Unreinforced Polypropylene Engineering Specifications


1.1 The work contained in these specifications consists of furnishing and installing Unreinforced Polypropylene lining as shown on the drawings or directed by the project engineer. All work shall be done in strict accordance with the drawings and these specifications and subject to the terms and conditions of the contract. It is intent of these specifications to ensure that a first quality finished product is provided.


2.1 At bid time the contractor must submit the qualifications as per section 5.

2.2 Submittals for the fabrication and installation of the Polypropylene lining material will be provided after the award of the contract. Factory fabrication shall not proceed until the submittals have been approved by the project engineer.

2.3 All certification and test results required in sections 6, 7 and 9 shall be submitted after completion of the Polypropylene installation.


3.1 Polypropylene lining shall consist of 62 inch minimum widths of manufactured Polypropylene sheeting fabricated into large panels by means of special factory bonded seams.

3.2 The Polypropylene must have been satisfactorily demonstrated by prior use to be suitable and durable for such purposes. The materials supplied under these specifications shall be first quality products manufactured specifically for the purposes of this work.


4.1 Polypropylene sheeting shall be manufactured from a composition of high quality ingredients suitably compounded for use in hydraulic structures. Reprocessed or reground materials shall not be used.

4.2 The Polypropylene membrane shall consist of thoroughly mixed Polypropylene compound. It shall be manufactured by the calendering process and shall be uniform in color, thickness, size and surface texture.

4.3 The sheeting shall contain no undispersed materials, divots, deep gas checks and shall exhibit cold flow.

4.4 The sheeting shall be flexible, durable, watertight product free of pinholes, blisters, holes and contaminants.

4.5 The material shall have the minimum physical property characteristics as outlined in the Unreinforced Polypropylene Specification Sheet.


5.1 The manufacturer of the Polypropylene membrane material shall have a minimum of four years of manufacturing experience totaling more than 5,000,000 square feet and shall meet all requirements shown on the Unreinforced Polypropylene Specification Sheet.

5.2 The fabricator and installing contractor of the Polypropylene membrane shall each have a minimum of four years of experience totaling more than 2,000,000 square feet.


6.1 The Polypropylene manufacturer shall show upon request where a minimum of 5,000,000 square feet of material has been manufactured.

6.2 The fabricator and installer of the Polypropylene shall show upon request where a minimum of 2,000,000 square feet of material has been fabricated and installed.

6.3 Certified test results from the manufacturer showing that the Polypropylene meets or exceeds the requirements on the Unreinforced Polypropylene Specification Sheet.

6.4 Third party certification may also be requested at the Owner's expense.



7.1.1 When Polypropylene roll goods are received from the manufacturer, the roll numbers and production lot number(s) given on the packaging list will be verified. The roll goods shall also be inspected for the following: Polypropylene is wound on a 3 inch inner diameter core. Cores extend a minimum 1/4 inch beyond each roll edge. Rolls have not been visibly damage during transit. Straight edges.

7.1.2 In addition to the inspection of the roll goods, random testing shall also be performed on all incoming material. Further evaluation of the Polypropylene shall include testing for the following: Gauge (thickness). Roll width. Dimensional stability. Minimum tensile strengths.

7.1.3 The above test results are compared with the minimum requirements shown on the Unreinforced Polypropylene Specification Sheet. All rolls that fail any of the above inspections or tests will be marked "REJECTED" and returned to the Polypropylene manufacturer.


7.2.1 In order to minimize field seaming requirements during installation, individual rolls of Polypropylene shall be factory fabricated into large panels as outlined on the engineer approved drawings.

7.2.2 Factory panels will be fabricated with thermal fusion bonding.

7.2.3 The following information is recorded for each roll when the Polypropylene rolls are being positioned on to the machine. Roll number. Lot number. Gauge (thickness)

7.2.4 In addition, the rolls are inspected for straight edges.

7.2.5 Rolls that do not meet the minimum thickness requirement will be marked "REJECTED" and returned to the Polypropylene manufacturer.

7.2.6 The seaming equipment will be inspected for proper working components before every production run. The computer on the fabricating machine is set to the pre-determined target temperature and speed. The heating sources on the machine are computer controlled by an infrared temperature probe located at each seaming station. Thus the required temperature for optimum sealing is automatically maintained throughout the production run. The material surface temperature immediately after fusion is monitored to a target temperature of plus or minus 3 degrees Fahrenheit. The computer controls the temperature of each seaming station every hundredth of an inch along the seam length. A detailed report showing the surface temperature of each seam at 12 inch intervals can be produced for each panel.

7.2.7 The machine operators are responsible for monitoring the following machine parameters at each seaming station as the panels are being fabricated: Nominal 2 inch bonded seam width. Static pressure weight is rolling properly. Polypropylene roll is not blocking. Roll tensioning system is operating properly.

7.2.8 A 6 to 12 inch cross-sectional panel retain shall be removed from each production run. This will be used for destructive seam strength testing (refer to section 7.5).


7.3.1 Panels less than 180 feet in length can also be thermally fabricated with a floor welding machine.

7.3.2 The welding machine is set to the pre-determined temperature and speed. A trial seam is then made and hand pulled in a peel mode to verify optimum bonding. The machine settings will be adjusted accordingly if the seam does not exhibit a film tearing bond (FTB). This process will continue until a FTB is achieved.

7.3.3 The machine operators are responsible for the following procedures and observations as the panels are being fabricated. Record the roll and lot numbers. Measure and record the thickness of the material. Visually inspect the material for surface imperfections. Align the two sheets so that there is a nominal 2 inch seam overlap. Tension the two sheets equally to minimize wrinkles. Seam has a smooth "railroad track" appearance.

7.3.4 The heat source on the welding machine will be removed approximately 6 inches from the end of each seam. This is done so that the seam can be hand pulled in a peel mode to verify that the seam has a FTB.

7.3.5 Any defect found in the material or seam will be marked and repaired.

7.3.6 A seam sample is made when fabrication begins and will be used to test for bonded seam strength (shear strength) and peel adhesion (refer to section 7.5).


7.4.1 All panels that were fabricated on our multi-station machine are pulled across an inspection table and visually inspected for the following: Continuity of seams. Surface imperfections. Adequacy of any cross seams. Confirm the total panel length.

7.4.2 If requested all seams can be air lance tested per ASTM D4545 at the Owner's expense.


7.5.1 Sample retains are tested for bonded seam strength (shear strength) and peel adhesion: Bonded seam strength tests for unreinforced Polypropylene are done in accordance with ASTM D3083 (modified 2 inch jaw separation plus seam width). Peel adhesion tests for unreinforced Polypropylene are conducted in accordance with ASTM D413 (modified rate to 20 in/min).

7.5.2 The test results are compared to the minimum seam requirements shown on the Unreinforced Polypropylene Specification Sheet.

7.5.3 All tests are conducted with an Instron Series IX Materials Testing System on an Instron model 1011.


7.6.1 Each panel will be packaged accordion-folded in both directions in a palletized box which allows panels to be installed without necessary repositioning in the field which can cause damage to the fabricated lining, disturbance of the site surface and needless soiling of the edges that must be bonded in the field.

7.6.2 The following information shall be labeled on each fabricated panel: Job Number. Thickness and manufacturer of the Polypropylene. Panel size. Panel identification number. Fabrication date.

7.6.3 The outside packaging of each palletized box shall be labeled with the following information: Job number. Thickness and manufacturer of the Polypropylene. Panel size(s). Panel identification number(s) Customer name and shipping address.

7.6.4 Panels which have been delivered to the job site shall be unloaded and stored in their original unopened containers. Each palletized carton should be wrapped in protective white reflective plastic sheeting if the material is to be stored for an extended period of time prior to installation. Whenever possible a space between the pallets should be provided.

7.6.5 Pallets shall not be stacked.


8.1 The lining installation shall not begin until after a proper base has been prepared to accept the Polypropylene membrane. The base material shall be smooth and free from sharp objects that could puncture the lining. All vegetation, roots and grass must be removed. Any cracks or voids shall be filled.

8.2 A soil sterilant may be required at the discretion of the engineer at additional cost.

8.3 The surface shall be made uniformly sloping per the engineer approved drawings. Abrupt changes in elevation grade of the prepared surface is to be avoided.

8.4 Acceptance of the subgrade surface by the installation contractor is required before proceeding with the installation of the liner. This acceptance will be limited to the amount of area that may be lined during a particular work shift. Direction and control of any subsequent repairs to the subgrade, including the subgrade surface shall remain the responsibility of the earthwork contractor. Subgrade acceptance by the installation contractor does not constitute acceptance of construction variables such as moisture content and compaction.



9.1.1 The Polypropylene lining shall be placed over the prepared surface, as outlined in the engineer approved drawings in a manner which minimizes handling.

9.1.2 The panels should not be unfolded under extreme cold or windy conditions.

9.1.3 The liner shall be installed in a relaxed condition, free of stress or tension. Stretching the liner to fit is not permissible.

9.1.4 Lap joints shall be used to seal factory fabricated panels of Polypropylene together in the field. The panels shall be positioned so that there is a nominal 4 inch seam overlap. The contact surfaces of the two sheets shall be wiped clean to remove all dirt, dust, moisture or other foreign materials.

9.1.5 Field seams are made by thermal fusion bonding.

9.1.6 The welding machine shall be set to the pre-determined temperature and speed. A trial seam shall be made and tested to verify these settings. The machine settings shall be adjusted accordingly. Throughout the seaming operation, occasional adjustments of temperature or speed as the result of changing ambient conditions may be necessary to maintain a consistent seam. A 1.5 inch nominal seam width is required for a single track welds. Dual track welds should have two 0.5 inch nominal seams separated by an air test channel.


9.2.1 Visual inspection.

9.2.2 Air lance test - ASTM D4437.

9.2.3 Pressurized air channel test (dual track seams only) - GRI GM6.


9.3.1 A start-up seam shall be provided at the beginning of each day's or shift's seaming operation. The sample shall be made from the same sheet material and using the same seaming method as will be used to fabricate the field seams. It shall be tested for bonded seam strength and peel adhesion (refer to section7.5).

9.3.2 One sample per 500 feet of field seam or one sample per seaming crew per 4 hour time period shall be tested for bonded seam strength and peel adhesion. The sample can either be made from excess material, or cut out from the installed lining. If the sample is cut out, the resulting hole shall then be patched (refer to section 9.5).

9.3.3 The above test results are compared to the minimum seam requirements shown on the Unreinforced Polypropylene Specification Sheet.


9.4.1 The polypropylene membrane shall be sealed to all concrete structures and other openings through the lining in accordance with details shown on the engineer approved shop drawings.

9.4.2 Factory and/or field fabricated boots shall be used to seal all pipes penetrating the liner. All joints shall be tightly bonded.


9.5.1 Any cuts, rips or tears in the membrane shall be patched with a piece of the same membrane material. Patches should be cut with rounded corners and should overlap the damaged area a minimum of 3 inches.

9.5.2 Patches are applied with a hand held heat gun and roller. The patch and damaged membrane area should be clean and dry. The heat gun shall be inserted between the patch and the membrane liner heating the surfaces of each to a molten state. A steel roller should be immediately applied smoothing out any wrinkles.


10.1 Polypropylene membrane lining does not normally require a protective cover. However, if a cover is required, a minimum 12 inches of approved cover material shall be placed over the Polypropylene lining as shown on the drawings.

10.2 Cover material shall be approved by the engineer prior to placement. Soil containing sharp, jagged rocks, roots debris or any other material which may puncture the membrane shall not be used as cover material.

10.3 The contractor may choose the equipment and manner in which the cover material is placed over the liner. However, the contractor should satisfactorily demonstrate to the engineer that the liner will not be damaged in any way. No equipment shall be driven directly on the liner without an earthen cover protection.


11.1 Written warranties shall be provided that as a minimum state that the Polypropylene liner furnished and installed will comply with the following:

11.1.1 The liner shall be free of defects in workmanship on materials for a period of one (1) year from date of shipping/final acceptance in accordance with the fabricator's/installer's written warranties.

11.1.2 The material shall be free of defects for a period of twenty (20) years on a pro rata basis from the date of final acceptance in accordance with the manufacturer's written warranty.


12.1 Payment for the Polypropylene liner will be a lump sum (progress) payment for the actual square footage amount of material shipped to the job site in accordance with the approved shop drawing panel layout including field seam overlaps and material installed in anchor trenches and on side slopes (slope increment).

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