master_spec_02821_en.pdf

Section 02821 1

SECTION 02821

CHAIN LINK FENCES AND GATES

PART 1 – GENERAL

1.1 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only.

ITALIAN NATIONAL INSTITUTE FOR THE UNIFICATION OF STANDARDS (UNI)

PUBLICATIONS:

UNI 3995 (1958) Single-twist steel netting, with rhomboidal mesh

UNI EN 10240 (1999) Internal and/or external protective coatings for steel tubes - Specification for hot dip galvanized coatings applied in automatic plants.

UNI EN 10217-1 (2002) Welded steel tubes for pressure purposes - Technical delivery conditions - Non-alloy steel tubes with specified room temperature properties

UNI ISO 9227 (1993) Corrosion test in artificial atmospheres. Salt spray tests

1.2 DELIVERY, STORAGE, AND HANDLING

Deliver materials to site in an undamaged condition. Store materials off the ground to provide protection against oxidation caused by ground contact.

PART 2 – PRODUCTS

2.1 CHAIN-LINK FENCING AND ACCESSORIES

Materials shall be in accordance with detailed specifications as referenced and other requirements as specified.

2.1.1 Fabric

UNI 3995, zinc-coated steel, 3.8 mm core wire size. Mesh size, 50 mm.

Provide selvage twisted and barbed at both selvages. Height of fabric, as indicated.

2.1.2 Gates

Gate fabric, as specified for fencing fabric. Coating for steel latches, stops, hinges, keepers, and accessories. Gate latches, plunger bar type.

Gate leaves less than 2.4 m wide shall have truss rods or manufacturer’s standards, except that welding will be not be permitted. Intermediate members as necessary to provide rigid construction, free from sag or

2 Section 02821 twist. Gate leaves less than 2.4 m wide shall have truss rods or intermediate braces. Attach gate fabric to the gate frame in accordance with the manufacturer’s standards, except that welding will be not be permitted. Arrange padlocking latches to be accessible from both sides of the gate, regardless of latching arrangement.

2.1.3 Posts, Top Rails, and Braces

UNI ISO 9227, UNI EN 10240, UNI EN 10217-1. Line posts, end, corner, and pull posts shall be first class steel pipe. Braces and rails shall be Class I, steel pipe minimum size listed for each class and grade.

2.1.4 Fencing Accessories

Provide wire ties constructed of the same material as the fencing fabric.

2.1.5 Concrete

Provide as specified in Section 03300, “Cast-In-Place Concrete.”

PART 3 - EXECUTION

3.1 SITE PREPARATION

3.1.1 Excavation

Depth of post embedment at Contractor’s option.

3.2 FENCE INSTALLATION

Install fence in accordance with fence manufacturer’s written installation instructions.

3.2.1 Post Spacing

Provide line posts spaced equidistantly apart, not exceeding 3 m on center. Provide gate posts spaced as necessary for size of gate openings.

Do not exceed 152 m on straight runs between braced posts. Provide corner or pull posts, with bracing in both directions, for changes in direction of 0.26 rad or more, or for abrupt changes in grade.

3.2.2 Post Setting

Set posts plumb.

3.2.3 Bracing

Brace gate, corner, end, and pull posts to nearest post with a horizontal brace used as a compression member, placed at least 300 mm below top of fence, and a diagonal truss rod and truss tightner used as a tension member.

3.2.4 Top Rails

Install top rails before installing chain-link fabric. Pass top rail through intermediate post caps. Provide expansion coupling in accordance with manufacturer’s installation instructions.

Section 02821 3

3.2.5 Bottom Tension Wires

Install bottom tension wires before installing chain-link fabric, and pull wires taut. Place bottom tension wires within 200 mm of respective fabric line.

3.2.6 Fabric

Pull fabric taut and secure fabric to top rail and bottom wire, close to both sides of each post and at maximum intervals of 600 mm on center.

Secure fabric to posts using stretcher bars, ties or clips spaced 375 mm on center, or by integrally weaving to integral fastening loops of end, corner, pull, and gates posts for full length of each post. Install fabric on opposite side of posts from area being secured. Install fabric so that bottom of fabric is 50 mm above ground level. Install fence fabric to provide approximately 50 mm deflection at center of fabric span between two posts, when a force of approximately 10 kg is applied perpendicular to fabric. Fabric should return to its original position when force is removed.

3.3 ACCESSORIES INSTALLATION

3.3.1 Gates

Install wing gates to swing through 90 degrees from closed to open.

3.3.2 Padlocks

Provide padlocks for gate openings and provide chains that are securely attached to gate or gate posts. Provide padlocks keyed alike, and provide two keys for each padlock.

3.4 CLEANUP

Remove fencing materials and other debris upon completion of construction.

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SECTION 02821 CHAIN LINK FENCES AND GATES