ESD Static Shielding Bags MEGA Guide

ESD Static Shielding Bags are commonly used for the packaging of electronic components to prevent damage caused by electrostatic discharge events that electronic devices can be prone to. In this article, we will discuss a few of the finer points that will hopefully point you in the right direction when selecting an ESD static shielding bag.

Here are the ESD topics we will be covering in this article:

• Static Shielding vs Anti-Static ESD Shielding Bags
• Tips for Proper Handling of ESD Shielding Bags
• Static Shielding Bag FAQs
• How to Choose the Correct ESD Shielding Bag
• Packing and Handling Requirements for ANSI/ESD Compliance

Remember, at any time you can visit our ESD Shielding products using the links down below 

Desco Static Shielding Bubble Bags

Desco Static Shielding Moisture Barrier Bags

Desco Metal-In Static Shielding Bags

Desco Fold Top Static Shielding Bags

Desco Metal-In Zip Top Static Shielding Bags

Protektive Pak Pink Poly Bags

Static Shielding VS Anti-Static ESD Shielding Bags

The terms “static shielding” and “anti-static” seem to be used as one in the same in many instances. However this is not the case, there are actually major differences between static shielding and and anti-static materials. Ordering the incorrect one for your application could mean product damage.

If the bag you're considering is a Static Shielding Bag, that means it prevents the build up of static electricity (meaning they have anti-static properties), it also means that the bag will protect from electrostatic discharge or ESD for short. These bags are made of multi-layer materials which create what is called a Faraday Cage that protects components from ESD.

What are the layers in Static Shielding Bags?

• The inner layer is a static dissipative polyethylene
• The inner layer is surrounded by a layer of aluminum shielding.
• The next layer is made of polyester
• The outer layer made of a static dissipative coating.

Unlike anti-static bags, static shielding bags protect components from static charges both inside and outside of the bag. In order to provide ESD protection, material is fashioned into a bag or enclosure of some sort and products are sealed inside the bag. No seal, no guarantee of protection. And be sure to pad sharp components and don’t use staples. They can compromise the static shielding properties of the bags.

Another class of static shielding bags are moisture barrier shielding bags (MBB).  These materials shield from electromagnetic interference (EMI) as well as radio frequency interference (RFI) and static. This is mainly accomplished by using a much thicker metal layer, inhibiting the moisture vapor transmission rate (MVTR) by a factor of over 20 times more compared to ordinary shielding bags.

Anti-Static Bags

Anti-static bags ONLY prevent the build up of static electricity. The material itself will not generate or hold a charge, so cannot be a carrier that introduces static into a static controlled environment. These materials do not protect from electrostatic discharge (ESD).  Anti-static bags and materials are ideal for packaging non-static sensitive parts used in electronics manufacturing, like nuts and bolts or manuals. Many people think of pink polyethylene bags when they think of anti-static bags. Pink poly anti-static bags should never be used as the only packaging to protect electronic components from electrostatic discharge.

Tips for Proper Handling of ESD Shielding Bags

1. Your ESD Shielding bags should obviously be large enough to contain the entire product within. The shielding bag should also have enough room in it to be closed (for fold-top style bags) with a label or tape. You can use a zipper-style shielding bag, which we call a "Zip Top Bag" and you can view them here. Sealing the bag (preferably by using the zip top) ensures that the device inside is being shielded from electrostatic. Remember, an unsealed ESD bag is not shielding the contained product. 
2. Be sure to remove any existing charge from the ESD Shielding Bags before use
   When you get an ESD sensitive device packaged in a shielded bag, be sure to place the closed shielded bag on the ESD work surface before removing the product. This will remove any charge that may have accumulated on the surface of the static shielding bag during transportation or subsequent handling.
3. It's best to not re-use or overuse static shielding bags
   Even if the shielding bags aappear to be undamaged, the bags are usually cost-effective enough to play it safe and use a new bag. Any holes, tears, wrinkles (seen or unseen) on the shielding bag are signs that it potentially has lost its ability to shield any product within
4. Use a properly grounded work surface area when handling ESD Products
   ESD shielding bags keep the ESD sensitive products away from ESD damage, however they can build a charge on the outside layer, so keep this in mind when being in a situation where you must place an ESD sensitive item on the outside of the static shielding bag and to mitigate risk, use a grounded ESD work surface when handling these sensitive products. 
   
   

Static Shielding Bag FAQs

• Is There a Difference Between an Anti-Static Bag and a Static Shielding Bag?

• Anti-static bags prevent triboelectric charge build up but do not shield components inside the bag from electrostatic discharge. Anti-static bags sustain safe component handling only in ESD protected areas. Static shielding bags provide a full encompassing ESD protection mechanism for components within the bag, meaning you can take them out of ESD protected areas ( like for shipping ) once they're properly enclosed in the bag.

• Is a Pink Anti-Static Bag the Same as a Static Dissipative Bag? 

• No. Static dissipative ESD bags provide static dissipative materials that slowly drain charge. In ESD areas, these bags simply hold documents or other non-sensitive items without transferring any charges from a non-ESD safe area.

  Clear static dissipative bags are not safe for components, as a component may absorb an ESD shock without the protection of a shielding bag. This is why, only non-ESD sensitive products are used with plain static dissipative bags. 

• Are Pink Poly Bags ESD Safe?

• Standard pink anti-static bags are made of polyethylene with an outer layer of ESD material. Sometimes, these bags can also be black when trace amounts of carbon are deposited during the manufacturing process. Pink are only safe for use in an ESD protected area. Transferring a component from an ESD protected area to a non ESD protected area inside of a pink anti-static bag is not safe.

• What is the Difference Between Metal-In and Metal-Out ESD Shielding Bags?

• Metalized shielded bags have either a metal-in or metal-out design. The metal-in design is common for the packaging of ESD sensitive components. Metal-out shielding bags also protect against static induced damage. The benefits of metal-in construction is usually a factor of cost and durability. A metal layer closer to the outside surface results in a lower resistant reading than the metal-in ESD bags. Integral antistatic and low tribocharging bags which will not electrostatically charge contents during movement. Bags have a protective coated aluminum metal outer layer of laminated film; this promotes a more rapid discharge of static fields creating the event which the metal layer then attenuates. If RF field sensitivity is an issue, metal-out bags may be unsuitable. The rapid discharge to the highly conductive outer layer can create a higher radiated field which in return can cause issues for objects inside or near the bag. Available with and without dissipative zipper.

How to Choose an ESD Static Shielding Bag for your Application

As your figuring out which ESD Static Shielding product to go with for your application, you need to be clear about the use of your ESD bag as well as the environment it’s being used in. Ask yourself the following questions:

• What do you intend to put inside the ESD bag? ESD sensitive items? Non-ESD sensitive items?
• Is moisture an issue you need to consider?
• Do you need your ESD bags to be self-sealable? Or will you be using ESD tape/labels to close your bags?
• Are the items inside your ESD bag sensitive to physical damage?
• Are the items you’re storing in your ESD bag particularly sharp which could potentially damage the material?
• Will the ESD bags (and obviously the items inside) be stored on a grounded shelf inside an EPA or are they being transported outside of an EPA, as well?

Calculating the correct size for your ESD bag
Once you have selected the correct type of material, it’s time to choose the right size for your ESD bag. There are different ways to determine this based on the type of material you use:

1.) Shielding and Black Conductive Bags:
A. Bag Width = Item’s Thickness + Item’s Width + 25mm
B. Bag Length = Item’s Thickness + Item’s Length + 50mm

Moisture Barrier Bags (MBB):
A. Bag Width = Item’s Thickness + Item’s Width + 25mm
B. Bag Length = Item’s Thickness + Item’s Length + 76mm

Cushioned Bags:
A. Bag Width = Item’s Thickness + Item’s Width + 76mm
B. Bag Length = Item’s Thickness + Item’s Length + 76mm

Bonus: Measuring a bag
It might seem obvious to some of you but given that we do get these types of queries on a regular basis, we thought this would be a good opportunity to include. Imagine you already have ESD bags that you use in your company. Someone has just taken the last one off the shelf and you need to order some more. How do you know what size ESD bag you have in front of you so you can place a new purchase order? No worries – we have the answer:

A. The width is measured from inside seam to inside seam. This is also your opening.
B. The length is measured from the top of the opening to the bottom of the bag.

Packing and Handling Requirements for ANSI/ESD Compliance

• The main ESD function of these packaging and materials handling products is to limit the possible impact of ESD from triboelectric charge generation, direct discharge, and in some cases electrostatic fields.
• A second requirement is that the material can be grounded so that the resistance range must be conductive or dissipative. A third property required outside the EPA is to provide protection from direct electrostatic discharges that is discharge shielding.
• A third property required outside the EPA is to provide protection from direct electrostatic discharges that is discharge shielding. ESDA.org 

ANSI/ESD STM11.31 provides a method of evaluation for the energy transferred from the package to the interior.

The ability of some packages to provide discharge shielding may be evaluated using ANSI/ESD STM11.31 which measures the energy transferred to the package interior. A material’s low charging properties are not necessarily predicted by its resistance or resistivity.