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9. GEOMEMBRANE MANUFACTURING, TRANSPORTATION, AND STORAGE

9.1 High Density Polyethylene Geomembrane Manufacturing

The geomembrane shall be manufactured from a medium or high density polyethylene resin. Only one type of resin (one manufacturer, one resin classification) shall be used to manufacture geomembrane for this project.

9.1.1 Raw Material

The raw material will be first quality polyethylene resin containing no more than 5% clean post-industrial (edge trim) recycled polymer by weight, and meeting the following specifications:

This is the industry standard. It is very difficult to analyze the amount of recycled polymer being used, although dirty badly degraded material could be detected. The use of post-industrial material (edge trim etc.) presents little concern, but post-consumer recycled material should not be used. In the gas pipe industry HDPE is regularly made with up to 10%, and even 100%, of clean recycled material, without loss of performance.

Specific Gravity (ASTM D792 Method A or ASTM D1505):
>0.930 (without carbon black);

The specific gravity of the geomembrane, with carbon black, should exceed 0.940. 1% of carbon black adds approximately 0.005 to specific gravity value.

Melt Index (ASTM D1238 (190/2.16)): 0.05 - 1.0; and

Stress Rupture Transition Time (ASTM D5397): > 200 hr

The stress rupture transition time should be an absolute minimum of 100 hr as specified in GRI-GM13 and could be as high as 600 hr or more depending on the criticality of the installation, the likely amount of installation damage, and the service conditions. There are presently only a few HDPE resins with transition times exceeding 5000 hr. In 1993, the stress rupture resistance of commercially available HDPE geomembranes varied by a factor up to 1000. Making this the single most important durability parameter for the different HDPE resins.

Quality Control certificates issued by the Resin Manufacturer shall be presented by the Installer to the CQA Consultant to show that these specifications have been met and to identify the type of resin.

Internal Quality Assurance testing will be carried out by the geomembrane Manufacturer to demonstrate that the incoming resin meets this specification. At the Owner's discretion, additional conformance testing, paid for by the Owner, may be carried out at the CQA Laboratory. If the results of the Manufacturer's Quality Control (QC) Laboratory and the CQA Laboratory testing differ, the testing will be repeated by the CQA Laboratory, and the Manufacturer will be allowed to monitor this testing. The results of this latter series of tests will prevail, provided that the applicable test methods have been followed.

Prior to the installation of any geomembrane material, the Manufacturer will provide the Project Manager and the CQA Consultant with the following information:

The origin (resin Supplier's name), identification (type, lot number), and production date of the resin;

a copy of the Quality Control certificates issued by the Resin Supplier;

reports on the tests conducted by the Manufacturer to verify the quality of the resin used to manufacture the geomembrane rolls assigned to the project. At a minimum, these tests should include specific gravity (ASTM D792 Method A or ASTM D1505), and Melt Index (ASTM D1238 (190/2.16)); and

a statement that no post-consumer recycled polymer has been added to the raw resin. However, the use of clean post-industrial polymer recycled during the manufacturing process may be permitted if done with appropriate cleanliness and if recycled polymer does not exceed 5% by weight).

The CQA Consultant will review these documents and report any discrepancies to the Project Manager.

9.2 Geomembrane Plant Audit

A Plant Audit and pre-delivery conformance testing are extremely beneficial if a large amount of material is being purchased or if it is being shipped long distances, when major delays could result if unsatisfactory material is discovered after delivery at the site.

9.2.1 Scope

The CQA Consultant shall (you may wish to say "may", thus leaving the option open) perform an audit of the manufacturing and quality control procedures used by the Manufacturer specifically for the production of the HDPE geomembrane to be used for installation at the Owner's facility. The Manufacturer shall give the CQA Consultant at least 48 hours notice of the start of production of geomembrane for this project. The Owner has the right to refuse acceptance of any geomembrane manufactured within this 48 hr period if his representative is not present. QC tests shall be performed as the geomembrane is manufactured.

9.2.2 Quality Control

The Manufacturer shall make available to the Owner and CQA Consultant Manufacturing Quality Control manuals which outline all quality procedures which will be implemented for the manufacture of the HDPE geomembranes.

The Manufacturer shall provide valid calibration certificates for laboratory testing equipment.

The CQA Consultant shall verify that, during select runs of material, all MQC procedures are performed.

9.2.3 Manufacturing Process

In general, the Manufacturer shall provide access for the CQA Consultant to all equipment used to manufacture the HDPE geomembrane. This does not include divulging trade secrets, additive formulations, and procedures which are not commonly known as basic manufacturing processes used for HDPE geomembranes. However, if the process is critical to the integrity of the manufactured geomembrane, the equipment shall be made accessible to the CQA Consultant.

The CQA Consultant shall monitor production and testing of geomembrane material allocated for this project. If material for this project has already been manufactured, the CQA Consultant shall monitor production of the same type of geomembrane on the same production line to verify that manufacturing controls are in place. The Manufacturer shall provide raw resin QC certificates, resin QA test results, and manufactured geomembrane QC certificates to the CQA Consultant prior to the loading and shipping of geomembrane to the site. The CQA Consultant shall immediately review the QC certificates and notify the Manufacturer in writing which geomembrane rolls are approved for shipping. The CQA Consultant shall be allowed to monitor the loading of the geomembrane for shipping.

You may wish to require the CQA Consultant to sign off the QC test results or certificates, to indicate that such testing has been satisfactorily performed. This could reduce the amount of conformance testing that is required.

9.3 Manufacturing

9.3.1 Submittals

Prior to the installation of any geomembrane, the Manufacturer will provide the Project Manager and the CQA Consultant with the following:

A certified properties sheet including, at a minimum, all specified properties, and test methods indicated in the specifications;

A list of quantities and descriptions of materials other than the base polymer which comprise the geomembrane; and

The internal MQC sampling procedures, frequencies of testing, and results of testing of material supplied to the project.

The CQA Consultant will verify that:

the property values certified by the Manufacturer meet all of the Manufacturer's specifications; and

the measurements of properties by the Manufacturer are properly documented, the test methods used are acceptable, and the geomembrane meets the Project Specifications.

9.3.2 Rolls

Prior to shipment, the Manufacturer will provide the Project Manager and the CQA Consultant with Quality Control certificates covering each roll of geomembrane and welding rod provided. (NOTE: Tests do not have to be done on each roll, they simply need to be done according to an agreed upon frequency, usually defined in the Manufacturer's QC plan.) The Quality Control certificate will be signed by a responsible party employed by the Manufacturer, preferably the QC Laboratory Manager. The Quality Control certificates will include:

resin Manufacturer, resin type, resin lot number, and geomembrane roll numbers; and

results of Quality Control tests. At a minimum, results will be given for thickness, specific gravity/density, uniaxial tensile strength and elongation at yield and break, single point stress rupture time, and carbon black content and dispersion, evaluated in accordance with the methods indicated in the specifications or equivalent methods previously approved by the Project Manager and CQA Consultant. No material will be installed until complete QC test data have been provided.

You may wish to require that no material shall be shipped from the plant until all QC data have been received. This can be difficult to achieve in practice.

The CQA Consultant will:

verify that the Quality Control certificates have been provided at the specified frequency for all rolls, and that each certificate identifies the rolls and resin related to it; and

review the Quality Control certificates and verify that the certified roll properties meet the Manufacturer's and Project Specifications.

9.3.3 Conformance Testing

Conformance testing is not an opportunity to reproduce the QC testing program, but is simply a spot-check to provide confidence that satisfactory material is delivered to the site.

Conformance Testing will, ideally, be performed before material is shipped from the Manufacturer's plant so that it may confidently be used immediately on arrival at the site. However, in many cases it is done when material arrives on the site.

9.3.3.1 In-Plant testing

The purpose of In-plant Material Conformance Test Sampling is to verify that geomembrane material which is designated for the Owner's project is confirmed as meeting the project specifications prior to shipment to the site. Thus, barring a transportation accident, the geomembrane can be installed immediately it arrives on site.

The Manufacturer will make available all necessary personnel and equipment to assist the CQA Consultant in retrieving conformance samples of the geomembrane material.

The CQA Consultant shall send to the CQA Laboratory conformance samples for testing as outlined in Section 9.3.4. The frequency of sampling shall be at the discretion of the CQA consultant but shall typically be between each 10,000 and 25,000 m2 of geomembrane. No material shall be shipped to the site until conformance test results are obtained.

The CQA Consultant shall report any nonconformance of sampling procedures as outlined in Section 9.3.8 to the Project Manager.

9.3.3.2 On-site material testing

If In-Plant conformance testing is not performed, upon delivery of the rolls of geomembrane to the site, the CQA Consultant will ensure that samples are removed at the frequency specified in the Project Specifications (or at the rate shown in Table 1 if not specified) and forwarded to the CQA Laboratory for testing to ensure conformance to both the Project Specifications and the Manufacturer's list of guaranteed properties.

9.3.3.3 Properties of the HDPE Geomembrane

In the absence of any Project Specifications, the HDPE geomembrane shall meet the specifications shown in Table 1.

TABLE 1. HDPE GEOMEMBRANE SPECIFICATIONS AND CONFORMANCE TESTING FREQUENCY

PARAMETER		METHOD	VALUE	CQA TEST FREQUENCY
Average Thickness		ASTM D751*	> nominal value	each roll
Minimum Thickness		ASTM D751*	90% nominal value	each roll
Density (g/cm³)		ASTM D1505ASTM D792	> 0.940	10,000 m2
Melt Index (g/10 min)		ASTM D1238(190/2.16)	0.05 - 1.0	25,000 m2
Tensile Properties		ASTM D638 (IV)*
	Yield Stress (MPa [psi])		>15.2 [2200]	N/A
	Yield Strain (%)		> 12	N/A
	Break Stress (MPa [psi])*		> 20.7 [3000]	10,000 m2
	Break Strain (%)*		> 600	10,000 m2
Tear Resistance (kN [lb])		ASTM D1004	> 1.02 [230]	N/A
Puncture Resistance (kN [lb])		FTMS 101C Method 2065	> 1.89 [425]	N/A
Dimensional Stability (%)		ASTM D1204 1 hr at 100ºC	< 2.0	N/A
Carbon Black Content (%)		ASTM D1603	2.0 - 3.0	10,000 m2
Carbon Black Dispersion		ASTM D2663 (B) ASTM D5596	A1, A2, B1	10,000 m2
Stress Rupture TransitionTime (hr)*		ASTM D5397	> 200	N/A
Stress Rupture Break Time - Single point (hr)*		GRI.GM5 (b)	> 300	N/A

* The thickness of textured sheet may be measured with a pointed tip micrometer - tip radius 0.75 m, tip angle 60°. Optical examination of cross sections offers another (preferred) method of measuring thickness of textured materials. The uniaxial break strength and elongation will vary depending upon the method of texturing. Textured blown film geomembrane will have lower values than secondary process, thermally bonded, textured materials which generally have similar values to smooth materials. For textured and structured materials, the measurement of stress rupture resistance must include the influence of the surface profile, thus notched specimen tests are not appropriate. Having confirmed that the basic resin has adequate stress rupture performance, perform a constant load test on an unnotched strip specimen, 10 mm wide, at 80°C and at a stress of 4 MPa. Repeat the test on the textured/structured material, the latter including the surface profile features. The failure time of the textured/structured specimen(s) should not be less than ____ hr. Seams can be treated the same way.

9.3.4 Conformance Tests

At a minimum, tests to determine the following parameters will be performed on HDPE geomembranes:

density/specific gravity;

melt index;

carbon black content and dispersion;

thickness;

uniaxial tensile break strength and elongation; and

There is no need to perform the following conformance tests, provided the same quality control tests have been performed and reported:

dimensional stability
tear resistance
puncture resistance
uniaxial strength and elongation at yield, and
notched constant tensile load stress rupture

There is no need to perform ESCR tests (ASTM D1693) at all - this test does not provide useful information. There is no need to perform Low Temperature Brittleness (LTB) tests (ASTM D746).

9.3.5 Test Procedures

The following test procedures will be complied with:

density: ASTM D792-66 Method A or ASTM D1505;

melt index: ASTM D1238 (190/2.16);

carbon black content: ASTM D1603;

carbon black dispersion: ASTM D2663 (B) or ASTM D5596;

thickness: ASTM D1593 or ASTM D751 for smooth and structured
geomembranes; optical method for textured geomembranes;

uniaxial tensile properties: ASTM D638 (IV) with no requirement for sample conditioning time.

Where optional procedures are noted in the test method, the requirements of the Project Specifications will prevail.

9.3.6 Sampling Procedures

Samples will be taken across the entire width of the roll and will not include the outer wrap of the roll. Unless otherwise specified, samples will be 500 mm long by the roll width. Specimens for testing will be taken across the full width of the sample.

If more than one resin type is used, each resin type shall be sampled at the same frequencies and tested.

If roll numbers are very different and non-sequential, consideration should be given to testing each block of roll numbers at the same frequency.

If adequate QC testing is performed by the Manufacturer it is not necessary to perform conformance testing at higher frequencies.

9.3.7 Test Results

The CQA Consultant will examine all results from laboratory conformance testing and will report any nonconformance to the Project Manager.

The following procedure will apply whenever a sample fails a conformance test that is conducted by the CQA Laboratory:

The Manufacturer will replace the roll of geomembrane that is in nonconformance with the specifications with a roll that meets specifications.

The CQA Site Superintendent will remove conformance samples for testing by the CQA Laboratory from the next higher and lower numbered rolls. These two samples must both conform to specifications. If either of these samples fail, testing shall continue until the defective rolls are isolated. These rolls will be replaced by the Manufacturer, at no expense to the Owner. This additional conformance testing will be at the expense of the Manufacturer.

The CQA Consultant will document actions taken in conjunction with conformance test failures.

9.4 Delivery

9.4.1 Transportation and Handling

Transportation of the geomembrane is the responsibility of the Manufacturer, Installer, or other party as agreed upon. All handling on-site is the responsibility of the Installer.

The CQA Consultant will verify that:

handling equipment used on the site is adequate and does not pose any risk of damage to the geomembrane particularly to the edges of the geomembrane; and

the Installer's personnel handle the geomembrane with care.

Upon delivery at the site, the Installer and the CQA Consultant will conduct a visual examination of all rolls for defects and signs of damage. This examination will be conducted without unrolling rolls unless defects or damage are found or suspected. The CQA Consultant will indicate to the Project Manager:

any rolls, or portions thereof, which should be rejected and removed from the site because they have unacceptable flaws; and

any rolls which contain minor repairable flaws.

9.4.2 Storage

The Installer will be responsible for the storage of the geomembrane on-site. The Project Manager will provide storage space in a location (or several locations) such that on-site transportation and handling are minimized. Geomembrane rolls will be stored on a smooth, dry, level surface in an area where the geomembrane, particularly the roll edge, is protected from damage. Rolls, particularly textured rolls, will not be allowed to get dirty.

The CQA Consultant will verify that storage of the geomembrane ensures adequate protection against dirt, impact, and other sources of damage.

Rolls will not be stored more than 3 high. Access will be provided to each end of stored rolls for the examination of identification labels and roll edges.