Page 36 - Gi flipbook_May 2019

igem news – yppc

MANAGING WATER INGRESS IN

GAS DISTRIBUTION NETWORKS

By Ben Smith, Senior Engineer for ROSEN and IGEM YPPC 2018 finalist

WHEN WATER ACCUMULATES inside Identify suitable portable equipment configuration of fittings to enable the
gas mains and service pipes it can for moisture measurement safe isolation, bypass, and venting of
restrict the flow of gas and result in low Assess how the investigation of water exhaust gas. A G/23 field trial procedure
pressure and gas supply interruptions ingress events might be supported was developed4. Figure 2 shows the
for customers. IGEM/TD/3 recommends using portable hygrometers and hygrometer system apparatus.
installing syphons at low elevation network analysis
points for the collection and removal Conduct a field trial using a Field trial (Beal, Yorkshire)
of condensate1. However, there is hygrometer to identify locations of A field trial at Beal, in Yorkshire,
currently no approved design for a water ingress/accumulation was conducted using the G/23
polyethylene (PE) syphon. field trial procedure. Customers on
The existing syphons on the gas Hygrometer performance requirements Holygarth Lane, in Beal, have reported
networks are checked manually. There NGN/PM/LC/16 provides guidance on interruptions to their gas supply. The
are no syphons on the gas network that dew point temperature and whether gas distribution network (indicated
are remotely monitored. the result is a wet or dry gas indication with purple lines) that supplies Beal is
A management procedure (NGN/PM/ when using a hygrometer (see Table 1). shown in Figure 3.
LC/16) exists for measuring moisture The ‘dew point’ is the point at which GIS datasets, which include flood
content in the gas network2, however, the gas is 100 per cent saturated with zones, pipe material and elevation, were
it is not within the scope of NGN/PM/ water. This is dependent upon the used in the desktop study (see Figure 4).
LC/16 to locate the source of the water. temperature and pressure of the gas at Following a desktop review, the
The aim of this project was to achieve the point of measurement. section of cast iron pipe located within
the following: The portable hygrometer must meet the flood zone (circled in Figure 4), was
1. Gas moisture content study the following criteria: identified as having a high potential of
To provide a pro-active solution for Capable of measuring the dew point of water ingress. Therefore, six hygrometer
identifying the location of water the gas over the range of -50°C to +15°C test locations were identified with
ingress/accumulation by using GIS Safe temporary installation onto the the aim of locating the point of water
data sets including flood mapping, gas distribution network ingress/accumulation (Figure 5).
pipe material and elevation to Rated for a maximum operating The increase in moisture content
support a strategic local hygrometry pressure (MOP) of 75mbar from test 1 to test 2, and then from test
assessment under the controls of a Enables safe venting 2 to test 3, indicates that the test points
NGN/PMG/233 (G/23) field trial. were approaching the location of water
2. Remotely monitored syphon Desktop study: technology search ingress and/or accumulation. The dry
To provide an efficient means to collect The AMS SADP mini-Ex Portable dew gas at test location 5 indicates that the
and remove water already in the gas point hygrometer is a handheld device water has accumulated at some point
network by designing a PE syphon which was selected for use in the field between test locations 3 and 5.
with remote monitoring capability trial (see Figure 1). A leakage survey was conducted
and to demonstrate performance by on the cast iron pipe section between
installing a prototype syphon under Measurement system configuration test locations 3 and 5. This identified
the controls of a G/23 field trial. Management procedure NGN/PM/LC/16 a leak source and remedial action was
includes instructions on the required planned and carried out.
Gas moisture content study
The aim of the gas moisture content
study was to design and implement a FIGURE 1 AMS SADP MINI-EX FIGURE 2 HYGROMETER SYSTEM CONFIGURATION (SYSTEM ISOLATED)
safe and efficient process for detecting PORTABLE DEW POINT
the likely location of water ingress and/ HYGROMETER
or accumulation in a gas distribution
network with the following objectives:
Define the performance requirements
for the use of portable hygrometers
Conduct a desktop study to compare
the performance requirements with
the performance specifications of
available portable dew point moisture
testing equipment

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IGEMNews_YPPC.indd 1 16/04/2019 19:01