Environmental Services - Department of Water and ... · 7.5 Nominated Chartered Engineer ... 7.16 Validation Certificates ... MDW Environmental Services (MDWES) was instructed by

Mobile Dewatering Environmental Services as trustee for

Mobile Dewatering Environmental Services Unit Trust

U1/22 Elmsfield Road, Midvale, Western Australia 6056

P: +61 (0) 8 9250 6960 F:+61 (0) 8 92508269

U2/7 Kulin Way, Mandurah, Western Australia 6210

P: + 61 (0) 8 9535 4398

W: www.environmentalservices.com.au

Environmental Services

Specialising in:

Acid Sulfate Soils Contaminated Site Assessment

Air Quality Investigations

Remediation Advice and Design Groundwater Management

Facility Maintenance

ABN 36 835 856 256

Environmental Site Management Plan For Proposed Dwellings

at

Lot 9002 Longford Road, Beaconsfield WA

PREPARED FOR:

Lot 9002 Longford Road Pty Ltd

http://www.environmentalservices.com.au/

MDW Environmental Services Job # E2014-004 Lot 9002 Longford Road – ESMP – Passive Ground Gas Installation

ii

Environmental Services

DOCUMENT DETAILS

Title: Environmental Site Management Plan for Proposed Dwellings at 9002 Longford Road, Beaconsfield.

Project Address Lot 9002 Longford Road, Beaconsfield, WA.

Client Lot 9002 Longford Road Pty Ltd.

Job Number E2014-004-ESMP-02

Author: Mathew Bulmer

Email: [email protected]

Status: V8

MDW Environmental Services Job # E2014-004 Lot 9002 Longford Road – ESMP – for Proposed Dwellings

iii

DOCUMENT DISTRIBUTION

Version No

Written by (Date)

Reviewed by (Date)

Issued by (Date)

Distributed to Copies

draft Mathew Bulmer

20/02/15

Greg Watts

20/02/15

Greg Watts

20/02/15 Client

Signed

Australian Environmental Auditors (AEA)

Electronic

V1 Mathew Bulmer

30/03/15

Greg Watts

30/03/15

Greg Watts

30/03/15 Client

Signed


Electronic

V2 Mathew Bulmer

13/04/15

Greg Watts

13/04/15

Greg Watts

13/04/15 Client

Signed


DER

X2 Hard Copies and an Electronic

Copy

V3 Mathew Bulmer

29/05/15

Greg Watts

29/05/15

Greg Watts

29/05/15 Client


DER


Copy Signed

V4 Mathew Bulmer

23/06/15

Greg Watts

23/06/15

Greg Watts

23/06/15 Client


DER


Copy Signed

V5 Mathew Bulmer

26/06/15

Greg Watts

26/06/15

Greg Watts

26/06/15 Client


DER


Copy Signed

V6 Mathew Bulmer

02/07/15

Greg Watts

02/07/15

Greg Watts

02/07/15 Client


DER


Copy Signed

V7 Mathew Bulmer

06/07/15

Greg Watts

06/07/15

Greg Watts

06/07/15 Client


DER


Copy Signed

V8 Mathew Bulmer

22/07/15

Greg Watts

22/07/15

Greg Watts

22/07/15 Client


DER


Copy Signed


iv

Disclaimer

This report has been prepared on behalf of and for the exclusive use of Lot 9002 Longford Road Pty Ltd (the Client), and is subject to and issued in accordance with the agreement between the Client and MDW Environmental Services. MDW Environmental Services accepts no liability or responsibility whatsoever in respect to its use, or reliance upon, by any third party outside of its intended use This document has commercial confidence status Copying of this report or any part thereof is not permitted without the authorisation of the Client, for the expressed purpose of regulatory assessment.

Statement of Limitations

This assessment was subject to the agreed scope of works and is subject to the limitations defined herein. The assessment has been undertaken and performed in a professional manner consistent with the skill and care ordinarily exercised by reputable consultants under similar circumstances No other warranty, expressed or implied, is given.

Where MDW Environmental Services has relied on verbal information and/or documentation provided by the client and/or third parties, MDW Environmental Services did not attempt to independently verify the accuracy or completeness of that information. However, MDW Environmental Services did not detect any error, omission or inconsistency that would call into question the validity of the information provided. To the extent that the conclusions in this report are based in whole or in part on such information, they are contingent on its validity. MDW Environmental Services assume no responsibility for any consequences arising from any information or condition that was concealed, withheld, misrepresented, or otherwise not fully disclosed or available to MDW Environmental Services.

Other than the visual observations and analytical data as stated in this report, no representations or warranties are made concerning the nature or quality of the soil, ground gas and/or water on the Site. On all Sites varying degrees of variance can be observed with the vertical and horizontal soil or groundwater conditions are encountered. Hence, no sampling technique can completely eliminate the possibility that samples are not totally representative of soil and/or groundwater conditions encountered. The sampling can only reduce this possibility to an acceptable level.

It should also be recognised that Site conditions, including contaminant extent and concentration can change with time. This is particularly relevant if this report is used after a protracted delay, such that further investigation of the Site may be necessary. This report has been prepared on behalf of the Client and for the benefit of the Client only. No person or organisations other than the Client are entitled to rely upon any part of it without the prior written consent of MDW Environmental Services or the Client. Where consent has been granted the report shall only be reproduced and presented in full. Any such third party in using or relying on this report shall have no legal recourse against MDW Environmental Services or its parent or subsidiaries, and shall indemnify and defend them from and against all claims arising out of, or in conjunction with, such use or reliance.

Acceptance of this document denotes acceptance of these terms.


v

Table of Contents

1 INTRODUCTION .................................................................................................................... 3

1.1 General .......................................................................................................................... 3

1.2 Form of Development ..................................................................................................... 3

1.3 Site Identification ............................................................................................................ 3

Table B: Site Boundary UTM Coordinates .............................................................................. 4

2 SITE CLASSIFICATION ......................................................................................................... 5

2.1 Ground Water Abstraction .............................................................................................. 5

2.2 Excavations .................................................................................................................... 5

2.3 Ground Gas .................................................................................................................... 5

3 BACKGROUND ..................................................................................................................... 6

3.1 Ground Gas Analysis ...................................................................................................... 6

4 SUMMARY OF GROUND GAS RESULTS ............................................................................ 8

4.1 Ground Gas Sampling Classification .............................................................................. 8

4.2 Additional Ground Gas Analytes ..................................................................................... 8

5 CIRIA CLASSIFICATION & PROTECTION REQUIREMENTS .............................................. 9

6 CURRENT GROUND GAS MONITORING WELL NETWORK ............................................. 10

6.1.1 De-Commissioning Objectives .................................................................................. 10

6.1.2 Monitoring Well De-Commissioning Process ............................................................ 10

7 GROUND GAS MEASURES & RECOMMENDATIONS ....................................................... 11

7.1 Introduction ................................................................................................................... 11

7.2 Nominated Membrane Installer ..................................................................................... 11

7.3 Nominated Membrane Supplier .................................................................................... 11

7.4 Nominated Membrane Product ..................................................................................... 12

7.5 Nominated Chartered Engineer .................................................................................... 12

7.6 Using Other Suppliers/Installers/Products .................................................................... 12

7.7 Earth Works Preparation .............................................................................................. 13

7.8 Protection of Gas Proof Membrane............................................................................... 13

7.9 Construction Principles – Concrete Slab ....................................................................... 13

7.10 Construction Principles – Granular Layer ..................................................................... 13

7.11 Installation Principles – Gas Proof Membrane .............................................................. 14

7.12 Installation Principles – Prefabricated Panels ............................................................... 14

7.13 Construction Principles – Services ............................................................................... 15

7.14 Gas Proof Membrane - Installation Sign Off .................................................................. 15

7.15 Gas Proof Membrane - Engineers Sign Off ................................................................... 16

7.16 Validation Certificates ................................................................................................... 16

7.17 Membrane Life Span & Warranty .................................................................................. 16

7.18 Design Alterations ........................................................................................................ 16

7.19 Further Requirements or Contingencies ....................................................................... 17

8 REFERENCES ..................................................................................................................... 18


vi

Tables in Report Table A – Site Identification

Table B – Site Boundary and UTM Co-ordinates

Table C – Determining Characteristic Situation (CS) of the Site

Table D – Ground Gas Monitoring Visit Classification Summary

Table E – Determining Characteristic Situation (CS) of the Site

List of Attachments

Figures

Figure 1 – Site Location

Figure 2 – Site Location (Aerial)

Figure 3 – Site Plan with Lot Divisions

Figure 4 – Site plan with Ground Gas Monitoring Wells.

Figure 5 – Passive Ventilation Plan

Appendix

Appendix A – Maccaferri/PuraFlex - Membrane Design & Installation Guide

MDW Environmental Services Job # E2014-004 Lot 9002 Longford Road – ESMP – Passive Ground Gas Installation

1

EXECUTIVE SUMMARY

MDW Environmental Services (MDWES) was instructed by Lot 9002 Longford Road Pty Ltd (the Client) to develop an Environmental Site Management Plan (ESMP) for the management and installation of passive ground gas measures during the construction of each of the proposed new dwellings. The Site is located at Lot 9002 Longford Road, Beaconsfield, Western Australia.

This ESMP has been written to provide additional installation details and requirements during construction at the foundation stage for new dwellings. This management plan should be read in conjunction with the attached Maccaferri design detail and installation guide providing the installation details. This report should be provided to the installation company for compliance with proposed measures.

The Site proposal allows for the development of 33 (total) residential subdivision lots. The areas of the subdivided lots range between 220m2 to 526m2. The development does not include the Public Access Way (PAW) located on site. Each of the residential Lots requires a membrane installation and passive ventilation measures.

The parameters and data that were recorded during each of the nine monitoring visits were in accordance (CIRIA guidelines). The results observed fluctuated between CS1 and CS2 however during the final ninth visit CS3 was recorded which came at a period of low pressure and high precipitation which created elevated concentrations. Therefore, based on the CIRIA guidelines a “worst case scenario” should be adopted. Therefore, the site was classified as CS3 over all for the monitoring program. Therefore, ground gas protection measures were adopted for this Site.

The Site contains twenty-one (21) ground gas monitoring wells (LGMW) which were utilised for the ground gas monitoring program. Once the ground gas monitoring program has been certified complete and there is no further requirement to monitor the site (DER/DoH to confirm), the monitoring wells should be decommissioned. The wells will be decommissioned prior to any construction taking place on site and the developing of any lot. The membrane required for the installation will be supplied by Maccaferri.

Perth Office - Geofabrics Australia, 44 Christable Way, Lansdale, WA, 6065

The nominated membrane used for the installation on each dwelling is a Puraflex membrane this

will be supplied by Maccaferri (Contact Above).

The nominated company for installing the membranes for each of the dwellings is Merit Lining Systems.

Merit Lining Systems, 43 Kirwan Street, Floreat, WA, 6014

The nominated person to provide the engineers certificate and sign-off on the installation is Robert Ronzon from Merit Lining Systems.


Adequate quality control during the laying of the membrane is extremely important. The membrane should be protected either through the use of temporary boarding (smooth, no nails or rough edges) over the whole area, or by the immediate laying of concrete or screed. The manufactures instructions should be followed whilst laying the membrane or the manufacture representative should oversee the installation. The nominal thickness is 0.45m with dimensions of 2.1m x 50m. Conventional thermal weld equipment will be used (hot air/wedge) to seal the membrane.

The membrane should be installed on a thin layer of fine soft builder’s sand (blinding layer), with no sharps or inclusions compaction should be minimal. This blinding layer should be approximately 2mm to 6mm in thickness prior to laying the membrane.

MDW Environmental Services Job # E2014-004 Lot 9002 Longford Road – ESMP – Passive Ground Gas Installation for Proposed Dwellings

2

As part of the CS3 classification the design proposals require passive ground gas mitigation measures. Therefore, under the slab a 300mm or greater of compacted granular material should be incorporated into the foundation design under the floor slab. The granular material should be sufficiently permeable to allow any gas to migrate with ease, the aggregate/particulate size should range from 5mm to 20mm. However, the greatest pore space should be adopted into the design to allow free flow of air. The permeability of the material should be at least 0.16m/s. To allow for ground gas to passively ventilate 100mmØ slotted pipe (2-6mm) should be installed within the granular layer (gas drain). The pipes should be continuous and should vent above the gravel sumps located at the end of the slab. The sumps should extend 0.5m from the slab and approximately 0.5m in width. The gas drain should periscope up out of the sumps to ventilate. The periscope vents should be fixed to the building and terminate approximately 250mm above ground level or for aesthetic reasons if the home owner wishes to hide the vent then the periscope should extend beyond the roof line. Either option should not be removed covered or altered in anyway after the construction. To assist in any gas movement, cowls should be fitted to the periscope vents which extend beyond the roof line this will allow for greater passive ventilation to be drawn up the vertical and will also reduce debris, foliage from blocking of the vent. Consideration should be given to the placement of garden beds, pavers, hardstand and driveways up to the building to allow for the sumps to be located.

The installation of the Puraflex membrane will completed by a competent, professional person the nominated company to complete this is Merit Lining Systems. Merit Lining Systems will provide the final inspection and certificate sign off on each Lot installation.

This will be validated by the nominated chartered engineer Robert Ronzan from Merit Lining Systems to ensure that the membrane has been installed in accordance with the manufacturer’s specification and is fit for purpose.

The validation certificate (Merit Lining Systems) and the engineers certificate (Robert Ronzon) from the installation for each Lot are to be presented to all relevant stakeholders. The Home Owner, The Client (9002 Longford Road Pty, Ltd), Environmental Consultant (MDWES), Environmental Auditor (AEA), Department of Environment Regulation (DER), Department of Health (DoH) and The City of Fremantle – Building Code Inspection Department.

Once the membrane has been certificated and “sign-off” has been completed no further alteration can be made to the membrane, structure and integrity there of. If alterations (retro fitting) are required then further validation/certification is required to ensure that the membrane is performing proficiently. The nominated membrane product (Puraflex) has been reported to have a 100 year life span, with a manufacturer’s warranty of 15 years. In future if the owner wishes to extend or redevelop the property then the measures outlined in this management plan must be adhered to and carried out on any remodeling or construction. Therefore, a membrane and passive ventilation as per the design specification must be incorporated in any redesign to the building footprint.


3

1 INTRODUCTION

1.1 General

MDW Environmental Services (MDWES) was instructed by Lot 9002 Longford Road Pty Ltd (the Client) to develop an Environmental Site Management Plan (ESMP) for the management for each of the proposed new residential dwellings. The Site is located at Lot 9002 Longford Road, Beaconsfield, Western Australia, as illustrated in Figure 1 & 2. This ESMP has been written to provide additional installation details and requirements during construction at the foundation stage for new dwellings. This management plan should be read in conjunction with the attached Maccaferri design detail and installation guide providing the installation details. This report should be provided to the installation company for compliance with proposed measures. In addition, the management plan also details the environmental responsibilities and requirements to the owner of the Lot within the Longford Road development in terms of the environment. The investigation and conclusions have been conducted in accordance with CIRIA Guidelines (CIRIA) – “Assessing Risk Posed by Hazards Ground Gasses to Buildings” (2007). Additional reference is drawn from the Building Research Establishment (BRE) report 212 (1991), for the construction of passive ground gas systems.

1.2 Form of Development

The Site proposal allows for the development of 33 (total) residential subdivision lots. The areas of the subdivided lots range between 220m2 to 526m2 (Figure 3). The development does not include the Public Access Way (PAW) located on site. Based on the monitoring data there is a requirement to develop remedial measures into the foundation construction for each of the dwellings. These measures comprise a passive ground gas system (membrane) and passive under slab ventilation to mitigate the risk to the end user (dwelling occupants).

1.3 Site Identification

Site identification details are summarised in Table A below, with Table B detailing the Site

boundary coordinates. The Site location is shown on figures 1, 2 and 3

Table A: Site Identification

Site Name: Beaconsfield

Site Location: Lot 9002 Longford Road, Beaconsfield, WA

Certificate of Title:

(Volume / Folio) Subject to Dealing (most recent CoT 2588/243)

Site Area Approximately 10,027m2

Site Owner Lot 9002 Longford Road Pty Ltd

Local Government City of Fremantle

Planning Scheme No 4 (District Scheme)

Proposed Zoning The site has been rezoned Residential (R35) and superseding Development Plan 19.

Locality Map See Figure 1, 2 and 3


4

Table B: Site Boundary UTM Coordinates

Site Co-Ordinates

Boundary Eastings Northings

A 0383352 6451365

B 0383363 6451364

C 0383339 6451174

D 0383367 6451175

E 0383340 6450993

F 0383315 6450994

G 0383317 6451177

A

D C

B

G

F E

PAW


5

2 SITE CLASSIFICATION

The Site has been classified by the DER under the Contaminated Site Act (2003) as “Remediated

Restricted use”.

The following memorials on title will be applicable to each Lot on the development Site.

2.1 Ground Water Abstraction

Ground water abstraction of the underlying aquifer is prohibited on each of the development Lots. This includes and not limited to ground water bores used for reticulation or irrigation within a Lot and/or groundwater abstraction for human consumption.

2.2 Excavations

Excavations or intrusive works are limited to the top 1.25m of soil cover. Excavations below this level will require a management plan due to the environmental nature and potential contamination of the underlying soils. There is a distinct horizon between the required 1.25m of clean soil cover and the underlying inert landfill material. This should be observed at all times during any intrusive ground works. This is applicable to but not limited to the following:

Gardening.

Underground Service Installations.

Repairs and Maintenance.

2.3 Ground Gas

Ground Gas has been monitored and assessed as part of the program of works for the subject Site. In conclusion residual ground gas is present on site and protective measures have been adopted and are presented in this management plan. All future dwellings must adhere to the building requirements stipulated in this management plan.


6

3 BACKGROUND

Potential contaminants can have a wide range of consequences for both human health and the environment. This is dependant upon the type of contaminant, the media it is in and its interaction with other substances. Some contaminants may be inert, while others may be mobile, nuisance or impacting. As part of the ground gas monitoring program the following parameters were reported to determine the potential for human health risks. The parameters and data that were recorded during each of the nine monitoring visits were: flow rate; barometric pressure; differential pressure; temperature and current weather conditions at each LGMW Monitoring well (see Figure 4). Each of the LGMW were sampled for a minimum of 300 seconds (5 minutes) or until stable readings were measured (which ever was greater). The following gas concentrations were continuously measured at each LGMW across the Site:

Methane (CH4)

Carbon Dioxide (CO2)

Carbon Monoxide (CO)

Oxygen (O2)

Hydrogen Sulfide (H2S)

Volatile Organic Compounds (VOC)

Lower Explosive Limit (LEL)

Ground gas can enter buildings through gaps around service pipes, construction joints and wall cavities. Ground gas can accumulate within voids created by settlement beneath the floor slabs, in drains and soak wells constructed on a site. The force driving ground gas ingress is principally the positive pressure arising from the conditions under the floor slab which is generated due to the slightly negative pressure relative to atmosphere there exist in as a results of the stack effect (warm indoor air is less dense than the outdoor air).

3.1 Ground Gas Analysis

At present there is no assessment criteria adopted by the DER for ground gas. Preference has been placed towards adopting the CIRIA guidelines for the investigations of this Site. The CIRIA guidelines utilises the concentration and gas flow rate to determine the risk posed by a gassing site. The determined risk is communicated by the use of a “traffic light system” to identify the risk level. The first step is to determine the Gas Screening Value (GSV) this is achieved by multiplying the maximum borehole flow rate by the gas concentration of methane or carbon dioxide. A visual representation of this calculation is below.

Gas Screening Value

(GSV)

Maximum bore hole gas

flow rate (l/hr)

Maximum gas concentration

(CH4 or CO2) (%)

Determination of the GSV enables the association of a characteristic situation (risk level) and determination of the types and levels of gas protection required. Table C details the assessment levels and GSV values.


7

Table C: Determining Characteristic Situation (CS) of the Site

Characteristic Situation

(CIRIA R149)

Comparable Classification

DETR et al (1999)

Risk Classification

Gas Screening Value (GSV) (CH4 or CO2) L/hr threshold

Additional Factors Typical Source of

Generation

CS1 A Very Low <0.07

Typical Methane around 1% and/or Carbon Dioxide around 5%. Otherwise

consider increasing to “CS2”

Natural Soils with low organic content “typical

Made Ground”

CS2 B Low Risk <0.7 Bore air flow rate not to exceed 70l/hr, otherwise

consider increasing to “CS3”

Natural high peat/organic content “Typical Made

Ground”

CS3 C Moderate

Risk <3.5 -

Old Landfill, Inert waste mine working flooded

CS4 D Moderate to High Risk

<15 Quantitative risk assessment required to evaluate scope

of protective measures.

Mine-working susceptible to flooding, completed

landfill (WMP 268 Criteria)

CS5 E High Risk <70 - Mine working Unflooded

inactive with shallow workings near surface.

CS6 F Very High

Risk >70 - Recent Landfill Site

Sourced from CIRIA guidelines: CIRIA C665, Table 8.5 - p88.


8

4 SUMMARY OF GROUND GAS RESULTS

The ground gas monitoring program undertaken by MDWES was over nine (9) ground gas sampling events in a six (6) month period. Each ground gas event obtained data at each of the twenty (21) LGMW’s for potential ground gas emissions.

A summary of the results and classification for each of the monitoring visits is presented in the following table D.

4.1 Ground Gas Sampling Classification

On each of the visits (9) MDWES presented a summary of the calculated classification for each of the individual LGMWs for methane and carbon dioxide (CIRIA Classification Criteria). The results observed fluctuated between CS1 and CS2 however during the final ninth visit CS3 was recorded. Based on the CIRIA guidelines a “worst case scenario” should be adopted under these conditions. Therefore, the site was classified as CS3 over all for the monitoring program.

Table D: Ground Gas Monitoring Visit Classification Summary

4.2 Additional Ground Gas Analytes

The ground gas monitoring program included gas analysis for volatile organic compounds (VOCs), Hydrogen Sulfide and other base ground gases using laboratory provided evacuated canisters. The results of the field data and laboratory analysis highlighted that VOCs and Hydrogen Sulfide were present on Site in low concentrations therefore protection measures would be required based on the concentrations. The site had been classified as requiring CS3 protective measures (see section 4). Therefore, the proposed protection measures would be deemed sufficient for VOC and hydrogen sulfide protection for this site.

CH₄ C0₂ CH₄ C0₂ CH₄ C0₂ CH₄ C0₂ CH₄ C0₂ CH₄ C0₂ CH₄ C0₂ CH₄ C0₂ CH₄ C0₂

LGMW1 CS2 CS2 CS1 CS2 CS1 CS2 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS2 CS1 CS1 CS1 CS1















BHB01 CS2 CS2 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1

BHA02 CS1 CS1 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS1 CS2 CS1 CS1

SB1 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS1 CS2 CS2 CS2

SB2 CS1 CS1 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2 CS2

BHB03 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS2 CS2 CS1 CS1 CS2 CS2

BHA06 CS1 CS1 CS2 CS2 CS1 CS1 CS2 CS2 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1 CS1

Event

ClassificationCS3

Event# 9

CS2CS2 CS2 CS2CS2 CS2 CS2 CS2

Event# 8Event# 1 Event# 2 Event# 3 Event# 4 Event# 5 Event# 6 Event# 7


9

5 CIRIA CLASSIFICATION & PROTECTION REQUIREMENTS

The results of the 9 ground gas monitoring visits have classified the site as being at a CS3 level. Therefore, the construction design should incorporate the ground gas protective measures set out in table E below for CS3 (highlighted grey). The membrane installation requirements for a CS3 classification are provided and summerised in section 6.4 & 6.11 of this ESMP. Membrane installation and specification is also expanded upon in the Maccaferri report attached, this also includes diagrams to pictorialise the membrane installation.

Table E: Determining Characteristic Situation (CS) of the Site

Characteristic Situation

(CIRIA R149)

Risk Classification

Number of Levels of Gas

Protection Measures

Scope of Ground Gas Protection Measures

CS1 Very Low None No Special Precautions

CS2 Low Risk 2

a. Reinforced concrete cast in situ floor slab (raft) with at least 1200 gauge DMP.

or

b. Passive venting System installed below precast raft.

All joints and penetrations to be sealed.

CS3 Moderate

Risk 2

All type of floor slab.

All joints and penetrations sealed into the building. Proprietary gas resistant membrane.

And

Passively ventilated underfloor sub-space or positively pressurised underfloor sub-space.

CS4 Moderate to High Risk

3

All type of floor slab.

All joints and penetrations sealed. Proprietary gas resistant membrane and passively ventilated underfloor sub-space or positively pressured underfloor sub space, over site capping and or blinding and in-ground venting layer.

CS5 High Risk 4

Reinforced concrete cast in-situ floor slab (suspended, non-suspended or raft). All joints and penetrations sealed. Proprietary Gas Resistant membrane and ventilated or positively pressurised underfloor sub-space, over site capping and in-ground venting layer and in ground venting wells and or barriers.

CS6 Very High

Risk 5

Not suitable unless gas regime is reduced first and quantitative risk assessment carried out to assess design of protection measures in conjunction with foundation design.

Sourced from CIRIA guidelines: CIRIA C665, Table 8.6 – p90.


10

6 CURRENT GROUND GAS MONITORING WELL NETWORK

The Site contains twenty-one (21) ground gas monitoring wells (LGMW) which were utilised for the ground gas monitoring program. Once the ground gas monitoring program has been certified complete and there is no further requirement to monitor the site (DER/DoH to confirm), the monitoring wells should be decommissioned. The wells will be decommissioned prior to any construction taking place on site and the developing of any lot. Decommissioning should be in accordance with Edition 3 of the Minimum Construction Guidelines for Water Bores in Australia (National Water Commission 2012).

6.1.1 De-Commissioning Objectives

The following objectives apply for the decommissioning of the wells.

Remove the hazard of an open hole.

Prevent the monitoring well acting as a conduit for contamination to migrate to lower soil horizons and or potentially the underlying ground water table.

Prevents a conduit for ground gas to migrate to the surface and potential ingress into new proposed dwellings.

To document and demonstrate the well has been decommissioned in accordance with industry standards (NWA 2012).

6.1.2 Monitoring Well De-Commissioning Process

1. Remove the concrete and head (riser) casing from the well exposing the 25mmØ UPVC installation.

2. During the monitoring program groundwater was not recorded within any of the wells. However, prior to filling, the wells will be dipped and any water encountered will be pumped and removed from the well.

3. The monitoring well should then be grouted with clean, inert, non polluting material and allowed to cure hard. Material used for grouting should be in the form of a bentonite slurry mix or concrete slurry to plug the well. Due to the diameter of the well a wet/liquid mix will be required to ensure encapsulation.

4. Sufficient time should be given to allow the slurry/grout to cure hard.

5. Excavation of the soils around the well should follow. Soils should be removed to the base of the current capping soils on site (approximately 1.25mbgl) to the horizon of the underlain landfill material.

6. The grouted monitoring well should then be cut (terminated) at the landfill horizon approximately 1.25mbgl.

7. Once the well has been terminated at the landfill horizon, the excavated capping sands should be placed back on top to provide the required 1.25m of cover. If an additional volume is required to return back to ground level then clean, verified soils should be used.

8. Decommissioning of the monitoring well should be undertaken by a professional person. This well decommissioning methodology should be verified and endorsed by the environmental auditor prior to being undertaken.

9. Documentation and records should be presented to demonstrate the wells have been decommissioned in accordance with industry standards.


11

7 GROUND GAS MEASURES & RECOMMENDATIONS

The ground gas results collected for the nine (9) visits over a 6 month period have shown the site to be characterised as being CS3 (section 3 and 4). Based on the results of the monitoring, so long as the following protection measures are adopted, the proposed site development should be able to proceed and would be suitable for the proposed residential development. The CIRIA guidelines and BRE 212 (1991) present recommendations for ground gas protection during construction. Under the current classification of CS3 the following protection measures are recommended and/or should be employed during construction of residential dwellings: MDWES state that as environmental consultants we recommend that the design parameters put forward are presented to a civil engineer and/or architect to ensure that the proposals do not undermine the integrity of the foundation and structure of the proposed dwelling. Given this is such a unique issue (preparing an ESMP for multiple dwellings), a higher level of detail is required with regards to the management plan of which this report is part. In particular this relates to the inclusion of products and services providers noted herein. Whilst we (MDWES) do not necessarily endorse these products or companies, we acknowledge they have been recommended by the developers and have been instrumental in our ability to prepare this ESMP (particularly Maccaferri). Similar products and providers are available on the market and can be sought, however, we cannot provide comment or effectiveness at this stage if used in your development..

7.1 Introduction

This report should be read in conjunction with the Maccaferri document which includes the “Design Detail & Installation Guide” by Puraflex Membranes (See Appendix A).

7.2 Nominated Membrane Installer

The nominated company for installing the membranes for each of the proposed dwellings is Merit Lining Systems. Perth office


Ph: 08 9383 7510

http://www.merit-linings.com.au/

7.3 Nominated Membrane Supplier

The installer will be obtaining the membrane from the following supplier Maccaferri. Head office Perth Office

Maccaferri Australia PTY LTD Geofabrics Australia 22 Powers Road 44 Christable Way Seven Hills, NSW, 2147 Lansdale, WA, 6065 Ph: 02 8825 6300 Ph: 08 6305 0561

http://www.maccaferri.com.au/

The nominated construction/building company developing each Lot on the Beaconsfield Site needs to provide the footprint and design of the dwelling to the installer so that the membrane geometry can be designed, cut and the installation can be arranged.

http://www.merit-linings.com.au/

http://www.maccaferri.com.au/


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7.4 Nominated Membrane Product

The design proposal recommends a ground gas protective scheme for the proposed dwelling to consist of a low permeability ground gas barrier. This is a propriety gas resistant membrane as part of the CS3 classification requirements as detailed in Table E. The nominated membrane used for the installation on each dwelling is a Puraflex membrane this

will be supplied by Maccaferri. The Puraflex membrane has been engineered specially for ground gas protection. The Puraflex membrane is a composite material comprising thermal weldable polymer layers on both sides of a chemical resistant core. Whilst the upper and lower polymer layers are UV stabilised, it is recommended that the membrane is only used for covered installations (Ground slab placed on top). Further installation and design procedures are presented in the appended Puraflex “Design Detail & Installation Guide”. Installation CAD drawing are also presented in sections 6.7.8 to 6.7.12 of the installation guide. Key Features

Exceptional chemical resistance to harmful gases, industrial chemicals and hydrocarbons.

Long-term durability.

Good mechanical properties including tensile, tear and burst strength, puncture resistance.

Good environmental stress crack resistance.

Good welded seam peel and shear performance.

Flexible to accommodate undulating ground contours.

Good elasticity to accommodate limited ground movement.

UV stabilised for added protection during the installation phase.

High-visibility yellow on upper surface for easy recognition during excavations.

7.5 Nominated Chartered Engineer

To validate the installation of the membrane for each Lot an independent inspector is required to deem the installation has been performed in accordance with the product specifications and is fit for purpose. The nominated chartered engineer is: Robert Ronzon


7.6 Using Other Suppliers/Installers/Products

The nominated membrane product, supplier and installer have been selected and approved for the installation for each of the dwellings to be constructed on the Beaconsfield Site. To validate the installation a chartered engineer is required to supply an engineer’s certificate to deem the installation fit for use. The use of other chartered engineers can be used providing that they have the credentials to supply a certificate of compliance. The certificate of compliance should be passed onto building control department or the building control officer as part of the development sign-off for the foundations.

If the builder or homeowner does not use the preferred suppliers recommended then justification has to be provided to the Environmental Auditor, DER and DoH as to reason why. Only through approval can another supplier or installer be used.


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7.7 Earth Works Preparation

All surfaces to be covered shall be smooth and free from foreign and organic material, sharp objects or debris of any kind. The subgrade shall perform a firm, unyielding foundation with no sharp changes or abrupt break in the grade. No standing water will be present on the Lot prior to installation. It is the responsibility of the builder and/or the installer to ensure the ground conditions are optimum and in line with the Puraflex design specifications for membrane installation.

7.8 Protection of Gas Proof Membrane

To minimise the risk of puncture, the barrier membrane should be adequately protected on either side with a suitable needle punched non woven geotextile or a thin layer of fine soft builder’s sand (2mm to 6mm), with no sharps or inclusions.

7.9 Construction Principles – Concrete Slab

The proposed foundations for the development are ground bearing slabs. The Puraflex membrane can be installed underneath the slab prior to the construction of the foundations. During installation it is imperative the membrane is not damaged or torn. Further foundation design details are presented within the Puraflex installation guide (section 6.7). The design of the foundations needs to be provided to the installer so the geometry of the membrane can be workout prior to the installation on site.

7.10 Construction Principles – Granular Layer

A concrete slab underlain with a gas proof membrane is proposed for each of the dwellings on each lot. As part of the CS3 classification the design proposals also require passive ground gas mitigation measures. Therefore, under the slab a >300mm granular layer should be incorporated into the foundation design under the floor slab with a passive venting system (See figures 5). The following design parameters should be adopted when constructing the granular layer.

1. Depth of granular fill should be >300mm.

2. The granular layer should be placed in compacted layers of no more than 150mm thickness.

3. Voids for granular fill are not to extend into the underlying landfill (1.25m below ground surface level). A tolerable allowance of 300mm (or greater) should be allowed between the underside of the foundations to the landfill horizon. This separation distance is also applicable to the granular fill.

4. Granular material used should be blue metal or similar (5mm-20mm or greater) of aggregate material to ensure sufficient spacing between allow for passive flow. Granular material should also be very low in fines. The permeability of the material should be at least 0.16m/s.A blinding layer should be placed on top of clean builder sand 2mm to 6mm to protect the membrane.

5. Gas drains are to be formed within the granular layer. The gas drain is to have a minimum diameter of 100mm, it should be machine slotted with a smooth internal surface.

6. The gas drains are to be formed from slotted pipe with machined slots between 2-6mm.

7. Gas drains pipe to have a minimum 10% and maximum 15% open area (slots).

8. Gas Drains to be formed from continuous lengths of pipe.

9. The gas drains are to be installed to avoid short circuiting of venting of the underside of the slab. i.e: gas drains that emerge on one side of the slab should not extend such that they emerge on the opposite side of the slab.


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10. The gas drains should be laid at approximate 1.25m centres with each drain inlet/outlet to exit around the slab and periscope upwards to ground level (see fig 5 for example).

11. Gas drain should extend from the edge of the slab and periscope upwards within the sump with dimensions of 0.5m x 0.5m for each the sumps.

12. Limited paving, garden beds and drive way should be allowed up to the building, but should not cover the ventilation sumps.

13. Gas drains on the opposite side should be completed by the use of a periscope vent:

Option 1 – Vent is to be terminated 250mm above ground such that the outlet will remain free from obstruction and attached to the building.

Option 2 – If for aesthetic reasons option 1 is not viable the home owner can extend the periscope up to the roof line. The vent should be fitted within a cowl to allow air to be drawn up the vertical and vent at the roof line.

14. The inlet/outlet vents should provide a minimum of 1500mm2 (0.0015m2) vent area per metre length of wall on both sides of the long side of the building

15. During the pouring of the concrete floor slab it is imperative that concrete does not fall or set between the aggregate as this could restrict passive venting.

16. The passive gas system is to be signed off by a professional person (engineer) to ensure the membrane has been installed correctly.

It should be noted as a requirement that the gas drain granular layer extensions (sumps) and periscope vents should not be removed, covered or alter in any way after construction.

7.11 Installation Principles – Gas Proof Membrane

The principal consideration for a gas-proof membrane is to provide protection and reduce the permeability of ground gas ingress (no membrane is 100% impermeable). The Puraflex membrane has to withstand the construction process because, once torn or damaged, the membrane ceases to be operate as an effective barrier. During construction the builder has to maintain the integrity of the membrane whilst the foundations are being constructed. If the membrane is torn or damaged then the installer (Merit Lining Systems), need to be informed and the membrane has to be fixed and sign off (again) by the installer to ensure the integrity of the membrane has not been compromised.

Adequate quality control during the laying of the membrane is extremely important. The membrane should be protected either through the use of temporary boarding (smooth, no nails or rough edges) over the whole area, or by the immediate laying of concrete or a screed. The manufactures instructions should be followed whilst laying the membrane or the manufacture representative should oversee the installation. The nominal thickness is 0.45mm with dimensions of 2.1m x 50m. Conventional thermal weld equipment will be used (hot air/wedge) to seal the membrane. The installation of the membrane will be conducted by the nominated installer highlighted in section 6.4.

7.12 Installation Principles – Prefabricated Panels

Pre-fabricated panels have the advantage of being installed relatively quickly and cleanly. They should be considered where site conditions make in-situ welding more difficult or inappropriate. Panels minimise weather – induced delays and reduce on-site welding and can be made to the necessary detail, shape and size and delivered to site folded and rolled ready for deployment. Preparation and deployment will be in accordance with the membrane specification procedures, with appropriate quality control measures undertaken by the installers.


15

If the membranes are delivered damaged or not cut to the bespoke footprint of the proposed new dwelling then the membrane is not to be installed. It is understood the prefabricated panels will be used where possible by Merit Lining Systems. However, it is anticipated that the membrane will be laid and cut on site to the bespoke foot print design. The foot print design needs to be presented to Merit Lining Systems prior to on site installation so the geometry of the membrane can be designed. This also includes the anchoring design which will be in line with the Puraflex specifications.

7.13 Construction Principles – Services

Service penetrations through the membrane should be kept to a minimum and to this end services can be directed into the building above the floor slab if design specifications allow. The installation should ensure that all membrane joints, seals and section breaks are sealed into the building, across any cavity walls creating a continuous barrier. If services have to come through the floor slab the Puraflex design parameters for service ingress should be followed. Merit Lining Systems will comply with the Puraflex design specifications to ensure a continuous membrane barrier. Inlet services need to be firmly anchored and service temperature not to exceeding 60ºC. Where a service pipe penetrates the membrane a cut hole in the membrane ensuring a tight seal is made without scratching the membrane. Top hats should be installed around penetrations. The pipe and membrane are flashed together by creating three cut-outs of the membrane material and hot air welded together. All services should be lapped and sealed to ensure a good seal. These points are developed further within the Puraflex installation guide (Section 6.1 to 6.6).

7.14 Gas Proof Membrane - Installation Sign Off

The installation of the Puraflex membrane should be completed by a competent, professional person (nominated - Merit Lining Systems). Merit Lining Systems will provide the final inspection and certificate “sign off” of ITP based on the Quality Assurance/Control and check list of the Puraflex specifications. The following highlights some of the design protocols.

1. Each membrane install should be signed off and verified by Merit Lining Systems in accordance with the Puraflex installation guidelines.

a. Qualitative Non-destructive testing of the entire membrane surface, seam welds and penetration seals are checked and verified.

b. Qualitative Destructive testing of seam welds. Preservation of the integrity of the membrane should be minimised checked and verified.

c. Photographs of all penetrations seals and damaged areas should be taken with subsequent repairs.

d. Any non-conformances or breaches will be repaired and actioned prior to final sign off of the membrane.

2. To minimise the risk of puncturing, the barrier membrane should be adequately protection with a suitable non-woven geotextile or sand (non sharp) sand is to comprise a thickness of 2mm to 6mm.

3. The underlying soil should be picked and free from sharp protruding objects.

4. Installers should wear protective shoes to ensure that no tear or rip occurs whilst walking and installing the membrane.

5. Separate sheets or breaks should be over-lapped and welded together to ensure continuity, although care should be taken to avoid damaging the membrane during installation.


16

6. Special pieces/sections can be used for edges and corners to continue the membrane over these awkward areas.

7. The installed membrane should be continuous across the slab. It should continue through the wall and any cavity wall to prevent any potential ground gas accumulating within them.

8. Damage or tears to the membrane during installation should be repaired with immediate effect in accordance with product specifications and signed off before continuing with the screed.

The installation and design guide of Puraflex should be consulted as part of the installation process. Merit Lining Systems should comply with the installation and design document, in depth design speciation’s are provided within attached document Appendix A.

7.15 Gas Proof Membrane - Engineers Sign Off

The installation of the Puraflex membrane by Merit Lining Systems requires and Engineers certificate. This should be completed by an accredited Chartered Engineer. The nominated chartered engineer is Robert Ronzon. The certificate will certify that the membrane has been installed professionally and is fit for use. The certificate of compliance for installation of the membrane should be passed to the building control officer as part of the foundation sign off.

7.16 Validation Certificates

Validation of the membrane installation is required as part of the quality control. Merit Lining Systems will install, validated and “sign-off” on each installation to certificate each Lot.

To provide quality assurance an independent inspector will provide an engineers certificate to verify the installation and materials used are correct. This will be completed and performed by a chartered engineer (section 6.5).

The validation certificates from the installer and chartered engineer will be presented to all relevant stakeholders to ensure compliance.

The Home Owner.

The Client (9002 Longford Road Pty Ltd).

Environmental Consultant (MDWES).

Environmental Auditor (AEA).

Department of Environment Regulation (DER).

Department of Health (DoH).

The City of Fremantle – Building Code Inspection Department.

7.17 Membrane Life Span & Warranty

The nominated membrane product (Puraflex) has been reported to have a 100 year life span, with a manufacturer’s warranty of 15 years. Puraflex is manufactured to ISO 9001 Quality Assurance Standards with batch traceability.

7.18 Design Alterations

Once the membrane has been certificated and “sign-off” no further alteration can be made to the membrane structure as it would remove the integrity.

If alterations (retro fitting) is required then further validation/certification is required to ensure that the membrane performing proficiently. This should be completed by the nominated installer Merit Lining Systems.

Alterations to foundation design and construction need to be approved by a certified engineer or architect.


17

7.19 Further Requirements or Contingencies

Once the wells on Site have been decommissioned there are no further monitoring requirements on Site. In future if the owner wishes to extend or redevelop the property then the measures outlined in this management plan must be adhered to and carried out on any remodeling or construction. Therefore, a membrane and passive ventilation as per the design specification must be incorporated in any redesign to the building footprint. There are no contingencies at this stage.


18

8 REFERENCES

Davidson, WA. (1995): Hydrogeology and Groundwater Resources of the Perth Region, Western Australia. Geological Survey of Western Australia Bulletin 147.

CIRIA. Assessing risks posed by hazardous ground gases to buildings, CIRIA (2007).

Building Research Establishment (BRE) report 212 (1991)

Nearmap (2012) PhotoMaps by Nearmap (Online), http://www.nearmap.com.

CRC CARE 2013, Petroleum hydrocarbon vapour intrusion assessment: Australian guidance, CRC CARE Technical Report no. 23, CRC for Contamination Assessment and Remediation of the Environment, Adelaide, Australia.

Puraflex (2014) - Hydrocarbon and Chemical Resistant Environmental Protection Barrier Membrane – Design Detail & Installation Guide (Revision 2.3)

Edition 3 of the Minimum Construction Guidelines for Water Bores in Australia (National Water Commission 2012).

http://www.nearmap.com/

FIGURES

T: (08) 9250 6960

F: (08) 92508269

www.environmentalserivces.com.au

[email protected]

Notes:

Site Boundary

B³ area

v1

Rev:

1Project No:

E2014-004

PERTH | PEEL

MDW Environmental Services

Date:

16/06/2014

Scale: Not to scale

Lot 9002 Longford Road, Beaconsfield

Drawing Title:

Site Location Map

Drawn by:

DA

Client:


Project:

Beaconsfield

Location:

North

Bent Street Jetty

MDWES - Figure Sheet (L) (v2) Jun2013

http://www.environmentalserivces.com.au/

mailto:[email protected]

T: (08) 9250 6960

F: (08) 92508269


[email protected]

Notes:

Site Boundary

v1

Figure No: Rev:

2Project No:

E2014 - 004

Not to Scale

PERTH | PEEL


Date:

7/07/2014

Scale:


Drawing Title:

Site Location

Drawn by:

MB

Client:


Project:

Beaconsfield

Location:

North

Bent Street Jetty

MDWES - Figure Sheet (A3 L) (v2) Jun2013



T: (08) 9250 6960

F: (08) 92508269

[email protected]

Notes:

Image sourced from the Land Survey document Proposed Green Title Subdivision.


Area B, New Landfill (B1 & B2)

Area A, old landfill

PERTH | PEEL


Client:


Project:

Beaconsfield

Location:

Date:

8/07/2014

Scale:


Drawing Title:

Site Boundary and Lot

Divisions

Drawn by:

MB

Not to scale.

v1

Figure No: Rev:

3Project No:

E2014 - 004

North

B1




T: (08) 9250 6960

F: (08) 92508269

[email protected]

Notes:

Image sourced from the Land Survey document Proposed Green Title Subdivision included wihtin Appendix F.


Previously installed land gas monitoring well

Newly installed land gas monitoring well

Area A, old landfill

Area B, New Landfill (B1 & B2)

PERTH | PEEL


Date:

17/06/2014

Scale:


Drawing Title:

Lot Subdivisions and LGMW

Locations

Drawn by:

DA

Client:


Project:

Beaconsfield

Location:

Not to scale.

v1

Figure No: Rev:

4Project No:

E2014 - 004

North




T: (08) 9250 6960

F: (08) 92508269


[email protected]

Notes:

v3

Figure No: Rev:

5Project No:

E2014 - 004

Not to Scale

PERTH | PEEL


Date:

23/06/2015

Scale:


Drawing Title:

Passive Ventilation System

Drawn by:

MB

Client:


Project:

Beaconsfield

Location:

North

Bent Street Jetty

Lot 71 Lot 70 Lot 72

Longford Road

Soft Landscaping

Outdoor Space

Drive

Vented void beneath floor slab, Blue Metal or similar. A granular depth >300mm depth is required on each lot. The granular layer is to be compacted in 150mm layers. Granular layer

Option 2 (see below)

Fence

Paver / Hardstand

Paving or Hardstand / garden bed (highlighted Green/Grey)

Underlying Clean Capping Soils

Inert Landfill Material

1.25m

Sumps to be located around the slab they should extend 0.5m from the edge away from the slab. The width of the sump should be approximately 0.5m.

Suggested lay out of the gas Drain to be installed within the granular layer See figure 6 for dimensions.

30m

Gravel Sump extended

0.5m from building

15m

Ventilation Granular Layer >300mm

100mmØ Slotted gas drain (pipe) with slots 2-6mm

Membrane

Foundation

Wall Option 1: (see below)

Periscope vents have been positioned so not to be intrusive of the final design and impact the aesthetics of the building.

Periscope Ventilation Options: Option 1) The inlet/outlet for the periscope vent terminate s at 250mm above ground level with a grate fitted to stop blockage. (similar to an over sewer over flow pipe). Option 2) If the home owner wants a more asthetically pleasing vent, then the periscope vent could be exteded up to the roof line /gutter. Installation of a cowl is required to draw air up the verical for the pipe and out of the down pipe.

Blind layer (sand) 2-6mm thick




Proposed layout and dimensionsT: (08) 9250 6960

F: (08) 92508269


[email protected]

Notes:

Proposed layout of the passive ventilationv2

Figure No: Rev:

6Project No:

E2014 - 004

Not to Scale

PERTH | PEEL


Date:

26/05/2015

Scale:


Drawing Title:

Passive Gas Ventilation for

Proposed Footprint

Drawn by:

MB

Client:


Project:

Beaconsfield

Location:

North

Bent Street Jetty

Drive

Soft Landscape

Hard

Land

scape

Outdoor Space

15m

30m

1.25m

1.25m

1.25m

1.25m

1.25m

1.25m

1.25m

1.25m

1.25m

1.25m

1.25m

1.25m

1.25m 1.25m

Outlets on oppersite site of







Appendix A – Ground Gas Membrane Design Detail & Installation Design

GROUND GAS

MEMBRANE

DESCRIPTION

The ground gas membrane, Puraflex is an extruded composite membrane

comprising protective polymeric layers on both sides of chemical resistant

inner core consisting of polar and non-polar polymers.

This unique composition prevents the migration of contaminants and gases

from the ground through the slab thereby protecting building occupants.

The nominal thickness is 0.45mm. Rolls are 2.1m x 50m.

In areas where cavity wall construction is used a damp proof course (DPC)

version is used to provide a gas tight solution. The DPC rolls are 600mm wide.

Installation should be carried out by competent membrane installers using

conventional thermal (hot air/wedge) welding equipment.

Detailed installation instructions and quality control procedures are detailed in

the following Design Detail and Installation Guide.

In the case of this project the Puraflex gas membrane shall be fabricated as to

mirror the footprint of the foundation slab with edge details to be determined

by the method of construction of the slab and footings.

PURAFLEX®

Hydrocarbon and Chemical Resistant E n v i r o nm e nt a l P r o t ec t i o n Ba r r i e r M em br an e

Design Detail & Installation Guide Revision 2.3 www.puraflex.com

Puraflex is a Trade Name of Industrial Textiles & Plastics Ltd. E&OE. Industrial Textiles & Plastics Ltd 2014

Industrial Textiles & Plastics Ltd Stillington Road Tel: +44 (0)1347 825200 Easingwold Fax: +44 (0)1347 825222 York YO61 3FA www.puraflex.com United Kingdom [email protected] Cert No. 2318/00

Table of Contents

1. Introduction ................................................................................................... 2 2. Quality Control .............................................................................................. 2

2.1 Installation QA Records........................................................................ 2 2.2 Installer Experience .............................................................................. 2 2.3 Installer Responsibilities ....................................................................... 2 2.4 Final Inspection and Integrity Testing ................................................... 2

3. Earthwork ..................................................................................................... 3 3.1 General ................................................................................................ 3 3.2 Barrier Membrane Protection ............................................................... 3 3.3 Preparation of the Subgrade ................................................................ 3 3.4 Panel Layout Plan ................................................................................ 3

4. Barrier Membrane installation ....................................................................... 4 4.1 Pre-fabricated Panels ........................................................................... 4 4.2 Weather Limitations ............................................................................. 4 4.3 Rolls ..................................................................................................... 4 4.4 Transport and Storage ......................................................................... 4 4.5 Deployment and Preparation ................................................................ 4 4.6 Seam Welding ...................................................................................... 4 4.7 Test Welds ........................................................................................... 5 4.8 Weld Quality ......................................................................................... 6 4.9 Cover Material and Backfilling of Anchor Trench ................................. 6 4.10 Barrier Membrane Acceptance ............................................................. 6

5. Sampling and Testing ................................................................................... 6 5.1 Non-Destructive Testing ....................................................................... 6 5.2 Qualitative Destructive Testing ............................................................. 7

6. Details ........................................................................................................... 7 6.1 Corners ................................................................................................ 7 6.2 Connections to concrete structures ...................................................... 8 6.3 Drains and flanges ............................................................................... 8 6.4 Ancillaries ............................................................................................. 9 6.5 Flashing of penetrations ....................................................................... 9 6.6 Anchor trenches ..................................................................................10 6.7 Foundations ........................................................................................10

7. Appendix ......................................................................................................17 7.1 Defects and Repair Procedure ............................................................17 7.2 Welding equipment .............................................................................17 7.3 Laboratory testing of welded seams ....................................................18 7.4 Weather Protection .............................................................................18 7.5 Sample Field Seam Weld Record .......................................................19 7.6 Useful References ...............................................................................20

Industrial Textiles & Plastics Ltd

DESIGN & INSTALLATION GUIDE

REVISION 2.0 PAGE 2 OF 20

1. INTRODUCTION

Industrial Textiles & Plastics Ltd. is an established producer of barrier membrane materials used for the manufacture of gas tight suits and chemical protection clothing fabrics. This barrier technology and manufacturing experience has been used to develop Puraflex

® which has been engineered specifically for the

remediation of contaminated land, water resources and groundwater protection, environmental protection and secondary containment installations.

Puraflex® has enhanced resistance to a wide range of pollutants including hydrocarbons, industrial chemicals,

and toxic waste, natural and radioactive gases. The material has been subjected to a detailed test programme and our data is the result of chemical resistance testing to both industry and proprietary test methods.

Puraflex® is a composite membrane comprising thermal weldable polymer layers on both sides of a chemical-

resistant inner core. Whilst the upper and lower polymer layers are UV stabilised, it is recommended that the membrane is only used for covered installations.

Installed using conventional hot air wedge-welding equipment, it is classed as a GBR-P polymeric geosynthetic barrier for covered installations. It can remain exposed prior to covering for up to 21 days.

This installation guide summarises best practice and procedures for different aspects of Puraflex® environmental

protection barrier membrane installation and welding.

All procedures, operations and methods shall be in accordance with the Engineer’s specifications, plans, and drawings.

2. QUALITY CONTROL

2.1 Installation QA Records

As detailed in the manufacturer’s installation instructions, the Installer shall record details of the following activities:

2.1.1 Materials inspection and tests

The Installer shall check material delivered to site for damage, checking and recording the roll serial numbers.

2.1.2 Panel Layout Plan

The Installer shall prepare a Panel Layout Plan to record the batch serial number and coverage of each roll.

2.1.3 Installation and weld testing

The Installer shall monitor, inspect and record all welding, including weld parameters and testing of regular test welds. Completed welded seams shall be tested by destructive and non-destructive methods.

2.1.4 Faults and repairs

The Installer shall record all faults and repairs to the membrane.

2.2 Installer Experience

The Installer shall have experience of installing geomembranes of the type specified for the Works.

The Installer shall be suitably qualified to install the manufacturer’s barrier membrane. An acceptable example is the British Geomembrane Association (BGA)/Thermal Welding Institute (TWI/CSWIP) third party accreditation scheme. In accordance with the Environment Agency requirements, at least two crew members must be accredited to BS EN 13067 and all other crew members (except for a maximum of one trainee) must be accredited to the CSWIP Entry Level.

The installation shall be under the constant direction of a field installation supervisor or master welder who shall remain on site and be responsible, throughout the membrane installation, for membrane layout, welding, testing, repairs, and all other activities.

2.3 Installer Responsibilities

The Installer shall be responsible for the membrane at all times during the Contract and shall adopt whatever measures are necessary to ensure its stability and protect it from damage. These measures shall include the use of sufficient temporary surcharge in the form of durable sandbags, tyres or similar weights without sharp edges, to be placed on the membrane immediately after laying and before welding to prevent slipping and damage by wind or other agents prior to covering.

The Installer's attention is drawn to the need to provide adequate restraint at free edges of sheet material before anchoring or welding to the adjacent seam in order to prevent uplift by wind.

2.4 Final Inspection and Integrity Testing

It is recommended that verification of the barrier membrane installation shall be performed by independent Inspectors.




Final Inspection and Integrity Testing shall be performed prior to covering the barrier membrane; covering the barrier must not begin until the installation has passed Inspection. All non-conformances shall be resolved by the Installer to the Inspector’s satisfaction before the Installation can be certified as passed.

The Final inspection should include:

Visual inspections of the entire barrier membrane surface, seam welds and penetration seals;

Non-Destructive testing of seam welds (see Section 5.1);

Dielectric Testing. A reliable method of detecting holes in barrier membranes is the Dielectric test method using electrical conductivity. Other test methods may include Smoke or Trace Gas testing (where smoke or trace gas is injected below the barrier);

There are advantages and disadvantages to the different methods. The main issue with smoke or trace gas testing is achieving sufficient pressure below the membrane to ensure that the smoke or tracer gas is present below all parts of the membrane. If done correctly it works well, if not it is not really effective. It is also difficult to inject the gas and build up a pressure below large slabs that are poured in sections since there will be a large unsealed open area around the edges.

Photographs of all penetration seals and damaged areas with subsequent repairs.

The information should be included in the inspection report.

3. EARTHWORK

3.1 General

All surfaces to be covered shall be smooth and free of all foreign and organic material, sharp objects, or debris of any kind. The subgrade shall provide a firm, unyielding foundation with no sharp changes or abrupt breaks in grade.

3.2 Barrier Membrane Protection

To minimise the risk of puncturing, the barrier membrane should be adequately protected on either side with a suitable needle-punched non-woven geotextile or sand.

3.3 Preparation of the Subgrade

3.3.1 So that damage to the membrane is avoided, the essential requirement for the installation of the barrier membrane is a smooth, dry and clean working surface.

3.3.2 No standing water or excess moisture shall be present.

3.3.3 The water table level should be determined and if it is higher than the base of the excavation, adequate drainage should be installed to prevent water pressure build up below the barrier membrane.

3.3.4 Particular attention should be paid to the following:

i Grain size and angularity: The subgrade should be free of all rocks, sticks, stones, roots, sharp objects

or any debris of any kind, which may puncture the membrane. Any stone, which protrudes above the level of the surface of the subgrade, should be stone picked and any indentation remaining should be filled and compacted with suitable material;

ii Smooth and firm: The surface should provide a firm unyielding foundation for the membrane with no

sudden, sharp or abrupt change or break in gradient.

3.3.5 When carrying out any welding procedure on a Bentonite Enhanced Soil (BES) subgrade, it is important that particular attention is given to the cleaning process in preparation for welding. When Bentonite attaches itself to the membrane, particularly in wet conditions, it is very difficult to clean the membrane and the number of weld failures increases without due care and attention.

3.3.6 Geosynthetic Clay Liners (GCL) also present welding problems when placed directly underneath the membrane since the Bentonite powder, which is placed in the overlaps of GCL panels, is often scattered by the wind or water and causes cleaning problems in preparation for welding. When placing the Bentonite powder, excess amounts of powder should not be placed in the joints and none on the membrane.

3.3.7 If after inspection of the material that is to be placed on top of the barrier membrane, it is deemed to be unsuitable, a needle-punched non-woven geotextile may be recommended as a protective layer.

Installation of a protective layer should be carried out after acceptance of the tested barrier membrane.

The protective cover shall be spread in a manner to ensure that the barrier membrane follows the contours of the ground and no bridging or stretching of the material occurs.

3.4 Panel Layout Plan

3.4.1 The Installer shall provide a detailed Panel Layout Plan showing the proposed layout and sequence of the membrane placement.

3.4.2 The Installer shall arrange the panels so that the seams are aligned parallel to the line of maximum slope (i.e. normal to contours), whenever practicable in accordance with accepted good practice.




3.4.3 The free edges of each panel shall be adequately weighed down with sand bags, tyres or by other means in readiness for seam welding.

3.4.4 Roll batch serial numbers should be recorded on the Panel Layout Plan to record the coverage and location of each roll.

4. BARRIER MEMBRANE INSTALLATION

On-site progress of the work, as well as the climatic and working conditions shall be recorded and on completion, a layout plan prepared to record the location and sizes of each panel of barrier membrane.

4.1 Pre-fabricated Panels

Pre-fabricated panels have the advantage of being installed relatively quickly and cleanly. They should be considered where site conditions make in-situ welding difficult or inappropriate. Panels minimise weather-induced delays and reduce on-site welding and can be made to the necessary detail, shape and size and delivered to site folded and rolled ready for deployment.

4.2 Weather Limitations

Barrier membrane deployment or welding shall only proceed between ambient temperatures of 4ºC and 30ºC. Placement can proceed below 4ºC only after it has been verified by the inspector that the material can be welded according to the specification.

No deployment of membranes or welding will take place during any precipitation or in the presence of excess moisture (fog, dew, rain), blowing dust or winds over 10 km/hr.

No placement or welding of membranes should take place in areas of standing water.

4.3 Rolls

The barrier membrane is supplied in rolls. The surface of the barrier membrane shall not have pinholes or bubbles.

Labels on each roll shall identify the manufacturer, product name and type, the weight per square metre, the length, width and weight of the roll and the batch number.

The roll serial number must be recorded on the Layout Plan.

4.4 Transport and Storage

Care should be taken when moving, transporting or handling rolls to avoid physical damage, puncturing or any tainting which may interfere with seam welding.

The barrier membrane shall be stored under cover so as to be protected from puncture, dirt, grease, moisture, sunlight and excessive heat. Damaged material shall be quarantined and stored separately for repair or replacement. The rolls shall be stored on a prepared smooth dry surface (or fully boarded wooden pallets; note that slatted pallets with sharp corners will damage the rolls) and stacked no more than two pallets high. The bottom rolls on the pallet need to be chocked to prevent them rolling.

Storage between 5 to 30 ºC at 40 to 65% humidity under non-condensing conditions is recommended.

4.5 Deployment and Preparation

4.5.1 Deployment

The rolls shall be deployed with care.

i Equipment or tools shall not damage the barrier membrane during handling, transportation and deployment;

ii Personnel working on the barrier membrane shall not smoke or wear damaging shoes;

iii The method used to unroll the panels shall not cause scratches or crimps in the barrier membrane and shall not damage the supporting soil;

iv Adequate loading (e.g. sand bags or similar items that will not damage the barrier membrane) shall be placed to prevent uplift by wind (in case of high winds, continuous loading is recommended along edges of panels to minimize risk of wind flow under the panels).

4.5.2 Preparation

After unrolling the membrane, its position is adjusted so that a suitable overlap is achieved for the welding process. Before welding, the membrane shall be checked for any damage and to ensure that it is clean, dry and free of any dust or dirt particles.

This is particularly important if the membrane is wet at the beginning of the day when it is likely that dew is present. Where the edge of a panel of membrane has been laying on wet sub-grade, it may be necessary to remove any mud stuck to the underside. Any surface water in the area of the seam must be removed.

4.6 Seam Welding

4.6.1 The approved seam welding process is hot air wedge welding. A Leister Twinny-S hot air wedge welder is recommended for optimum results using a 25mm knurled roller for a single seam overlap-weld.




4.6.2 Puraflex® incorporates an inner chemical resistant core with a protective thermally weldable modified polyolefin

coating on both sides which is compatible with conventional hot air wedge welding equipment.

4.6.3 Conventional overlap-welding is recommended for joining.

.

Fig. 4b

Standard single seam overlap-weld with 25mm knurled roller. A Leister Twinny-S hot air wedge welder is recommended for optimum results.

4.6.4 Proposed Joining Techniques

The Installer should submit method statements prior to commencing installation, detailing the following as a minimum:

i Proposed welding technique, joining machinery, overlap widths and overlap preparation prior to welding, acceptable temperature ranges for welding, acceptable maximum welding speed.

ii Proposed non-destructive test technique or techniques.

4.6.5 On side slopes, welds shall be oriented in the general direction of maximum slope, i.e. oriented down, not across, the slope. In corners and odd-shaped geometric locations, the number of field welds shall be minimised. No base T-weld shall be closer than 2 metres from the toe of the slope. Welds shall be aligned with the least possible number of wrinkles and “fish-mouths.” If a fish-mouth or wrinkle is found, it shall be relieved and patched.

4.6.6 Barrier membrane panels must have a finished overlap of 100mm.

4.6.7 Cleaning solvents may not be used.

4.7 Test Welds

4.7.1 Field test welds shall be conducted on the barrier membrane to verify that welding conditions are satisfactory.

The Installer shall perform test welds with each welding machine and operator at least at the start of each shift, after every four hours of operation and also following any period of machine shutdown or change of operator.

The test welds shall be made and the Installer shall cut five 25mm wide field tabs from the seam length. The tabs shall be subjected to field qualitative destructive testing using a tensometer. The five tabs shall be tested in peel mode.

NOTE: Welded seams must be allowed to cool before performing any peel testing; testing warm seams will

provide false peel test results.

The seam will be deemed to have passed if the failure occurs solely in the parent material and does not encroach into the seam. The seam will be deemed to have failed if any of the failure encroaches the seam.

The peel test indicates whether or not the sheets are homogeneously and satisfactorily joined through the material thickness. The test specimen is pulled perpendicular to the weld until complete separation occurs. Analysis of the fracture surfaces provides qualitative information about the joint integrity. Ductile failure in the parent material indicates a good quality weld.

If the correct welding parameters have not been followed during the welding process, it will become clear when specimens are peel tested. This type of test is an aggressive test of a seam weld. For example, if the temperature of the hot air wedge was set too hot in relation to the speed of operation, then it is most likely that the area of the material beside the weld is brittle and will break at a lower than expected value.

If a test weld fails field destructive testing then the welding machine and the Operator shall not be allowed to perform field welding until the deficiencies are corrected and both machine and Operator have achieved a conforming test weld.

4.7.2 Assessment of Test Weld Results

Each specimen shall be 25mm wide with a grip separation of 100mm. The weld shall be centred between the clamps. The rate of grip separation shall be 50mm per minute.

The seam will have deemed to pass if the failure occurs solely in the parent material and does not enter the seam. Elongation measurements are omitted for field-testing.




4.8 Weld Quality

4.8.1 Types of Imperfection

The most important step in identifying weld imperfections is to inspect the weld visually. In the case of hot air wedge welded seams, a visual inspection should take account of the following:

i The nip/drive roller marks may show on the surface of the membrane when using knurled rollers. Their depth should be examined to ensure that the rollers have not created a rut, i.e. the indentation should be barely capable of being felt;

ii The seam should be checked for uniformity of width and surface continuity. In the case of dual track seam both seams should be clearly identifiable and separated by an air channel;

iii There should be enough of a flap outside of the weld to allow for peel testing of the weld during a destructive test;

4.8.2 Origins of Imperfections

The origin of weld imperfections could include the following:

i Welding in unsuitable environmental conditions, i.e. during rain, excessive wind or on poor subgrade;

ii Unsuitable welding equipment or machine settings, i.e. using the incorrect welding parameters;

iii Poor operation of the equipment, lack of operator training or awareness.

Either one or a combination of the above list could lead to poor quality welds being produced.

4.9 Taped joints

4.9.1 To maintain the installation’s integrity, seam welding is the recommended method for jointing.

4.9.2 Taped joints compromise any membrane’s integrity by providing a pathway for the challenge chemical through the adhesive. An adhesive claiming to be ‘Hydrocarbon Resistant’ may simply mean that an adhesive may be resilient to certain hydrocarbons which have no obvious relationship to the adhesive’s ability to block a challenge hydrocarbon to a level that ensures adequate protection over time. Furthermore the vagueness of the word “hydrocarbon” can lead to false claims that an adhesive good for one hydrocarbon (e.g. methane) is automatically good for a very different type of hydrocarbon (e.g. benzene).

4.9.3 Where taped joins are a necessity, tape joints should only be used where joints are under continuous compressive loads e.g. under-slab installations. Tape joints are not suitable for wall installations or other installations where the joint is not under compression.

4.10 Cover Material and Backfilling of Anchor Trench

The barrier membrane shall be covered within 21 days of exposure. The covering operation shall not damage the barrier membrane.

The cover soil material shall be free of foreign and organic material, sharp objects, or debris of any kind, which could potentially damage the barrier membrane.

No construction equipment or machinery shall operate directly on the barrier membrane. The use of lightweight machinery (e.g. generator) with low ground pressure may be allowed subject to the approval of the Engineer.

Any damage shall be repaired prior to backfilling.

4.11 Barrier Membrane Acceptance

The Installer shall be responsible for the barrier membrane until accepted by the client. Final acceptance is when all of the following conditions are met:

i The Installation is finished.

ii Installation QA Records are complete.

iii The Installation has been certified as passed by the Final Inspection and Integrity Testing Inspector.

5. SAMPLING AND TESTING

5.1 Non-Destructive Testing

The Inspector shall perform non-destructive testing along the entire lengths of all seams including patches and repairs.

In the event of a seam failing non-destructive testing the Inspector shall identify the failed area. The Inspector shall then subject the repair to further non-destructive testing until any repair passes the test.

Recommended non-destructive testing techniques are visual inspection, air lance and vacuum box testing.

5.1.1 Active Weld Inspection

The installer/operator inspects the seam area during the welding process, however only certain defects affecting weld quality can be detected. Therefore further Air Lance Testing and/or Vacuum Box Testing is required to check and validate the integrity of the welding.

5.1.2 Air Lance Testing




This technique involves forcing a high-pressure jet of air along the weld edge. Signs of lifting or bubbling provide an indication of an unsatisfactory seam weld.

5.1.3 Vacuum Box Testing

This method is used in areas of complex welding detail, or where other methods are not feasible, and comprises treating the area of the barrier membrane to be tested with a soap solution and a vacuum box over the soaped area. Leaks are detected by the appearance of bubbles.

5.1.4 Air Pressure Testing of Double Seam Welds

There is a risk of irrevocably stretching the material when over-pressurising the channel. Air Pressure Testing of double seam welds is therefore not recommended.

5.2 Qualitative Destructive Testing

Destructive testing should be minimised to preserve the integrity of the barrier membrane. If specified, the following is recommended:

5.2.1 Sampling Procedure

The Installer shall cut a 25mm wide field tab from the beginning and end of each completed seam and shall subject it to qualitative destructive testing in peel mode using an independently calibrated field tensometer.

Using a field tensometer, the inspector shall test a minimum of five 25mm wide samples for peel strength.

The Installer shall also record the date, location, and pass or fail description.

NOTE: Welded seams must be allowed to cool before performing any peel testing; testing warm seams will

provide false peel test result.

5.2.2 Field Testing

The seam will be deemed to have passed qualitative destructive testing if the failure occurs solely in the parent material and does not encroach into the seam. The seam will be deemed to have failed if any of the failure encroaches the seam.

The peel test indicates whether or not the sheets are homogeneously and satisfactorily joined through the material thickness. The test specimen is pulled perpendicular to the weld until complete separation occurs. Analysis of the fracture surfaces provides qualitative information about the joint integrity. Ductile failure in the parent material indicates a good quality weld.

If the correct welding parameters have not been followed during the welding process, it will become clear when specimens are peel tested. This type of test is an aggressive test of a seam weld. For example, if the temperature of the hot air wedge was set too hot in relation to the speed of operation, then it is most likely that the area of the material beside the weld is brittle and will break at a lower than expected value.

5.2.3 Procedures for Destructive Test Failure

Whenever a sample fails the field destructive test, the following procedures shall apply:

The Installer can retrace the welding path to an intermediate location (usually 3 metres from the location of the failed test), and take a sample for an additional field test. If this test passes, then the weld shall be patched between that location and the original failed location. If the test fails, then the process is repeated.

The Installer shall patch the weld between the failed location and any passed test locations.

Over the length of weld failure, the Installer shall either cut out the old weld, reposition the panel and re-weld or weld a patch.

5.2.4 Archive Samples

The installer should prepare a welded seam sample 0.5m wide by 1.5m long which will be cut into three sections; one section to be tested by the Installer, one section to be sent to an off-site laboratory if required, and the third section to be kept in archive storage by the client. Standard procedure is for the Installer to cut ten tabs from his portion of the sample and to test each alternative one in peel and shear.

6. DETAILS

6.1 Corners

In tight corners, trimming away excess membrane may be necessary. When trimming the membrane, sufficient overlap (minimum 100mm) should be left to provide material for hot air welding. The corner should be reinforced with a formed patch of the membrane and should extend at least 150mm outside the first corner welds in order to ensure that they are completely covered.




Outside corners should also be reinforced by hot air welding a strip of membrane material extending a minimum of 50mm either side of the corner.

6.2 Connections to concrete structures

Connections to concrete structures are typically made by either embedding a Polyethylene channel into the concrete to which the membrane can be welded or by mechanically fixing using a drilled steel flatbar.

6.3 Drains and flanges

A concrete base is required to anchor the discharge pipe and flange. The membrane should be mechanically fastened to the flange and sealed.




6.4 Ancillaries

Gasket Materials:

Sealants:

Metal battens:

Fastenings:

Embedded channels:

Vents and Top hats:

min. 5mm closed-cell Neoprene

Bitumen or Silicone, as compatible

min. 6mm x 60mm stainless steel

Stainless steel (bolts, nuts, washers etc.)

High Density Polyethylene (HDPE)

Vents and Top hats shall be made from Puraflex

6.5 Flashing of penetrations

The pipe needs to be firmly anchored and the pipe temperature must not exceed 60 ºC.

Where the pipe is to penetrate, cut a hole in the membrane ensuring a tight seal is made without stretching the membrane. Top hats should be installed around penetrations.

The pipe and the membrane are flashed together by creating three cut-outs of the membrane material and hot-air welding as illustrated.




6.6 Anchor trenches

Top anchoring the membrane is achieved by holding it in place in a trench, minimum 400 x 400 mm. All corners over which the membrane rests should be rounded. The membrane should be covered where intermediate or base anchoring is necessary, the membrane can be anchored using an anchor trench or ballast. Where the ballast is above the membrane, a protective geotextile should be used.

6.7 Foundations

6.7.1 When used as a barrier in building foundations, Puraflex® membrane should be continuous over the whole floor

plan area of the structure and stepped down across the cavity. Cavity walls, voids formed in hollow concrete block walls etc. should be sealed to avoid accumulation of vapours or gas.

6.7.2 Puraflex barrier membrane can be laid over raft formations and suspended concrete floors or under-ground bearing slabs and suspended timber floors.

6.7.3 When placed over concrete, the concrete should be dense, smooth and free from any projections which may damage the barrier membrane. The barrier membrane should then be covered with the insulation, screed or other suitable protective layer as soon as possible after installation.

6.7.4 When placed beneath ground bearing slabs, both sides of the barrier membrane should be adequately protected with a sand or concrete blinding layer to a minimum thickness of 50mm or a suitable needle-punch geotextile. The underside of the barrier membrane should not be laid directly onto a granular fill. When reinforced concrete is to be laid over the membrane, wire reinforcements or spacers must not contact the barrier membrane.

6.7.5 The barrier membrane should be sufficiently loosely laid against upstands to ensure that the barrier membrane is not stretched or displaced when applying the screed or concrete.

6.7.6 Service penetrations should enter the building above the sealed floor slab. Where this is not possible, penetrations should be kept to a minimum. Where services need to penetrate the membrane, Top Hat gas tight seals are required around each point of entry.

6.7.7 Where applicable, soap bars should be positioned on the inside cavity wall blocks so that timber frame constructions do not puncture the barrier membrane.




6.7.8 Typical Arrangements – Raft Formation (CAD Drawings available on request)




6.7.9 Typical Arrangements – Ground Bearing Slab (CAD Drawings available on request)







6.7.10 Typical Arrangements – Suspended Concrete Floor (CAD Drawings available on request)




6.7.11 Typical Arrangements – Suspended Timber Floor (CAD Drawings available on request)




6.7.12 Typical Arrangements – Service Penetrations (CAD Drawings available on request)




7. APPENDIX

7.1 Defects and Repair Procedure

All welds and non-weld areas of the barrier membrane shall be inspected by the Inspector for defects, holes, blisters, un-dispersed raw materials, and any sign of contamination by foreign matter. The surface of the barrier membrane shall be clean at the time of inspection.

Any lining surface showing injury due to scuffing, penetration by foreign objects, or distress from rough subgrade, shall be replaced or covered, and sealed with an additional layer of lining of the proper size, in accordance with the repair procedure.

7.1.1 Evaluation

Each suspect location in weld and non-weld areas shall be non-destructively tested as appropriate in the presence of the Inspector. Each location that fails the non-destructive testing shall be marked by the Inspector, and repaired accordingly.

7.1.2 Repair Procedures

Defective welds shall be patched or replaced.

Pinholes and small holes shall be repaired by patching.

Tears shall be repaired by patching. If the tear is on a slope or an area susceptible to stress and has a sharp end it must be rounded prior to patching.

Blisters, large cuts and un-dispersed raw materials shall be repaired by patching.

The patch shall be round or oval in shape made of the same barrier membrane and should extend at least 150mm outside the damaged area in order to ensure that the damaged area is covered completely. The patch should be prepared and welded using a hot air gun with a fishtail nozzle. The two surfaces to be welded are heated with the hot air gun until melting occurs on both surfaces. Pressure is then applied to the patch by means of a hand roller until the weld cools.

7.1.3 Verification of Repairs

Each repair shall be non-destructively tested. Repairs that pass the non-destructive test shall be taken as an indication of an adequate repair. Failed tests indicate that the repair shall be repeated and retested until passing test results are achieved.

The Inspector shall keep documentation of all non-destructive and destructive testing. This documentation shall identify all welds that initially failed the test and include evidence that these welds were repaired and successfully retested.

7.2 Welding Equipment

Welding trials were carried out using a Leister Twinny-S hot air wedge welding machine with a maximum welding pressure of 500N at the nip, a maximum temperature of 600 ºC, a maximum traverse speed of 4m/min and a power rating of 1900W.

7.2.1 Summary of hot air wedge welding trials:

Sample No.

Temp Speed Pressure Roller Type

1

Av. Max Load (N)

ºC m/min Newtons start mid end

1 500

4.0 400

25mm knurled

single seam

157 163 160

2 475 160 162 163

3 450 158 155 152

i Smooth rollers tended to leave a rippled surface finish that may lead to a possibility of stresses being unevenly distributed leading to premature failure.

ii Trials using heated wedge machines determined that it was difficult to start the weld run and unsatisfactory joints were produced. This is a common problem with electrically heated wedge welding of thinner sheets because of the physical contact between the hot wedge and the material.

7.2.2 Welding equipment recommendations:

Type: Hot air wedge welder, Leister Twinny-S or similar

Roller: Single seam with 25mm knurled roller

Initial Settings: Hot air temperature 450-500 ºC, approx. 4m/min at 400N

These settings are recommended as a starting point when welding on site. Mechanical testing of ‘start-up’ trial welds should be carried out at the start of each day so that, depending upon site conditions, the appropriate machine adjustments can be made to ensure that a good weld is achieved.




7.3 Laboratory Testing of Welded Seams

Laboratory testing of seam welds should be in accordance with BS EN 12814

Specimens should be 25mm wide x 150mm long and tested at a constant crosshead speed of 50mm/min until failure or excessive yield occurs.

Independent laboratory test results of seam welds to BS EN 12814 are as follows:

Specimen No. 1 2 3 4 5 6 7 8 9 Mean

Tensile Strength (N) 170.0 165.0 163.5 166.5 170.0 170.0 163.5 168.5 166.5 167.1

7.4 Weather Protection

The two main elements that cause disruption to the installation are water and wind.

7.4.1 The only effective protection against rain is to utilise a tent or canopy when carrying out repairs or localised welding but in general, rain will bring to a halt all welding procedures.

Membranes should not be deployed in areas of standing water. However, where there is standing water on the surface of the membrane it is possible to remove it by means of a pump, wet-vac or by a hand held squeegee. Dry cloths can then be used to dry the seam prior to welding.

7.4.2 Wind causes problems in two ways.

i The membrane lifts once the wind gets under it and is impossible to control. Therefore, membrane deployment should only take place during calm conditions. It is crucial that exposed membrane panels are ballasted immediately after deployment using sandbags or tyres, particularly in the area of the exposed edge. On embankments trout-lines are used to ballast membrane panels. Trout-lines are a line of sandbags (usually at one metre intervals) connected by a rope secured in an anchor trench at the top of the slope using an anchor pin.

ii It has the effect of decreasing the temperature of the hot air flow during welding. The only means of protecting against wind is to use a shield held in place by a technician directly in the path of the wind, just in front of the welding device.

The sun may also cause the membrane to wrinkle that can be a problem for welding. The top membrane expands more than the bottom membrane that leads to problems feeding the membrane through the welder drive rollers resulting in the welder burning through the material.

Wherever possible, perimeter connections between embankments and flat areas should be carried out at the coolest time of the day or night when the membrane is fully contracted. This minimises the risk of causing a trampoline effect at this critical point.



PAGE 19 OF 20

7.5 Sample Field Seam Weld Record

INSTALLATION TEST

Date Time Seam

Ref.

Welder

Name

Equipment Weather

Sample No.

NDT

Visual Inspection

Peel Test

Pass or Fail

Inspection

Machine Ref. No

Hot Air Temp

ºC

Machine Operating

Speed

m/min

Ambient

Temp

ºC

Wind

Speed

m/sec

Date

Pass

or

Fail

Date Tab 1 Tab 2 Tab 3 Tab 4 Tab 5

CQA Name



Puraflex is a Trade Name of Industrial Textiles & Plastics Ltd. E&OE. Industrial Textiles & Plastics Ltd 2014

Industrial Textiles & Plastics Ltd Stillington Road Tel: +44 (0)1347 825200 Easingwold Fax: +44 (0)1347 825222 York YO61 3FA www.puraflex.com United Kingdom [email protected] Cert No. 2318/00

7.6 Useful References

ASTM D 6392 - Standard Test Method for Determining the Integrity of Nonreinforced Geomembrane Seams Produced using Thermo-Fusion Methods

BS EN 12814-4 - Testing of welded joints of thermoplastics semi-finished products. Peel test

BS EN 13067 - Plastics Welding Personnel - Qualification testing of welders - thermoplastics welded assemblies

BS EN 13719 - Determination of the long term protection efficiency of geotextiles in contact with geosynthetic barriers

LFE2 - Cylinder testing geomembranes and their protective materials

LFE4 - Earthworks on landfill sites

LFE5 - Using geomembranes in landfill engineering

LFE6 - Guidance on using landfill cover materials

LFE7 - Using nonwoven protector geotextiles in landfill engineering

LFE8 - Geophysical testing of geomembranes used in landfills

Quality Assurance and Quality Control for Waste Containment Facilities (United States Environmental Protection Agency - USEPA).

Waste Management Paper No. 26B, Landfill Design, Construction and Operational Practice

FURTHER INFORMATION

For the latest technical information, please refer to the following publications which are available from our technical department or in digital format from our website (Registration required):

Puraflex Brochure

Product information detailing relevant standards and test methods, our comprehensive chemical resistance testing programme, production and quality assurance

Puraflex Technical Briefing

An technical summary of chemical resistance test methods and details of the science incorporated in Puraflex’s barrier technology

Puraflex Permeation Modelling (PPM) Software

PPM is a unique software program which uploads soil analysis concentrations to report and provide permeation data of priority hydrocarbons and toxic industrial chemicals for incorporating in contaminated site risk assessment models (e.g. CLEA)

Puraflex Product Data

Comprehensive test data for mechanical, hydraulic, thermal, durability and chemical resistance to BS, EN, ISO and ASTM test methods

Puraflex Model Specification

Suggested specification to assist design engineers in the preparation of project documentation

Puraflex Safety Information

Control of Substances Hazardous to Health (COSHH) & Material Safety Data Sheets (MSDS)

Disclaimer of Express and Implied Warranties

Subject to the limitations, disclaimers and statements as set forth below, Industrial Textiles & Plastics Ltd. (ITP) represents to the Buyer that the product or products delivered to the Buyer conform(s) to the manufacturer's description and specifications attached to or delivered with

the product.

The representation that ITP makes to the Buyer that the product or products conform(s) to the manufacturer's description and specifications applies only under such circumstances when the Buyer utilises the product or products as specified and under normal use for which said product was intended. Any alleged nonconformity shall be made in writing to ITP specifically

stating and describing any such alleged nonconformity.

The representation by ITP that the product or products delivered to the Buyer conform(s) to the manufacturer's description and specification as attached to or delivered with the product is expressly in lieu of all other representations, warranties, expressed or implied, and of all other obligations and liabilities, including consequential damages, on the part of ITP. ITP neither assumes nor authorises any person to assume for it any other liability in connection with the sale of the product.

The representation of conformity by ITP as represented by ITP shall in addition to the above be null and void in the event that the product is misused or handled in a negligent manner by

the Buyer or any third party.

ITP shall not be liable for damages or delays, if such occur, on account of defective material or workmanship or delays in shipment, nor will any allowances be granted for any repairs, alterations, work done or expense incurred in connection with any repairs, alterations or

replacements except on specific written authority by ITP.

ITP excludes to the fullest extent permitted by law any liability or responsibility for injuries or damages to persons or property arising out of the use or operation of the product as herein contemplated, and Buyer hereby agrees to indemnify and save harmless ITP from all such excluded liability and responsibility. Nothing in this disclaimer of express and implied warranties shall limit or exclude ITP’s liability for death or personal injury caused by its negligence or for any other matter in respect of which it will be unlawful for ITP to exclude or

restrict liability.

ITP shall not be liable for any consequential damages for any reason including but not limited to those contemplated herein and whether such consequential damages may have been

foreseeable, proximately caused or otherwise occurring.

ITP emphasises that the data for the chemical resistance is based on data from multiple sources. ITP does not guarantee the accuracy and correctness of such data, and does not accept any responsibility for any loss or damage that result from the use by customers or by any third parties to whom such data may be transmitted.

The user is required to carry out the appropriate tests to ensure the suitability and safety of the products for the use envisaged in accordance with all applicable regulations. No warranties or assurances of reliability, suitability or fitness for a particular purpose of specimens or data are offered. Final determination of the suitability of any information or material for the use contemplated and the manner of use is the sole responsibility of the user and the user must

assume all risk and liability in connection therewith.

The information in this document, specifications, samples and Puraflex Permeation Modeller software are merely illustrative and do not form part of any contract or any intended contract. They are supplied free of charge. Test results are obtained under laboratory conditions on new material and not under actual usage conditions. Test results only relate to the sample

tested.

Due to a policy of continued research & development, ITP reserves the right to alter the details as described without notice. Products are offered subject to our Conditions of Sale, which are

available on request.

This disclaimer of Express or Implied Warranties constitutes a significant limitation on the rights and remedies otherwise available to the Buyer, which the Buyer freely and voluntarily acknowledges and accepts as part of the consideration for the contract to purchase the product or products from ITP.

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