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Product name : AWWA C 214 standard tape coatings for steel water pipe
Item : 201844155233
Film : LDPE,HDPE
Adhesive : BUTYL RUBBER
Release paper : 
Standard : AWWA C 214 C 209
Storage life : 3 YEARS
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Details:
 AWWA C 214 STANDARD TAPE COATINGS FOR WATER STEEL PIPE

Coating system:

The pre-fabricated polyolefin tape coating system shall consist of the following layers to provide an applied coating system thickness of 80 mils (2mm) on the exterior of the steel pipes.

 

  1. A liquid adhesive layer.
  2. An inner-layer tape for corrosion protection.
  3. An intermediate-layer tape for mechanical protection.
  4. An outer-layer tape for mechanical and UV protection.

 

The inner-layer tape and outer-layer tape shall be made of prefabricated tapes in rolls.

 
Liquid Adhesive layer:

 

The liquid adhesive layer shall consist of a mixture of suitable rubber and synthetic compounds and solvent. The liquid adhesive layer shall be spray applied to the abrasive blasted prepared pipe surface before application of the inner-layer tape. The function of the liquid adhesive is to provide a bonding medium between the pipe surface and the inner-layer tape.

 

The liquid adhesive shall be supplied by the manufacturer that supplies the inner-layer tape. The liquid adhesive shall not settle in the container forming a cake or sludge that cannot be easily mixed by hand or mechanical agitation and it shall have good machine-application properties.

 

Table I - Physical Properties of the Liquid Adhesive

Color

    Base

Weight

Flash Point

 

Black

 

Rubber and Synthetic Resins

Flammable

-

6-8 lb/gal (0.72 – 0.965g/l)

-10oF (-17oC) or greater

Non flammable

-

10 – 12 lb/gal (1.20 – 1.44 kg/l)

none

 

 


Inner-layer tape:

 

The inner-layer tape shall be a two-layer tape consisting of a polyolefin backing layer with a laminated butyl-based adhesive layer. The inner tape shall be compatible with the liquid adhesive. The manufacturer shall certify that the backing material shall be polyolefin only, containing not more than 3.5 percent, by weight, of non-polyolefinic material consisting of carbon black and antioxidants. The inner-layer tape shall be applied after the liquid adhesive and before the outer-layer tape.

 

The backing and adhesive shall be made from materials that provide high electrical resistivity, resistance to corrosive environments, low moisture absorption and permeability, and shall provide an effective bond to a primed steel surface. The inner-layer tape shall be of material that will resist excessive mechanical damage during normal application operations and shall be sufficiently pliable for the intended use. The inner-layer tape shall withstand, without tearing, the tensile force necessary to obtain a tightly wrapped inner coating free of voids. The inner-layer tape shall be supplied in roll form wound on hollow cores with a minimum inside diameter of 75mm.

 

To ensure a proper smooth coating, the inner-layer tape shall be provided in standard widths as per manufacturer recommendations consistent with the pipe diameter.  Width shall be approved by Employer’s representative.

Table – I Physical Properties of Inner Layer Tape

Property

Requirement

 

Minimum

Maximum

Test Method (Ref AWWA C214-14)

Width deviation

-5% or -1/4 in. (-6 mm) whichever is smaller

+5%

Sec. 5.2.3

Nominal thickness 20mil (0.508 mm)

19 mil (0.48 mm)

 

Sec. 5.2.4

Ratio of adhesive to total inner- layer tape thickness, t

40% of total t

60% of total t

Sec, 5.2.4

Adhesion to prepared steel

12.5 lb/in. width

-

Sec. 5.2.5

Water absorption (24 h)

-

 0.2% by wt

Sec. 5.2.6

Water-vapor transmission

                      -

0.10 g/(h.m2)

 

Sec. 5.2.7

Dielectric strength

450 V/mil

 

Sec. 5.2.8

 

Insulation resistance

500,000 megohms

 

Sec. 5.2.9

Tensile strength

20 lb / in width

 

Sec. 5.2.10

Elongation

300%

 

Sec. 5.2.11

Nonpolyolefinic Material Percent by Weight

-

3.5%

Sec. 5.2.12

 

 

 

Intermediate- layer tape / Outer-layer tape:

The intermediate -layer tape / outer-layer tape shall be a two-layer tape consisting of a polyolefin backing layer with a laminated butyl adhesive layer. The manufacturer shall certify that the backing material shall be polyolefin only containing not more than 7.0 percent, by weight, of non-polyolefinic material consisting of pigments, antioxidants and stabilizers. The intermediate -layer shall be compatible with the inner-layer tape and the outer-layer tape shall be compatible with the intermediate-layer tape.  The primary function of the intermediate - layer tape is to provide mechanical protection to the inner-layer tape and of outer-layer tape to provide mechanical and outdoor weathering (UV) protection to the tape system, and secondarily, to contribute to the overall corrosion-protection properties of the system. The outer-layer tape backing shall be compounded so that it will be resistant to outdoor weathering. To distinguish the intermediate- layer tape from outer-layer tape the colors of the two layers shall be different. The intermediate- layer tape color shall be grey and the outer-layer tape color shall be white.

 

The outer-layer tape should be of suitable quality for the local environment, as follows:

 

Storage Temperature

: 0 to 500C.

Over-ground Condition

: 0 to 600C.

Under-ground Condition

: 70C to 350C.

Ultraviolet-ray Protection

: Required in outer layer.

 

Materials used in the intermediate-layer & outer-layer tape shall have high electrical resistivity, low moisture absorption and permeability, and shall provide mechanical protection during handling and outdoor storage. The intermediate - layer & outer-layer tapes shall be sufficiently pliable for normal application operations and shall form an effective bond to the inner-layer / intermediate-tape layers. The intermediate- layer & outer-layer tape shall be supplied in roll form wound on hollow cores with a minimum inside diameter of 75mm.

 

Dimensions: The intermediate- layer tape & outer-layer tape shall be provided in standard widths and lengths. The width of the intermediate - layer & outer-layer tape shall be at least equal to that of the inner-layer tape.

 

Table II - Physical Property of Intermediate Layer Tape & Outer Layer Tape

Property

Requirement

 

Minimum

Maximum

Test Method (Ref AWWA C214-14)

Width deviation

-5% or -1/4 in. (-6 mm) whichever is smaller

+5%

Sec. 5.2.3

Nominal thickness 30mil (0.762 mm)

28.5 mil (.724 mm)

-

Sec. 5.2.4

Adhesion to Inner layer

 

Dielectric Strength

1.25 lb /in. width

450 V/mil

-

Sec. 5.2.5

 

Sec. 5.2.8

Tensile strength

40 lb/in width
(7.0 N/mm Width)

-

Sec. 5.2.10

Elongation

300%

-

Sec. 5.2.11

Nonpolyolefinic Material Percent by Weight

-

7.0%

Sec. 5.2.12

Coating-system Thickness:

The installed coating system thickness shall not be less than 80 mils (2mm) and shall comprise of the following.

 

  1. A liquid adhesive layer       (50-75 microns)
  2. An inner-layer tape     (Nominal 20 mils i.e. 0.50mm)
  3. An intermediate tape          (Nominal 30 mils i.e. 0.75mm)
  4. An outer-layer tape    (Nominal 30 mils i.e. 0.75mm)

 

The properties of the complete coating system shall conform to the following requirements.

 

Table – III - Physical Properties of Total System

Property

Requirement

 

Minimum

Maximum

Test Method (Ref AWWA C214-07)

Thickness

 

 

 

80 mil, nominal

73 mil

(1,854 μm)

-

 

Sec.5.5.4

Dielectric strength

12000V

 

Sec. 5.3.6

Impact resistance

25 lb * in.

(2.8 N*m)

 

Sec. 5.2.13

Penetration/deformation resistance

 

 

 

 -

25% with no holiday at 220C

Sec. 5.2.14

Cathodic Disbondment

-

12mm

Sec 5.2.15

 
Coating Application:
General:
The coating application shall be a continuous operation starting with properly abrasive blasted pipe surface. Longitudinal & spiral welds of the pipe shall not exceed a height of 3/32 inch (2.4mm) above the pipe surface and shall be ground flush a full 18 inch (450mm) along the length of the pipe from both ends prior to the coating process.

 

Four steps, which shall be performed consecutively, shall consist of (1) liquid adhesive application; (2) application of the inner-layer tape directly onto the prepared pipe surface; and (3) application of the intermediate-layer tape directly on top of the inner-layer tape and (4) application of outer-layer tape directly on top of the intermediate-layer tape.

 
Pipe preparation:

 

Metal surface condition:

Bare pipe shall be free from mud, mill scale, mill lacquer, wax, coal tar, asphalt, oil, grease, or any other foreign material. Before blast cleaning, surfaces shall be inspected and pre-cleaned according to SSPC-SP 1 to remove oil, grease, and loosely adhering deposits. Visible oil and grease spots shall be removed using a solvent. Only solvents that do not leave a residue shall be used. Preheating to remove oil, grease, and mill scale may be used provided that all pipe is preheated in a uniform manner to avoid distortion.

 

After drying and removing all loosely adhering foreign materials, the pipe surface shall be cleaned by blasting with grit or steel shots to achieve a surface preparation at least equal to that specified in SSPC: SP6/NACE3.  The blast anchor pattern or profile depth shall be 2 mil to 3 mils (50 µm to 75 µm) measured in accordance with ASTM D-4417.

 

For consistent surface finish, a stabilized working mix shall be maintained in abrasive recycling blasting machines by frequent small additions of new grit, shot infrequent large editions shall be avoided.  The abrasive working mix, abrasive recycling blasting machines shall be maintained clean of contaminants by continuous effective operation of blasting machine scalping and air-wash separators.

 

The cleaned exterior pipe surface shall be in inspected for adequate surface preparation. Surface imperfections, such as slivers, scabs, burrs, weld spatter, and gouges, shall be removed by hand filing or grinding if necessary to prevent holidays.

 

Blast-cleaned pipe surfaces shall be protected from conditions of high humidity, rainfall, or surface moisture. No pipe shall be allowed to flash rust before coating. To ensure a dry pipe surface at the time of liquid adhesive application, the minimum steel substrate temperature shall be 30°C and at least 3°C above the dew point.

 

Coating Application:

 

Liquid adhesive application:

The liquid adhesive shall be applied in a uniform thin film at the coverage rate recommended by the manufacturer. The liquid adhesive shall be thoroughly and continuously mixed and agitated during application to prevent settling. The liquid adhesive shall be applied to the entire exterior surface of the pipe by spray to cover the entire exterior surface of the pipe.

 

The liquid adhesive coat shall be uniform and free from floods, runs, sags, drips, or bare spots. The liquid-adhesive-coated pipe surface shall be free of any foreign substances, such as sand, grease, oil, grit, rust particles, or dirt.

 

Before applying the inner-layer tape, the liquid adhesive layer shall be allowed to touch dry in accordance with the manufacturer's recommendation.

 

Application of inner-layer tape:

The inner-layer tape shall be applied directly onto the prepared pipe surface using mechanical constant-tension coating equipment. The inner layer tape shall be spirally applied with neck down tension as recommended by manufacturer. When applied to spirally welded pipe, the direction of the tape spiral shall be generally parallel to the weld spiral. The minimum overlap shall not be less than 25 mm. When a new roll of tape is started, the ends shall be overlapped at least 150 mm measured circumferentially.

 

Application of Intermediate-layer tape:

The intermediate-layer tape shall be applied over the inner-layer tape using the same type of mechanical equipment used to apply the inner-layer tape. The intermediate- layer tape shall be spirally applied with neck down tension as recommended by manufacturer. The overlap of the intermediate -layer tape shall not coincide with the overlap of the inner-layer tape. The minimum overlap shall not be less than 25 mm. When a new roll of tape is started, the ends shall be overlapped at least 150 mm measured circumferentially. The intermediate-layer tape shall be applied at a minimum roll body temperature of 21°C or as recommended by the tape manufacturer.

 

Application of outer-layer tape:

The outer-layer tape shall be applied over the intermediate-layer tape using the same type of mechanical equipment used to apply the inner and intermediate layer tapes. The outer layer tape shall be spirally applied with neck down tension as recommended by manufacturer. The overlap of the outer-layer tape shall not coincide with the overlap of the intermediate-layer tape. The minimum overlap shall not be less than 25 mm. When a new roll of tape is started, the ends shall be overlapped at least 150 mm measured circumferentially. The outer-layer tape shall be applied at a minimum roll temperature of 21°C or as recommended by the tape manufacturer.

 

Cutbacks

Coating cutbacks shall be 150 mm + 0 / - 25 mm. 


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