O F F S H O R E
GRP SHELTERS PROVIDE
ADVANCED PROTECTION
FOR OFFSHORE PROCESS ANALYSERS
Shelters fabricated from glassfibre-reinforced polyester are protecting gas metering instrumentation from
the harsh North Sea environment on an offshore platform upgrade project engineered by Oil & Gas Systems
Limited. Two outdoor shelters - supplied by Intertec Instrumentation - provide lightweight and corrosionresistant
protection for gas chromatograph analysers and process transmitters mounted above new natural
gas export pipelines connecting the platform to an onshore UK terminal. The instrumentation provides critical
monitoring data on gas quality as part of the custody transfer metering system.
This particular platform
upgrade project
presented a number of
challenges, including
the harsh operating
environment of the southern North
Sea, and the space and weight
restrictions of adding the new
facilities onto a working platform.
Metering systems for fiscal,
allocation and custody transfer
applications are a significant part of
the systems integration work of Oil
& Gas Systems (OGS) - which has a
reputation for being able to rapidly
design and build efficient solutions
for complex project requirements.
Glassfibre-reinforced polyester
(GRP) materials were specified to
protect the instrumentation. This
allowed weight to be reduced
significantly compared with metal
shelters. GRP construction also
provided excellent protection
against both the harsh weather
in the offshore location, and the
local environmental conditions.
Intertec Instrumentation was
selected to build the custom GRP
shelters because of previous good
experience of working with the
company on projects, including
shelters and enclosures already
installed in the same gas field.
The lightness of GRP compared
to steel helped to reduce the
size and weight of the metalwork
structure that mounts the shelters
directly above the export pipelines.
The location - in the middle of a
crowded working platform - also
presented access difficulties. So,
natural ventilation according to IEC
EN DIN 61285 was specified. This
eliminates routine maintenance
visits that would be required with
other shelter ventilation approaches
such as fans or an HVAC system.
To support natural ventilation for
safe operation in the hazardous
environment, Intertec supplied
explosion-proof heaters and
installed louvre panels at the top
and bottom of shelter walls. This
maintains the interior environment
a few degrees above ambient
temperature, and ensures an
efficient convection cycle to meet
the air change requirements of
OGS. All of the shelter fittings, apart
from the finned aluminium bodies
of the heaters, are fabricated from
316 stainless steel for corrosion
resistance - including the panic bar
door opening mechanism.
"It can be a significant challenge
to add new facilities into existing
processing plants, and especially
so when they are located offshore,"
says Anthony Dingle, OGS's sales
manager. "Intertec's ability to
design and build custom enclosure
solutions was a big help to us in
meeting the design constraints of
this complex and fast-track offshore
instrumentation project."
34 February 2020