Product Qualification in an ESD Control Program

What Should My Product Qualification Plan Include?

Section 7.3 in ANSI/ESD S20.20–2014 includes a requirement for a product qualification plan. This requirement is completed before the selection of ESD control items that will be used for the ESD control program. The product qualification requirements for each ESD control item can be found in Table 2 for personnel grounding, Table 3 for ESD control items used in the ESD protected area (EPA), and in ANSI/ESD S541 for packaging of ESD sensitive items.

There are no humidity control requirements in ANSI/ESD S20.20. However, the testing requirements for product qualification may include low humidity environments to conduct the tests. For example, one ESD control item, worksurfaces, is required in Table 3 to be tested according to ANSI/ESD STM4.1. The limits in ANSI/ESD S20.20 are a point to point resistance of less than 1.0 x 109 ohms and a point to groundable point resistance of less than 1.0 x 109 ohms. The test method in ANSI/ESD STM4.1 requires testing at 23oC at 12% RH and 50% RH. The testing at these two humidity levels is to ensure that the ESD control item works regardless of the humidity level where the ESD control item is installed.

Table 3 in ANSI/ESD S20.20 is the list of optional ESD control items that can be found inside an EPA. However, not all materials that may be used in an ESD control program are included in the table. For an ESD control item to be included in Table 3, there needs to be a standard test method and a defined limit. In some cases (for example gloves) the current test method is not a standard test method and a limit has not been established. For these items, the user must present the rationale for qualification if used in an ESD control program.

Objective evidence of qualification can come from various sources. If the capability exists, in house testing is a source. An independent third-party lab could also be a source of information. The manufacturer’s product data sheet is another alternative. These reports must contain at a minimum, the values measured, the standard test method used, and exceptions, if any, to the test method.

Exceptions would have to be documented with a tailoring statement (more information below). An additional method of qualification can be used if the ESD control items have been in place for a while. The compliance verification data can be used for qualification but it should contain more than one data set and at least one of the data points coming from a low humidity time of the year. Keep in mind that the compliance verification data needs to exist before using this as objective evidence. For example, if a footwear/flooring system is used for personnel grounding and has been in place for years, the compliance verification data for the floor and footwear system could be used for the floor and shoes, but data that shows body voltage generation would still be required as per ANSI/ESD STM97.2.

Exceptions to a product qualification requirement can be done using tailoring in ANSI/ESD S20.20. Technical justification and rationale will need to be documented for the exception to be accepted during an audit. An example of a tailoring situation would be a facility that does have humidity controls. While not required in ANSI/ESD S20.20, if the facility had a minimum humidity level of 30%, then qualification could be done at that minimum level provided the objective evidence exists that the EPA does not drop below that level. This tailoring statement only applies to ESD control items that remain inside the defined EPA. Items such as packaging, which may travel to uncontrolled environments, must be tested at the prescribed humidity levels as per ANSI/ESD S541.

Product qualification is an essential part of any ESD control plan and is necessary to become certified to ANSI/ESD S20.20. Objective evidence through various alternative options can be used for demonstrating qualification of an ESD control item. With the proper qualification testing, humidity may not be required to control static within an EPA. As discussed above, a reduction in the humidity range necessary for qualification may be allowed if objective evidence of a controlled humidity range in the EPA can be provided. This is just one example in which tailoring can be used to modify a product qualification to meet specific user needs.

John Kinnear is an IBM senior engineer specializing in process & system technology, and facility certification in accordance with ANSI/ESD S20.20. He has a BS degree from University of Buffalo and a MS degree from Syracuse University. John is well known globally for his technical contributions to national and international standards. He has been the IBM ESD site coordinator for the Poughkeepsie site since 1989. He is past chairman of the IBM inter-divisional technical liaison committee for ESD protection and is an important member of his company’s committee to develop and implement the ESD corporate program for IBM. John has coordinated the testing of large mainframes for compliance to EMC, safety, environmental, shipping, and volatile organic emission standards. He has also been the lead engineer on testing large mainframe systems to EMC emissions and immunity standards for FCC, CE Mark, VCCI, and other national requirements. As a member of the ESD Association since 1990, John has served in several standards development committees as well as association management positions. John is the appointed technical adviser to the United States National Committee/IEC technical committee 101, where he represents the United States to the International Electrotechnical Commission (IEC). In this position he assisted in the evolution of international ESD standards and supports international adoption of ANSI/ESD S20.20. As chair of the ESDA’s facility certification (ANSI/ESD S20.20) development program, John played major roles in the program’s development and industry launch. In particular, John coordinated the initial development of lead assessor training, ISO registrar certification, and witness audits. John has served in every ESD Association officer’s position, including vice president, senior vice president, and president. He is the past chairman of the EOS/ESD Symposium technical program committee and past general chairman of the 2004 EOS/ESD Symposium. For his contributions to the ESD Association, John was presented with the Outstanding Contribution award in September 2006.

Founded in 1982, EOS/ESD Association, Inc. is a not for profit, professional organization, dedicated to education and furthering the technology Electrostatic Discharge (ESD) control and prevention. EOS/ESD Association, Inc. sponsors educational programs, develops ESD control and measurement standards, holds  international technical symposiums, workshops, tutorials, and foster the exchange of technical information among its members and others.

About The Author

EOS/ESD Association, Inc.

Founded in 1982, EOS/ESD Association, Inc. is a not for profit, professional organization, dedicated to education and furthering the technology Electrostatic Discharge (ESD) control and prevention. EOS/ESD Association, Inc. sponsors educational programs, develops ESD control and measurement standards, holds international technical symposiums, workshops, tutorials, and foster the exchange of technical information among its members and others.

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One Response

  1. RAVINDRAN JAYARAMAN

    Hi Ron

    Need your technical explanation on the below reference standard on the production qualification.

    During recent ANSI/ESD S20.20 certification audit by DEKRA, the auditor issue an NC due no evidence of product qualification of the floor material (conductive tiles) at low RH – 13%.
    We have perform the walking test on installed flooring.
    The floor size installed is 2 X 2
    The below 3 standards are having difference size of floor specimen.

    Will be there any difference on the result of using the actual installed size vs as per the standards below and what is the rational of having different floor specimen size

    Is a compulsory to perform product qualification at low RH since our region’s RH does not fluctuates and maintain minimum 50% at all time.

    ANSI/ESD STM97.1-2015

    5.2 Test Procedures – Qualification Testing
    5.2.1 Specimen Preparation 5.2.1.1 Minimum size of specimen is 91 cm x 91 cm (36 inches x 36 inches) or larger.

    ANSI/ESD STM97.2-2006
    5.2.1 Floor Specimen Preparation

    5.2.1.1 The preferred size of specimen shall be 91 x 91 cm (36 x 36 inch) although 122 x 122 cm (48 x 48 inch) may be used. In the case of the larger sample, the 6.3 mm (0.25 inch) hardboard may have to be backed by another nominal 6.3 mm (0.25 inch) thick plywood or hardboard for strength.

    ANSI/ESD STM7.1-2013
    6.1.2.2 Specimen A specimen shall be large enough that a 305 mm by 610 mm (12 inches x 24 inches) test area can be defined as in Figures 1 and 2. If the installed product has seams, then the test sample must include a seam.

    Thanks
    Ravindran

    Ravindran Jayaraman
    esd2020@yahoo.com
    +60 19-410 9604

    Reply

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