Page 17 - Gi_October2021

To identify and quantify safety
related issues which may need to be
resolved, DNV, the independent energy
expert and assurance provider, was
commissioned by Norway’s Defence
Research Establishment and the Public
Roads Administration to conduct a
series of experiments investigating the
behaviour of large releases of LH₂ into
the atmosphere and in a closed but
ventilated area.
The build and operation of
the experimental facilities at
DNV’s Spadeadam Research and
Development Centre in Cumbria, UK,
delivered a programme of research
pertaining to the outdoor and confined
leakage phenomena.

EXPERIMENTAL ARRANGEMENT A HYDROGEN ELECTRIC FERRY
A total of 15 large releases (up to
-1
50 kg/min ) from a liquid hydrogen ELEVATED CAMERA
storage tanker were performed with POSITION
variations in source tanker pressure,
30m X 30m
flow rate, orientation, ignition, and CONCRETE PAD
atmospheric conditions.
The outdoor releases were initially
illustrated using predictions from PIPEWORK
DNV’s GasVLE, FROST and Phast ARRANGEMENT
software packages to analyse the
expected behaviour for: RELEASE OBSTACLES
Outflow - assessments of the mass POINT
flow versus pipeline and outlet
conditions are made including
assessments of the level of flashing
(liquid mass fraction) within the pipe
Pooling - measurements of ground
surface and subsurface temperature
around the releases were made and
interpreted for the presence of liquid
hydrogen or condensed products of air
Dispersion - determination of the
extents of the flammable limits near EXPERIMENTAL ARRANGEMENT FOR OUTDOOR RELEASES
to ground level from each release
Thermal properties - thermal
radiation measurements recorded
around each ignited release are VENT STACK
interpreted against simple models
and existing correlations and
guidance for hydrocarbons.

Bulk LH₂ delivery was from a bulk ADDITIONAL TANKER VENT STACK
tanker located in a protective mound SHELTER SUPPORT
at the test site, which included a tall
camera tower equipped with wind
instrumentation. A 30x30m concrete 3
pad was constructed to contain the 30m TEST
release arrangement. This incorporated ENCLOSURE
a 40m vacuum insulated pipe with
instruments to analyse temperature
and pressure conditions, the release
point was located in the centre of the
900m2 concrete pad. Some obstacles in PIPEWORK
the form of ISO containers and smaller ARRANGEMENT
infrastructure were located on the test ENCLOSURE
pad. The release of LH2 was directed SIDE VENT

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