05420 Grating and Stair Treads.pdf

Standard Drawings for Doppler (VHF)

Omni Directional Range (DVOR) Counterpoise June 2020

GRATING AND STAIR TREADS 05420-1

SECTION 05420

GRATING AND STAIR TREADS

PART 1 - GENERAL

1.1 Scope: Provide fabrication and erection of the grating and stair treads as shown on the drawings or required by other divisions of these specifications.

1.2 References: Industry publications controlling the work of this Division include:

A. American Society for Testing and Materials (ASTM):

ASTM A123 Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products.

ASTM A153 Zinc Coating (Hot-Dip) on Iron and Steel Hardware.

ASTM A307 Carbon Steel Bolts and Studs, 60,000 psi Tensile.

ASTM A385 Providing High Quality Zinc Coatings

ASTM A563 Carbon and Alloy Steel Nuts

ASTM A569 Steel, Carbon (0.15 Maximum, Percent), Hot-Rolled Sheet and

Strip, Commercial Quality.

B. American Welding Society (AWS):

AWS D1.1 Structural Welding Code

C. Federal Specification (FS)

FS RR-G-661E Grating, Metal, Bar Type (Floor, Except for Navy Vessels)

D. National Association of Architectural Metal Manufacturers (NAAMM):

Metal Bar Grating Manual

1.3 Submittals: Submit the following to the Government in accordance with general requirements. Submittals are for approval

A. Fabrication and erection drawings

B. Manufacturer's specifications and other data needed to prove compliance with the specified requirements.

1.4 Quality Assurance: Quality assurance for the work of this Section includes:

A. Material or workmanship will be subject to Government inspection in the shop and field.

B. Welders shall be qualified as prescribed in the AWS D1.1.

Standard Drawings for Doppler (VHF)

Omni Directional Range (DVOR) Counterpoise June 2020

GRATING AND STAIR TREADS 05420-2

PART 2 - PRODUCTS

2.1 Grating: Grating shall be a galvanized, banded, type I, class 1, steel grating complying with FS RR-G-661E.

Unless shown otherwise on the drawings, bearing bars shall be 1-1/2" x 3/16", spaced 1-3/16" on center, and cross bars shall be spaced 4" on center.

2.2 Stair Treads: Stair treads shall be fabricated from grating and shall be as specified herein.

A. Bearing bars shall be not less than 3/16" x 1 1/4" spaced 1-3/16" on center.

B. The nominal width of all stair treads shall be equal to or be the next nominal width greater than the tread run indicated on the design drawings.

C. End carrier plates shall be provided. Bearing bars shall be attached to the carrier plates with fillet welds as detailed in the National Association of Architectural Metal Manufacturers' (NAAMM)

"Metal Bar Grating Manual." Punching of carrier plates shall be as detailed in the same manual.

D. Each tread shall be provided with a continuous steel abrasive nosing.

2.3 Bolts: Bolts shall conform to ASTM A307 Grade A and nuts to ASTM A563. One common bolt assembly shall consist of a heavy hex head structural bolt, a heavy hex nut and a hardened washer.

PART 3 - EXECUTION

3.1 Fabrication: Fabricate all materials as specified herein.

A. All floor grating and stair treads shall be in accordance with the NAAMM "Metal Bar Grating

Manual."

B. Both ends of all sections of grating shall be banded.

C. All gratings shall lie flat with no tendency to rock when installed. Poorly fitting grating will be rejected.

D. All welding shall be done neatly and substantially, with all fillets dressed to uniform radius, all excess metal removed, and all welds ground smooth and flush. All welding shall comply with AWS

D1.1.

3.2 Galvanizing: All grating and stair treads shall be hot-dip galvanized after fabrication in accordance with

ASTM A123, ASTM A153, and ASTM A385, unless noted otherwise. Materials specified to be galvanized shall be prepared for galvanizing by being properly cleaned, pickled, rinsed, and dried. The cleaned materials shall be immediately galvanized before any rusting can occur.

END OF SECTION