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Scottish Government
GB/610
August 2019
Buchanan and St Ambrose High School Campus
Technical Report by Dr G B Card
BUCHANAN AND ST AMBROSE HIGH SCHOOL CAMPUS Technical Report by Dr G B Card
GB/610 1 | P A G E
CONTENTS
1. INTRODUCTION 2
1.1 Qualifications and experience 2 1.2 Instructions and background 2
2. ANSWERS TO SPECIFIC QUESTIONS 4
2.1 Question 1 4 2.1.1 Purpose and function 4 2.1.2 When would it typically be installed? 5 2.1.3 Why would it typically be installed 6 2.1.4 Installation details 8
2.2 Question 2 10 2.2.1 Site context 10 2.2.2 What is meant by Characteristic situation 4? 10 2.2.3 Gas protection design 12
2.3 Question 3 16
3. CONCLUSIONS 17
APPENDICES A. Worst credible gas screening values
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1. INTRODUCTION
1.1 Qualifications and experience 1. I am Dr Geoffrey Bernard Card. I am a Chartered Civil Engineer and a Director of
GB Card & Partners Limited, a consultancy specialising in civil, geotechnical and
geo-environmental engineering design and construction.
2. I have some 45 years of experience in land reclamation and regeneration projects
including redevelopment on contaminated land and landfill sites such as former
industrial and petrol-chemical works, gas works, areas of mining. I have expertise
in the assessment of hazards from landfill gas and associated gases in the ground
together with design of appropriate protection measures to allow safe development.
3. I am author of several guidance documents regarding hazards on contaminated
land for the NHBC and gas protection to development for BRE (Report 414) and
CIRIA Report 149). I was Chairman of CIRIA publication C665 ‘Protection Systems
for Buildings against Hazardous Ground Gases’ and advisor to British Standards
(BS: 8485), National and Local Government with respect to contaminated land
policy including landfill gas.
4. I have been responsible for design and installation of ground gas protection
measures for public buildings including schools constructed on landfill. Recent
projects include (1) the National Autistic School, Chigwell, Essex which was
constructed on a former municipal landfill in 2017 and (2) Erith Hills Primary School
also constructed on a gassing landfill.
1.2 Instructions and background 5. The Scottish Government, following consultation with North Lanarkshire Council
and NHS Lanarkshire, have asked Paul Cackette, the Scottish Government Chief
Planning Reporter and Dr Margaret Hannah, Former Director of Public Health to
undertake an independent review of the evidence in relation to the reported health
and safety concerns at Buchanan and St. Ambrose High School campus including
the history of construction and maintenance of the site.
6. I have been requested by Paul Cackette and Dr Margaret Hannah to assist in their
review and provide an opinion on the installed gas protection measures and
specifically the gas membrane at the school campus.
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7. I have been requested to address a number of questions regarding the gas
protection measures at the school campus and my responses are set out in Section
2 of this report.
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2. ANSWERS TO SPECIFIC QUESTIONS
2.1 Question 1 Understand in general terms the purpose, specification and public safety security features of methane membranes used for purposes such as those in the present case
2.1.1 Purpose and function
8. A gas membrane is installed within a building to provide a low permeability barrier
against the ingress of gas from the ground into the building fabric and indoor air
space. The membrane usually comprises a synthetic sheet or strip of material
placed within or beneath the ground slab and walls of a building to form an integral
barrier across the plan area of the structure. The low permeability of the membrane
resists the flow or diffusion of gas which instead is encouraged to migrate and
disperse in a safe and controlled manner to atmosphere on the outside of the
building.
9. Usually passive or active venting is used to dilute and disperse gases beneath the
ground slab of a building. The type of under slab ventilation is a function of the gas
regime as well as method of construction of the ground slab and foundations.
10. A wide variety of membranes are available with different properties and
performance characteristics. The most common materials used in membranes for
ground gas protection in the UK are :
a) Flexible polypropylene (FPP);
b) High density polyethylene (HDPE);
c) Low density polyethylene (LDPE) or linear low-density polyethylene (LLDPE);
d) Reinforced LDPE with an aluminium core;
e) HDPE reinforced polypropylene (FPP) with an aluminium core;
f) HDPE/ethylenevinylalcohol (EVOH)/HDPE-sandwich; and
g) Spray applied asphalt-latex membrane (bitumen/polystyrene emulsions).
11. The most suitable type of gas membrane for a site will depend on the level of risk
and the installation environment and should take account of the material in question
(virgin polymer), its permeability to the nature and composition of the ground gas,
its physical properties and puncture resistance.
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12. The permeability of a membrane to gas is extremely low. Typically, the
transmissibility of a gas membrane to methane is of the order of 10-10 to 10-13
m3/m2/s (at 1 atmosphere). British Standard BS8485:20151 for design of gas
protection systems in new buildings states that a membrane with a methane gas
transmission rate of less than 40.0 ml/day/m2/atmos (average value, equivalent to
4.6 x 10-10 m3/m2/s) for sheets and joints (tested in accordance with BS ISO
15105‑1:2007 manometric method) is regarded as sufficiently impervious and
adequate to act as a low permeability gas membrane.
13. Preventing damage to the membrane during placement and correct installation is
critical in the performance of the membrane. Studies show that once the membrane
has the slightest puncture (1mm diameter) the rate of gas flow into an overlying
room will increase by a factor of over 12 million times2.
14. The membrane should be installed, and joints and services sealed in accordance
with manufacturer’s instructions. Complex structural forms require good detailing
and careful installation of membranes to ensure they are gas tight. A membrane
function is to prevent gas ingress through the building fabric via such features as:
a) Porous construction materials;
b) Construction joints and openings;
c) Shrinkage cracks;
d) Service entry points.
2.1.2 When would it typically be installed?
15. Gas membranes are only one type of gas protection system that can be used to
ensure that ground gas does not enter the building fabric and/or the indoor air
space. Their use is not obligatory, but they are a common component of any gas
protection system in a building because they are often used as a combined gas and
damp-proof membrane to also prevent condensation affecting the building fabric.
Furthermore, where block and beam suspended ground floor construction
techniques are adopted there is a high risk of gas entry points. In these
circumstances a gas membrane is an effective and economical way to seal the slab
particularly if it is combined as a damp-proof membrane.
1 BS8485:2015+A1:2019. Code of practice for the design of protective measures for methane and carbon
dioxide ground gases for new buildings. 2 Wilson, SA., Card, GB. and Haines, S. (2009). Ground Gas Handbook. Whittles Publishing.
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2.1.3 Why would it typically be installed
16. The requirement for gas protection measures is determined from a thorough
assessment and characterisation of the site and follows guidance published in
BS8485:2007 (with updated in 2015 and 2019) and CIRIA Report C665 (2007)3 and
C7354. The first step in the assessment of a site affected by ground gas is to
construct a conceptual site model (CSM) from information acquired from a desk
study and ground investigation. The CSM includes (1) ground conditions below a
site, (2) all potential sources of ground gas or vapours, (3) all potential migration
pathways, (4) all potential receptors and (5) any natural barriers to gas migration.
17. An appropriate period of gas monitoring is undertaken at the site for example this
can range from four visits over one months for a low sensitivity development on a
site with very low generation potential of source, to 24 visits over 24 months for a
high sensitivity development on a site with a very high generation potential of source
(CIRIA Report C665). It is also important that a range of different atmospheric
pressures are targeted by the monitoring, including low and falling.
18. From the monitoring data a borehole hazardous gas flow rates (BHGFR) are
calculated for each gas monitoring borehole as described in BS8485. The (BHGFR)
are calculated by multiplying the maximum flow rate (l/hr) by the maximum gas
concentration (%) (steady state or average values can be used in some
circumstances). From this data, together with other factors such as development
layout and location relative to the monitoring points a gas screening value (GSV) is
derived. The GSV is then compared to the Characteristic situation, a series of
criteria from CS1 to CS6 where CS1 represents a site where no gas protection is
required to CS6 where building development is not appropriate without source
removal of the gas. Table 1 below is taken from BS8485 which sets out the GSV’s
and Characteristic situations for gas protection requirements to new building
development.
19. The required scope of gas protection for type of development and gas regime is
determined from BS8485 from a scoring system. This is shown in Table 2. The
designer of the gas protection system can select what gas protection components
best fit for the type of construction and setting of the development.
3 CIRIA (2007). Assessing risks posed by hazardous ground gases to buildings. Construction Industry
Research and Information Association, London, UK. 4 CIRIA (2014) Report C735. Good practice on the testing and verification pf protection systems for buildings
against hazardous ground gases. Construction Industry Research and Information Association, London, UK.
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20. Typically, for Characteristic situations CS2 to CS4 a gas membrane will typically
be incorporated into the building gas protection design as it is an effective way to
meet the scoring requirements for gas protection set out in BS8485.
Nevertheless, it is not obligatory that a membrane need be used if the designer is
able to justify a different protection system that will have an equivalent score and
satisfy the requirements of BS8485.
Table 1: Characteristic situation and GSV’s (from BS:8485:2015)
Table 2: Characteristic situation and scoring for gas protection (from BS:8485:2015)
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2.1.4 Installation details
21. Figures 1 to 4 are taken from CIRIA 7355 and are examples of good membrane
installation.
Figure 1: (a) Gas membrane lapped and taped; (b) Prefabricated corner detail
Figure 2: (a) Installation of preformed “top hat” around service entry ducts; (b) good detailing around stanchion
5 CIRIA (2014). Good practice on the testing and verification of protection systems for buildings against hazardous ground
gases. C735.
(a) (b)
(a) (b)
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Figure 3: Membrane installation and welding of seams
22. Guidance on verification of the gas membrane installation is well documented and
widely practiced. CIRIA Report C735 provides good practice guidance for the
verification of gas membranes and this documented is also referenced in
BS8545:2015. The guidance, however, is focused on the verification of membranes
at the time of installation rather the verification or checking membrane integrity at
any time in the future.
23. In my experience the integrity of an existing membrane can be undertaken by using
a smoke or tracer gas (such as sulphur hexafluoride, SF4) that is introduced into the
space beneath the slab. A gas detector is then used to check for smoke of gas
inside the building and in confined spaces or near service entry points and ducts in
the floor slab.
24. It is also good practice to install a gas alarm with the gas protection system to
monitor the performance of the system. This is common in public buildings or
buildings with an onsite management service team. As described in paragraph 41
the trigger of an alarm does not mean that there is an immediate risk from ground
gas, such as an explosion from methane or asphyxiation from carbon dioxide. An
alarm will be set to trigger to detect the presence of ground gas and/or a warning
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that the ventilation system or gas monitoring sensors require maintenance or
servicing.
2.2 Question 2 Understand the answers to the foregoing questions under reference to the membrane installed at this site based on key documents enclosed.
2.2.1 Site context
25. The ground conditions are summarised in the 2010 Ramboll report6 as follows ‘the
geology underlying the site is understood to comprise Made Ground including
topsoil overlying probable landfill material up to a maximum depth of 8.45mbgl. No
significant capping layer is present above the probable landfill material. Underlying
the Made Ground are superficial deposits of peat, glaciolacustrine clay, silt and
sand and glacial till to a maximum depth of 23.2mbgl. These superficial deposits
overlie the solid geology of the Middle Coal Measures, reported at depths
between 7.40mbgl and 23.20mbgl and comprise sandstone and mudstone with
occasional bands of coal. The site is underlain by several coal seams, some of
which have been historically mined by shallow workings. In addition, mine shafts
have been identified in and St. Ambrose Ground Contamination Risk Assessment
Report.’
26. There have been three main phases of investigation relating to ground gas.
These are;
a) 2006, three boreholes, monitored on four occasions;
b) 2008, 25 boreholes, monitored on 19 occasions during 2008 and 2009;
c) 2009, seven boreholes, monitored on 4 occasions (awaiting data).
27. The response zones of the monitoring wells were either within the Made Ground,
peat or silty/sandy clay or a combination.
2.2.2 What is meant by Characteristic situation 4?
28. Characteristic Situation 4 (CS4) is indicated by a GSV of over 3.5l/hr and less than
15l/hr represents a ground gas regime as “moderate to high risk” as stated in
BS8585 and shown in Figure 1. It is typified by a gas regime from mine workings
and closed landfills of typically greater than 25 years of age. In order to evaluate
6 Ramboll (2010). St Ambrose. Ground Contamination Risk Assessment Report. February 2010.
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the scope of gas protection measures required for a development on a site
designated as CS4 a quantitative risk assessment is required.
29. I agree with the statement made by Ramboll 20097 that the ‘worst case results
from all available data would classify the site as Characteristic 4’. This can be
calculated by taking the maximum concentration of methane (75.4% recorded in
borehole S210/RBH210 on the 29/4/2009) and the maximum flow recorded (16.2
l/hr recorded in borehole BH402) which gives a GSV of 12.2l/hr and Characteristic
situation of CS4.
30. I consider that using this worst possible approach to calculate the GSV is very
conservative especially based upon the large data set available. I have assessed
the data based upon the worst credible approach. This is achieved by calculating
the GSVs directly for each set of gas monitoring readings. The GSVs calculated
for each monitoring reading are presented on Figure 3 as well as the boundaries
for CS1, CS2 and CS3. The locations of the monitoring boreholes and GSV
distribution is also shown on the drawing in Appendix A.
Figure 3: Methane gas screening values
31. The worst credible GSV for methane is 1.12l/hr (CS3). The majority of the GSVs
calculated are within CS1, as indicated in Figure 4, suggesting no gas protection
measures are required. There are three boreholes, however, where the GSV was
7 Ramboll (2009). Ground contamination risk assessment report. Rev 1A, dated 26 November 2009, Ref:
5311.E.GQRA.1A
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identified to be within the CS3 range during one or more monitoring visits, these
were boreholes S304, S305 and S308. It’s understood that these boreholes were
undertaken as part of the investigation of the periphery of the site for the hard-
standing, sports pitches and landscaping areas associated with the school
campus and are not located beneath any building or structure.
32. From the ground gas monitoring data that I have reviewed I consider that the
adoption of a characteristic situation CS4 is over conservative for the gas regime
identified. In my opinion a gas regime of CS2 to CS3 is appropriate.
Figure 4: Assessment of worst credible GSVs
2.2.3 Gas protection design
33. The architect’s drawings provide details of the gas protection measures to be
installed. These are:
a) Cast-in-place reinforced concrete slab
b) A damp-proof and gas membrane
c) Active venting layer
d) Hardcore
An extract of the typical ground floor make-up drawing is shown in Figure 5.
0
50
100
150
200
250
300
350
400
CS1 CS2 CS3
Num
ber o
f occ
uren
ces
Characteristic Situation
Assessment of Worst Credible GSVs (CH4)
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34. I consider that the gas protection measures as shown in Figure 5 are more than
adequate for the gas regime identified at the school campus. Comments on the
individual components are described below:
35. The membrane specified on the drawing is a proprietary gas impermeable
membrane manufactured by Visqueen. It has a BBA Certificate 13/5069 and CE
Mark 13967:2012 . In my experience it is a product widely used in the building
industry for ground gas and radon protection to buildings. In this project the
membrane is designed to be below the concrete slab and laid on a sand blinding.
In my experience the location and detailing of the membrane is common for
structural slabs of this nature and I have also designed a similar detail for the
National Autistic School , Chigwell, Essex and Erith Hills Primary School, Erith,
Kent.
36. Based on the gas protection that has been specified for the school buildings, I
consider that the gas protection score total is 5 to 6 as set out in Tables 5, 6 and 7
of BS8545:2015. The required score to be attained in Table 4 of BS8545:2015 is
5.5. In my opinion the gas protection measures installed satisfy the requirements
of BS8545:20158, albeit I consider that a characteristic situation of CS4 that has
been adopted is overly conservative for the reasons I state in paragraphs 30 and
31 of this report.
8 At the time the school buildings were constructed BS8486:2007 would have been the current document.
Table 2 of this document requires a gas protection score of 5. The gas protection system is therefore compliant with the British Standard current at the time of design and construction.
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Figure 5: Typical ground slab make up (from JM Architects drawing A(I)I202 Rev C)
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37. The ground slab is a cast-in-place reinforced concrete slab and will have been
designed to current UK engineering standards. There will be minimal construction
joints and although not shown all ducting through the slab will be cast into the
slab.
38. In addition to the gas membrane and concrete slab an active gas venting system
has also been specified to remove and ground gas beneath the ground slab. The
active ventilation system has a gas detection and fan control system for methane
and carbon dioxide. Commissioning records have been provided and are dated
16th March 2012 to 8th March 2012. The manual for the system states that
‘maintenance of this system is essential to ensure reliable operation. The system
utilises mechanical components that run continuously, and these require overhaul
on an annual basis and inspection every six months. Maintenance should only be
carried out by a trained technician.’
39. I have not received evidence of any service records after the initial calibration. I
understand the monitoring system alarm has been activated on occasions. The
alarm does not mean that hazardous gas concentrations have been detected
beneath the ground slab. In my experience the alarm to the ventilation system
has been triggered when:
a) a concentration of ground gas reaches a percentage of the lower explosive
limit for methane which is 5% methane in air. It is normal to set the alarm
criteria at <1% methane in air, i.e. at least 1/20th of the lower explosive limit;
or
b) a gas monitoring sensor in the ventilation system Is not working and needs
servicing or requires replacement.
40. Methane and carbon dioxide readings have been provided to me from late 2012
which show a peak methane concentration of 0.43% and a peak carbon dioxide
concentration of 3% in the active ventilation system. These concentrations
confirm non-hazardous gas concentrations detected beneath the ground slab.
41. In order to assess the ongoing effectiveness of the gas protection measures it
would be useful to obtain the current data relating to the gas concentrations
recorded within the void as well as indoor air quality monitoring at various points
throughout the school building including confined spaces such as cupboards.
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2.3 Question 3 Building settlement concerns expressed to the Review that inter-act with points raised about the methane membrane.
42. In theory, any differential settlement between building components such as the
foundations to the school buildings and the ground slab will affect the risk of
membrane failure. In my experience such failures have occurred to the gas
membrane where excessive differential ground settlement has occurred causing
the floor slab to settle relative to the deep foundations which have remained fixed.
43. For the Buchanan and Ambrose school buildings it appears from review of the
architect’s drawings that the buildings are supported on piled foundations. The
piles will have been designed and constructed to transfer building loads to
competent natural ground beneath any Made Ground or Fill and zone of potential
significant ground settlement.
44. The ground slab is designed as a suspended slab such that if the ground
settlement occurs, for whatever reason, the slab will remain fully supported by the
piled foundations and will not deflect or crack. If there is significant ground
settlement beneath the slab there is the possibility that the gas membrane will
also drop resulting in a void being produced between the membrane and the
underside of the slab. For a small degree of settlement, typically up to 100mm,
the membrane will stretch and accommodate the movement. For settlements of
greater magnitude there is the possibility that the membrane will tear along joints
or at fixed points where it is held up by the slab and/or foundation. If this occurs,
then ground gas could migrate to the underside of the slab. The integrity of the
membrane and concrete slab to resist ground gas cab be tested by carrying out a
smoke or gas tracer test as set I describe in paragraph 23 of this report
45. It has been claimed that parts of the school hardstanding areas are “bubbling
upwards” and that this could that be a sign of an accumulation of gas under
pressure forcing the overlying ground and hardstanding to rise. In my opinion this
is not as a result of ground gas accumulating under pressure. This is because the
gas monitoring records to date show no evidence of high gas pressures in the
boreholes. I consider that these apparent “bubbles” are probably the results of
localised settlement in the surrounding Made Ground creating the impression of a
localised area of rising ground at its centre.
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3. CONCLUSIONS
46. Based on a review of the information made available to me my conclusions are as
follows.
47. The ground gas regime as monitored on the site during the period of ground
investigation identified a low gassing regime. Most of the data indicated a
Characteristic situation of CS1 indicating that no gas protection measures were
necessary. Nevertheless, given the history of the site and the presence of Made
Ground and mine workings at depth I concur that a higher Characteristic situation
for design was prudent and was adopted for design. In my opinion a
Characteristic situation CS2 would have been adequate.
48. Notwithstanding my comments in paragraph 47 the ground gas protection system
has been designed for a higher gas regime, CS4. I consider that this is overly
conservative for the gas regime and nature of the development. I consider that
the gas protection as designed, specified and installed is more than adequate to
resist ground gas migration into the building(s) and adversely affect indoor air
quality.
49. The gas protection system and, the configuration and detailing of the membrane,
has been adopted on similar school buildings that I have been involved with which
are built on landfilled sites with no adverse impact on human health.
50. Verification of the current membrane integrity could be confirmed by carrying out a
smoke or tracer gas test. The tracer gas can be introduced beneath the floor slab
and its presence within the school buildings and impact on indoor air quality
identified using a handheld gas detector.
Appendix A
Worst credible gas screening values
SC
SC
SC
SC
SC
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M
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3
m
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3
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3
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M
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a
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R
a
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g
0
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3
m
Rough
Grass
Rough
Grass
Rough
Grass
Rough
Grass
Rough
Grass
Trees
C
h
a
in
lin
k
1
.1
m
C
h
a
in
lin
k
1
.1
m
Rough
Grass
Rough
Grass
Trees
Trees
Trees
Rough
Grass
Grass
Sports Pitch
Sports Pitch
Sports Pitch
Grass
Grass
Sports Pitch
Sports Pitch
Sports Pitch
Sports Pitch
Sports Pitch
Sports Pitch
Sports Pitch
Rough
Grass
Tarmac
Pavilion
M
e
ta
l R
a
ilin
g
0
.3
m
U
n
s
u
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T
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U
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s
u
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f
a
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d
T
r
a
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Mature
Woodland
Tantallon D
rive
Green
Impenetrable
Rhododendrons
Mature
Woodland
Mature
Woodland
Mature
Woodland
Mature
Woodland
Grass
U
n
s
u
r
f
a
c
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T
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a
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a
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m
a
c
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d
T
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rm
a
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R
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Grass
T
a
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m
a
c
R
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a
d
Grass
Grass
BH
BH
BH
BH
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T
a
r
m
a
c
R
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d
T
a
r
m
a
c
R
o
a
d
M
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s
s
p
a
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k
R
o
a
d
Grass
Rough
Grass
Rough
Grass
Grass
Rough
Grass
Rough
Grass
Grass
Grass
Grass
Rough
Grass
Rough
Grass
Grass
Woodland
Woodland
BH
T
a
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m
a
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F
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t
p
a
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ac Footpath
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Grass
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T
a
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m
a
c
F
o
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t
p
a
t
h
Tarmac
Rough
Grass
Rough
Grass
Rough
Grass
Grass
Impenetrable
Rhododendrons
G
r
a
s
s
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
LP
RS
RS
RS
RS
TP
TP
P
P
Stay
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Bol
Bol
Bol
CTV
CTV
CTV
CTV
CTV
CTV
CTV
CTV
CTV
CTV
CTV
CTV
CTV
PB
GV
GV
GV
GV
MP
MP
MP
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TL
TL
TL
ER
2
1
3
4
5
6
7
10
8
9
11
12
11A
13
12A
15
14
16
11B
11L
18
17A
Grass
Grass
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Tarmac
S
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R
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W
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l
R
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3
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h
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Mature
Woodland
Mature
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U
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Grass
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T
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Rhododendrons
G
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SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
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LP
LP
LP
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LP
LP
LP
LP
LP
LP
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LP
LP
LP
LP
LP
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GV
GV
GV
MP
MP
MP
MP
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TL
TL
TL
ER
2
1
3
4
5
6
7
10
8
9
11
12
11A
13
12A
15
14
16
11B
11L
18
17A
Grass
Grass
Grass
Grass
Tarmac
S
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R
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a
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W
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G
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h
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lin
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Impenetrable
Rhododendrons
Mature
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Mature
Woodland
Mature
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Mature
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Grass
U
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T
a
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t
p
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Woodland
T
a
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m
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F
o
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t
p
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t
h
Tarmac
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Grass
Rough
Grass
Rough
Grass
Grass
Impenetrable
Rhododendrons
G
r
a
s
s
GB Card & Partners
23 Southernhay West
Exeter
Devon EX1 1PR
01392 790020
Title:
Date:
Scale:
Drawing No:
Drn:
Chk:
Aprv:
Job reference:
Status:
GB610-DWG-001
02/08/2019
Worst Credible Gas Screening Values
Draft
GB610
GBCBG
LB
1:2500 @ A3
scale 1:2500
0m 160m40 80 120
ID Easting Northing CS Level
RBH201 271522.441 665991.061 CS1 0.0008
RBH202 271456.233 665981.58 CS2 0.237
RBH203 271596.173 665959.277 CS1 0.0084
RBH204 271570.94 665892.015 CS1 0.0372
RBH205 271651.263 665933.496 CS1 0.0037
RBH206 271747.583 665974.994 CS1 0.0002
RBH207 271725.9 665906.514 CS1 0.0002
RBH208 271672.537 665934.513 CS1 0.066
RBH209 271825.877 665864.977 CS1 0.0001
RBH210 271761.712 665890.972 CS2 0.2754
RBH211 271669.022 665878.532 CS1 0.003
RBH213 271808.604 665943.354 CS1 0.0001
SBH301 271462.227 666087.506 CS1 0.0005
SBH302 271466.597 666004.446 CS1 0.0698
SBH303 271507.627 666054.535 CS1 0.0639
SBH304 271489.129 665871.792 CS3 0.9464
SBH305 271480.494 665818.576 CS3 1.1178
SBH306 271618.272 666059.929 CS1 0.0042
SBH307 271632.151 665887.653 CS1 0.003
SBH308 271602.609 665834.804 CS3 0.9324
SBH309 271592.199 665782.854 CS1 0.0168
SBH310 271719.737 665796.972 CS1 0.0002
SBH311 271709.605 665743 CS1 0.0001
SBH312 271868.8 665898.694 CS1 0.0004
SBH313 271796.054 665791.64 CS1 0.0002
BH1 271412.3599 666029.0255 CS1 0.0025
BH2 271587.3599 665993.0255 CS1 0.0672
BH3 271787.3599 665873.0255 CS1 0.0022
GB Card & Partners Limited Dixcart House, Addlestone Road, Bourne Business Park, Addlestone Surrey, KT15 2LE 0203 795 9990 [email protected]
