What Are the Standards for Electrostatic Protection?
So, you’ve just been tasked with building or designing your first Electrostatic Protection Area (EPA). You’ve started doing your research, but there are so many choices, from so many different companies. Suppliers, manufacturers, third party providers… If only there was some established standard for judging the efficacy and reliability of all those pieces and parts.
Well, you’re in luck! In 2007, the American National Standards Institute (ANSI) in cooperation with ElectroStatic Discharge Association (ESDA) released a unified set of standards for the design, implementation and maintenance of ElectroStatic Discharge control programs.
In the midst of World War I, five engineering organizations recognized the need to develop standards that could eliminate confusion and could be adhered to across all disciplines, without regard to politics, profits or personal preferences. These groups reached out to the U.S. Departments of War, Navy, and Commerce to form an impartial third party non-profit organization, then known as the American Engineering Standards Committee.
Following the war, the organization spent the next 20 years establishing several safety protocols still observed today, like eye protection, hard hat standards and in-house electrical safety while at the same time reaching out to other similarly tasked international organizations.
When the United States entered World War II, the organization, which would eventually come to be known as ANSI, helped to accelerate the war effort and productivity, created more effective quality control measures, as well as helping to advance photography, radio, and even the development of Velcro.
In 1970’s, ANSI established a public review process and began the herculean effort of moving the United States to the metric system. While the general public never really connected with the metric system, the effort did bring ANSI to the forefront of private sector companies who discovered standardization was a way to stay more competitive in an increasingly global economy.
With the advancement of personal computers in the late 70’s and early 80’s, engineers at several companies recognized a need for more understanding of electrostatic discharge and its prevention. They formed the ESD Association, a non-profit, voluntary professional organization that for almost 35 years has sponsored educational programs and developed standards to help eliminate losses due to electrostatic discharges.
Together, leaning on the historical experience of both military and several commercial organizations, ANSI and ESDA developed the definitive standard for ESD protection, the very cleverly named ANSI/ESD S20.20-2007.
Covering about every conceivable area of ElectroStatic Discharge, the ANSI/ESD S20.20-2007 utilizes both the human body model and the machine model to provide a broad set of guidelines for ESD protection.
The Human Body Model is the military standard that defines and rates the vulnerability of an electronic device to the ESD generated by a human being touching it. The Machine Model works similarly, except it rates the vulnerability of a device receiving a machine discharge into ground. It was originally developed by car manufacturers as their plants moved to more mechanized production technology. The Human Body Model is about 10 times more sensitive than the Machine Model.
There is a lot to explore in the ANSI/ESD S20.20-2007 guidelines, but for the purpose of this primer, the document highlights 3 fundamental ESD control principles:
- All conductors should be grounded. This includes the personnel and the surfaces they are working on. We recommend, at a minimum, personal grounding wrist straps, ESD table or bench mats, and a common ground cord.
- Necessary non-conductors – certain circuit board materials, device packaging, etc. – cannot lose their electrostatic charge by being grounded and appropriate precautions must be implemented.
- Static protective materials, such as ESD shielding bags or ESD totes and boxes must be utilized when transporting sensitive electronics outside a properly prepared EPA.
There are slightly less stringent standards that apply to floors and bench mats, but ANSI/ESD S20.20-2007 is the highest and most comprehensive guideline so far. So when you’re shopping for the parts needed to establish your EPA area, always look for companies that maintain that standard in their products and services.
We would love to be your full service, seamless ESD solution provider; contact us today for more information.