NHA NOTES

Codes and Standards Update


by Karen Miller, Program Manager, National Hydrogen Association

The NHA held a Codes and Standards Workshop on 16-17 July 1998 in the NHA office in Washington, D.C., U.S.A. Sixteen members and experts attended to discuss ongoing work items and identify new potential work items.

The status of the existing work groups follows.

NHA Work Group 1: Connectors

A draft standard has been submitted to ISO/TC-197 for consideration as an ISO [International Standards Organization] Work Item. The committee recommendation on the next steps for this activity is to continue working with ISO to develop an international standard, and to concurrently validate and certify manufacturing testing procedures. This certification process should take one year, once funding is available.

Sherex OPX, the manufacturer of the hydrogen connectors being used worldwide today in demonstrations, is looking for a cost-share partnership for the costs of independent certification. No further action is required of NHA WG1, other than working within the ISO structure, assuming the item is accepted by the ISO.

NHA Work Group 2: Tanks/Containers

This item has been accepted by ISO and is in need of experts to serve as delegates to lead this effort. A discussion of the refueling station of the future brought out a need for smart cylinders (i.e., the tank must tell a fueling station what it is for proper refueling). This could reduce safety issues associated with the public using a refueling station which dispenses hydrogen, natural gas, and gasoline, as well as differences in fuel pressures. It was agreed that this issue may merit development, but that it is outside the scope of the existing work group.

Another safety issue relating to tanks which was discussed is the need to get data on the integrity of the tank degradation. The thinning needs to be known to assess loss of strength. There are many nondestructive techniques used to measure tank and cylinder wall thickness. Issues to be resolved are: who would perform the inspection, how often, and would it be onboard the vehicle or off line. Again, while these issues are important, they are outside the scope of this work group. The Society for Automotive Engineers (SAE) and the American Society for Nondestructive Testing (ASNT) may be able to have a role in addressing these issues.

NHA Work Group 3: Refueling Stations

This item has also been accepted by ISO and is in need of experts to work on that effort. The NHA is also still working with the NFPA [National Fire Protection Association] to enable siting of hydrogen refueling stations. Building code officials in the U.S. will likely require NFPA documentation.

Work must continue on other issues related to siting. According to Dave Conover of the Pacific Northwest National Lab, reforming of natural gas to hydrogen in building codes makes it a hazardous hydrogen production facility. This type of zoning problem needs to be addressed. Coordination with building codes, CNG [compressed natural gas] folks, model building codes (IBCO, ICC, BOCA), and fire marshals are a must for siting hydrogen refueling stations on public property.

Other C&S Issues

Other codes and standards issues raised at the workshop follow.

The NFPA has started a multifuel group and is considering retiring NFPA 52 to include alternative fuels. Working Group 3 in NFPA 52 is now Alternative Fuels. Even within NFPA, NFPA 32, 52, and SOA will have to coordinate to enable a multifuel service station (for customer convenience). NFPA 32 now is for liquid fuels; NFPA 52 is for gaseous fuels only.

The hydrogen community is developing experience in conjunction with the development of codes and standards. Steve Lelewer of Bechtel Nevada presented a diagram of a proposed refueling station in Nevada. It will be sited at DOE North Las Vegas off a natural gas line. It will use reformation, clean up the gas, and provide excess capacity to the refueling station. This activity is a 50/50 cost share and, because it is on government land, it is exempt from state and local building codes. The Nevada Test Site (NTS) is already working with the local fire marshal, who is enthusiastic about the effort. The facility is near an access point of the site, 65 miles from NTS. This will allow use by neighboring hydrogen fleets in the future.

The NHA has an opportunity, through a DOE funding request, to validate its draft standards on the Nevada refueling station. This effort could benefit the refueling station project as well as the hydrogen community in general. Lessons learned would then be fed into the work groups which are developing these draft standards, such as ISO/TC-197.

Allan Coutts, chairman of NHA WG3 and a participant of NFPA Alternative Fuels Vehicles Committee (NFPA 52, 58), discussed the ongoing issue of hydrogen leak detection. Both detectors and odorants are proven to work with natural gas. There was a discussion about which is best for hydrogen. The committee wants to allow the choice where practical; however, there is concern that an odorant could pollute a fuel cell. In addition, there is no known case of any odorant working with hydrogen.

Matti Mikor of Ford admitted that the diffusion rate of hydrogen is faster than any other gas. Ongoing work by Michael Swain at the University of Miami shows adequate mixing. Bob Zalosh of Worchester Polytechnic Institute expressed that there are issues about the extent to which can you obtain adequate mixing of odorant and hydrogen. Scrubbing of mercaptans would also be an issue.

Hydrogen detectors are commercially available now, and have been shown to provide a superb level of reliability. The group considered a standard specifying a minimum level of detection, such as:

The group agreed that the market should decide the odorants versus sensor issue.

Bob Zalosh discussed ventilation issues for indoor hydrogen storage and dispensing facilities. The introduction to his report, “Hydrogen Ventilation and Deflagration Venting Analysis for Indoor Storage and Dispensing Facilities,” is excerpted.

The group discussed the results of the NHA membership-wide poll on new work items the NHA should consider. The candidates under consideration are:

It was agreed that none would be ruled out at this juncture. Instead, the workshop participants took action to prepare a justification page for each proposed work item, with a recommendation for whether the NHA should lead this work item, participate but have another agency lead, or not pursue it at this time. These results are being reviewed by the Codes and Standards Committee, and will be published in the workshop proceedings, to be available in late Fall.

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