1.0       INTRODUCTION

This construction quality assurance (CQA) plan provides guidance to COMPANY NAME’s environmental quality control (QC) and quality assurance (QA) personnel (or their representatives) and their contractors involved with the installation of geomembrane lining systems in existing concrete secondary containment structures, such as under transformers.  This document specifically covers the use of PVC – KEE (ketone ethylene ester) alloy geomembranes of which XR-5 is one trade-named product.

The premise of geomembrane lining systems is that the geomembrane functions solely as a barrier and not a load-bearing member of the system.

2.0       QUALITY PROGRAMS

QC is a system of procedures observed by a contractor on its own work to ensure that the quality objectives are met.

QA is a system of procedures observed by the owner or a third party to ensure that the work of a contractor meets the designed objectives with good workmanship.  QA cannot be performed by a contractor on its own work on behalf of the owner.

3.0       PARTIES TO THE PROJECT

3.1       Resin Manufacturer - manufactures the resin from which the geomembrane rolls are made.   

3.2       Geomembrane Manufacturer – manufactures the geomembrane rolls.  The geomembrane manufacturer is ________________________.

3.3       Fabricator – assembles the rolls into large panels in a controlled plant environment.  The fabricator is ___________________.

3.4       Installer – installs the lining system.  The installer is _________________________.

3.5       Project Engineer – designs and is responsible for the functioning of the lining system.  The project engineer is __________________________.

3.6       CQA monitor – the owner’s representative monitoring the quality of the material and its proper installation.   The CQA firm is _______________________.

3.7       CQA laboratory – an independent laboratory that tests material samples on behalf of the owner.  The CQA laboratory is _______________________.

4.0       QUALIFICATIONS OF THE PARTIES

4.1       Manufacturer

The geomembrane manufacturer shall have manufactured at least 1,000,000 m² of the same geomembrane proposed for use in the project and shall have a comprehensive QA/QC program that provides a QC certificate for each roll of geomembrane manufactured

4.2       Fabricator

The geomembrane fabricator shall have fabricated at least 1,000,000 m² of the same geomembrane proposed for use in the project and shall have a comprehensive QA/QC program that provides a QC certificate for each panel of geomembrane fabricated and shipped to the site.

4.3       Installer

The geomembrane installer shall have installed at least 500,000 m² of the same geomembrane as proposed for use in the project and shall have a comprehensive QA/QC program that generates a formal comprehensive QC report for the project engineer/owner. 

The installer shall have QC personnel specifically identified for monitoring each project.  This QC manager shall have experience of installing at least 250,000 m² of the same geomembrane proposed for use in the project.   The QC manager for the project is _______________________.

The installer’s Master Seamer on the project shall have experience of welding at least 250,000 m² of the same geomembrane as proposed for use in the project, of which at least 50,000 m² shall be in concrete structures.  The Master Seamer is ______________________.

4.4       CQA

CQA personnel shall have performed CQA on at least 500,000 m² of reinforced geomembrane of which at least 50,000 m² is the same geomembrane as proposed for use in the project.   The CQA Superintendent is __________________.

4.5       CQA Laboratory

The laboratory shall be accredited with the Geosynthetic Accreditation Institute Laboratory Accreditation Program (GAI-LAP) for all tests to be performed on the project geomembrane and its seams.

5.0       SCOPE OF CQA

The scope of this CQA Plan includes:

1.                  Review of project documents

2.                  Resin manufacturing

3.                  Geomembrane manufacturing

4.                  Geomembrane panel fabrication

5.                  Transportation and handling

6.                  Condition of concrete and soil substrates

7.                  Liner installation

8.                  Material, seam, and liner testing

9.                  Covering the geomembrane

6.0       UNITS

In this CQA Plan, all parameters, properties, and dimensions are expressed in SI units.   If the geomembrane manufacturer, fabricator, or installer provide US or Imperial units a hard conversion to SI units shall govern.   Conversion factors shall be as presented in ASTM standard E380.

The CQA laboratory shall provide all test results in SI units.

7.0       SUBMITTALS

The following submittals shall be required with the Installer’s proposal:

• Resin manufacturer’s QC Program including a sample of a QC certificate
• Geomembrane manufacturer’s QC Program including a sample of a roll QC certificate  
• Manufacturer’s geomembrane specification sheet
• Manufacturer’s list of recent projects totaling 1,000,000 m² and associated contact details
• Fabricator’s QC Program including a sample of a panel QC certificate, and a sample of a factory seam
• Fabricator’s list of recent projects totaling 1,000,000 m² and associated contact details
• Details of folding/rolling panels for shipping
• Installer’s QC Program including samples of all field logs/records, a sample of a field seam, and an outline of a final installation report
• Installer’s list of recent projects totaling 500,000 m² and associated contact details
• Details of all liner connections at batten strips, pipe penetrations, grounding wire penetrations, and inside corners
• A list of questions concerning any unclear items in project documentation

The following submittals will be required two weeks prior to delivery of material to the site:

1.                  Installer’s proposed panel layout for the project

2.                  Resume of proposed QC manager for the project and a list of recent projects/contacts

3.                  Resume of proposed Master Seamer for the project and a list of recent projects/contacts

4.                  A statement by the Installer that all project documents have been reviewed, all queries satisfactorily answered, and that all project requirements can be complied with by manufacturer, fabricator, and installer

The following submittals will be required prior to shipping materials from the Fabricator:

1.                  Resin QC certificate

2.                  Manufacturer’s QC certificates for each roll of geomembrane

3.                  Fabricator’s QC certificates for each panel, including test results for each factory seam.   Seam tests shall be performed on production seams and not on separately made seam samples.

No material shall be shipped from the Fabricator prior to receipt of these documents nor without the approval of the Project Engineer.

8.0       PROJECT MEETINGS

Prior to the start of liner installation a Preconstruction meeting shall be held between Owner, Project Engineer, Installer, and CQA superintendent to jointly agree on the installation procedures and to clarify any unclear details of project documents.

An Action Decision Meeting will be held when a problem occurs that requires a procedural decision by the Owner/Project Engineer.   The problem shall be documented together with proposed actions, the action finally agreed upon, and the party responsible for implementation of the action.

9.0       GEOMEMBRANE MANUFACTURING

The geomembrane material shall be an ethylene interpolymer alloy (EIA) such as 8130 XR-5 manufactured by Seaman Corporation, or an equivalent EIA with specifications as shown in Table 1.

All rolls shall be manufactured from the same batch of resin.

Rolls shall have the reinforcement covered by polymer along each edge.

Table 1.           Geomembrane specifications

10.0     PANEL FABRICATION

Geomembrane rolls shall be fabricated into large panels under controlled environmental conditions.   Welds shall be made using hot wedge or dielectric equipment.   Welds shall be single track welds a minimum of 25 mm wide or double track welds.  

The welding process shall generate similar small visible “squeeze-out” beads along each edge of each seam.   The reinforcement shall not be exposed along roll edges.

All seams shall be 100% nondestructively tested using the air lance technique.

One seam at each end of each panel (not the same seam) shall be destructively tested in peel and shear according to ASTM standard D751 as modified in National Sanitation Foundation International Standard NSF 54.    Five specimens shall be tested in peel and five in shear from both samples.   Both samples shall meet the seam specifications listed in Table 2.

Table 2.           Seam specifications

11.0     PACKING AND TRANSPORTATION

When possible panels shall only be rolled for shipping.    If panel widths require it, they shall be accordion folded along the length and rolled for shipping to the site.   A rigid core shall be used to aid with handling.   Panels will not be accordion folded in more than one direction.

Each panel shall be identified with a label showing product type, panel number, width, length, and weight.

Sufficient excess material shall be supplied to allow discarding of the outer wrap should it be damaged during shipment and on-site storage and handling.

The bed of the shipping truck shall be examined carefully and all sharp rough objects removed prior to loading the geomembrane rolls.

12.0     GEOMEMBRANE STORAGE AND HANDLING ON SITE

Geomembrane rolls shall be lifted from the truck using appropriate equipment with at least two broad slings.

Rolls shall be stored on a smooth flat clean surface in a location close to the transformer where they will not be damaged, where there is no possibility of standing water, and where they will not become dirty.

Rolls shall be stacked no more than three high.

13.0     INSTALLATION

Folded geomembrane panels shall not be unrolled or unfolded at geomembrane temperatures below 0^oC.   Panels may, however, be unrolled at lower temperatures if they have not been folded.

13.1     Subgrade

The surface of the concrete on which the geomembrane is to be placed shall be carefully examined for unacceptable roughness and steps exceeding 2 mm in height or depth.  Any such roughness shall be ground smooth or filled.    Cracks exceeding 1 mm in width shall be filled with a supporting grout.   Outside corners shall be rounded to a minimum radius of 5 mm.

Any soil subgrade shall be compacted smooth to an adequate uniform density to prevent differential settlement.   The top 50 mm of the subgrade shall be free from angular rocks larger than 5 mm, roots, grass, and biodegradable vegetation.   Foreign materials and protrusions exceeding 5 mm shall be removed.   All desiccation cracks shall be filled/smoothed and all steps exceeding 5 mm shall be smoothed.  

The subgrade surface shall be maintained in a firm, clean, smooth, and dry condition during liner installation.   Unless otherwise agreed the Installer shall be responsible for maintaining the condition of the subgrade surfaces.

The Installer shall provide and sign documentation indicating that the subgrade is acceptable for the installation of the geomembrane and that it will not compromise the performance of the geomembrane.

The geomembrane shall be installed without stress and in such a way that it is fully supported by the subgrade, including in 90^o inside corners.   It shall not bridge corners or other geometrical features.

The number of field seams shall be minimized.

13.2     Batten strip attachments

Batten strip attachments to the concrete shall be made according to the project drawings or according to ASTM standard D6497.   Batten strips shall be manufactured using Type 304 stainless steel with a minimum cross section of 35 mm by 7 mm.   Type 304 stainless steel threaded stock and bolts shall be used at a maximum center-to-center spacing of 300 mm.   The nearest fastener shall be centered no more than 75 mm from the end of a batten strip.   Batten strips shall extend completely into the inside, or to the edges of outside, corners.    At inside corners and at other locations where the geomembrane could be tensioned against a corner of the batten strip the corner shall be ground round and smooth.    Similarly, at outside corners where sharp corners on the batten strip might present a hazard to workers the corners of the batten strip shall be ground round and smooth.

The primary gasket, between geomembrane and concrete shall be a non-connected porosity neoprene rubber.  There shall also be secondary gasketing between the batten strip and the geomembrane, in which the bolt holes shall be no larger than the bolts.   Elongated holes in the batten strip shall be filled with sealant compressed by the washer under the fastening nut.

At inside and outside corners where tightening the batten strips might lift the geomembrane away from the corner, sealant shall be carefully placed between the geomembrane and the concrete.

Pipe penetrations shall be booted according to the project drawings or according to ASTM standard D6497.   Corrugated pipes shall be replaced with smooth plastic pipes.

Every attempt shall be made to avoid folds and creases in the geomembrane particularly under batten strips.    Folds (commonly referred to as “fishmouths”) shall be cut along the peak, the edges overlapped and a hot-air seam made to minimize the thickness of the liner behind the batten strip.   Where folds are unavoidable, a thin layer of sealant shall be placed on the mating surfaces inside the fold, to eliminate leakage down the inside of the fold.

At features such as fishmouths and folds that are cut, overlapped, and seamed, where there is insufficient overlap to make an effective seam, such as at the end of the cut, a patch shall be placed over the end of the cut.

When liner edges are left exposed for any length of time, such as overnight, they shall be suitably ballasted (using sandbags, undamaged tires, or other smooth-surface items) against uplift by reasonably expected winds.

13.3     Trial Seaming

Prior to the start of a production seaming shift and at least every 5 hr a trial seam shall be made by each weld machine/operator combination using a fragment of geomembrane.    The trial seam shall be made under the conditions of the planned production seaming – on a horizontal or vertical concrete or soil substrate accordingly.    The trial seam shall be at least 1.5 m long.

Five peel and five shear specimens shall be cut from the center of the trial seam and tested alternately in peel, shear, peel, shear, etc.   All specimens shall meet the seam specifications listed in Table 2.   In the event of nonconformance, an additional trial seam shall be made and tested.  If this still fails to meet specifications the welding machine shall be examined and adjusted and not used for production seaming until two passing trial welds have been made.

New trial welds will be required whenever the geomembrane temperature changes by more than 25^oC.

13.4     Production Seaming

Production seaming shall only commence when passing trial seams have been made.   If adjustments to the machine are felt to be necessary, the machine is switched off for any reason, or the operator is changed, new passing trial welds will be required before production seaming can continue.

At least once per hour a field seam shall be extended longer than required and four specimens removed from it – two to be tested in peel and two in shear.   All four specimens shall meet seam specifications.   If seam specifications are not met the seam shall be sampled at intermediate locations since the last passing test until the full extent of the nonconformance can be defined.   The seam shall be made good from the last passing test sample.

When recording seam test data all failing test data shall be recorded.

13.5     Nondestructive testing

Every millimeter of all seams shall be nondestructively tested by air lance testing (single track welds), air pressure testing (dual track welds) according to ASTM standard D5820, or vacuum box testing (single track welds) according to ASTM standard D5641.

13.6     Seam edge air lance testing

Air lance testing will performed using a 5 mm diameter nozzle and an air pressure exceeding 400 kPa with the nozzle held no more than 100 mm from the edge of the seam.   The speed of the nozzle along the edge of the seam shall not exceed 15 m/min.    Any location of seam edge flapping, whistling, or other abnormal motion/noise shall be marked for repair.  

13.7     Center channel air pressure testing

When air pressure testing is performed the applied pressure shall be between 165 and 210 kPa, and pressure loss shall not exceed 4 kPa in 5 minutes after a 2 minute stabilization period.  At the conclusion of the test the pressure shall be released from the opposite end of the seam to the end at which the pressure is applied to demonstrate that the full length of seam has been tested.    All needle holes shall be repaired. 

13.8     Vacuum box testing

When vacuum box testing is performed, the applied vacuum shall be between 20 and 35 kPa.  The locations of any bubbling within 10 seconds of vacuum application shall be repaired.

At the conclusion of seam nondestructive testing the complete lining system shall be filled with water to at least 50 mm above the top edge of the highest batten strip for a hydrostatic pressure test.  With all outlets sealed, the water level decrease shall not exceed 20 mm in 24 hr.   If this loss rate is exceeded the source of leakage shall be located, repaired, and the structure refilled and retested.

Where possible inner and outer sections of the containment structure shall be hydrostatically tested separately.

13.9     Laboratory testing

Samples shall be removed by the project engineer from the ends of two factory seams of each panel delivered to site for CQA laboratory testing.   Testing shall be performed according to ASTM D751 (modified by NSF 54) and the specifications of Table 2 shall be met by all five peel and all five shear specimens.    Failure of this testing shall result in rejection of the panel which shall be replaced by the Installer at its expense.

A section of at least one trial seam made by each machine/operator combination each day shall be submitted to the CQA laboratory for seam testing according to ASTM D751 (modified by NSF 54).   All five peel and shear specimens shall meet project specifications as listed in Table 2.   A failure of this testing shall result in removal of a sample from the field seam previously made by that machine, for CQA laboratory testing.   Failure of this additional sample shall result in rejection of all field seams made by that machine/operator combination since the last sample passed by the CQA laboratory.

13.10   Defects and repairs

All repairs will be made using a patch cut from the geomembrane material delivered to site.

Patches will overlap any damaged area by at least 75 mm in all directions.

Patches will have rounded corners and will be attached using hot air welding equipment such that there are no loose edges.

All patches will be tested using an air lance or a vacuum box.

Patches shall not be placed overlapping other patches.   Where this might occur one large patch will be placed to avoid the appearance of multiple patches.

14.0     RESPONSIBILITY FOR LINER

The liner will remain the responsibility of the Installer until a completed construction report has been presented to the Owner by the Installer and all test results have been satisfactorily obtained from the CQA laboratory.    The construction report will include:

• Material QC certificates
• Subgrade acceptance documents
• Trial welding records, including all failing test details
• Production welding records
• All seam test results including failing results
• All repair records, including test results
• All hydrostatic test data
• Details of any problems and their resolution e.g. concrete condition, pipe  or grounding wire penetrations
• Modifications to liner required during construction
• Copies of Manufacturer’s and Installer’s warranties
• Evidence of satisfactory covering of the geomembrane when covering layers are the responsibility of the installer

15.0     COVERING LAYERS

The geomembrane shall be covered in such a way that it is not damaged.  

A nonwoven polypropylene (stabilized against ultraviolet and thermal degradation) geotextile cushion layer, with a minimum mass/unit area of 540 g/m² shall be used.   Geotextile overlaps shall be stitched or thermally bonded.

A “fire quenching” layer of 19 – 37.5 mm crushed stone shall be placed on top of the geotextile without damaging the geomembrane.   The crushed rock shall not be dumped directly from a truck onto the liner.   It shall initially be dumped on to adjacent ground and spread from there by wheelbarrow, or other moving equipment, to produce an area with a thickness of at least 600 mm.   Care shall be taken that projections on the equipment do not damage the liner when it is emptied.    Subsequently, stones may be dumped on this area, and spread from there using motorized equipment with ground pressures of less than 75 kPa.   Nevertheless such equipment shall not stop or start suddenly, nor turn sharply such that shear forces are generated at the stone/geotextile/geomembrane interfaces.

The covering layer shall be a minimum of 750 mm thick.

16.0     CQA REPORT

A CQA report will be prepared by the Project Engineer to demonstrate clearly that all requirements of the project specifications, the project drawings, and this CQA Plan have been complied with.   The objective of the CQA Plan is to provide full traceability of materials, men, and equipment such that the potential extent of any problem that arises during service can be quickly defined.

17.0     WARRANTY

TO BE COMPLETED BY COMPANY NAME IF REQUIRED.   WARRANTY SHOULD BE AT LEAST ONE YEAR ON INSTALLATION (FIVE YEARS SHOULD NOT BE UNREASONABLE, AS PROVEN BY AN ANNUAL HYDROTEST) AND 20 YEARS ON MATERIALS.   HOWEVER, A 20 YEAR PRO-RATED MATERIALS WARRANTY HAS RELATIVELY LITTLE PRACTICAL VALUE.   THE FABRICATOR SHOULD ALSO PROVIDE A WARRANTY OF AT LEAST TEN YEARS ON THE FACTORY SEAMS.