Fairly regularly we are seeing low charging or antistatic Pink Poly bags being used for the wrong application. These bags are made from a tinted polyethylene material with an antistatic coating that can wear away. This turns the bag insulative and high charging over time, making it noncompliant to ANSI/ESD S541 recommendations.
They also lack discharge shielding protection which makes components within the bag susceptible to ESD event damage. It is this distinction that is most important – as Pink Poly bags don’t provide shielding, they should not be used to carry ESD Susceptible (ESDS) items outside the EPA, i.e. when the sensitive item isn’t grounded. Per ANSI/ESD S541-2018, Table 1. ESD Protective Packaging Requirements by Location, Discharge Shielding is Required for Outside the EPA (UPA).
SCS Metallized Shielding bags are constructed from a metalized polyester film and a low charging polyethylene laminate. This provides the bags with a shielding layer that creates a Faraday cage protecting the ESD sensitive components within the bag from possible ESD event damage. The low charging inner layer and outer layer of the bag prevent tribocharging from occurring, minimizing the build-up of ESD charges when handling components. This low charging layer is longer lasting than a pink antistatic bag.
Per ANSI/ESD S541-2018 – Table2. Summary of ESD Protective Properties
“Discharge Shielding“
“Protects packaged items from the effects of static discharge that are external to the package and limits current flow through package”
Per ANSI/ESD S541-2018 – Per 7.3.1 Electrostatic Discharge Shielding
“Electrostatic discharge shielding materials are capable of attenuating an electrostatic discharge when formed into a container such as a bag”
Watch our video for a simple demonstration on how pink poly bags differ from static shielding bags:
For more information on the differences between these two materials, and a demonstration on how to test per ANSI/ESD S11.31 and ANSI/ESD S541 visit this page.
SCS’s upcoming webinar will review various ESD Bag test methods. With our in-house equipment, we will demonstrate how to test your bags per the most current ANSI/ESD and Mil-Spec standards.
Have you been questioned by your quality manager about shelf life on ESD bags? Maybe it’s an internal quality procedure that is being written and you would like to know where the manufacturer stands on the shelf life of ESD packaging. Well today we will address the topic of ESD Static Control bag storage and the expected shelf life.
There are many ways to manufacture an ESD shielding bag with low charging properties on the inner and outer layers. This is the first factor to consider so I will address only the items that I convert here at SCS. In our process, I achieve shielding values via a buried metal layer. The metal layer is laminated between two layers of polyethylene. This process makes a very robust and long- lasting product in terms of shielding values as per ANSI/ESD S541-2018, the electronic industry’s most recognized standard for ESD packaging. Still the metal layer is exposed to oxidization if not stored properly and subject to extreme climate or moisture.
SCS Metal-In shielding bag layers
To achieve the outer and inner low-charging properties, I use a topical anti-stat solution. This provides the outer and inner resistance readings of >/= 1 x 10^4 to < 1 x 10^11 ohms as called out in ANSI/ESD S541-2018 packaging standard. This property is the most vulnerable to change and should be tested frequently.
How does all this pertain to shelf-life you ask? SCS provides a Static Control Bag Storage document with a 1 year warranty from the date of purchase. I have witnessed SCS ESD bags stored in a controlled climate, well-ventilated area that have maintained passing surface resistance results after 5 yrs. on the shelf. Some customers have relied on our Moisture Barrier products to archive various critical products for as long as 20 yrs. They found through extensive testing that SCS had the highest quality and most repeatable results to trust with their archived product.
End users cannot always provide a climate and humidity-controlled atmosphere for our raw material, so it is recommended that you test your bags periodically per the S541 standard and dispose of any materials that are found to be questionable. As a best practice, you can log your products by purchase date or lot number and create an annual spot check audit to assure that your bags are still in compliance. Using a FIFO First In First Out process is critical in keeping your inventory fresh. You can imagine that there are 1000’s of variations to consider when we discuss shelf life. Heat, storage rack conditions, travel method and local climate to name a few, so the points to take away are this:
Test your ESD bags periodically
Avoid extremes
Hot, Cold, sunlight, moisture
Add controls when possible
In a controlled environment, SCS ESD bags have seen 5 yrs. of proven shelf life.
Follow the FIFO process as a best practice for inventory.
SCS warranties the product for a period of 1 year from the date of purchase. You need to audit annually or prior to use as a best practice and assure that your devices are getting the best protection.
If the bags are questionable, recycle the product at your local recycler and order and new lot from SCS – Static Control Solutions.
Thank you, Kevin Cleary ESD Packaging Specialist – Sales Direct Line: (919) 903-1724
Welcome back to “A Minute with Miranda.” This week we will be discussing how to store and ship your static sensitive assemblies within and outside of an ESD Protected Area using an In-Plant Handler.
ANSI/ESD S20.20 requires that ESD protective packaging is necessary to store, transport and protect ESD sensitive electronic items during all phases of production and shipment. Beyond the static protection, packaging also provides protection from physical damage, moisture, dust and other contaminates. Per the ANSI/ESD S541 Packaging Standard packaging that is used inside and outside of an EPA shall be low charge generating, constructed from dissipative or conductive material for intimate contact with ESD items and provide electrostatic discharge shielding.
The Protektive Pak In-Plant Handlers are constructed from an impregnated dissipative corrugated material that has a surface resistance range of 1 x 106 to less than 1 x 109 ohms per ANSI/ESD STM11.11. This minimizes the potential of rapid discharge or sparking. The in-plant handlers will shield ESD sensitive items from charge and electrostatic discharges with the lid in place. The partition sets are constructed from the same impregnated dissipative material and are available in over 300 cell size configurations to suit your specific packaging needs.
View the full range of Protektive Pak In-Plant Handlers here.
ElectroStatic Discharge (ESD) can pose danger to a Printed Circuit Board (PCB). A standard bare PCB (meaning that it has no semiconductor components installed) should not be susceptible to ESD damage, however as soon as you add electronic (semiconductor) devices, it becomes susceptible according to each of the individual’s susceptibility.
While ESD damage can post a danger, there is another risk factor many operators forget: moisture.
Today’s blog post is going to address both risks and will explain how you can protect your PCBs from both when storing them.
The problem with moisture
If you have been following along with our blogs, you will be well aware of the problems ESD damage can cause.
Moisture, on the other hand, may be a new issue to you. Surface Mounted Devices (SMDs), for example, absorb moisture and then during solder re-flow operations, the rapid rise in temperature causes the moisture to expand and the delaminating of internal package interfaces, also known as “pop corning.” The result is either a circuit board assembly that will fail testing or can prematurely fail in the field.
Moisture from air diffuses inside the plastic body & collects in spaces between body & circuit, lead frame and wires. Expanding vapor can crack (popcorn) the plastic body or cause delamination.
Storing PCBs
All PCBs should be stored in a moisture barrier bag (MBB) that is vacuum sealed. In addition to the bags, Desiccant Packs and Humidity Indicator Cards must be used for proper moisture protection. This ‘package’ is also known as a dry package.
Most manufacturers of the Moisture Sensitive Devices (MSD) will dictate how their product should be stored, shipped, etc. However, the IPC/JEDEC J-STD-033B standard describes the standardized levels of floor life exposure for moisture/reflow-sensitive SMD packages along with the handling, packing and shipping requirements necessary to avoid moisture/reflow-related failures.
The ESD Handbook ESD TR20.20 mentions the importance of moisture barrier bags in section 5.4.3.2.2 Temperature: “While only specialized materials and structures can control the interior temperature of a package, it is important to take possible temperature exposure into account when shipping electronic parts. It is particularly important to consider what happens to the interior of a package if the environment has high humidity. If the temperature varies across the dew point of the established interior environment of the package, condensation may occur. The interior of a package should either contain desiccant or the air should be evacuated from the package during the sealing process. The package itself should have a low WVTR.”
Components of a dry package
A dry package has four parts:
Moisture Barrier Bag (MBB)
Desiccant
Humidity Indicator Card (HIC)
Moisture Sensitive Label (MSL)
Moisture Barrier Bags (MBB) work by enclosing a device with a metal or plastic shield that keep moisture vapor from getting inside the bag. They have specialized layers of film that control the Moisture Vapor Transfer Rate (MVTR). The bag also provides static shielding protection.
Desiccant is a drying agent which is packaged inside a porous pouch so that the moisture can get through the pouch and be absorb by the desiccant. Desiccant absorbs moisture vapor (humidity) from the air left inside the barrier bag after it has been sealed. Moisture that penetrates the bag will also be absorbed. Desiccant remains dry to the touch even when it is fully saturated with moisture vapor.
The recommended amount of desiccant depends on the interior surface area of the bag to be used. Use this desiccant calculator to determine the minimum amounts of desiccant to be used with Moisture Barrier Bags.
Humidity Indicator Cards (HICs) are printed with moisture sensitive spots which respond to various levels of humidity with a visible color change from blue to pink. The humidity inside barrier bags can be monitored by the HIC inside. Examining the card when you open the bag will indicate the humidity level the components are experiencing so the user can determine if baking the devices is required.
The Moisture Sensitive Level (MSL) label tells you how long the devices can stay outside the bag before they should be soldered onto the board. This label is applied to the outside of the bag. If the “level” box is blank, look on the barcode label nearby.
5 Steps to Create a Dry Package
Now that we know the risks moisture poses to ESD components, follow these 5 steps to create a secure, dry package which will protect your PCBs against ElectroStatic Discharge and moisture:
Place the desiccant and HIC onto the tray stack. Trays carry the devices. Remember to store desiccant in an air tight container until it used.
Place the MSL label on the bag and note the proper level on the label.
Place the tray stack (with desiccant and HIC) into the moisture barrier bag.
Using a vacuum sealer, remove some of the air from the bag, and heat seal the bag closed. It is not good to take all the air out of the bag. Only slight evaluation is needed to allow the bag to fit inside a box.
Now your devices are safe from moisture and static.
With the steps taken above, your package should now be properly sealed from moisture and protected from ElectroStatic discharge.
Are your static and moisture sensitive components protected by your packaging? Learn how to minimize potential product failures by protecting your products from Electrostatic Discharge (ESD) and moisture during the manufacture, transportation, and storage process.
“Desiccant” and “humidity indicator cards” must be used for proper moisture protection.
But what exactly are “desiccant” and “humidity indicator cards” and how are they used? These are the questions we will clarify in today’s blog post.
What is desiccant?
Desiccant is a drying agent that absorbs moisture from its surrounding area. Desiccant will stay dry to the touch even when it is fully saturated with moisture.
In a Moisture Barrier Bag it is used to ‘soak up’ moisture from the air inside the bag AFTER it has been sealed. Any moisture that gets through the bag from the outside will also be absorbed.
How is desiccant purchased?
Desiccant is available as a “unit” or fractional “unit”. A unit of desiccant absorbs a specific amount of moisture. One unit of desiccant weighs about 28g.
How is desiccant packaged?
Desiccant is packed in small sealed pouches made from a white plastic called “Tyvek” or brown “Kraft” paper. Tyvek pouches are very clean and Sulphur free. Kraft pouches are economical.
Pouches of desiccant are placed into metal pails – this ensures the desiccant is kept dry during transport and storage.
How much desiccant do you need?
There are 2 different methods you can use:
Method 1 per MIL-P-116 Formula: Unit = 0.011 x bag area in square inches What you need: Bag area (2 times the surface area of your bag as there are 2 sides to a bag) Example: 10” x 20” MBB bag Apply formula: 0.011 x (10” x 20” x 2) = 4.4 rounded up to 4.5 units of desiccant
Method 2 per EIA 583 (allows you to tailor desiccant to your specific needs) Formula: Unit = 0.231 x Bag Area x Bag MVTR x Months divided by Moisture Capacity What you need: Bag area, Bag MVTR, Months of Storage, Maximum Interior Humidity (MIH), Moisture capacity table below:
10% MIH
3.0 g/unit
20% MIH
4.8 g/unit
30% MIH
5.8 g/unit
40% MIH
6.2 g/unit
Example: 10” x 20” bag with a 0.02 MVTR, a 12 month storage time and a MIH of 20% Apply formula: 0.231 x (10″ x 20″ x 2) x (0.02) x (12/4.8) = 4.62 rounded down to 4.5 units of desiccant
What is a humidity indicator card?
A humidity indicator card allows for quick visual inspection of the relative humidity levels within its surrounding area. They are printed with moisture sensitive spots which respond to various levels of humidity with a visible color change from blue to pink.
In a Moisture Barrier Bag they provide a low-cost method of verifying the effectiveness of the moisture barrier packaging. If you are using Moisture Barrier Bags, moisture will be an issue in your application so you’re obviously aiming for as little moisture as possible. However, if you happen to open your MBB and the humidity indicator card shows a relative humidity of 60%, you’ll know that the contents of your bag have been exposed to moisture and may not be safe for use anymore.
How are humidity indicator cards purchased?
Humidity indicator cards come in many shapes and forms. Some will show relative humidity from 10% – 60%; others from 5% to 15%. Depending on the sensitivity of your application to moisture, the correct type of card should be chosen.
Bear in mind that not all humidity indicator cards are reversible. Some cards will measure the relative humidity only once and then halt at that reading. These types of humidity indicator cards are NOT re-usable. This is important to know so make sure you check before purchasing!
How are humidity indicator cards packaged?
Humidity indicator cards are sold in containers. It is recommended that cards are stored in their original un-opened canister in a dry, well ventilated room with a reasonably consistent temperature of 20°C. Humidity indicator cards should not be stored in ultraviolet sunlight, moisture or heat.
How many humidity indicator cards do you need?
One humidity indicator card per MBB is needed for proper verification of relative humidity.
Conclusion
Moisture Barrier Bags, desiccant and humidity indicator cards all play a very unique and important role when protecting ESD sensitive devices from moisture.
Protect your static and moisture sensitive components with proper packaging
They should always be used together to ensure maximum protection. However, remember that all three tools need to be used correctly as otherwise all your efforts have been in vain. And don’t forget: your Moisture Barrier Bag must be heat sealed with a vacuum sealer to eliminate the amount of “moisture laden air” within the package.
If your company has an ESD Control Program per ANSI/ESD S20.20 in place, you need to define ESD protective packaging for ESD sensitive items (ESDs).
“The Organization shall prepare an ESD Control Program Plan that addresses each of the requirements of the Program. Those requirements include: – Training – Product Qualification – Compliance Verification – Grounding / Equipotential Bonding Systems – Personnel Grounding – ESD Protected Area (EPA) Requirements – Packaging Systems – Marking” [ANSI/ESD S20.20 clause 7.1 ESD Control Program Plan]
But where do you start? Don’t panic – we’re here to help and we’ll be following the guidelines set-out in the ESD Standard.
Definition and Purpose of ESD Protective Packaging ESD Protective Packaging covers any materials coming into direct contact with ESD sensitive devices during handling, shipping and storage. You don’t need to worry about secondary or exterior packaging unless it’s used for ESD protection purposes.
“Packaging for ESD sensitive items is commonly derived by modifying existing packaging to prevent the packaging itself from causing static damage. The packaging generally retains physical and environmental protective qualities. ESD protective packaging has been modified further to prevent other sources of static electricity from damaging a packaged item.“ [ANSI/ESD S541 Foreword]
The fundamentals of ESD control include grounding all conductors in the EPA. ESD packaging will have special material composition to lower the resistance so that when grounded, electrostatic charges will be removed to ground thus protecting your ESD sensitive devices inside.
“Transportation of electrostatic sensitive devices requires packaging that provides protection from electrostatic hazards in the transportation or storage system. In the case of an EPA designed with continuous grounding of all conductors and dissipative items (including personnel), packaging may not be necessary.” [ANSI/ESD S541 clause 6. Packaging Application Requirements]
Example of ESD Packaging
Packaging is to be determined for all material movements inside and outside of the ESD Protected Area (EPA). Best practice is to define the required packaging or material handling item on the product’s bill of materials. Remember: the ESD packaging is just as important as a component part.
Customer contract packaging can take precedence, but otherwise “the organization shall define ESD protective packaging requirements, both inside and outside the EPA per ANSI/ESD S541 or in accordance with the contract, purchase order, drawing or other documentation necessary to meet customer requirements.” [ANSI/ESD S20.20 clause 8.4 Packaging]
Choosing your ESD Protective Packaging Numerous factors need to be taken into consideration when choosing your ESD protective packaging including the “environment and device sensitivity.” [ANSI/ESD S541 Annex A.1 Environment and Device Sensitivity]
It is best recommended to follow these 6 steps:
Understand the product sensitivity You can gather information about the ESD sensitivity of an item by either measuring it in-house, contacting the manufacturer of the product or by analyzing published ESD sensitivity data.
Determine the distribution environment for the packaged product Knowing the environment in which the product is shipped and how it will be handled is extremely important. Humidity and temperature are the main factors to consider when it comes to choosing the right type of packaging for your ESD sensitive items. If items are susceptible to moisture, a barrier material should be chosen to prevent excessive humidity exposure. On the other hand, condensation may occur inside the packaging if temperatures vary around the dew point of the established interior conditions. In those instances, desiccant should be put inside of the package or the air should be removed from the package before shipment.
A Moisture Barrier Bag – click here for more information
Determine the type of packaging system that is best suited for the intended application The first step is to choose low charging or static dissipative materials when in contact with ESD sensitive devices. Many companies also require the packaging to protect the contents from a direct discharge or exposure to electric fields. In addition to these requirements, there are further questions that need to be asked:
Returnable or reusable packaging?
Disposable or one-time only packaging?
Aesthetic requirements for packaging?
Select and test packaging materials Test methods are explained in ANSI/ESD S541 and will classify packaging materials as conductive, static dissipative or insulative.
Design a packaging systemOnce the ESD sensitivity and distribution environment have been evaluated and available materials have been selected, the design of the packaging system can begin. Per the ANSI/ESD S541, the following general rules apply:
Inside an EPA: “Packaging used within an EPA (that satisfies the minimum requirements of ANSI/ESD S20.20) shall be:
Low charge generation.
Dissipative or conductive materials for intimate contact.Items sensitive to < 100 volts human body model may need additional protection depending on application and program plan requirements.” [ANSI/ESD S541 clause 6.1 Inside an EPA]
Outside an EPA: “Transportation of sensitive products outside of an EPA shall require packaging that provides:
Low charge generation.
Dissipative or conductive materials for intimate contact.
A structure that provides electrostatic discharge shielding.”
[ANSI/ESD S541 clause 6.2 Outside an EPA]
Example of ESD Packaging
In addition to these guidelines, there may be additional factors that should be considered, e.g.:
Cost/value relationship: The cost of the packaging compared to the total value of the contents is important. Some companies choose less expensive packaging for less valuable parts.
Handling: If rigorous handling is expected, cushioned packaging may need to be considered.
Test the final packaging design for effectiveness It is highly recommended to subject packages to the type of hazards that can be expected during shipments. These tests can, for example, involve the following:
High voltage discharges to the exterior of the packaging
Simulated over the road vibration
Drop tests
Environmental exposure
Final thoughts on ESD Protective Packaging Now that you have an understanding of the factors to consider when choosing your ESD Protective Packaging, you’re ready to implement the above guidelines. ESD packaging comes in all sorts of shapes and forms so bear in mind to not just look at bags when deciding what type of packaging to choose.
Also, remember that ESD packaging should be marked. We’ll cover the specifics in a later post.
Last time we explained how to easily create a compliance verification plan and why it’s important to have one in place. Today’s post will elaborate on the subject of periodic verification and highlight common products in your EPA that should be regularly verified and more importantly how they should be checked.
Why periodic verification Compliance verification is a requirement of ANSI/ESD S20.20:
“The Organization shall prepare an ESD Control Program Plan that addresses each of the requirements of the Program. Those requirements include: – Training – Product Qualification – Compliance Verification – Grounding / Equipotential Bonding Systems – Personnel Grounding – ESD Protected Area (EPA) Requirements – Packaging Systems – Marking” [ANSI/ESD S20.20 clause 7.1 ESD Control Program Plan]
Installed ESD Control products must be checked regularly to ensure they meet the required limits per the ESD Standard. “Compliance verification records shall be established and maintained to provide evidence of conformity to the technical requirements. The test equipment selected shall be capable of making the measurements defined in the Compliance Verification Plan.” [ANSI/ESD S20.20 clause 7.3 Compliance Verification Plan]
Below, you will find a list of the most common ESD Control Products in your EPA and how to test them:
Worksurface Matting The purpose of ESD workbench matting is to ensure that when charged conductors (conductive or dissipative) are placed upon the surface, a controlled discharge occurs and electrostatic charges are removed to ground. However, this only occurs if the ESD worksurface is connected to ground. If the matting is out-of-spec, not grounded at all, or the stud on the mat has become loose or if the ground cord has become disconnected, charges cannot be removed.
Many companies use a daily checklist, which includes the operator having to verify that ground cords are firmly connected.
Remember to regularly clean your workbench matting to maintain proper electrical function. Do not use cleaners with silicone as silicone build-up will create an insulative film on the surface.
The company’s compliance verification plan should include periodic checks of worksurfaces measuring:
A surface resistance tester can be used to perform these tests in accordance with ANSI/ESD S20.20 and its test method ESD TR53; if these measurements are within acceptable ranges, the worksurface matting and its connections are good.
Wrist Straps As discharges from people handling ESD sensitive devices cause significant ESD damage, the wrist strap is considered the first line of ESD control.
Before handling ESD sensitive items, you should visually inspect the wrist strap to see if there are any breakages etc. The wrist strap should then be tested while worn using a wrist strap tester. This ensures all three components are checked: the wrist band, the ground cord (including resistor) and the contact with the operator’s skin. Records of each test should be kept. Wiggling the resistor strain relief portion of the coil cord during the test will help identify failures sooner. Analysis and corrective action should take place when a wrist strap tester indicates a failure.
It is recommended that wrist straps are checked at least daily. An even better solution to daily wrist strap checks is the use of continuous monitors. They will alarm if the person or worksurface is not properly grounded.
A note on worksurface matting and wrist straps: if you are using common ground points to ground the operator and/or work surface matting, remember to measure resistance to ground regularly as well (every 6 months for example).
Floor Matting A flooring / footwear system is an alternative for personnel grounding for standing or mobile workers. Foot grounders quickly and effectively drain the static charges which collect on personnel during normal, everyday activities. Foot grounders should be used in conjunction with floor surfaces which have a surface resistance of less than 1010 ohms.
As ESD floors get dirty, their resistance increases. For optimum electrical performance, floor matting must be cleaned regularly using an ESD mat cleaner. Do not use cleaners with silicone as silicone build-up will create an insulative film on the surface.
Dissipative floor finish can be used to reduce floor resistance. Periodic verification will identify how often the floor finish needs to be applied. As the layer(s) of dissipative floor finish wear, the resistance measurements will increase. So, after some amount of data collection, a cost-effective maintenance schedule can be established.
Floor matting can be checked using a resistance meter. A surface resistance meter is designed to measure resistance point-to-point (Rp-p) or surface to ground (Rg) in accordance with ANSI/ESD S20.20 and its test method ESD TR53.
Footwear ESD Shoes or foot grounders play an essential part in the flooring/footwear system.
Before handling ESD sensitive devices, visually inspect your ESD footwear for any damage. Just like wrist straps, footwear should be checked while being worn using a wrist strap/footwear tester.
Records of each test should be kept. Analysis and corrective action should take place when a footwear tester indicates a failure. Footwear needs to be checked daily.
ESD Packaging Re-using shielding bags is acceptable as long as there is no damage to the shielding layer. Shielding bags with holes, tears or excessive wrinkles should be discarded.
Make sure your ESD shielding bags are un-damaged
It is up to the user to determine if a shielding bag is suitable for re-use or not. The testing of every bag before re-use is not practical. Many companies will discard the shielding bag once used and replace it with a new one. Others will use a system of labels to identify when the bag has gone through five handling cycles:
Non-reusable labels are used that require the label be broken to open the bag.
The bag is then resealed with a new label.
When there are five broken labels, the bag is discarded.
The same principle applies to other ESD packaging, e.g. component shippers.
Ionizers Ionizers are intended to neutralize static charges on insulators thereby reducing their potential to cause ESD damage. However, poorly maintained ionizers with dirty emitter pins and out-of-balance ionisers can put a charge on ungrounded items.
Remember to clean ionizer emitter pins and filters regularly. You can now even purchase ionizers that will alarm when emitter pins need to be cleaned or the ionizer is out of balance.
Static neutralization (the ability to reduce or eliminate a charge on a surface) is an important quality for ionizers. Static decay time is defined as the time interval needed to reduce a defined voltage potential on an object to a defined lower potential by means of applied ionized air. Another important aspect for ionizers is the ability to produce a balanced stream of positive and negative ions. A charged plate monitor or equivalent can be used to accurately measure both of these parameters.
For more detailed information on measuring the performance of ionizers refer to the ESD standard ANSI/EOS/ESD-S3.1 for Protection of Electrostatic Discharge Susceptible Items-Ionization.
Wrist Strap/Footwear and Resistance Testers etc. So, you check your wrist straps and/or footwear and workbench and/or floor matting regularly. But have you remembered the testers themselves? What good do all the checks do, if the testers you use are out-of-spec and show you incorrect results?
Yearly calibration is recommended – many manufacturers offer a calibration service or alternatively you can purchase calibration units from them and perform the calibration yourself.
There you have it – a list of the most commonly used products in your ESD Protected Area (EPA) that you should check on a regular basis.
Questions for you: Do you have a verification plan in place? If so, how often do you check your ESD protection products?
