less than +/-50 offset voltage.  Discharge time to be determined by user.

 

Observation:

·         Ionizers are part of the ESD Control Program.

·         The following ionizer(s) are currently used:

·         Benchtop / AC

·         Ionizers do not have auto-feed back alarm systems to maintain performance and balance.

·         Filters are not used.

·         Ionizers had calibration stickers indicating that they were last serviced < 90 days ago.

 

Measurement:

·         The following “process essential” insulators were identified, were charged to >2000 volts:

·         -  Scotch Tape 

·         -  Serial Number Stickers

 

·         Offset voltage/balance of all ionizers tested <+/- 50 volts – In spec.

·         Distance from ionizer to point of use measured 12”.

·         Discharge time was within “customer defined” acceptable limits of 5 seconds.

 

Estimated number of ionizers:  2

 

Recommendation:

·         No corrective action required.

·         All ionizers need to be periodically (90 days) cleaned and checked for proper performance (off-set and decay time +/-).  This requires a charge plate monitor or a field meter with ionization test kit attachment.

 

Informational:

·         For ionizers to function properly, they require periodic maintenance, generally every 90 days.  However, depending on your product and environment, maintenance may need to be more frequent.

·         The equipment to properly test for offset voltage balance and discharge times is necessary.

 

 

2.6        Seating/Chairs – RTG < 1 x 10^9 ohms if part of ESD program.  

 

Observation:

·         ESD Chairs are part of the ESD Control Program.

·         ESD chairs are easily identified by ESD protective marking.

·         Chairs are grounded to floor via:

No              Conductive wheels

Yes                        Drag chain

 

Measurement:

·         Chairs tested measured <1 X 10^9 ohm RTG – In spec.

 

Estimated number of ESD chairs:  4

 

Recommendation:

·         No corrective action required.

 

2.7        Shelves grounded.  RTG to be > 1 X 10^6 to <1 X 10^9 ohms if storing unprotected ESD susceptible items.

 

Observation:

·         Shelves are part of the ESD Control Program and thus considered part of an ESD worksurface

·         ESD Shelves are used solely for the purpose of storing packaged devices

·         ESD shelves are properly identified by signage.

·         Insulators are present on ESD shelves

·         All ESD sensitive items are properly packaged in ESD shielding bags so the insulators are not a major concern

 

Measurement:

·         All ESD shelves tested, measured >1 X 10^6 to <1 X 10^9 ohm RTG – In spec.

 

Estimated number of ESD shelves:  10

 

Recommendation:

·         No corrective action required.

 

Informational:

·         Shelves are an optional part of your ESD Control Plan.   If ESD susceptible devices are packaged in closed ESD shielding ESD containers, the shelf may not have to be grounded.  

 

2.8        Mobile carts / racks grounded.  RTG less than 1.0 x 10^9 ohms.  If storing unprotected ESD susceptible items, cart shelves are to be >1 X 10^6 to <1 X 10^9 ohms RTT.

 

Observation:

·         Mobile carts / racks are not part of the ESD Control Program and thus not considered an ESD workstation.

 

Recommendation:

·         No corrective action required.

 

 

2.9        ESD protective garments used to cover worker’s synthetic clothing.

            Categories:  

·         ESD Protective Smocks used to cover worker’s synthetic clothing or kept 12” from ESDS.  RTT 10^5 to 10^10 ohms.  Smock should be grounded via operator’s wrist strap system or ESD footwear/floor system. If grounding operator / Smock / Ground cord system < 3.5 x 10^7 ohms

 

Observation:

·         ESD smocks are part of the ESD Control Program.

·         ESD smocks are identified by ESD Protective symbol.

·         According to smock label, the ESD smocks have:

·         >9% carbon.

 

Measurement:

·         Groundable Static Control Garment System

·         All smocks tested measured <3.5 x10/7th ohms sleeve-to-sleeve – in spec.

 

Estimated number of ESD smocks: 5

Number of smocks tested: 1 

 

Recommendation:

·         No corrective action required.

 

2.10      Solder Iron Tips – AC Powered Tools < 1 ohm to ground per ESD DS 13.1 < 20 ohms for verification purposes.

 

Observation:

·         This Technical element was NOT covered during the survey at this time.