Hydrogen Fuel Standards Progress at ISO Meeting
The fifth plenary meeting of the International
Standards Organization’s (ISO) Technical Committee 197 and parallel
meetings of three ISO working groups were held 26-28 June 1996, in Stuttgart,
Germany.
A proposal by Daimler-Benz Aerospace Airbus—part
of the German delegation—for a new work item on an Airport Hydrogen
Fueling Facility was accepted. The use of hydrogen as a fuel for aircraft
instead of a hydrocarbon fuel will affect many of the standards currently
used in the industry. Target date for use of the international standard
is December, 1999.
This work item, introducing standards for the
use of hydrogen at airports and on aircraft, is being modeled on existing
ones for kerosene fueling facilities. The standards most directly affected
are the Federal Airworthiness Standards for Transport Category Airplanes
(FAR Part 23/25), Airworthiness Standards for Aircraft Engines (FAR Part
33), and the National Fire Protection Association documents for Aircraft
Fuel Servicing (NFPA No. 407) and Aircraft Fuel System Maintenance (NFPA
No. 410C).
The U.S. delegation announced its intention
to submit formal proposals for three new work items related to the use of
gaseous hydrogen: fuel tanks, fueling stations, and connectors. It was agreed
to eventually establish three new working groups upon approval of these
proposed work items. Project leaders will be confirmed at the same time
the proposals are forwarded to the technical committee for voting. The NHA
is leading these proposals.
H2 Product Specifications
ISO Working Group 3 reviewed a working draft
(WD) of product specifications for hydrogen fuel. The purpose of this standard—which
would apply to all modes of transportation and hydrogen fueling applications
(ground, water, air, and space)—is to describe the quality characteristics
of hydrogen fuel and to assure uniformity in the quality of the hydrogen
produced and used.
In the working draft, gaseous hydrogen (GH2), for the purpose of this international standard,
is defined as hydrogen that has been produced to gaseous form typically
by any number of methods—including petrochemical, thermochemical, solar,
electrolytic, or biological processes—and brought to essentially ambient
conditions as an equilibrium mixture of ortho-hydrogen and para-hydrogen
purified to a minimum of 98 mole percent. GH2
is classified as Type I and can be designated as Grade A, B, or C.
Liquid hydrogen (LH2)
is defined as hydrogen that has been liquefied (i.e., brought to a liquid
state) either by chilling and compression or other means, such as magneto-caloric
effect; it is classified as Type II. Slush hydrogen (Type III) is hydrogen
that is a mixture of solid and LH2 at the
triple-point temperature.
Applications of Hydrogen Fuel
The following information characterizes a representative
application of each type and grade of hydrogen fuel as specified by the
WD. It is noted that suppliers commonly transport hydrogen (especially liquid
transporters) in a higher purity than some users may require. The “lower”
grades of A or B provide less stringent requirements, which may be more
suitable for “captive” systems such as vehicle fleets/common fill
or on-site hydrogen production/use as in industrial complexes.
- Type I, Grade A: Internal combustion engines/fuel cells for
transportation, residential/commercial appliances.
- Type I, Grade B: Industrial use as a fuel such as power generation
or heat energy source.
- Type I, Grade C: Aircraft and space vehicle ground-support systems.
- Type II: Aircraft and space vehicle onboard propulsion and electrical
energy requirements.
- Type III: Aircraft and space vehicle onboard propulsion.
Other parameters covered by the proposed standard
include quality verification, sampling, test methods, safety, and detection.
©1996. All Rights Reserved. A Publication of
the National Hydrogen Association.
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