Section 02726 MANHOLE AND PRECAST VAULT CONSTRUCTION

Section 02726

MANHOLE AND PRECAST VAULT CONSTRUCTION

PART 1 - GENERAL

1.1 THE REQUIREMENT

A. This section covers the Work necessary for the construction of manholes and precast vaults. Manhole and vault details are as shown on the Plans. This section does not cover electrical manholes and vaults.

B. The CONTRACTOR shall furnish all tools, equipment, materials, and supplies and shall perform all labor required to complete the work as indicated in the Contract Documents.

C. Manhole locations are fixed and cannot be moved or relocated from locations shown on the Plans to accommodate pipe manufacturing or laying. If necessary, special lengths of pipe shall be provided to meet manhole location requirements.

D. Manholes and precast vaults shall be built without steps or ladders. Flattop manholes shall only be used in locations specifically shown on the Plans.

E. Manhole and precast vault covers located in areas subject to vehicular traffic shall be designed for AASHTO H-20 loading. Manholes and vaults located in all four-way street intersections shall have bolt-down covers. Manholes and vaults located along gutters or surface run-off areas shall also have bolt-down covers.

F. All manholes connected to sewers 12 inches or larger shall have PVC liner. New manholes shall be lined with ribbed PVC sheet, cast-in-place during manufacturing on precast shaft sections. Concrete bases shall be lined in accordance with the Contract Documents. Existing unlined manholes that are being repaired shall be lined in accordance with the Contract Documents.

G. Precast Manholes: Precast manholes shall conform to the size, shape, form and details shown on the Contract Documents and shall be installed in accordance with Standard Drawing S-050 for PVC-lined manholes, S-045 for unlined manholes, or S-051 for drop manholes The precast cylinder units, precast concrete taper sections, and precast eccentric flat-top sections shall be designed and manufactured for AASHTO H-20 loading. The CONTRACTOR shall submit shop drawings of all precast manholes. The minimum allowable steel shall be hoops of No. 4 wire cast into each unit sufficient for handling. The Keylock joint between precast concrete shaft units, including the joint with the cast-in-place concrete base, shall be filled with plastic sealing compound conforming to Federal Specification SS-S-210A, to make a watertight joint. Once the shafting has settled, the outside of all joints shall then be sealed with a 6-inch-minimum wide joint wrap of EPDM base and butyl mastic except for the joint to the cast-in-place concrete base. Sections of various heights shall be set perfectly plumb and used to bring the top of the manhole ring and cover to the required elevation.

H. Drop Manholes: Drop manholes shall conform to the requirements of Standard

Drawing S-051. The drop inlet pipe shall be the same diameter as the intercepted sewer.

1.2 RELATED WORK SPECIFIED ELSEWHERE

A. The requirements of the following sections and divisions apply to the Work of this section. Other sections and divisions of the Specifications, not referenced below, shall also apply to the extent required for proper performance of this Work.

1. Section 02200, Earthwork

2. Section 02550, Asphalt Concrete Pavement

3. Section 02730, Sanitary Sewer System Testing

4. Section 03300, Cast-in-Place Concrete

5. Section 06620, Plastic Liner (Polyvinyl Chloride)

6. Section 09800, Protective Coating

1.3 REFERENCE SPECIFICATIONS, CODES AND STANDARDS

A. All Work specified herein shall conform to or exceed the applicable requirements of the referenced portions of the following publications to the extent that the provisions thereof are not in conflict with other provisions of these Specifications.

B. Comply with the applicable editions of the following codes, regulations and standards.

1. 1. Industry Standards:

ASTM A 48 Standard Specification for Gray Iron Castings

ASTM A 615 Standard Specification for Deformed and Plain

Carbon-Steel Bars for Concrete Reinforcement

ASTM C 14 Standard Specification for Non-reinforced

Concrete Sewer, Storm Drain, and Culvert Pipe

ASTM C 33 Standard Specification for Concrete Aggregates

ASTM C 94 Standard Specification for Ready-Mixed

Concrete

ASTM C 150 Standard Specification for Portland Cement

ASTM C 387 Standard Specification for Packaged, Dry, Combined Materials for Mortar and Concrete

ASTM C 478 Standard Specification for Precast Reinforced

Concrete Manhole Sections

ASTM C 1244 Standard Test Method for Concrete Manholes by the Negative Air Pressure (Vacuum) Test Prior to Backfill

SSPWC Subsection 206-3 Standard Specifications for Public Works

Construction, Gray Iron Casting

SS-S-210A Federal Specifications, Plastic Sealing

Compound

C. Comply with the applicable reference Specifications as specified in the General

Requirements and the Additional General Requirements.

1.4 CONTRACTOR SUBMITTALS

A. Submittals shall be made in accordance with the General Requirements, Additional

General Requirements and as specified herein.

B. Shop Drawings: The CONTRACTOR shall furnish complete shop drawings for all precast manhole sections, cast iron frames and covers, and appurtenances for review by the ENGINEER in accordance with the section entitled “Shop Drawing Submittals” of the General Requirements.

1.5 QUALITY ASSURANCE

A. Inspection: After installation, the CONTRACTOR shall demonstrate that all manholes have been properly installed, level, with tight joints, at the correct elevations and orientations, and that the backfilling has been carried out in accordance with the Contract Documents.

PART 2 - PRODUCTS

2.1 GRANULAR BASE

A. Granular base shall conform to Section 02200, Earthwork. The thickness of the granular base material used to support concrete manhole bases shall be the same as the adjacent pipeline bedding.

2.2 CONCRETE

A. Ready-mixed, conforming to ASTM C 94, Alternate B. The concrete class for manhole bases shall be 650-CW-4000. The concrete class for precast manhole and vault walls and top shall be 650-CW-4000 and contain at least 6 sacks of cement per cubic yard. Maximum size of aggregate shall be 1.5 inches. Slump shall be between 2 and 5 inches.

B. All concrete, mortar, and grout used in the construction of manholes shall conform to

SSPWC Section 201. Mortar shall be Class C.

2.3 FORMS

A. Provide forms on all vertical surfaces. Wood or sandbags are acceptable form material.

2.4 REINFORCING STEEL

A. Conform to ASTM A 615, Grade 60, deformed bars.

B. Reinforcement for poured-in-place concrete bases shall be #6 bars @ 12 inches on center in each direction in accordance with Standard Drawing S-050, unless otherwise shown on the Drawings.

C. Reinforcement for precast sections shall conform to ASTM C 478.

2.5 MANHOLE BASES

A. Precast manhole bases shall not be permitted unless accepted by the ENGINEER.

B. Manhole bases shall be poured in place and constructed of Class 650-CW-4000 concrete to the form and dimensions shown on the Contract Documents.

2.6 POURED-IN-PLACE MANHOLES

A. Poured-in-place type manholes may be used, conforming to Standard Drawing S-049 or S-050, provided all details of construction are accepted by the ENGINEER.

2.7 PRECAST MANHOLE SECTIONS

A. Precast manhole sections shall conform to Standard Detail 14 on Drawing C1-5002 as applicable, all in accordance with ASTM C 478. The precast cylinder units, precast concrete taper sections, and precast eccentric flat-top sections shall be designed and manufactured for AASHTO H-20 loading. The CONTRACTOR shall submit shop drawings of all precast manholes. The minimum allowable steel shall be hoops of No. 4 wire cast into each unit sufficient for handling.

B. Provide eccentric cones for all manholes. Cones shall have same wall thickness and reinforcement as manhole sections. Top and bottom of all sections shall be parallel. Joints shall be Keylock with plastic sealing compound.

C. Prior to the delivery of any size of precast manhole section on the jobsite, yard tests will be conducted at the point of manufacture. The precast sections to be tested will be selected at random from the stockpiled material, which is to be supplied for the job. All test specimens will be mat tested, and shall meet the permeability test requirements of ASTM C 14.

2.8 MANHOLE EXTENSIONS

A. Concrete grade rings for extensions shall be a maximum of 6 inches high and shall be accepted by the ENGINEER before installation.

B. In general, manhole extensions shall be used on all manholes in roads or streets or in other locations where a subsequent change in existing grade may be likely. Total height of stacked grade rings shall be limited to a maximum of 12 inches. Finish grade for manhole covers in paved areas shall conform to finished ground or street surface level, unless otherwise directed by the ENGINEER.

2.9 MORTAR

A. Mortar shall be used only for keylock joint while adjusting rings to grade in accordance with Standard Detail 14 on Drawing C1-5002. Standard premixed mortar conforming to ASTM C 387 or proportion 1 part Portland cement to 2 parts clean, well- graded sand which shall pass a 1/8-inch screen. Admixtures may be used not exceeding the following percentages of weight of cement: Hydrated lime, 10 percent; diatomaceous earth or other inert materials, 5 percent. For the Keylock type joint between grade rings, the consistency shall be such that excess mortar shall be forced out of the groove and finished flush with the surface. Mortar mixed for longer than 30 minutes shall not be used.

2.10 PLASTIC SEALING COMPOUND

A. Preformed plastic sealing compound shall be 1-1/4-inch square beads, Kent-Seal No.

2 manufactured by Hamilton Kent Manufacturing Company, Kent, OH; Ram-Nek, manufactured by Henry Sealants, Houston, TX; Or Equal, meeting all requirements of Federal Specification SS-S-210A.

2.11 JOINT WRAP FOR MANHOLE SECTIONS

A. Joint wrap for manhole sections shall be 6 inches wide; of EPDM base and butyl mastic, Rub’R-Nek by Henry Company, Seal Wrap by Sealing Systems, Inc.; or of synthetic polymer, StopAQ EZ Wrap by Amcorr Inc.; Or Equal.

2.12 PIPE STUBOUTS FOR FUTURE SEWER CONNECTIONS

A. Pipe stubouts shall be 8-inch VCP unless otherwise specified on the Drawings. Strength classifications shall be the same class as in adjacent trenches. Where there are two different classes of pipe at a manhole, the higher strength pipe shall govern the strength classification. Rubber gasketed watertight plugs shall be furnished with each stubout adequately braced against all hydrostatic or air test pressures. Stubouts shall be installed as shown on Standard Detail 14 on Drawing C1-5002, as applicable, unless otherwise shown on the Drawings.

2.13 PRECAST CONCRETE VAULT

A. The precast concrete vault shall be precast with a 28-day, 4,000-pounds per inch minimum compressive strength concrete and designed for AASHTO H-20 loading. Minimum dimensions are shown on the Drawings. Provide openings for pipes and grating as shown on the Drawings.

2.14 MANHOLE FRAMES AND COVERS

A. Manhole frames and covers shall be fabricated of cast iron in the size and shape detailed on the Drawings. Castings shall be tough, close-grained gray iron, sound, smooth, clean, free from blisters, blowholes, shrinkage, cold shuts, and all defects, and shall conform to ASTM A 48, Class 35B. Plane or grind bearing surfaces to ensure flat, true surfaces. Covers shall be true and seat within ring at all points.

B. Frames shall have a minimum opening diameter of 36 inches.

C. Manhole frame and cover sets of the type, size and quantity indicated on the Contract Documents, shall be installed at the locations shown on the Drawings in accordance with Standard Drawing S-055.

D. Frames and covers shall be designed for H-20 loading. Before leaving the foundry, all castings shall be thoroughly cleaned and subjected to a hammer inspection. The interior surfaces of the manhole frame and cover shall be coated in the field with not less than 6 mils of bituminous paint as specified in Section 09800, Protective Coating, of these Specifications.

E. Each cover shall be ground or otherwise finished so that it will fit in its frame without rocking. Frames and covers shall be shipped to the site in match-marked sets. Covers shall have the word "SEWER" and "O.C.S.D." cast thereon in 3-inch high letters, and “DANGER DO NOT ENTER” in 1” high letters as shown on the Standard Drawings S-

052, S-053 and S-054. No other lettering shall appear on the top of the covers.

F. Manholes and vaults located in all four-way street intersections shall have bolt-down covers. Manholes and vaults located along gutters or surface run-off areas shall also have bolt-down covers.

G. Standard manhole frame and cover shall be Model A-1251-4 as manufactured by Alhambra Foundry Co., Ltd., Or Equal from Neenah Foundry. Bolted manhole frame and cover shall be Model A-1251B-4 as manufactured by Alhambra Foundry Co., Ltd., Or Equal from Neenah Foundry.

H. Certification: When required by the ENGINEER, covers shall be tested by use of the Transverse Test and be able to sustain a minimum breaking load of 2,200 pounds using a test bar measuring 1.2 inches in diameter and 21 inches long, with a distance between supports of 18 inches. A laboratory certification containing transverse test results for each lot of castings shall be furnished by the foundry.

2.15 PVC LINER

A. All manholes connected to sewers 12 inches or larger shall be lined with PVC liner in accordance with Section 06620, Plastic Liner (Polyvinyl Chloride). New manholes shall be lined with ribbed PVC sheet, cast-in-place during manufacturing on precast shaft sections. Concrete bases shall be lined in accordance with the Contract Documents. Existing unlined manholes that are being repaired shall be lined in accordance with the Contract Documents.

PART 3 - EXECUTION

3.1 GENERAL

A. Manholes shall be constructed in accordance with Standard Detail 14 C1-5002.

B. Manholes and precast vaults shall be built without steps or ladders. Flattop manholes shall only be used in locations specifically shown on the Drawings.

3.2 EXCAVATION AND BACKFILL

A. Conform to applicable portions of Section 02200, Earthwork. Backfill around manholes shall be 1½-sack cement sand slurry.

3.3 PAVING

A. Pavement removal and replacement for all excavations necessary for the construction or repair of manhole shall conform to the provisions of Section 02550, Asphalt Concrete Pavement, of these Specifications.

3.4 CONCRETE BASES

A. Manhole bases shall be poured in place to the form and dimensions shown on the Contract Documents. Manhole locations are fixed and cannot be moved or relocated from locations shown on the Drawings to accommodate pipe manufacturing or laying. If necessary, special lengths of pipe shall be provided to meet manhole location requirements.

B. All concrete manhole bases shall be formed and poured on a granular base (6 inches minimum) having the same thickness as the bedding under the sewer on which the manhole base is being built. Place and thoroughly compact base with a mechanical or power vibrating tamper.

C. That portion of the base above the invert elevation of the sewer pipe shall be formed to provide a smooth channel section as indicated in the Contract Documents. The radius of the channel shall be no less than the internal radius of the inlet pipe. The forms shall be checked and accepted by the ENGINEER for accuracy of dimensions and relative smoothness prior to pouring of the base. If accepted by the ENGINEER, free forming of bases may be allowed on pipelines 10 inches or smaller. The concrete shall be vibrated while it is being poured into the form. Channels shall vary uniformly in size and shape from inlet to outlet, if required. The manhole base shall be poured as one monolithic pour.

D. Lateral connections, typically those 12 inches or smaller, where the main size is less than 39 inches in diameter, shall be constructed with gas flaps in accordance with Standard Drawing S-056.

E. Construct concrete base in conformance with the details shown on the Drawings. Vibrate to densify the concrete and screed so that the first precast manhole section to be placed has a level, uniform bearing for the full circumference.

F. Form a Keylock joint in the base and install three beads of plastic sealing compound at the joint to assure watertight seal between base and manhole wall. First section shall be properly located and plumb.

G. If material in bottom of trench is unsuitable for installation of the manhole, excavate below the flow line as directed by ENGINEER, and backfill to required grade with gravel.

3.5 PLACING PRECAST MANHOLE SHAFT SECTIONS

A. Clean ends of sections of foreign materials. The keylock joint between precast concrete shaft units, including the joint with the cast-in-place concrete base, shall be filled with plastic sealing compound conforming to Federal Specification SS-S-210A, to make a watertight joint, in accordance with Standard Detail 14 on Drawing C1-5002. Sections of various heights shall be set perfectly plumb and used to bring the top of the manhole ring and cover to the required elevation.

B. Prevent mortar from drying out and cure by applying an approved curing compound or comparable approved method. Chip out and replace all cracked or defective mortar. Completed manhole shall be rigid and watertight.

3.6 MANHOLE INVERT

A. Construct manhole inverts in conformance with details shown on the Drawings, and with smooth transitions to ensure an unobstructed flow through the manhole. Remove all sharp edges or rough sections which tend to obstruct flow. Where a full section of pipe is laid through a manhole, saw cut and break out the top section as indicated and cover exposed edge of pipe completely with mortar. Trowel all mortar surfaces smooth.

3.7 FLEXIBLE JOINTS

A. Furnish and install two (2) each 2-foot long pipe joints from all manhole walls per Standard Drawing S-050. Lay pipes entering manhole connections on firmly compacted granular base to undisturbed earth. Base materials shall be as previously specified.

3.8 PIPE STUBOUTS FOR FUTURE SEWER CONNECTIONS

A. Install vitrified clay pipe stubouts in manholes for future sewer connections as shown on the Drawings or as required by the ENGINEER. Grout pipes in precast walls or manhole base to provide watertight seal around pipes. Construct invert channels in accordance with details shown on the Drawings.

B. All stubs shall be plugged with a factory made stopper at the socket end per manufacturer’s recommendations. Brick and mortar plugs may be used on stubs greater than 21 inches in diameter. Plugs shall be capable of withstanding all internal, external, and test pressures without leakage. Plugs shall be braced as necessary during testing to prevent dislodging.

3.9 PERMANENT PLUGS

A. Clean interior contact surfaces of all pipes to be cut off or abandoned as shown. Construct concrete plugs or factory-made stoppers at the end at of all pipes 18 inches or less in diameter. Minimum length of concrete plugs shall be 8 inches. For pipe 21 inches and larger, the plugs may be constructed of common brick or concrete block. Plaster the exposed face of block or brick plugs with mortar. All plugs shall be watertight and capable of withstanding all internal and external pressures without leakage.

3.10 MANHOLE EXTENSIONS

A. Install extensions in conformance with the details shown on the Drawings, and to height determined by the ENGINEER. Seal grade ring joints with mortar as required for final leveling. Seal remaining exterior joints and interior joints of unlined manholes with mortar Extensions shall be watertight.

3.11 MANHOLE FRAMES AND COVERS

A. Install frames and covers on top of manhole to positively prevent all infiltration of surface or groundwater into manholes. Frames shall be set in mortar on top of grade rings in unlined manholes. Frames rest directly on the formed piece of PVC liner in PVC- lined manholes as shown on Standard Drawing S-050. Set frames so that tops of covers are flush with surface of adjoining pavement unless otherwise shown or directed.

B. The elevation at which manhole frames and covers are to be set shall be as directed by the ENGINEER in the field. Covers shall be installed flush with traveled pavement and shoulders, 1/10-foot above the surface if located between the traveled way and the roadside ditch, and 18 inches above the surface in the roadside ditch, where applicable. Flush installations are flush to 1/8-inch maximum height with installation as shown on Standard Drawing S-055.

C. The frames and covers shall be cleaned of all foreign materials and to a fine appearance and fit. All costs for installing manhole frame and cover sets in place as described herein, including all necessary concrete work, shall be included in the applicable contract price.

3.12 MANHOLE ADJUSTMENT TO GRADE

A. After compacting the soil around manholes in roadways and pavement is installed, excavate neatly about 12 inches out from the frame for access to grade rings for final leveling.

B. Make the adjustment with mortar between the first and second grade rings.

C. Fill the excavation with rapid set concrete to form a concrete collar around the exterior perimeter of the manhole frame and grade rings as shown on Standard Drawing S-055.

D. Complete or repair the manhole liner installation. Make the final weld to the topmost PVC section mounted under the frame for PVC-lined systems. Apply polyurethane coating as required for manhole repairs to all exposed concrete below the frame for polyurethane-lined systems.

3.13 MANHOLE OVER EXISTING SEWERS

A. Construct manhole over existing operating sewer lines at locations shown in accordance with Standard Drawing S-049 and elsewhere in the Contract Documents. Perform necessary excavation as specified above around existing line and construct manhole.

B. Maintain flow through existing sewer lines at all times, and protect new concrete and mortar work for a period of 7 days after concrete has been placed. Advise ENGINEER of plans for diverting sewage flow and obtain ENGINEER’s acceptance before starting. ENGINEER’s acceptance shall not relieve CONTRACTOR of responsibility for maintaining adequate capacity for flow at all times and adequately protecting new and existing work.

C. Construct the new base under the existing sewer and the precast sections as specified herein.

D. Break out the existing pipe within the new manhole, cover the edges with mortar, and trowel smooth. Install liner as necessary to cover all exposed concrete.

3.14 FLOW BYPASSING

A. Bypassing of wastewater flow shall be performed in accordance with Section 02999, Temporary Handling of Sewage Flow.

3.15 CONNECTION TO EXISTING MANHOLE

A. To use an existing stub, ensure that lateral enters the stub at the slope of ¼-inch per foot. Remove the plug and install new pipe in the socket. Install gas flap inside manhole in accordance with Standard Drawing S-056, if there is no existing gas flap.

B. If no usable stub exists, core drill through the manhole base and install a new stub in accordance with Standard Drawing S-057. After core drilling, install the PVC turnback, position the pipe in the hole, and grout in place. Repair the PVC liner and attach the turn back.

C. Maintain flow through existing sewer lines at all times, and protect new concrete and mortar work for a period of 7 days after concrete has been placed. Advise ENGINEER of plans for diverting sewage flow and obtain ENGINEER’s acceptance before starting. ENGINEER’s acceptance shall not relieve CONTRACTOR of responsibility for maintaining adequate capacity for flow at all times and adequately protecting new and existing work.

D. For laterals that are not at the proper elevation, create a drop manhole per Standard Drawing S-051 only upon acceptance by the ENGINEER. Penetrating the manhole riser wall directly for a lateral is not acceptable.

3.16 SPECIAL MANHOLES

A. Construct special manhole in conformance with applicable parts of these

Specifications and as shown on the Drawings.

3.17 PRECAST CONCRETE VAULT

A. Install precast concrete vault at the locations shown on the Drawings. Provide necessary excavation and backfill as specified herein.

3.18 VACUUM TESTING

A. Vacuum testing shall be performed for all new or retrofitted manholes per ASTM C

1244 unless otherwise noted, or unless those manholes are in service. Manholes that are not vacuum tested shall be visually inspected for infiltration.

3.19 MANHOLE REPAIR A. General:

The CONTRACTOR shall perform all concrete, mortar, gunite, grout and lining repair; installation of new liner, frame and cover; adjustment to grade; and paving as necessary for a complete repair of manholes as indicated on the Contract Documents. All Work shall be performed without restriction or interruption of sewer flows. Detailed plans shall be submitted by the CONTRACTOR prior to the beginning of construction, showing the type of any proposed or required bypass systems to be used.

It is the responsibility of the CONTRACTOR to take adequate measures to ensure that no debris is allowed to enter the sewer. If at any time debris does enter the sewer, the CONTRACTOR shall clean the sewer to a point downstream as determined by and to the satisfaction of the ENGINEER. All costs for cleaning the sewer to remove the debris that was allowed to enter the sewer shall be borne by the CONTRACTOR. Existing rings and covers shown to be replaced shall be broken and disposed of by the CONTRACTOR in the presence of the ENGINEER.

B. Surface Preparation:

All interior surfaces shall be water blasted to remove all deteriorated brick, concrete, or any existing coating until a solid structure of brick or concrete is exposed. All grease and attached residue shall be removed during the surface preparation. Water blasting shall be performed with a high-pressure water blaster with an adjustable pressure range of

5,000 to 8,000 pounds per inch. Debris from water blasting shall not be allowed to enter the sewer. Provide additional surface preparation in accordance with the Article entitled “Manhole Lining” herein.

C. Leak Stoppage:

Prior to the application of the mortar-leveling course for any liner, the CONTRACTOR shall stop all leaks in the structure. The method for stopping the leaks shall be the CONTRACTOR's option as accepted by the ENGINEER. OCSD shall not be responsible for any method or procedure that fails to stop leaks.

D. Mortar Application:

Preparation of the existing surfaces shall be accepted by the ENGINEER before application of the mortar-leveling course. Mortar or gunite shall be applied to remove all surface irregularities and to provide a smooth surface on which to apply the liner. All surfaces shall be as dry as possible prior to the installation of the liner. Provide mortar leveling in accordance with the Article entitled “Manhole Lining” herein.

A mortar-leveling course shall be required on all brick manholes. A mortar-leveling course is not required on precast concrete manholes unless indicated otherwise.

3.20 MANHOLE LINING A. PVC Liner:

PVC liner for new manholes shall be furnished and installed according to Section 06620, Plastic Liner (Polyvinyl Chloride), of these Specifications, Standard Drawing S-050, and as described herein.

All T-lock ribs shall be oriented vertically. Field joints in liner between precast concrete sections shall not be made until the joint mortar has been allowed to cure at least 48 hours.

The liner shall be continuous, seamless, free from any holes or defects, and completely bonded to the existing structure, and have returns at joints with unlined surfaces.

PVC lining not cast in place, but installed onto an existing concrete surface (for example, Ameron Arrow Lock), shall be installed using mastic in accordance with manufacturer recommendations and per Section 06620, Plastic Liner (Polyvinyl Chloride).

The coating shall be continuous, seamless, and free from any holes or defects.

The coating Contractor shall spark test the completed lining per applicable sections of Section 06620 Plastic Liner in the presence of the ENGINEER. All holidays shall be repaired to the satisfaction of the ENGINEER and retested.

CONTRACTOR shall furnish two plugs to permit measurement of the lining thickness.

Only those workers trained by and licensed as installer by the manufacturer shall be used.

The CONTRACTOR shall take all necessary precautions to prevent the installed coating from being damaged by equipment used in or taken through the Work.

Upon completion of the Work, all tools and excess material shall be removed and the structure shall be left in a clean and presentable condition.

All personnel working in the area shall wear personal protective air support equipment as recommended by the coating manufacturer.