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Accreditation of EMC Laboratories in the US

Since 1990, the accreditation of EMC laboratories has become increasingly important in many parts of the world. This development has been mainly driven by the sharp increase in the number of electric and electronic products that have been introduced to the global marketplace.

 

Technological advances in the high tech areas of data communication, wireless communication, computer networking, and many others lead to a proliferation of products not only in the business and professional but also in the residential environment. This proliferation of electronic products and the trend to shorter product life cycles and more rapid consumer product turnovers lead to a drastic increase in the total number of electronic products that are in use today. The compliance of most of these products with national and international electromagnetic compatibility (EMC) requirements is to be determined and documented before they can be marketed. In many countries like the US or economies like the European Union, the manufacturers themselves can declare the conformity of their products with applicable standards. This approach is called Declaration of Conformity (DoC) and is applicable to certain product categories as determined by the regulatory authority of the different countries. This way of determining and documenting product compliance is more efficient than the verification or certification schemes that were in use in the past and required direct involvement of regulatory authorities to various degrees. A rapid product introduction is of the essence today, in light of decreasing product life cycles and the increasing number of product introductions. Many other product categories like those with transmit functions (above a certain level of transmit power) still require specific approval of the regulatory authority in many countries.

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The measurements associated with the determination of product compliance with applicable EMC standards and the approvals of products by regulatory authorities can be very time consuming. Qualified test laboratories can help reduce the test and approval periods, especially when regulatory authorities accept test data and reports documented by the test laboratories without further evaluations. For example, in the US, an EMC test laboratory that is accredited by A2LA (American Association for Laboratory Accreditation), NVLAP (National Voluntary Laboratory Accreditation Program) or another recognized accreditation body to perform EMC tests in accordance with applicable FCC rules may prepare test reports which can serve as the basis of a DoC by the manufacturer for information technology equipment (ITE). The regulatory body for EMC in the US, the Federal Communications Commission, (FCC), will not have to be involved in the product approval process for ITE equipment in this case. In the international context, many mutual recognition agreements (MRAs) between the US and foreign economies are in place to allow swifter product introductions into foreign markets and thus stimulate trade. These product introductions involve, among other testing activities, EMC compliance testing by US test laboratories to foreign EMC requirements (like Korean or Taiwanese standards). Accreditation of US EMC test laboratories to these foreign standards serves as a basis for their recognition by the foreign regulatory authority as a conformance assessment body (CAB). There is an additional recognition process established that EMC laboratories in the US have to follow to obtain this recognition.

Due to the author’s familiarity of the policies and procedures of the American Association for Laboratory Accreditation, this article will focus on the accreditation process of EMC laboratories in the US today, from the A2LA perspective. It is to be assumed that the application, assessment and overall accreditation procedures and requirements for EMC laboratories used by the two recognized accreditation bodies in the US are similar and deviate only in details of implementation. Additional topics of discussion in this paper are the main principles of the internationally accepted test and calibration laboratory standard ISO/IEC 17025:2005 and the advantages of laboratory accreditation for regulatory authorities, laboratory customers and the general public.

The Benefits of EMC Laboratory Accreditation [1]

Accreditation provides a formal recognition to competent EMC testing laboratories based on the verification of implementation of a quality system in the laboratory (in accordance with ISO/IEC 17025) and the determination of a minimum level of technical proficiency to perform the EMC tests for which the laboratory is accredited. This formal and public recognition allows customers to identify and select independently verified testing services. For EMC laboratories to maintain this recognition, regular evaluations by the accreditation body are performed to ensure the on-going compliance with requirements and to verify that the standard of operation is being maintained or improved. The accredited EMC laboratory is also required to participate in relevant proficiency testing programs between reassessments as a further demonstration of technical competence, or the laboratory must design their own testing activities that demonstrate the quality of their test data over time.

There are at least four distinct groups that benefit from accreditation in general: EMC laboratories themselves, users of laboratory testing services, regulatory authorities (private and public entities that require quality test data to operate), and the general public.

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EMC test laboratories benefit from a technically sound assessment and accreditation by an internationally recognized accreditation body. Some of these benefits are:

  • An independent and public statement of a recognized third party that designates the laboratory as qualified to provide services in the EMC field.
  • A regular and objective surveillance that aids the management of an EMC laboratory in the continuous improvement its operation.
  • In an increasing number of instances, an entry to a given market that would otherwise be closed to the laboratory.
  • Increased laboratory productivity resulting from a decrease in the number of clients who insist on having their own staff members audit the laboratory. More of these clients now base their confidence on third-party accreditation.
  • International recognition of the competence of an accredited EMC laboratory is obtained if the accreditation body is a signatory to the mutual recognition arrangement of the International Laboratory Accreditation Cooperation (ILAC).
  • On-site assessments help the technical staff members of the accredited EMC laboratory verify that the latest requirements in applicable standards are properly implemented and applied.
  • Improved performance by laboratory staff members. Undergoing regular assessments enhances staff discipline and its sense of professionalism. Employees are more likely to be committed to observing the quality management system and standards of performance of the laboratory.

Users of EMC laboratory testing services are a second group of beneficiaries of laboratory accreditation. Customers have greater confidence in the accuracy of the test report they are purchasing because it has been generated by a competent facility. This is particularly true for an educated client who is conscious of the scope of the laboratory’s accreditation.

Manufacturers (for example, in the automotive industry) may also gain efficiency because of accreditation since these organizations do not have to perform their own on-site assessments but can defer to the assessments of competent accrediting authorities. Other manufacturers who have in-house EMC testing capabilities can reduce or even eliminate these overhead costs by using external accredited laboratories with the assurance of technical proficiency.

Regulatory authorities often require accreditation to national or international standards. With restricted budgets, many regulatory authorities can no longer perform EMC testing and product approvals themselves and must rely on third-party laboratories to support their regulatory efforts. These authorities need a comparable and meaningful basis for identifying qualified EMC test service providers, which can be achieved through the accreditation process.

Accreditation also has a positive impact on the general public by stimulating higher standards of quality within EMC testing laboratories. This leads to more consistently reliable test data, thereby contributing to more effective EMC regulations, more consistent product quality and the proper functioning of electronic devices within close proximity of each other.

Laboratory Accreditation from an International Perspective [2]

Many countries around the world have one or more organizations responsible for the accreditation of their nation’s laboratories. Most of these accreditation bodies have adopted ISO/IEC 17025 as the basis for accrediting their country’s testing and calibration laboratories. This has helped countries employ a uniform approach to determining laboratory competence. It has also encouraged laboratories to adopt internationally accepted testing and measurement practices, where possible.

This uniform approach allows countries to establish agreements among themselves, based on mutual evaluation and acceptance of each other’s accreditation systems. Such international agreements, specifically mutual recognition arrangements (MRAs), are crucial in enabling test and calibration data to be accepted between these countries. In effect, each partner in such an MRA recognizes the other partner’s accredited laboratories as if they themselves had undertaken the accreditation of the other partner’s laboratories.

Over 40 laboratory accreditation bodies have signed a multilateral recognition agreement called the ILAC Arrangement, which greatly enhances the acceptance of data across the national borders of the signatory countries. This developing system of international MRAs among accreditation bodies has enabled accredited laboratories to achieve a form of international recognition and allowed data accompanying exported goods to be more readily accepted by overseas markets. This effectively reduces costs for both the manufacturer and the importer, as it reduces or eliminates the need for products to be retested in another country.

MRAs rely on accreditation as a basis for establishing technical competence and building regulator confidence. The accreditation bodies are responsible for accrediting competent conformity assessment bodies (CABs) in accordance with international standards and to the importing party’s technical requirements. In the United States, NIST (National Institute of Standards and Technology) currently lists A2LA, ACLASS and NVLAP as acceptable for use by MRAs for EMC and telecommunications test laboratories (ISO/IEC 17025). Both A2LA and ANSI are recognized through the National Voluntary Conformity Assessment Systems Evaluation (NVCASE) Program as accreditors of certification bodies (ISO/IEC Guide 65).

NIST serves as the U.S. Designating Authority. NIST receives and processes applications from U.S. testing laboratories and certification bodies seeking to be recognized under the MRAs by specific economies/regions as applicable. NIST is responsible for nominating qualified CABs to MRA partner economies/countries. The MRA partners then formally recognize the qualified testing laboratories and/or certification bodies.

From a laboratory perspective, accreditation by an accreditation body that is a signatory to the ILAC Arrangement offers various advantages, especially when a laboratory seeks recognition under a specific MRA through NIST. The benefits of MRAs include:

  • Reduced time and costs. Requirements for duplicative
  • testing are eliminated. Products
  • can be tested in one country to another county’s regulations, thus allowing products to reach the market faster than before. This is especially important in the telecom sector since the lifecycle of a product is typically short.
  • EMC and telecom regulations, laws, policies, and procedures become more transparent.
  • Frequent dialogue between regulatory authorities, designating authorities, and accreditation bodies exists in order to maintain consistency of programs.
  • Laboratories, product certification bodies, and manufacturers are more knowledgeable and stay up-to-date on changes in technical regulations and policies.
  • Industry committees have formed as a means of sharing information and communicating with regulatory authorities, designating authorities, and accreditation bodies.

Again, the basis for recognition as a CAB under a specific MRA is the proper accreditation by an accreditation body that is a signatory to the ILAC Arrangement.

ISO/IEC 17025 – The Standard for Laboratory Competence [1]

The general requirements for laboratory competence are described in the ISO/IEC 17025:2005 standard. This standard establishes a global baseline for accreditation of all types of laboratories. Since its origin in the mid-70’s, ISO/IEC 17025 (formerly ISO/IEC Guide 25) emphasizes competence of laboratories to perform specified tests, not merely compliance with requirements.

Several important principles are imbedded in the requirements of the standard. These principles are summarized as follows:

Capacity
An EMC laboratory must have the resources (staff members with the required skills and knowledge, test environment with the required facilities, equipment and instrumentation, procedures to ensure consistency of test processes, and quality control for the key steps in the testing processes) in order to carry out the tests and produce reliable results.

Responsibility
An EMC laboratory must have staff members in the organization who have the authority to execute specific functions with the overall scope of test work. They also have to be able to demonstrate accountability for the published test results.

Scientific Approach
An EMC laboratory will carry out its work based on accepted scientific principles, preferably following published EMC standards. If deviations from accepted methods are necessary to perform an evaluation of a specific device, the deviations must be substantiated and documented in a manner considered generally acceptable by experts in the field.

Objectivity
The test results produced should be based upon measurable quantities. If results are subjective (applicable to some immunity tests), they must be produced by testing personnel deemed qualified to make subjective judgments.

Impartiality
The pursuit of reliable results through the use of accepted scientific principles is the primary and overriding influence on the persons carrying out the testing. All other influences are secondary and not permitted to take precedence.

Measurement Tractability
The results produced are based on a recognized system of measurement that is derived from accepted known quantities (i.e., SI system) or other well-characterized references. The chain of measurement comparison between these accepted known quantities and the device providing the objective measurement result is unbroken for the transfer of measurement characteristics, including uncertainty, for the whole of the measurement chain.

Reproducibility
The EMC test methods used to achieve measurement results will produce results that are comparable to future testing results, which will be produced under similar circumstances. These circumstances are defined primarily by the applied EMC standard, the equipment used, and the knowledge and technical proficiency of test personnel.

Transparency
The test and quality processes within an EMC laboratory must be open to both external and internal scrutiny in order to easily identify factors which may adversely affect the laboratory’s pursuit of objective results based on published standards.

Accreditation versus Certification

Laboratory accreditation uses criteria and procedures specifically developed to determine technical competence. Qualified technical assessors conduct a thorough evaluation of all factors in a laboratory that affect the production of test or calibration data. Very often these criteria are based on ISO/IEC 17025, which is used for evaluating EMC test laboratories throughout the world. Laboratory accreditation bodies use this standard specifically to assess factors relevant to the laboratory’s technical competence.

These factors include:

  1. technical competency of staff members
  2. validity and appropriateness of EMC test methods
  3. traceability of measurements to national standards
  4. adequacy, calibration and maintenance of test equipment (for example, in accordance with CISPR 16-1-1/2/3/4)
  5. adequacy of test environment (for example, in accordance with CISPR 16-1-4)
  6. handling and transportation of test samples
  7. quality assurance of test data over time
  8. reporting of EMC test results

By applying this process, laboratory accreditation aims at assuring the accuracy and reliability of test data of an EMC test laboratory. The ISO 9001 quality system standard, is widely used in manufacturing and service organizations to evaluate their system for managing the quality of their product or service. The goal of certifying a quality management system of an organization against ISO 9001 is the confirmation of compliance of the management system to this standard. An EMC test laboratory may be certified to ISO 9001, but such a certification does not make any statement about the technical competence of a laboratory. Despite the fact that accreditation also covers certain elements that are evaluated during a certification process, no minimum level of technical proficiency is established, which is very often required by regulatory bodies (for example, within the framework of the product approval process).


Summary

The accreditation of EMC test laboratories around the world becomes more important with the globalization of trade and the proliferation of electronic and electric products in all aspects of life. Regulatory authorities in many countries have changed product approval processes for various product categories and now allow manufacturers to determine and declare product compliance with applicable standards. Furthermore, qualified EMC test laboratories can now test products in accordance with foreign requirements/standards and prepare test reports that serve as the basis for product approval in foreign markets. In both cases, EMC test laboratories must demonstrate their technical proficiency to perform these tests and also establish a quality framework that allows testing under repeatable and consistent conditions. The laboratory accreditation process (applied by recognized accreditation bodies), based on the generally accepted standard ISO/IEC 17025, allows test laboratories to obtain this independent determination and documentation of technical proficiency in the technical field of EMC


References

  1. Peter S. Unger, “The Benefits of Laboratory Accreditation”, October 2002.
  2. ILAC Brochure “The Advantages of being an Accredited Laboratory”.

 

Werner Schaefer
is a compliance quality manager and technical leader for EMC and RF/uwave calibrations at Corporate Compliance Center of Cisco Systems in San Jose, CA. He has 25 years of EMC experience, including EMI test system and software design, EMI test method development and EMI standards development. He is the chairman of CISPR/A/WG1 and a member of CISPR/A/WG2 and CISPR/B/WG1. He also is the US Technical Advisor to CISPR/A and a member of ANSI C63, SC1/3/5/6/8, and serves as an A2LA and NVLAP lead assessor for EMI and wireless testing, software and protocol testing and RF/microwave calibration laboratories. He also serves as an ANSI representative to ISO CASCO, responsible for quality standards like ISO 17025 and ISO 17043. He is a member of the Board of Directors of the IEEE EMC Society.
He was actively involved in the development of the new standard ANSI C63.10 and the latest revision of ANSI C63.4, mainly focusing on test equipment specifications, use of spectrum analyzers and site validation procedures.

Werner Schaefer is also a RAB certified quality systems lead auditor, and an iNARTE certified EMC engineer. He published over 50 papers on EMC, RF/uwave and quality assurance topics, conducted numerous trainings and workshops on these topics and co-authored a book on
RF/uwave measurements in Germany.

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