While Underwriters Laboratories Inc. (UL) is respected as an independent, not-for-profit organization providing global testing and certification services, it is also a world leader in standards development. Through more than a century of involvement in standards and conformity assessment, UL is recognized for its unrivaled technical expertise in the areas in which it develops standards. UL's safety standards are used throughout the world to evaluate and certify products and systems for the U.S. market. UL's standards continue to be used as a basis for harmonization with other international standards. This article provides information on UL's harmonization philosophy, a discussion of the international harmonization process, and a brief description of the role of national differences in the United States.

UL's Harmonization Philosophy
The future of UL as a standards developer will rely on keeping pace with emerging technology, anticipating new challenges and market demands, responding with flexible and efficient processes for developing standards, and remaining committed to UL's mission of public safety. A key ingredient in UL's future is the company's commitment to international harmonization.

Since the market has become more global, many U.S.-based manufacturers distribute products in Canada, Europe, Asia and other international locations. Similarly, products manufactured in other countries increasingly are being made available in the United States. This means that these global products must meet the requirements of multiple countries, and, specifically, multiple safety standards. The promulgation of multiple standards has resulted in redundant testing, and, in some cases, the need to manufacture different products as a result of conflicting or mutually exclusive requirements.

UL has recognized the manufacturers’ dilemma, and has supported harmonization efforts to minimize redundant or conflicting standards where strong support for such harmonization exists. UL's primary focus with respect to harmonization is international harmonization. Typically, international harmonization implies the adoption of an International Electrotechnical Commission (IEC) or International Organization for Standardization (ISO) standard, with a minimum of national differences. International harmonization could also mean the propagation of a UL Standard, as a proposed IEC or ISO standard, where none existed previously.

International Harmonization Process
The process for developing and publishing an IEC-based UL standard consists of the following basic steps, many of which are conducted with the help of a harmonization committee:

• Identifying an IEC standard of interest;
  
• Determining strong Standards Technical Panel (STP) and
  constituency support for the harmonization effort;
  
• Securing the rights to the IEC standard in the United States;
  
• Identifying those national differences that must be retained in order to address key U.S. installation code requirements, U.S. component requirements, or requirements essential to the U.S. safety system;
  
• Proposing the IEC standard and the national differences as the UL Standard through UL's standards development
  process;

U.S. National Differences
Harmonization efforts often involve the difficult task of addressing differences between the standards being harmonized. Differences in national codes, laws, and practices may result in certain national differences from the IEC version. UL places importance on keeping the national differences incorporated in an IEC-based UL Standard to a minimum.

There are five types of national differences, based on the following considerations:

• U.S. National Electrical Code (NEC) and other U.S.
  Regulatory Requirements;
  
• Basic safety principles and requirements;
  
• Safety practices;
  
• Component requirements; and
  
• Editorial comments or corrections.

In addition to attempting to minimize national differences as it publishes new IEC-based UL Standards, UL also places an emphasis on the need to reduce national differences in existing IEC-based UL Standards. This reduction can be accomplished by either identifying and removing those national differences that are not critical to the U.S. standards system, or by proposing revisions to the IEC standard, thereby eliminating the need for the national differences in the U.S. version. The goal is to minimize national differences to the greatest extent possible without compromising safety in the U.S.

Conclusion
International harmonization remains an important aspect of UL standards development. Where harmonization has proved to be a viable option, UL will continue to support international harmonization, and UL will continue to identify ways to minimize national differences in the currently published IEC-based UL Standards. Additionally, UL will continue to encourage the participation by interested parties around the globe in the UL standards development and harmonization process. By including diverse views on UL's Standards Technical Panel, the end product will be a more globally accepted document.