As AC electricity did in 1893, today, hydrogen has the potential to improve our quality of life and in addition, may solve a wealth of environmental concerns. There is currently a high degree of public interest in hydrogen, however, acceptance of this energy carrier will be based on proof-of-safety in addition to cost and performance concerns. In the former regard, codes and standards are widely recognized as adding value to the marketability of products, both from a buyer’s perspective of safety and from a manufacturer’s desire to show safety conformance while competing on a level playing field with other manufacturers.

To date, UL has published 886 standards, of which 431 are a joint effort between the American National Standards Institute (ANSI) and UL. Recently, UL has begun the process of developing an ANSI safety standard for hydrogen generators using its Standards Technical Panel (STP) method. The STP is an ANSI-balanced consensus body composed of participants from industry, regulatory agencies, government, consumers, etc. that are selected for their knowledge and experience in a particular product field. The STP process is a method of creating and maintaining a UL/ANSI standard where each proposed draft goes through a consensus review before it is adopted and published.

Hydrogen Generator Standards – Similarities and Differences
In the past few years, the need to quickly generate new standards for hydrogen and fuel cell technology has increased substantially, stretching intellectual and financial (primarily travel) resources thin. In this regard, any duplication of efforts should be eliminated whenever possible. Although this is a worthy goal, it is frequently a challenge to determine whether duplication has occurred. This is certainly true of the present hydrogen generator standards. The table below indicates four current standards activities that are also at four different stages of development by different Standards Development Organizations (SDO’s). This table represents a fair and current snapshot of each standard’s technology coverage and exclusions, although two of them, UL2264 and ISO TC197 N238 are at relatively early stages of development.

Table 1. Hydrogen Generator Standards Comparison

Standard	SDO	Coverage	Exclusions
UL2264	UL	· Electrolysis [1] · Water reaction (e.g. sodium borohydride) · Fuel-processing	· Systems above 600 V. · Systems that can also produce electricity. · Gaseous phase fuel feedstocks other than natural or methane gas mixtures.
CSA Req. 5.99	Canadian Standards Association, America (CSA America)	· Hydrogen generators using chemical reactions or other processes.  Note: This document anticipated use for fuel processing technologies as described in para. 1.2.1.	· Fuel feedstocks other than natural gas or liquefied petroleum gas.
WD 22734.4	ISO TC197 - WG 8	· Electrolysis (see footnote 1)	· Residential generators. · Systems that can also produce electricity.
N238	ISO TC197: WG 9	· Fuel-processing	· Systems with a capacity over 500 Nm3/hr (final value to be determined) · Systems that are not stationary/ fixed.

As indicated in Table 1, UL2264’s coverage touches upon similar activities in each of the other remaining standards with the following exceptions:

1. Water reaction technologies are not currently being covered in any other standard.
   
2. WD 22734.4 is not presently covering electrolyzers intended for residential application.
   
3. CSA Requirement No. 5.99 does not currently cover fuel-processing technologies that use methane and methane gas mixtures; petroleum-derived liquids such as kerosene, diesel and gasoline; and methanol or ethanol.
   
4. UL2264 currently does not restrict generator capacity or device portability as in N238.

A final difference is that UL2264 is alone in the restriction of supply voltages to 600V or less. This limitation reflects the National Electrical Code (US) requirements, which change considerably for systems rated at higher voltages. 

Future Direction
UL promotes international harmonization efforts and recognizes the need and value of aligning UL2264 to the efforts currently underway in ISO TC197 Working Groups 8 and 9. As a principle, we are also actively engaged in this and other Technical Committees with ISO and the International Electrotechnical Commission (IEC) to promote international implementation of North American safety practices. In turn, this minimizes the need for national deviations [2] in any adopted international standard. Thus it is a strategy of the STP that UL2264 should use relevant ISO-developed requirements whenever possible, although US installation codes must be incorporated if no equivalent ISO requirement exists.

ISO/IEC Guide 21, Adoption of International Standard as Regional or National Standard, provides the groundwork from which national adoption of ISO or IEC standards can proceed. In a very abridged sense, Guide 21 requires that the structure of the international standard reflect the national standard and be either identical in content or modified to include such things as national deviations. For the specific case of UL2264, the fundamental structure of this document includes three hydrogen generation technologies, whereas ISO TC197 WG’s 8 and 9 cover a single technology in their respective working documents. As a result, UL is considering division of the UL2264 standard into three documents that will separately cover electrolyzers, water reaction and fuel processing hydrogen generator technologies. Such a proposal will require formal STP review and approval, but the distinct advantage is that it will allow for future North American adoption of the relevant ISO standards.

If the STP approves this division of UL2264 into three documents, a potential exists to speed the development of an ANSI standard for hydrogen generators using fuel-processing technologies. CSA’s Requirements No. 5.99, as identified by the Hydrogen Codes and Regulations Matrix, is a “specification for developing standards for hydrogen generators.”(1) It specifically sets forth requirements for the evaluation of generators that employ fuel-processing techniques and, therefore, could advance the development of the ANSI/UL standard for this technology. As a result, it is being proposed that UL and CSA work jointly to speed development of a national fuel-processing technologies standard. This will ensure the fastest completion of this effort.

Another aspect of ISO/IEC Guide 21 is the possibility of adopting an international standard with modifications where “the regional or national standard adds aspects or types, has more stringent requirements, includes additional tests, etc.”(2) This allows for the possibility that the international electrolyzer standard could be adopted by ISO or IEC with added requirements for residential-type generators. Certainly, such a modification would have to proceed with thoughtful deliberation that aligns with the intent of the ISO document, but goes further to contain the necessary national installation code requirements that will be needed for a residential hydrogen generator.

As mentioned earlier, there is no present international equivalent for water reaction hydrogen generators. As a result, this portion of the UL effort will proceed on course as an ANSI/UL standard. If industry interest in this technology warrants, a new work item proposal with ISO TC197 should be considered.

UL believes that the strategy outlined above will provide manufacturers with the fastest domestic access to hydrogen generator standards without compromising future potential adoption of the ISO TC197 work. Further, discussion has begun with CSA America on the topic of collaboration on fuel-processing standard development. The next step will be to obtain concurrence with the STP and then begin to develop the three separate documents.

[1] Electrolysis, as mentioned here, pertains only to electrolysis using aqueous base ion transport or solid polymeric materials with acidic group function additions.


[2] A national deviation specifies practices required for safety in the region of adoption. 

Reference
ISO/IEC Guide 21, “Adoption of International Standards as regional or national standards”, 2nd Ed, 1999.