**Minnesota Construction Specification 51---Corrugated Metal Pipe**

**1. SCOPE**

The work shall consist of furnishing and placing circular, arched or
elliptical corrugated metal pipe and the necessary fittings.

**2. MATERIAL SPECIFICATIONS**

Pipe and fittings shall conform to the requirements of Material
Specification 55l or Material Specification 552, whichever is specified.

Unless otherwise specified in Section 10 of this specification or as
shown on the construction drawings, perforated pipe furnished shall meet
the requirements for Class I perforations as described in ASTM A 760 or
A 762.

**3. COUPLING BANDS AND HARDWARE**

Pipe joint coupling bands shall be provided meeting the requirements
specified in Section 10 or as shown on the construction drawings.

Hardware consisting of coupling bands and band fastening devices such as
connecting bolts, rods, lugs and angles used in conjunction with
zinc-coated iron or steel pipe shall be galvanized by the hot-dip
method. Hardware used in conjunction with aluminum pipe and aluminum or
aluminum-zinc alloy-coated iron and steel pipe shall be of the same
material as the pipe except that hot-dip galvanized or cadmium plated
fasteners may be used. The surface of all band fastening devices for
pipe specified with bituminous or polymer coating shall be coated with
asphalt mastic materials meeting the requirements of ASTM A 849. The
coupling band shall be coated similar to that specified for the pipe
unless otherwise specified in Section 10 or as shown on the construction
drawings.

Coupling bands shall be installed to provide straight alignment of the
connecting pipe ends. Unless otherwise specified in Section 10 or as
shown on the construction drawings, the band width shall be as specified
in ASTM A 760 and A 762. The bands shall be positioned to overlap
adjacent pipe ends equally. The coupling bands shall be corrugated to
match the corrugations of the connecting pipe ends.

**4. FABRICATION**

Fabrication of appurtenant sections shall be done as shown on the
construction drawings and described in Section 10 of this specification.
The items may consist of inlet sections, outlet sections, end sections,
elbows, skew or beveled sections, rod reinforced ends, cut-off collars,
or headwalls. Fabrication of these appurtenant sections shall be made
from metallic-coated materials identical to those from which the
attached pipe is fabricated. Fabrication shall be of a quality and
finished workmanship equal to that required for the pipe.

**5. HANDLING THE PIPE**

The Contractor shall furnish equipment as necessary to place the pipe
without damaging the pipe or coatings. The pipe shall be transported and
handled in a manner to prevent damage to the pipe or coating.

**6. LAYING AND BEDDING THE PIPE**

Unless otherwise specified, the pipe shall be installed in accordance
with the manufacturer\'s recommendations. The pipe shall be laid with
the outside laps of circumferential joints pointing upstream and with
longitudinal laps at the sides at about the vertical midheight of the
pipe.

Field welding of corrugated galvanized iron or steel pipe will not be
permitted. The pipe sections shall be joined with fabricator-supplied
coupling bands meeting the specified joint requirements. The coupling
shall be made as recommended by the fabricator.

The pipe shall be firmly and uniformly bedded throughout its entire
length to the depth and in the manner specified on the drawings.

Perforated pipe shall be laid with the perforations down and oriented
symmetrically about a vertical center line. Perforations shall be clear
of any obstructions at the time the pipe is laid.

The pipe shall be loaded sufficiently during backfilling around the
sides to prevent its being lifted from the bedding.

**7. STRUTTING**

When required, struts or horizontal ties shall be installed in the
manner specified on the drawings. Struts and ties shall remain in place
until the backfill has been placed above the top of the pipe to a height
of 5 feet or the pipe diameter, whichever is the greater, or has been
completed if the finished height is less than 5 feet above the top of
the pipe; at which time struts or ties used shall be removed by the
Contractor.

**8. EMBEDMENT IN CONCRETE**

Special treatment shall be provided to pipe embedded in or attached to
concrete when the pipe is aluminum or aluminum-coated and aluminum-zinc
alloy-coated. Potential contact surfaces shall be insulated. All
aluminum, aluminum-coated, and aluminum-zinc alloy-coated pipe surfaces
in contact with concrete and masonry surfaces shall be coated with two
coats of a bituminous paint of the cut-back type. Placement of the pipe
shall be such that direct metal-to-metal contact with other metallic
materials, such as embedded steel reinforcement or water control gates,
is prevented.

**9. REPAIR OF DAMAGED COATINGS**

Any damage to the metallic coating shall be repaired by cleaning the
damaged surface area by sand blasting, power disk sanding or wire
brushing. All loose and cracked coating, dirt, and any products of
corrosion shall be removed prior to application of two (2) coats of
paint. Oil and grease materials shall be removed by use of a solvent.
The surface shall be clean and dry during the painting period and until
the coating has dried.

Painting shall be by use of one of the following options based upon
installed exposure of the pipe as determined by the Engineer:

Normal exterior or interior atmospheric exposure:

a.  Zinc dust - zinc oxide primer, Federal Specification TT-P-641, Type
    I or Type II, or

b.  Single-package, moisture-cured urethane primer in silver metallic
    color, or

c.  Zinc-rich cold galvanizing compound, brush, or aerosol application.

Submergence in water exposure:

a.  Zinc dust - zinc oxide primer, ASTM D 79 and D 520

b.  Zinc dust paint, ASTM D 4146

If the metallic coating is damaged in any individual area larger than 12
square inches, or if more than 0.2 percent of a total surface area of a
length of pipe is damaged, the length will be rejected.

Breaks or scuffs in bituminous coatings that are less than 36 square
inches in area shall be repaired by the application of two coats of hot
asphaltic paint or a coating of cold-applied bituminous mastic. The
repair coating shall be at least 0.05 inches thick after hardening and
shall bond securely and permanently to the pipe. The material shall meet
the physical requirements for bituminous coatings contained in ASTM A
849 and A 885. Whenever individual breaks exceed 36 square inches in
area or when the total area of breaks exceeds 0.5 percent of the total
surface area of a length of pipe, the pipe length will be rejected.

Bituminous coating damaged by welding of coated pipe or pipe fittings
shall be repaired as specified in this Section for breaks or scuffs in
bituminous coatings.

Breaks or scuffs in polymer coatings that are less than 36 square inches
in area shall be repaired by the application of two coats of a polymer
material similar to and compatible with the durability, adhesion and
appearance of the original polymer coating, not as described in ASTM A
762, paragraph 11.5.1. The repair coating shall be a minimum thickness
of 0.010 inches (10 mils) after drying. Whenever individual breaks
exceed 36 square inches in area or when the total area of breaks exceeds
0.5 percent of the total surface area of a length of pipe, the pipe
length will be rejected.

**10. CONSTRUCTION DETAILS**

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