| Metering system validation, if carried
out correctly will reduce exposure to commercial risk
created over time by possible over or under metering of
total energy i.e. volume and heating value. There is a
perception in many quarters that modern "fiscal standard"
metering systems are "fit and forget" black box systems.
This is most definitely not the case. Metering
systems comprise of many separate measurement elements,
all of which are susceptible to calibration drift and
measurement bias over time. In addition, the flow
computer system must be correctly set up and configured to
use the
correct constants and parameters from the outset and
updated as appropriate. |
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| EffecTech are independent gas metering
specialists with a wealth of experience gained from across the
globe. We specialise in performing comprehensive and
regular traceable validations of the entire metering
system. We typically work with large consumers of gas such
as power stations and other energy intensive industries
including gas transmission and LNG terminal operators. |
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| In addition to metering validations we
offer a troubleshooting and consultancy service to
investigate and identify metering errors, lost or
unaccounted for gas and suspected metering or energy
imbalances across plant and hydrocarbon accounting chains. |
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| We also to witness metering validations
as an independent third party where the end user of the
gas does not own and maintain the flow measuring
equipment. |
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| Auditing of metering system maintenance,
preparation of metering validation procedures, training
and mentoring and attending factory acceptance tests (FAT)
as well as advice on metering system design and
specification are other areas where we are able to assist
clients. |
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| Typically a metering validation will include
performance evaluation of the following: |
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 Primary
instrumentation |
Orifice plates
must be inspected, cleaned
and regularly re-certified by an accredited metrology laboratory.
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Ultrasonic flow
meters can be "health checked" in situ by
monitoring various operating parameters. They are also
removed periodically and sent to an accredited
calibration facility for re-calibration with high
pressure natural gas.
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Turbine meters should be monitored for "missing or bad"
pulses. They are also removed periodically and sent to
an accredited calibration facility for re-calibration
with high pressure natural gas.
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|
Secondary
instrumentation |
Differential
pressure (DP), pressure and temperature transmitters must be
checked and
calibrated with certified, traceable UKAS test equipment to a high
standard of accuracy using appropriate and specific
procedures. DP transmitters often have a
"footprint" calibration performed off site by an
accredited calibration facility.
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Flow computer |
Functions
and calculations, e.g totalisation must be tested against
independent off-line calculations to ensure they are
correct. In addition, constants and system data such as orifice plate, pipe sizes and gas composition
dependant factors entered into the flow computer must be
verified.
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Gas analyser |
Such as gas chromatographs
must be checked and tested and the validity of the data
they produce confirmed. EffecTech are world leaders
in providing this service.
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