Metal Gratings and Floor Plates
Remade from scratch to the authoring rules: defaults asserted only where four of five projects would choose them, and scope boundaries matched to the neighboring standards
Showing changes from Rev 2
to Rev 3
in Metal Gratings and Floor Plates.
---
title: Metal Gratings and Floor Plates
category: Structural / Steel & Metal Fabrications
−toc_depth: 3
description: >
− When to use: metal bar gratings and hot-rolled floor (checker/diamond) plate
− used as pedestrian and light-vehicular walking surfaces, drainage and trench
− covers, equipment platforms, mezzanine floors, catwalks, and access areas in
− commercial, industrial, institutional, water/wastewater, power, and process
− facilities. Covers carbon and stainless steel, aluminum, and FRP gratings in
− welded, pressure-locked, and swaged configurations, plus ASTM A786 floor plate;
− including grades, surface treatment, fastening, banding, and finishes.
− Not intended for: stair treads, nosings, and stair framing or handrails and
− guardrails at openings (use [[sync/metal-stairs-and-railings]]); support framing
− beams and angles under grating (use [[sync/metal-fabrications]] or the structural
− steel standard); ornamental miscellaneous metalwork that is not a walking surface
− (use [[sync/miscellaneous-metals]]); structural roof/floor metal deck (use the
− structural metal deck standard); full structural FRP design in aggressive chemical
− service (use the FRP manufacturer's engineering documentation); and pavement or
− site drainage grates (use civil/site utility standards).
+ When to use: Open-grid bar grating of carbon steel, stainless steel, and aluminum in welded, pressure-locked, swaged, and riveted construction, molded and pultruded fiberglass-reinforced plastic grating, and solid raised-pattern floor plate of steel, stainless steel, and aluminum, furnished as the walking surface of equipment platforms, mezzanines, catwalks, pipe-rack and tank-top access ways, and as removable covers over trenches, pits, sumps, and equipment wells in commercial, institutional, industrial, water and wastewater, power, and process facilities. Covers the design loads and the deflection limit the panels are sized to, the derivation of bearing bar depth, thickness, and spacing from the NAAMM load tables, the opening-size limit on accessible routes and in the means of egress, bar surface, banding, FRP construction, resin, surface, and fire performance, floor plate pattern, thickness, and slip-resistant treatment, finishes, fastening, removable panels and their handling weight, trench and pit covers, installation, field verification, delivery, warranty, and spare clips.
+ Not intended for: Stair treads of bar grating or plate, stair stringers and landings, and the handrails, guards, and toe boards at the open edges of any walking surface (see [[sync/metal-stairs-and-railings]]); the beams, channels, and angles that carry the panels where they appear on the structural drawings (see [[sync/structural-steel-framing]]), loose support framing, equipment supports, and the angle frames of utility trench and pit covers (see [[sync/miscellaneous-metals]]), and access hatches and pit covers with architectural frames and finishes (see [[sync/metal-fabrications]]); fixed ladders and ship's ladders (see [[sync/miscellaneous-metals]]); steel floor and roof deck (see [[sync/steel-deck]]); the grates, frames, and channel bodies of plumbing trench drains and floor drains (see [[sync/trench-drains-and-interceptors]]) and the grates and frames of site inlets and catch basins (see [[sync/storm-drainage]]); the process requirements of hot-dip galvanizing and shop priming (see [[sync/shop-painting-and-galvanizing]]); field-applied paint over galvanized, primed, or bare panels (see [[sync/interior-painting]] and [[sync/exterior-painting]]) and chemical-resistant and washdown coating systems (see [[sync/high-performance-coatings]]); the project welding program (see [[sync/welding-requirements]]); post-installed anchors into concrete (see [[sync/post-installed-anchors]]); overhead coiling grilles (see [[sync/coiling-grilles]]) and wire mesh partitions and cages (see [[sync/wire-mesh-partitions]]); and the structural design of FRP framing members in chemical service, which is engineered for the project from the FRP manufacturer's documentation.
---
# Scope {toc}
−## This standard governs the materials, fabrication, finishes, fastening, and installation of metal bar grating and hot-rolled floor plate furnished as walking-working surfaces, drainage and trench covers, and access flooring. {note}
+## This standard governs the walking surface itself: the grating or plate panel, its material and construction, the loads it is sized to, the openings it may present to a shoe, a cane, or a wheel, its surface, its edges, its finish, and the way it is held to and lifted from the framing that carries it. {note}
−## The covered products are open-grid bar gratings (carbon steel, stainless steel, aluminum, and fiberglass-reinforced plastic) and solid floor plate (steel checker/diamond plate and aluminum tread plate). Both serve the same architectural role - a slip-resistant, often removable, walking surface - but they are selected and detailed differently, so the requirements below are organized by product family. {note}
+## The furnished work shall comprise every grating and floor plate panel at the walking surfaces, platforms, catwalks, and covers the drawings show, with the banding, trim, cutouts, lifting provisions, clips, fasteners, bearing strips, and isolation the panels require, and the installation of all of it.
−## Bar grating types covered are welded, pressure-locked, and swaged construction. {note}
+## Whether each area receives metal bar grating, FRP grating, or solid floor plate shall be as indicated on [[drawing: the plans and platform details]].
−## Welded grating is the dominant carbon and stainless steel product. Pressure-locked and swaged construction are used primarily for aluminum, where welding distortion and heat-affected-zone loss of temper are undesirable. The grating type, material, and load class are selected together from the manufacturer's load tables; this standard fixes the rules that govern that selection. {note}
+## Bar grating and floor plate are drawn as the same hatch on many platform plans and they are not the same product. Grating drains, ventilates, passes light, and sheds nothing onto the surface below; plate holds spilled liquid, blocks light and air, and carries a cart with no wheel chatter. The drawings decide between them area by area, and this standard holds the requirements for both so the decision does not have to be revisited in the specification. {note}
−## This standard does not cover the following related scope items: {note}
−- Stair treads, nosings, and stair framing — see [[sync/metal-stairs-and-railings]].
−- Handrails, guardrails, and toe-board/kick-plate railing assemblies at grating openings — see [[sync/metal-stairs-and-railings]].
−- Structural support framing (beams, channels, and support angles) that carries grating panels — see [[sync/metal-fabrications]] or the project structural steel standard.
−- Structural roof, floor, or composite metal deck; ornamental miscellaneous metalwork that is not a walking surface; and pavement and site drainage grates.
−- Full structural FRP design in aggressive chemical service (resin chemistry qualification, load-and-deflection certification, fire performance) — see the FRP manufacturer's stamped engineering documentation and ICC-ES evaluation report.
+## The following are governed elsewhere and are outside this standard: {note}
+- Stair treads, whether of bar grating or of plate, with their nosings, stringers, and landings, and the handrails, guards, and toe boards at the open edge of every platform and walkway, are governed by [[sync/metal-stairs-and-railings]]. The grating edge is detailed under this standard to receive them.
+- The beams, channels, and angles that carry the panels are governed by [[sync/structural-steel-framing]] where they appear on the structural drawings, and by [[sync/miscellaneous-metals]] where they are loose equipment supports or framing outside the structural drawings. The angle frames of utility trench and pit covers are governed by [[sync/miscellaneous-metals]]; access hatches and pit covers with architectural frames and finishes are governed by [[sync/metal-fabrications]]. The panel that sits in any of those frames is governed here.
+- Fixed ladders, ship's ladders, and guard posts protecting building elements and equipment are governed by [[sync/miscellaneous-metals]]; site bollards are governed by [[sync/site-furnishings-and-bollards]]; steel floor and roof deck is governed by [[sync/steel-deck]].
+- The grates, frames, and channel bodies of plumbing trench drains and floor drains are governed by [[sync/trench-drains-and-interceptors]]; the grates and frames of site inlets and catch basins are governed by [[sync/storm-drainage]]. A grating panel that covers an open process trench or a sump is governed here.
+- The process requirements of hot-dip galvanizing and shop priming are governed by [[sync/shop-painting-and-galvanizing]]; field paint over galvanized, primed, or bare panels is governed by [[sync/interior-painting]] and [[sync/exterior-painting]]; chemical-resistant and washdown coating systems are governed by [[sync/high-performance-coatings]].
+- The project welding program, with procedure and welder qualification and weld acceptance, is governed by [[sync/welding-requirements]]; post-installed anchors into concrete are governed by [[sync/post-installed-anchors]].
−## Where FRP structural design is required, the specifier shall reference the FRP manufacturer's stamped engineering documentation and ICC-ES evaluation report.
+## Where a frame, a support, or an embedded seat angle is furnished under another standard, the Contractor shall coordinate the seat depth, the seat width, and the anchor locations of that frame with the panel depth, the bearing length, and the fastening selected under this standard before either is fabricated.
+## A seat angle cast into a slab at the depth of the grating that was priced, and then a deeper grating ordered to carry the load the structural drawings state, leaves a panel standing proud of the floor at every edge of the trench. The seat is set by others and the panel is sized here, which is why the two are reconciled before fabrication rather than at the first pour. {note}
+
# Referenced Standards {toc}
…2 unchanged lines
## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
−## The opening-size limit shall be taken from the building code edition adopted by the Authority Having Jurisdiction for the project, because the section numbering of the half-inch sphere rule varies between code editions.
+## The opening-size limit on walking surfaces in the means of egress, the minimum live loads, and the guard and toe board provisions at platform edges shall be taken from [[parameter: adopted-building-code]], whose numbering of those provisions differs between editions.
| Standard | Title |
|----------|-------|
| ANSI/NAAMM MBG 531 | Metal Bar Grating Manual |
−| NAAMM MBG 532 | Heavy Duty Metal Bar Grating Manual |
−| ASTM A786/A786M | Hot-Rolled Carbon, Low-Alloy, HSLA, and Alloy Steel Floor Plates |
+| ANSI/NAAMM MBG 532 | Heavy Duty Metal Bar Grating Manual |
+| ANSI/NAAMM MBG 533 | Welding Specifications for Fabrication of Steel Bar Grating |
+| ANSI/NAAMM MBG 534 | Metal Bar Grating Engineering Design Manual |
| ASTM A36/A36M | Carbon Structural Steel |
+| ASTM A1011/A1011M | Steel, Sheet and Strip, Hot-Rolled, Carbon, Structural, High-Strength Low-Alloy |
+| ASTM A786/A786M | Hot-Rolled Carbon, Low-Alloy, High-Strength Low-Alloy, and Alloy Steel Floor Plates |
+| ASTM A793 | Rolled Floor Plate, Stainless Steel |
+| ASTM A240/A240M | Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip |
| ASTM A276/A276M | Stainless Steel Bars and Shapes |
−| ASTM B221 | Aluminum and Aluminum-Alloy Extruded Bars, Rods, Profiles, and Tubes |
+| ASTM A380/A380M | Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems |
+| ASTM B221 | Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes |
+| ASTM B209/B209M | Aluminum and Aluminum-Alloy Sheet and Plate |
| ASTM A123/A123M | Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products |
| ASTM A153/A153M | Zinc Coating (Hot-Dip) on Iron and Steel Hardware |
+| ASTM A385/A385M | Providing High-Quality Zinc Coatings (Hot-Dip) |
| ASTM A780/A780M | Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings |
−| ASTM D7290 | Evaluating Material Property Characteristic Values for Polymeric Composites (FRP grating basis) |
−| ASCE 7 | Minimum Design Loads and Associated Criteria for Buildings and Other Structures |
−| IBC Chapter 10 | International Building Code - Means of Egress (opening-size and toe-board provisions) |
−| ADA Standards | ADA Standards for Accessible Design, Section 302 - Floor or Ground Surfaces |
−| OSHA 29 CFR 1910.23 | Walking-Working Surfaces |
−| AWS D1.1/D1.1M | Structural Welding Code - Steel |
+| ASTM F593 | Stainless Steel Bolts, Hex Cap Screws, and Studs |
+| ASTM E84 | Surface Burning Characteristics of Building Materials |
+| ASTM D7290 | Evaluating Material Property Characteristic Values for Polymeric Composites for Civil Engineering Structural Applications |
+| ASCE/SEI 7 | Minimum Design Loads and Associated Criteria for Buildings and Other Structures |
+| AASHTO LRFD | AASHTO LRFD Bridge Design Specifications (design vehicle wheel loads) |
+| AWS D1.1/D1.1M | Structural Welding Code – Steel |
+| AWS D1.2/D1.2M | Structural Welding Code – Aluminum |
+| AWS D1.6/D1.6M | Structural Welding Code – Stainless Steel |
+| ICC A117.1 | Accessible and Usable Buildings and Facilities |
+| 2010 ADA Standards | ADA Standards for Accessible Design |
+| 29 CFR 1910 Subpart D | OSHA Walking-Working Surfaces |
# Submittals {toc}
−## The Contractor shall submit the following action submittals before fabrication:
−- Shop drawings showing panel layout, panel marks, bearing bar size and spacing, cross bar spacing, banding, support framing bearing, fastener type and location, and field-cut locations.
−- Product data for each grating type, material, surface treatment, and finish, including the manufacturer's load-and-deflection table for the specified bearing bar and span.
−- Manufacturer's certification that the selected bearing bar spacing satisfies the project opening-size requirement on accessible routes and means of egress.
−- Samples of each grating type and finish, minimum 12 in. by 12 in., showing surface treatment (smooth or serrated) and banded edge condition.
−- Floor plate product data identifying pattern, thickness, grade, and finish.
+## Action Submittals {toc}
+### The Contractor shall submit the following for review before any panel is released for fabrication:
+
+- Shop drawings showing the panel layout and panel marks, bearing bar direction and span, bearing bar depth, thickness, and spacing, cross bar spacing, banding and trim, every cutout and opening with its reinforcement, the support and bearing length at every edge, the clip or weld type and its location, the panels designated removable with their handling weight, and the lifting provisions
+- Load and deflection data for every bearing bar section, material, and construction furnished, taken from the NAAMM load tables or from the manufacturer's published tables, showing the capacity at the span and the deflection limit of this standard
+- Product data for each grating type, floor plate, surface treatment, finish, clip, and fastener
+- A sample of each grating type and finish, not less than 12 in. by 12 in., with one banded edge and the surface treatment furnished, and a sample of each floor plate pattern and treatment, not less than 12 in. by 12 in.
+- For FRP grating, the resin designation, the surface veil, the flame spread index test report, and the manufacturer's load and deflection tables for the construction and depth furnished
+
```datasheet
−label: Action submittals required
+label: Action Submittals Required
type: checkbox
options:
− - Shop drawings (panel layout, marks, banding, fasteners)
− - Product data with load/deflection tables
− - Opening-size compliance certification (accessible routes / egress)
− - Grating and finish samples (12 in. x 12 in.)
− - Floor plate product data
+ - "Shop drawings"
+ - "Load and deflection data"
+ - "Product data"
+ - "Grating and floor plate samples"
+ - "FRP resin, surface, fire, and load data"
default:
− - Shop drawings (panel layout, marks, banding, fasteners)
− - Product data with load/deflection tables
− - Opening-size compliance certification (accessible routes / egress)
− - Grating and finish samples (12 in. x 12 in.)
− - Floor plate product data
+ - "Shop drawings"
+ - "Load and deflection data"
+ - "Product data"
+ - "Grating and floor plate samples"
+ - "FRP resin, surface, fire, and load data"
```
−## The Contractor shall submit the following informational submittals:
−- Mill test reports or certificates of conformance for bearing bar, cross bar, and floor plate material.
−- Galvanizing certification per ASTM A123 (and A153 for hardware) stating coating grade and average coating weight.
−- For FRP grating, the manufacturer's resin-system data sheet and ICC-ES evaluation report.
−- Welding procedure specifications and welder qualifications per AWS D1.1 for field-welded panels.
+### The shop drawings shall state, for every panel, the design uniform load and the design concentrated load it was checked against and the deflection the load table gives at that load and span.
+### A grating order placed by panel size alone is sized by the fabricator to whatever bar is on the floor that week, and a 1 in. bar at a 4 ft span carries a person and bounces under a cart. Writing the load and the deflection on the panel schedule is what lets the reviewer check the bar against the span without reconstructing the fabricator's arithmetic. {note}
+
+## Informational Submittals {toc}
+
+### The Contractor shall submit the following for record before the corresponding work begins:
+
+- Mill certificates or certificates of conformance for bearing bar, cross bar, and floor plate material, stating the specification and grade
+- Galvanizing certificate for each lot, stating the ASTM A123 coating grade achieved and the ASTM A153 class for hardware
+- Welding procedure specifications and welder qualification records for shop welding of grating under ANSI/NAAMM MBG 533 and for any field welding, as the project welding program under [[sync/welding-requirements]] requires
+- For stainless steel panels, the passivation record under ASTM A380
+- For FRP grating, the manufacturer's statement of the test basis of the load tables and the evaluation report or stamped engineering that supports them
+- Fabricator qualification statement
+
```datasheet
−label: Informational submittals required
+label: Informational Submittals Required
type: checkbox
options:
− - Mill test reports / certificates of conformance
− - Galvanizing certification (A123 / A153)
− - FRP resin data sheet and ICC-ES report
− - AWS D1.1 WPS and welder qualifications
+ - "Mill certificates"
+ - "Galvanizing certificates"
+ - "Welding procedures and welder qualifications"
+ - "Stainless passivation record"
+ - "FRP load table basis"
+ - "Fabricator qualification statement"
default:
− - Mill test reports / certificates of conformance
− - Galvanizing certification (A123 / A153)
+ - "Mill certificates"
+ - "Galvanizing certificates"
+ - "Welding procedures and welder qualifications"
+ - "Fabricator qualification statement"
```
−## The Contractor shall submit the following closeout submittals:
−- Operation and maintenance data for removable panels, including fastener torque and panel handling weights.
−- Touch-up coating product data and field touch-up records for galvanized panels per ASTM A780.
+## Closeout Submittals {toc}
+### The Contractor shall submit the following before the work is accepted:
+
+- A record panel plan showing every panel mark as installed, the panels that are removable, and the handling weight of each removable panel
+- The clip and fastener type, size, and torque for every removable panel, with the manufacturer's instructions for re-securing a lifted panel
+- Coating repair record listing every field cut and field weld on galvanized panels and the repair applied under ASTM A780
+- Field verification record
+
```datasheet
−label: Closeout submittals required
+label: Closeout Submittals Required
type: checkbox
options:
− - O&M data for removable panels (torque, handling weight)
− - Touch-up product data and field touch-up records
+ - "Record panel plan with removable panels and weights"
+ - "Clip and fastener data for removable panels"
+ - "Coating repair record"
+ - "Field verification record"
default:
− - O&M data for removable panels (torque, handling weight)
− - Touch-up product data and field touch-up records
+ - "Record panel plan with removable panels and weights"
+ - "Clip and fastener data for removable panels"
+ - "Coating repair record"
+ - "Field verification record"
```
+### The panel plan is the document the maintenance crew reads before lifting a cover to reach the valve beneath it. Without it, the crew lifts a panel that was welded, or lifts a panel that weighs twice what two people can hold, and the first injury on a platform is often at the cover that nobody recorded as fixed. {note}
+
# Quality Assurance {toc}
−## Steel and stainless steel bar grating shall be manufactured, fabricated, and load-rated in accordance with ANSI/NAAMM MBG 531.
+## Fabricator Qualifications {toc}
−## Heavy-duty bar grating subject to vehicular or forklift wheel loads shall additionally comply with NAAMM MBG 532.
+### Metal bar grating shall be fabricated by a firm that produces bar grating as a regular part of its business and that has done so for not less than the period indicated in the datasheet.
−## Aluminum bar grating shall be fabricated and load-rated in accordance with the aluminum grating provisions of ANSI/NAAMM MBG 531.
+```datasheet
+label: Minimum Fabricator Experience
+type: range
+unit: years
+min: 0
+max: 10
+step: 1
+default: 5
+```
−## FRP grating shall be furnished with manufacturer load-and-deflection tables developed in accordance with ASTM D7290 and supported by a current ICC-ES evaluation report.
+### FRP grating shall be produced by a manufacturer that publishes load and deflection tables for the product furnished, developed from physical load tests of that product.
−## Welded grating fabrication and field welding of grating to support framing shall conform to AWS D1.1.
+### Welding of steel bar grating in the shop shall comply with ANSI/NAAMM MBG 533, welding of aluminum grating with AWS D1.2, and welding of stainless steel grating with AWS D1.6.
−## The grating manufacturer shall be a single source for each material type on the project.
+## Source Limitations {toc}
−## Panels of differing manufacture shall not be intermixed within a continuous walking area.
+### Bar grating of each material shall be furnished by one fabricator for the whole project.
−## Single-sourcing each material type keeps bearing bar height, cross bar pitch, and surface treatment uniform so that adjacent panels sit flush and present a consistent slip-resistant surface. {note}
+### Panels of differing manufacture shall not be mixed within one continuous walking surface.
−# Environmental and Service Conditions {toc}
+### Two fabricators' 1-1/4 in. welded panels set side by side differ in cross bar pitch, in bar top profile, and in serration pattern, and the joint between them is visible and is a change in footing under a shoe. One source per material keeps every panel in a run the same panel. {note}
−## The grating material shall be selected for the corrosion environment, structural load, and budget of the installation, and the selected material shall be recorded on the drawings or in the datasheet below. {note}
+## Load Table Basis {toc}
−## Carbon steel (galvanized) is the default for dry and ordinary exterior service. Stainless steel (Type 304, or Type 316 for chloride or chemical exposure) and aluminum are selected where corrosion resistance, weight, or non-sparking properties govern. FRP is selected for chemically aggressive wet environments such as water and wastewater treatment, where steel and aluminum corrode and weight reduction aids removability. {note}
+### Carbon steel, stainless steel, and aluminum bar grating shall be sized from the load tables of ANSI/NAAMM MBG 531 for the material, construction, bar section, and span furnished.
−## The grating material shall be specified for each location based on the corrosion resistance, weight, or non-sparking properties required by the service environment.
+### Bar grating subject to wheel loads shall be sized from the load tables of ANSI/NAAMM MBG 532 for the wheel load, the tire contact area, and the span furnished.
+### FRP grating shall be sized from the manufacturer's published load and deflection tables for the construction, depth, and resin furnished, and those tables shall be supported by a current ICC-ES evaluation report or by engineering sealed by a professional engineer licensed in the state of the project.
+
+### The NAAMM tables give a uniform load and a concentrated load, with the deflection under each, for every standard bar section at every span, so a metal grating panel is checked by reading a table rather than by analysis. FRP has no industry table; each manufacturer tests its own product, and the characteristic values of ASTM D7290 are the basis a reviewer can hold a manufacturer's table to. {note}
+
+# Design Loads and Deflection {toc}
+
+## Uniform and Concentrated Loads {toc}
+
+### Every panel shall carry the design uniform live load and the design concentrated load stated for the area it serves, with the larger effect governing, and the loads shall be as indicated in the datasheet.
+
```datasheet
−label: Grating material
−type: radio
−options:
− - Carbon steel (ASTM A36), hot-dip galvanized
− - Stainless steel Type 304 (ASTM A276)
− - Stainless steel Type 316 (ASTM A276)
− - Aluminum 6061-T6 (ASTM B221)
− - Fiberglass-reinforced plastic (FRP)
−default: Carbon steel (ASTM A36), hot-dip galvanized
+label: Design Uniform Live Load
+type: range
+unit: psf
+min: 40
+max: 1000
+step: 10
+drawing_ref: "the structural drawings and the platform live load schedule"
+default: deferred
```
−## Aluminum grating and aluminum floor plate shall be isolated from concrete, mortar, and dissimilar metals by an isolating coating, neoprene pad, or non-metallic bearing strip.
+```datasheet
+label: Design Concentrated Load
+type: range
+unit: lbf
+min: 300
+max: 20000
+step: 100
+drawing_ref: "the structural drawings and the platform live load schedule"
+default: deferred
+```
−## Bare aluminum in contact with embedded concrete or carbon steel forms a galvanic cell that corrodes the aluminum at the contact line. Isolation at every bearing and fastener interrupts the cell. {note}
+### The live loads for each area are set by the structural engineer under [[parameter: adopted-building-code]] and ASCE/SEI 7 for the occupancy served, and they differ from a 40 psf catwalk to a 250 psf heavy storage floor on the same project, which is why the values live on the structural drawings and the datasheet carries them only where one value applies across the project. {note}
−## For FRP grating the resin system shall be selected and called out explicitly for the chemical exposure; "fiberglass grating" without a resin designation shall not be accepted.
+### The concentrated load shall be applied over the contact area stated with it on the structural drawings, or over a 1 ft by 1 ft area where no contact area is stated.
+### A concentrated load governs a narrow panel and a short bar more often than the uniform load does, because the uniform table assumes the load spreads across every bearing bar and a point load is carried by the bars under it plus whatever the cross bars distribute. The NAAMM tables give both, and the panel is checked against both. {note}
+
+## Wheel Loads {toc}
+
+### The wheel load basis for grating and plate subject to vehicle traffic shall be as indicated in the datasheet.
+
```datasheet
−label: FRP resin system (when FRP grating is selected)
−type: radio
+label: Wheel Load Design Basis
+type: select
options:
− - Isophthalic polyester (standard corrosion service)
− - Vinyl ester (strong chemical / chlorinated service)
− - Phenolic (fire-rated service)
−default: Isophthalic polyester (standard corrosion service)
+ - "No wheel loads, pedestrian and hand-cart traffic"
+ - "Forklift or pallet-jack wheel load"
+ - "AASHTO H-20 design vehicle wheel load"
+ - "AASHTO HS-20 design vehicle wheel load"
+default: "No wheel loads, pedestrian and hand-cart traffic"
```
−## Isophthalic polyester is the standard corrosion-resistant resin, vinyl ester is selected for strong oxidizers and chlorinated water/wastewater service, and phenolic is selected where a fire-rated surface is required. The resin determines chemical and fire performance, so it is a required selection, not a default. {note}
+### The areas subject to wheel loads, and the wheel load and tire contact area of the truck where the forklift basis is selected, shall be as indicated on [[drawing: the structural drawings]].
−# Opening Size and Accessibility {toc}
+### A pedestrian panel is sized by the uniform and concentrated loads above and needs no wheel check. A forklift wheel is a concentrated load on a small solid tire, and its magnitude and contact area come from the truck the Owner runs, which is why the structural drawings state them. The AASHTO H-20 and HS-20 wheel loads are the design vehicle loads for a trench cover a truck may cross in a loading area or a yard, and the HS-20 wheel load is the same 16,000 lbf per wheel as the H-20 with a tandem axle arrangement that governs longer spans. A wheel-loaded panel goes to the MBG 532 heavy-duty tables and to a deeper, thicker bar than any pedestrian panel. {note}
−## Grating used on an accessible route or in a means of egress shall have openings that do not permit passage of a 1/2 in. sphere in the direction of travel.
+### Grating and plate subject to wheel loads shall be checked for the impact allowance the structural drawings state for the vehicle, and where none is stated, for an impact allowance of 30 percent of the wheel load.
−## This single rule controls bearing bar spacing more often than load does. ADA Section 302 limits floor and ground surface openings to 1/2 in. maximum in the direction of travel, and the building code applies the same half-inch sphere limit to egress walking surfaces. Standard 1-3/16 in. bearing bar spacing leaves a clear opening that fails this test, so accessible and egress areas require close-mesh grating. {note}
+## Deflection {toc}
−## Bearing bar spacing on accessible routes and egress walking surfaces shall be close-mesh, with center-to-center spacing not exceeding 15/16 in., or another spacing the manufacturer certifies passes the 1/2 in. sphere test.
+### Deflection of any panel under the design uniform live load shall not exceed the lesser of the absolute limit and the span ratio indicated in the datasheet.
−## Standard 1-3/16 in. bearing bar spacing may be used only in non-accessible, non-egress areas where the half-inch sphere limit does not apply.
+```datasheet
+label: Maximum Deflection Under Design Uniform Load
+type: range
+unit: in
+min: 0.125
+max: 0.5
+setpoints: [0.125, 0.25, 0.375, 0.5]
+default: 0.25
+```
−## The bearing bar spacing shall be selected from the datasheet below and verified against the governing opening-size rule before fabrication.
+```datasheet
+label: Maximum Deflection as a Span Ratio, L/n
+type: range
+unit: "span ratio denominator n"
+min: 240
+max: 600
+setpoints: [240, 360, 400, 480, 600]
+```
+### A 1/4 in. limit is the pedestrian comfort limit the NAAMM tables are read against, and a panel within it does not feel springy under a walking person at the spans grating is used at. The span ratio matters on a long span, where 1/4 in. at 8 ft is L/384 and at 12 ft is L/576, and on a platform under vibrating equipment, where a stiffer ratio limits the resonance a walker feels. A tighter absolute limit buys a stiffer floor under a cart at the cost of a deeper bar on every panel. {note}
+
+### Deflection under a wheel load shall be checked at the wheel load with its impact allowance and shall not exceed the absolute limit above.
+
+## Span {toc}
+
+### The clear span of every panel, measured between the faces of its supports in the direction of the bearing bars, shall be as indicated on [[drawing: the framing plans and platform details]].
+
+### Bearing bars shall span in the direction shown on the framing plans, and where no direction is shown, bearing bars shall span the shorter dimension of the opening.
+
+### The span is the one input the fabricator cannot change and the one the structural engineer sets when the framing is laid out. A bearing bar depth that works at 4 ft fails at 5 ft, so a support that moves on a later framing revision moves the grating order with it, which is why the span is read from the framing plans rather than carried as a project value. {note}
+
+### Where the support spacing on the framing plans exceeds the span the load table allows for the bearing bar selected, the Contractor shall report the condition to the Engineer of Record before fabrication and shall not resolve it by substituting a deeper bar without the Engineer's written acceptance.
+
+# Opening Size and Walking-Surface Safety {toc}
+
+## Grating on an accessible route and grating in a walking surface of the means of egress shall not have an opening that passes a sphere 1/2 in. in diameter, measured in the direction of travel, in accordance with ICC A117.1 Section 302.3, the 2010 ADA Standards Section 302.3, and [[parameter: adopted-building-code]].
+
+## Where grating on an accessible route has elongated openings, the long dimension of the opening shall be placed perpendicular to the dominant direction of travel.
+
+## The accessible routes and the egress walking surfaces that cross grating shall be as indicated on [[drawing: the code plans]].
+
+## The half-inch sphere rule limits bearing bar spacing more often than the load does. A standard 1-3/16 in. bar spacing leaves a clear opening near 1 in. between bars, which passes a cane tip and a wheelchair caster and fails the rule; a 15/16 in. spacing leaves a clear opening near 3/4 in. and still fails it in the direction along the bars, which is why the opening is measured across the direction of travel and the bars are set across it. Where the direction of travel is not controlled, a close-mesh spacing with the cross bars carrying the opening down to 1/2 in. is what passes. {note}
+
+## Walking surfaces shall comply with 29 CFR 1910 Subpart D, including the load capacity marking, the surface condition, and the fall protection and toe board provisions that apply to the platform or walkway the panels form.
+
+## The walking surface of adjoining panels within a continuous area shall be flush, with no step between adjacent panel tops greater than 1/8 in., and no gap between adjacent panels or between a panel and a wall, curb, or frame greater than 1/4 in. where the surface is walked on.
+
+## The 1/8 in. step is the lip that a shoe catches and the 1/4 in. gap is the one a heel or a cane tip drops into; the accessibility standard allows a 1/4 in. vertical change at a floor surface and a gap up to 1/2 in. at a grating opening, and the tighter limits here hold the joint between panels to the condition a walker does not notice. {note}
+
+## The bearing bar depth shall be uniform within a continuous walking area, and where differing depths are unavoidable, the supports shall be set at elevations that keep the panel tops flush.
+
+## A deeper bar at the longer span next to a shallower bar at the shorter span puts a 1/4 in. lip at the joint unless the supports are dropped to meet it, and a lip at the joint is the trip that a load table never shows. {note}
+
+## Where a panel is removed from a walking surface for access below, the Contractor shall guard the opening in accordance with 29 CFR 1910 Subpart D until the panel is replaced.
+
+# Metal Bar Grating {toc}
+
+## Bar Grating Material {toc}
+
+### The material of metal bar grating shall be as indicated in the datasheet.
+
```datasheet
−label: Bearing bar spacing (center-to-center)
−type: radio
+label: Bar Grating Material
+type: select
options:
− - 15/16 in. close-mesh (accessible routes / egress)
− - 1-3/16 in. standard (non-accessible areas only)
−default: 15/16 in. close-mesh (accessible routes / egress)
+ - "Carbon steel"
+ - "Stainless steel Type 304"
+ - "Stainless steel Type 316"
+ - "Aluminum"
+default: "Carbon steel"
```
−# Bar Grating Construction {toc}
+### Carbon steel is the stock bar grating product, carries the most load per depth, and relies on its coating for every corrosion exposure. Stainless steel Type 304 resists atmospheric and most process exposures without a coating; Type 316 adds molybdenum for chloride service such as coastal air, brine, chlorinated water, and salted floors. Aluminum weighs about one third of steel at the same section, is lifted by one person where a steel panel takes two, and does not spark, which is why it appears over removable covers and in flammable-vapor areas; it carries less load per depth and is attacked by wet concrete and by contact with steel unless isolated. {note}
−## Bearing bar depth and thickness shall be selected from the manufacturer's load table for the design span and design load, not chosen by habit.
+### Carbon steel bearing bars shall be of ASTM A36 or ASTM A1011 CS Type B, and carbon steel cross bars shall be of the same specification or of a carbon steel wire or rod of a grade the fabricator's load tables are based on.
+### Stainless steel bearing bars shall be cut from ASTM A240 strip or plate or furnished as ASTM A276 bars of the type selected, and stainless cross bars shall be of the same type.
+
+### Stainless steel grating shall be pickled and passivated after fabrication in accordance with ASTM A380, and the cleaning shall remove every trace of embedded carbon steel from the fabrication tooling.
+
+### Aluminum bearing bars and cross bars shall be extruded of alloy 6061-T6 or 6063-T6 in accordance with ASTM B221.
+
+### Aluminum grating and aluminum floor plate shall be isolated from concrete, mortar, and from any carbon steel or galvanized surface they bear on by a bituminous coating on the contact surface, a neoprene bearing strip, or a non-metallic isolator at every bearing and at every fastener.
+
+### Bare aluminum against steel in the presence of moisture forms a galvanic couple in which the aluminum is consumed at the contact line, and bare aluminum against fresh concrete is etched by the alkalinity of the cement. The isolation breaks the couple at every point the two meet, including the clip that holds the panel. {note}
+
+## Bar Grating Construction {toc}
+
+### The construction of metal bar grating shall be as indicated in the datasheet.
+
```datasheet
−label: Bearing bar depth
+label: Bar Grating Construction
type: select
options:
− - 3/4 in.
− - 1 in.
− - 1-1/4 in.
− - 1-1/2 in.
− - 1-3/4 in.
− - 2 in.
− - 2-1/2 in.
−default: 1-1/4 in.
−unit: in.
+ - "Welded"
+ - "Pressure-locked"
+ - "Swaged"
+ - "Riveted"
+default: "Welded"
```
+### Welded grating fuses twisted or straight cross bars to the bearing bars by resistance welding at every intersection, which makes the stiffest and lowest-cost panel in steel and is the construction every NAAMM steel load table is built from. Pressure-locked grating presses rectangular cross bars into slots in the bearing bars under hydraulic pressure, which gives a flush-top, uniform panel without weld marks and is the construction most used for aluminum, where welding softens the heat-affected zone and distorts the panel; it is also furnished in steel where appearance governs. Swaged grating passes a round cross bar through punched holes in the bearing bars and deforms it to lock, which is the lightest aluminum construction and the one most used for aluminum walkway panels. Riveted grating connects the bearing bars with crimped reticuline bars riveted at each contact, which carries a concentrated wheel load with the least local deflection and is furnished for heavy-duty steel panels. {note}
+
+### The bearing bar section shall be as indicated in the datasheet.
+
```datasheet
−label: Bearing bar thickness
+label: Bearing Bar Section
type: radio
options:
− - 1/8 in. (standard service)
− - 3/16 in. (heavy / abrasive service)
− - 1/4 in. (vehicular)
−default: 1/8 in. (standard service)
+ - "Rectangular bar"
+ - "I-bar"
+default: "Rectangular bar"
```
−## The bearing bar is the load-carrying member; its depth governs span capacity and its thickness governs robustness in service. For pedestrian and light-industrial platforms, 1 in. and 1-1/4 in. depths cover the large majority of spans, with 3/4 in. reserved for very short spans and 1-1/2 in. and deeper used as spans or loads increase. Thickness is 1/8 in. for standard service and 3/16 in. for heavy or abrasive service. {note}
+### An I-bar carries the same bending capacity as a rectangular bar in less metal and is the section aluminum fabricators extrude for lighter panels at the same span; it has a wider top flange, which closes the opening between bars and changes the spacing that passes the half-inch sphere rule. {note}
−## Cross bars shall be provided at a maximum 4 in. center-to-center spacing for standard W-type grating unless a closer pitch is required by the manufacturer's load table.
+## Bearing Bar Depth, Thickness, and Spacing {toc}
+### The bearing bar depth and the bearing bar thickness of every panel shall be the smallest standard section in the applicable load table that carries the design uniform load, the design concentrated load, and any wheel load at the span of that panel within the deflection limit of this standard.
+
```datasheet
−label: Cross bar spacing (center-to-center)
−type: radio
+label: Bearing Bar Depth
+type: range
+unit: in
+min: 0.75
+max: 6
+setpoints: [0.75, 1, 1.25, 1.5, 1.75, 2, 2.25, 2.5, 3, 4, 5, 6]
+derived: "the design loads, the span on the framing plans, and the deflection limit, read from the ANSI/NAAMM MBG 531 or MBG 532 load table for the material and construction selected"
+default: derived
+```
+
+```datasheet
+label: Bearing Bar Thickness
+type: range
+unit: in
+min: 0.125
+max: 0.5
+setpoints: [0.125, 0.1875, 0.25, 0.3125, 0.375, 0.5]
+derived: "the design loads, the span on the framing plans, and the deflection limit, read from the ANSI/NAAMM MBG 531 or MBG 532 load table for the material and construction selected"
+default: derived
+```
+
+### The bar is not a preference; it is the row of the load table that the span and the load land on. A 1 in. by 3/16 in. carbon steel bar carries a 100 psf pedestrian floor to about a 4 ft span within 1/4 in. of deflection, a 1-1/4 in. bar reaches about 5 ft, a 1-1/2 in. bar about 6 ft, and a wheel-loaded trench cover at the same spans takes a 2 in. or deeper bar at 1/4 in. or 3/8 in. thickness from the heavy-duty tables. Thickness above 3/16 in. is selected for abrasion and impact as much as for load; a 1/8 in. bar in a scrap yard or a foundry wears through at the top edge long before it overloads. Where the span, the load, and the deflection limit are stated, every fabricator reads the same row, which is why the field records the result rather than the choice. {note}
+
+### Bearing bar thickness shall be not less than 3/16 in. where the panel carries a wheel load, and not less than 1/8 in. elsewhere.
+
+### The bearing bar spacing shall be the widest standard spacing that satisfies the opening-size limit applying to the area served and the concentrated-load distribution of the load table.
+
+```datasheet
+label: Bearing Bar Spacing, Center to Center
+type: range
+unit: in
+min: 0.6875
+max: 1.5
+setpoints: [0.6875, 0.9375, 1.1875, 1.5]
+derived: "the opening-size limit that applies to the area served and the ANSI/NAAMM load table for the bearing bar selected"
+default: derived
+```
+
+### The standard spacings are 11/16 in. (0.6875), 15/16 in. (0.9375), 1-3/16 in. (1.1875), and 1-1/2 in. (1.5) center to center, and the NAAMM designation of a panel names the spacing in sixteenths, so a 19-W-4 panel is welded grating at 1-3/16 in. with cross bars at 4 in. The 1-3/16 in. spacing is the stock industrial panel; it drains and sheds debris best and it fails the half-inch sphere rule. The 15/16 in. spacing with close cross bars is the panel that passes on an accessible route. The 1-1/2 in. spacing appears on heavy-duty panels where thick bars are set wider to hold weight down. The 11/16 in. spacing is a close-mesh panel for small-wheeled carts and for areas where tools must not fall through. {note}
+
+## Cross Bars {toc}
+
+### Cross bar spacing shall be as indicated in the datasheet.
+
+```datasheet
+label: Cross Bar Spacing, Center to Center
+type: range
+unit: in
+min: 2
+max: 4
+setpoints: [2, 4]
+default: 4
+```
+
+### The 4 in. pitch is the basis of every stock load table and holds the bearing bars at the spacing the opening-size check assumes. The 2 in. pitch doubles the cross bars, which carries a small-wheeled cart across the bars without chatter, reduces the opening in the direction along the bars for the half-inch sphere check, and adds weight and cost to every panel. {note}
+
+### Cross bars shall be twisted square bars, straight rectangular bars, or round bars as the construction selected requires, and shall be flush with or below the top of the bearing bars.
+
+## Bearing Bar Surface {toc}
+
+### The top surface of the bearing bars shall be as indicated in the datasheet.
+
+```datasheet
+label: Bearing Bar Top Surface
+type: select
options:
− - 4 in. (standard W-type)
− - 2 in. (concentrated-load distribution)
−default: 4 in. (standard W-type)
+ - "Plain"
+ - "Serrated"
+ - "Grooved"
```
−## Cross bars lock the bearing bars into a panel and distribute concentrated loads between bearing bars. The standard 4 in. pitch is the basis for the published W-type load tables; a closer pitch increases panel weight and is specified only when concentrated-load distribution requires it. {note}
+### A plain bar top is the full bearing bar section and is the surface a dry interior platform is furnished with. A serrated top carries notches punched into the top edge that cut through water, oil, ice, and process film under a shoe, and it is the surface specified where the grating is wet, outdoors, or in a process area; the notches remove a fraction of the top edge, so a serrated bar carries a little less than the plain bar of the same section and is read from its own column of the load table. A grooved top is the aluminum I-bar surface with longitudinal ridges extruded into the flange, which gives traction without notching the section. {note}
−## Grating panels shall be designed for the project design live load, and the design live load shall be recorded so the panel span can be verified against the load table. {note}
+### Serrations shall be formed before galvanizing, and the serrated depth shall be the fabricator's standard for the bar section furnished.
−## ASCE 7 establishes minimum live loads: ordinary occupied floor areas are designed for 100 psf, catwalks and light access platforms for a reduced uniform load (commonly 40 to 60 psf), and heavy industrial floors subject to forklift or wheel loads for 250 psf and above per MBG 532. Concentrated-load checks from the load table also apply and frequently govern narrow panels. {note}
+## Banding and Trim {toc}
−## The design uniform live load for grating shall be specified based on the occupancy or traffic type served, in accordance with ASCE 7 and the governing concentrated-load checks.
+### The extent of banding shall be as indicated in the datasheet.
```datasheet
−label: Design uniform live load
+label: Banding Extent
type: radio
options:
− - 40 psf (catwalk / light access platform)
− - 60 psf (access platform)
− - 100 psf (occupied floor / typical platform)
− - 250 psf (light vehicular)
− - 500 psf (heavy vehicular per MBG 532)
−default: 100 psf (occupied floor / typical platform)
−unit: psf
+ - "Banding at cut bearing bar ends and at openings"
+ - "Banding at every edge of every panel"
+default: "Banding at cut bearing bar ends and at openings"
```
−## Grating deflection under the design uniform load shall not exceed the lesser of L/400 of the span or 1/4 in.
+### Band bars shall be of the same material as the bearing bars, of a depth equal to the bearing bar depth, and of a thickness not less than the bearing bar thickness, welded or otherwise connected to every bearing bar end they close.
+### Banding closes the open ends of cut bearing bars so that a bar end cannot snag a shoe, lift under a load at the edge, or expose a bare cut face to corrosion. The NAAMM standard panel is banded at the ends where the bars are cut and left open along the sides, where the outside bearing bar is the edge; banding every edge adds a bar along both sides, which stiffens the panel edge under a cart wheel and gives a finished appearance where the edge is seen. {note}
+
+### Every opening cut through a panel for a pipe, a column, a duct, or a stanchion shall be banded, and where the opening interrupts more than four bearing bars, the band bar shall be a load-carrying band of the thickness the fabricator's engineering requires to carry the interrupted bars.
+
+### A pipe cut through the middle of a panel severs the bearing bars that crossed it, and the cut bars then hang on the cross bars alone. A banded opening with a load-carrying bar picks up the severed bars and carries them to the uncut bars beside the opening. {note}
+
+### Cutouts shall be made in the shop from the dimensions on the approved shop drawings, and field cutting shall be limited to the openings the shop drawings mark as field-cut.
+
+### Where a toe board is required at an open edge, the grating edge shall be banded and the band bar shall be detailed to receive the toe board furnished under [[sync/metal-stairs-and-railings]].
+
+# FRP Grating {toc}
+
+## FRP Grating Construction {toc}
+
+### The construction of FRP grating shall be as indicated in the datasheet.
+
```datasheet
−label: Deflection limit under design load
+label: FRP Grating Construction
type: radio
options:
− - Lesser of L/400 or 1/4 in. (NAAMM basis)
− - Lesser of L/240 or 1/4 in. (architectural comfort)
−default: Lesser of L/400 or 1/4 in. (NAAMM basis)
+ - "Molded"
+ - "Pultruded"
```
−## The NAAMM load tables are published on this deflection basis. In architectural settings a stricter comfort limit (often expressed as L/240 perceived bounce) may be specified, but the L/400-or-1/4 in. limit is the structural acceptance criterion for pedestrian grating. {note}
+### Molded grating is cast in a mold as one square-mesh panel with continuous glass rovings in both directions, so it carries load both ways, is cut to shape in the field without exposing a weak direction, and resists the chemical exposure that a water or wastewater plant presents; it spans about half as far as a steel bar of the same depth. Pultruded grating assembles continuous pultruded I-bars or T-bars with cross rods, carries load one way like a bar grating, spans farther and weighs less per square foot, and relies on the cross rods and the bar connections for its panel action. {note}
−## Bearing bar tops shall be serrated for wet, oily, exterior, or otherwise slippery-when-wet walking surfaces.
+### FRP grating shall be sized from the manufacturer's load and deflection tables for the construction, depth, and mesh furnished, and the tables shall be based on physical load tests of that product.
+## FRP Resin {toc}
+
+### The resin system of FRP grating shall be as indicated in the datasheet.
+
```datasheet
−label: Bearing bar surface
−type: radio
+label: FRP Resin System
+type: select
options:
− - Serrated (wet / oily / exterior / industrial)
− - Smooth (dry interior only)
−default: Serrated (wet / oily / exterior / industrial)
+ - "Orthophthalic polyester"
+ - "Isophthalic polyester"
+ - "Vinyl ester"
+ - "Phenolic"
```
−## Smooth bar grating becomes dangerously slick when wet or contaminated and does not satisfy the slip-resistance expectation of OSHA 29 CFR 1910.23 for walking-working surfaces. Serrated bearing bars carry notches in the top edge that bite through surface films. Serration reduces the effective bearing area slightly and adds cost, so smooth grating is retained only for dry interior service. {note}
+### The resin sets the chemical and the fire performance of an FRP panel, and the panel is ordered by its resin or it is not ordered at all. Orthophthalic polyester is the lowest-cost resin and serves dry and mildly wet general service. Isophthalic polyester resists water, mild acids, and salts and is the usual resin for a water plant and for exterior walkways. Vinyl ester resists strong acids, caustics, oxidizers, chlorine and hypochlorite, and solvents, and is the resin for chemical feed areas, wastewater headworks, and plating lines, at a higher cost. Phenolic gives the lowest smoke and flame spread of the four and is selected where a fire-rated or low-smoke walking surface is required, such as an offshore or a tunnel installation, at the highest cost and with a darker color range. {note}
−## Cut and exposed bearing bar ends shall be banded with a flat bar of the same material and thickness welded across the cut ends.
+### The resin shall be stated by its chemistry on the product data and on the panel label, and a panel described as fiberglass grating without a resin designation shall not be accepted.
+### FRP grating shall contain an ultraviolet inhibitor in the resin and a surfacing veil on every exposed face, and a panel installed outdoors shall be furnished with the manufacturer's exterior-grade surface.
+
+## FRP Grating Surface {toc}
+
+### The walking surface of FRP grating shall be as indicated in the datasheet.
+
```datasheet
−label: Edge banding of cut/exposed bearing bar ends
−type: radio
+label: FRP Grating Walking Surface
+type: select
options:
− - Banded (all exposed cut ends)
− - Unbanded (concealed ends or toe-plate-trimmed only)
−default: Banded (all exposed cut ends)
+ - "Grit-bonded surface"
+ - "Concave meniscus surface"
+ - "Covered plate top with grit"
+default: "Grit-bonded surface"
```
−## Banding closes the open ends of cut bearing bars so they cannot snag, lift, or present a trip edge, and on galvanized grating it eliminates the bare cut faces that otherwise corrode preferentially. Banding is required wherever cut ends are exposed to foot traffic and no toe plate or trim closes them. {note}
+### A grit-bonded top embeds silica or aluminum oxide grit in a resin layer on every bar top and is the surface molded grating is stocked with; it holds its footing wet and oily and wears down under heavy wheeled traffic. A concave meniscus top is molded into the bar top as a shallow dish that gives traction at the edges without grit, is easier on bare knees and on hoses, and is selected where grit would abrade what is dragged across it. A covered plate top bonds a solid FRP plate with grit to the open grating, which closes the openings for a floor that must be solid, sheds liquid like a plate, and loses the drainage that grating gives. {note}
−## Minimum bearing length of grating on its support shall be 1 in. for grating depth up to and including 2-1/4 in., and 2 in. for grating depth of 2-1/2 in. and greater.
+## FRP Fire Performance {toc}
−## Adequate seat length prevents the panel end from rolling off its support under eccentric or impact load. The threshold follows NAAMM MBG 531; deeper, heavier panels carry larger end reactions and need the longer seat. {note}
+### FRP grating shall have a flame spread index not greater than the value indicated in the datasheet when tested in accordance with ASTM E84.
−# Floor Plate Construction {toc}
+```datasheet
+label: FRP Flame Spread Index, Maximum
+type: range
+unit: "flame spread index"
+min: 25
+max: 200
+setpoints: [25, 75, 200]
+default: 25
+```
−## Solid floor plate shall be furnished only where a continuous, non-draining walking surface is required; open grating shall be used where drainage, ventilation, or light passage is required.
+### A flame spread of 25 or less is the Class A range that every major FRP grating line is stocked to and that satisfies the strictest interior finish class [[parameter: adopted-building-code]] assigns to an exit; 75 is the Class B range a lower-cost resin meets, and 200 is the Class C range permitted where the code assigns its least restrictive finish class. The resin and the fire-retardant filler set the index, so the flame spread and the resin are selected together. {note}
−## Floor plate and grating are frequently shown interchangeably as generic "platform" on layout drawings, which is a common coordination error. Floor plate sheds liquids and blocks light and airflow; grating drains and ventilates. Confirm the functional intent before selecting between them. {note}
+## FRP Color {toc}
−## Steel floor plate shall conform to ASTM A786, with raised pattern (diamond/4-way, 2-way, or raised bar) as scheduled. {note}
+### The color of FRP grating shall be as indicated in the datasheet.
−## ASTM A786 governs the pattern dimensions, mechanical properties, and permissible thickness variation of hot-rolled floor plate. The diamond (4-way) pattern is the default for general walking surfaces; 2-way and raised-bar patterns are selected for directional traction. {note}
+```datasheet
+label: FRP Grating Color
+type: select
+options:
+ - "Gray"
+ - "Dark gray"
+ - "Yellow"
+ - "Green"
+ - "Orange"
+default: manufacturer
+```
−## The steel floor plate pattern shall be specified per ASTM A786, with a directional pattern selected where directional traction governs.
+### The color is pigmented through the resin, so it does not wear off; gray and dark gray are the stock colors of most lines, yellow and orange mark a hazard edge or a walkway in a plant where color is used for wayfinding, and green is stocked by some makers for the same purpose. The manufacturer's stock color is accepted where no color is selected. {note}
+### Where FRP grating is field cut, every cut edge shall be sealed with the resin the manufacturer supplies for that purpose before the panel is set.
+
+### A cut through FRP exposes glass fiber that wicks water into the laminate; the sealing resin closes the cut, and the fine glass dust the cut produces is controlled at the saw as the manufacturer's safety data sheet directs. {note}
+
+# Floor Plate {toc}
+
+## Floor Plate Material {toc}
+
+### The material of solid floor plate shall be as indicated in the datasheet.
+
```datasheet
−label: Steel floor plate pattern
−type: radio
+label: Floor Plate Material
+type: select
options:
− - Diamond (4-way)
− - 2-way
− - Raised bar
−default: Diamond (4-way)
+ - "Carbon steel"
+ - "Stainless steel"
+ - "Aluminum"
+default: "Carbon steel"
```
−## Steel floor plate thickness shall be selected for the load and traffic, with 3/16 in. for pedestrian platforms, 1/4 in. for light vehicle or heavy foot traffic, and 3/8 in. or thicker for heavy service.
+### Carbon steel floor plate under ASTM A786 is the stock raised-pattern plate, rolled in every pattern and thickness and relying on its coating outdoors. Stainless floor plate under ASTM A793 holds its surface in washdown, food, and chemical areas without a coating and costs several times the carbon plate. Aluminum tread plate under ASTM B209 weighs a third of steel, is the plate for a removable cover one person lifts and for a truck bed or a marine deck, and carries less load per thickness than either steel. {note}
+### Carbon steel floor plate shall conform to ASTM A786, in a commercial or structural grade the fabricator's engineering is based on.
+
+### Stainless steel floor plate shall conform to ASTM A793, Type 304 or Type 316 to match the stainless grating type selected where both are furnished, and shall be pickled and passivated in accordance with ASTM A380.
+
+### Aluminum tread plate shall conform to ASTM B209 in the alloy and temper indicated in the datasheet.
+
```datasheet
−label: Steel floor plate thickness
+label: Aluminum Tread Plate Alloy
type: select
options:
− - 3/16 in. (pedestrian platform)
− - 1/4 in. (light vehicle / heavy foot traffic)
− - 3/8 in. (heavy service)
− - 1/2 in. (heavy service)
−default: 3/16 in. (pedestrian platform)
−unit: in.
+ - "3003-H22"
+ - "5052-H32"
+ - "6061-T6"
```
−## Aluminum tread plate, where specified, shall be alloy 3003-H22 or 5052 with raised diamond pattern and mill finish.
+### Alloy 3003-H22 is the lowest-cost tread plate, forms easily, and serves a light-duty cover or a trim panel. Alloy 5052-H32 is stronger and more corrosion resistant, and it is the marine tread plate for a wet or a salt exposure. Alloy 6061-T6 is the structural tread plate with the highest strength and is selected where the plate spans a load rather than covers a hole; it is the least formable and the least corrosion resistant of the three in chloride service. {note}
−## Floor plate in wet or washdown areas shall be furnished with an applied anti-slip grit surface or abrasive nosing strips at the leading edges.
+## Floor Plate Pattern {toc}
+### The raised pattern of floor plate shall be as indicated in the datasheet.
+
```datasheet
−label: Floor plate anti-slip treatment (wet areas)
−type: radio
+label: Floor Plate Pattern
+type: select
options:
− - Applied anti-slip grit surface
− - Abrasive nosing strips at leading edges
− - None (dry interior only)
−default: Applied anti-slip grit surface
+ - "Raised diamond, four-way"
+ - "Raised pattern, two-way"
+ - "Raised bar"
+default: "Raised diamond, four-way"
```
−## The raised diamond pattern improves traction but does not make floor plate slip-resistant when wet; the smooth field between ribs remains slick. An applied grit coating or abrasive nosing at step and ramp edges provides the wet slip resistance the pattern alone cannot. {note}
+### The four-way diamond is the pattern every mill rolls and every stock sheet carries, and it gives traction in every direction of travel at the same cost. A two-way pattern raises its ribs along two directions and is selected where traffic runs one way, such as a ramp, because it drains and traction aligns with the travel. A raised bar pattern is a coarser, higher rib for heavy boots and wheeled loads, and it collects less debris between ribs in a plant floor. The pattern alone does not make a plate slip resistant when wet; the smooth field between ribs is as slick as flat plate. {note}
+## Floor Plate Thickness {toc}
+
+### The thickness of floor plate shall be the smallest standard thickness that carries the design uniform load, the design concentrated load, and any wheel load at the span of the panel within the deflection limit of this standard, by the fabricator's engineering, and shall be as indicated in the datasheet.
+
+```datasheet
+label: Floor Plate Thickness, Exclusive of Pattern
+type: range
+unit: in
+min: 0.125
+max: 0.5
+setpoints: [0.125, 0.1875, 0.25, 0.3125, 0.375, 0.5]
+derived: "the design loads, the span on the framing plans, and the deflection limit, by the fabricator's engineering for the plate material selected"
+default: derived
+```
+
+### Plate thickness is stated exclusive of the raised pattern, because the pattern adds no section to the plate in bending. A 3/16 in. steel plate carries a pedestrian floor across about 2 ft between supports, a 1/4 in. plate across about 3 ft, and a cart or a forklift wheel takes 3/8 in. or 1/2 in. at the same spans; aluminum at the same thickness spans about two thirds as far. Plate has no industry load table, so the fabricator's engineering reads the span and the load and the deflection limit to the thickness. {note}
+
+### Floor plate thickness shall be not less than 3/16 in. for steel and stainless steel, and not less than 1/4 in. for aluminum, where the plate is walked on.
+
+## Floor Plate Slip-Resistant Treatment {toc}
+
+### Floor plate at a wet, washdown, oily, or exterior location shall receive the slip-resistant treatment indicated in the datasheet.
+
+```datasheet
+label: Floor Plate Slip-Resistant Treatment
+type: select
+options:
+ - "None"
+ - "Aggregate-filled coating over the full surface"
+ - "Abrasive strips at leading edges and nosings"
+```
+
+### The raised pattern gives footing on a dry plate and gives none on a wet one. An aggregate-filled epoxy or urethane coating over the whole plate puts grit under every step and is the treatment for a plate that is wet all day, at the cost of a coating that wears under wheels and is renewed. Abrasive strips bonded or mechanically fastened at the leading edge of each plate, at a ramp, and at each step put the grit where a foot lands first, cost less, and leave the field of the plate as rolled. A dry interior plate under foot traffic alone is served by the pattern. The coating system, where one is selected, is specified under [[sync/high-performance-coatings]] for washdown and chemical service and under [[sync/interior-painting]] or [[sync/exterior-painting]] elsewhere. {note}
+
+### The wet, washdown, oily, and exterior locations at which floor plate receives the treatment shall be as indicated on [[drawing: the plans]].
+
+## Floor Plate Attachment and Edges {toc}
+
+### Floor plate shall be attached to its supports by the method indicated in the datasheet.
+
+```datasheet
+label: Floor Plate Attachment
+type: select
+options:
+ - "Countersunk flat-head screws into tapped or clipped supports"
+ - "Hex-head bolts through the plate into the supports"
+ - "Welded to the supports"
+```
+
+### A countersunk screw leaves the plate top flush and lets a cover come up with a driver, which is the attachment for a removable cover in a walking surface. A hex-head bolt stands proud of the plate and is lifted out with a wrench, which suits a plate in a yard or an equipment well where the head is not stepped on and the bolt is reached from above. A welded plate is permanent, sheds no fastener, rattles under no wheel, and is cut out to reach anything beneath it. {note}
+
+### Floor plate edges shall be ground smooth with no burr, the corners shall be eased, and the exposed edge of a plate at a walking surface shall be beveled or trimmed so that no edge stands more than 1/8 in. above the adjacent surface.
+
+### Where floor plate is removable, each cover shall be sized to the handling weight limit of this standard and shall be furnished with the lifting provisions selected for removable panels.
+
+### Floor plate panels shall bear on their supports along every edge and at intermediate supports at the spacing the thickness was sized for, and no panel shall be supported on two edges where the thickness was engineered for four.
+
# Finishes {toc}
−## Carbon steel grating and floor plate shall be hot-dip galvanized after fabrication in accordance with ASTM A123, Grade 65 minimum (2.0 oz/ft² average coating weight). {note}
+## The finish of carbon steel grating and carbon steel floor plate shall be as indicated in the datasheet.
−## Galvanizing after fabrication coats the cut ends, welds, and banding that would otherwise be the first points of corrosion. It is the dominant finish for exterior and exposed industrial grating. Grade 65 sets the minimum average coating weight for the fabricated assembly. {note}
+```datasheet
+label: Carbon Steel Finish
+type: select
+options:
+ - "Hot-dip galvanized after fabrication"
+ - "Shop primed"
+ - "Shop primed and painted"
+ - "Bare, uncoated"
+default: "Hot-dip galvanized after fabrication"
+```
−## Grating fasteners, clips, and bolted hardware shall be hot-dip galvanized in accordance with ASTM A153.
+## Galvanizing after fabrication coats the cut ends, the welds, and the banding that would otherwise be the first metal to rust, and it is the finish that carries a steel panel outdoors and in a wet plant without maintenance. A shop primer protects the panel to installation and under a dry roof, and takes a field topcoat where color or a longer life is wanted. A painted panel is selected where a color is scheduled or where galvanizing is not available in the panel size. A bare panel rusts to a stable brown under a dry interior roof and is selected where the surface will be coated in the field under another standard, or where the Owner accepts rust on a plant floor. {note}
−## Hollow or closed sections within fabricated panels to be galvanized shall be provided with vent and drain holes coordinated with the galvanizer before fabrication.
+## Galvanized grating and floor plate shall be hot-dip galvanized after fabrication in accordance with ASTM A123, with the coating grade ASTM A123 assigns to the thickness category of the bearing bar or plate, and the fabrication shall follow ASTM A385 so that the panel galvanizes without distortion or trapped flux.
−## Sealed cavities trap moisture or cleaning solution that flashes to steam in the molten zinc bath, which can warp the panel or cause a violent ejection of metal. Vent and drain holes let the cavity fill and drain safely. {note}
+## Galvanized clips, bolts, and hardware shall be hot-dip galvanized in accordance with ASTM A153.
−## Field-damaged galvanized coatings shall be repaired in accordance with ASTM A780. {note}
+## Shop priming, the galvanizing process, the handling of vents and drains on closed sections, and the acceptance of the coating are governed by [[sync/shop-painting-and-galvanizing]], and this standard selects the finish only.
−## Cutting, welding, and handling inevitably break the shop coating; A780 zinc-rich or sprayed-zinc repair restores the cut-edge and weld protection that field exposure would otherwise attack. {note}
+## Field cuts, field welds, and damaged areas on galvanized panels shall be repaired in accordance with ASTM A780 with a zinc-rich coating or a zinc-based solder to the coating thickness of the surrounding galvanizing, before the panel is set.
−## Stainless steel and FRP grating shall be furnished in their natural finish and shall not be coated unless an architectural finish is scheduled.
+## The finish of aluminum grating and aluminum tread plate shall be as indicated in the datasheet.
```datasheet
−label: Finish
−type: radio
+label: Aluminum Finish
+type: select
options:
− - Hot-dip galvanized (ASTM A123) - carbon steel
− - Mill / natural (stainless, aluminum, FRP)
− - Painted or powder-coated (architectural)
− - Anodized (architectural aluminum)
−default: Hot-dip galvanized (ASTM A123) - carbon steel
+ - "Mill finish"
+ - "Clear anodized"
+ - "Painted or powder coated"
+default: "Mill finish"
```
−## Stainless and FRP are corrosion-resistant in their as-supplied state; a coating adds cost and a maintenance liability without improving durability. Anodizing or paint on aluminum, and any architectural finish on stainless, are specified only when the appearance is scheduled. {note}
+## A mill-finish aluminum panel forms its own oxide and needs no coating anywhere it is not in contact with steel or concrete, which is why it is the stock finish. Clear anodizing thickens the oxide for a more uniform appearance and a harder surface where the panel is seen and handled, and it is specified where the aluminum is architectural. Paint or powder coat is selected where a color is scheduled, and it is the finish that shows wear first under traffic. {note}
−# Fastening and Removability {toc}
+## Stainless steel grating and stainless floor plate shall be furnished in the mill finish of the bar or plate, pickled and passivated, and shall not be coated.
−## Grating panels shall be anchored to their supports by saddle clips, welds, or bolted connections as required by the removability and uplift conditions of the installation.
+## Field painting of galvanized, primed, or bare panels, where scheduled, is governed by [[sync/interior-painting]] and [[sync/exterior-painting]], and chemical-resistant and washdown coating systems by [[sync/high-performance-coatings]]; this standard furnishes the shop finish the field coating is applied over.
−## Saddle clips are the standard fastening and allow panels to be lifted for access. Welding is used where panels are permanent and uplift or vibration is a concern. Bolted connections are used where a removable but positively secured connection is required. {note}
+# Fastening and Removable Panels {toc}
−## Panels over equipment, valves, or services that require maintenance access shall be removable and shall be fastened with saddle clips or bolts, not welded.
+## Fastening Method {toc}
+### Grating panels shall be fastened to their supports by the method indicated in the datasheet.
+
```datasheet
−label: Panel fastening method
−type: radio
+label: Grating Fastening Method
+type: select
options:
− - Saddle clips (removable - default)
− - Bolted (removable, positively secured)
− - Welded (permanent, uplift/vibration)
−default: Saddle clips (removable - default)
+ - "Saddle clips with bolts"
+ - "Flange clips bolted to the support"
+ - "Self-locking wedge clips"
+ - "Welded to the supports"
+default: "Saddle clips with bolts"
```
−## Welding a panel shut over equipment that must later be reached generates a field change order to cut it out. Removable fastening is a coordination requirement, not merely a convenience, wherever access below the grating is foreseeable. {note}
+### A saddle clip straddles two bearing bars and bolts to a plate or a clip below the support flange, holds the panel down against uplift and vibration, and comes off with a wrench, which is why it is the stock fastening on every removable and every ordinary panel. A flange clip hooks the support flange and bolts to the grating from above without reaching below the flange, which serves a panel set over a beam that is enclosed or inaccessible beneath. A wedge clip drives between bearing bars and locks without a tool below, installs fastest, and is removed with a pry bar, which fits a panel that is lifted often and a panel the installer cannot reach beneath. A welded panel is fixed, is the fastening for a panel under vibrating equipment or in a wheel path where a clip can loosen, and is cut to remove. {note}
−## A minimum of four fasteners shall be provided per grating panel, with at least one fastener within 6 in. of each corner.
+### Every panel shall be fastened with not fewer than four fasteners, one within 6 in. of each corner, and panels longer than 6 ft shall be fastened at intermediate supports at not more than 4 ft on center along each side.
−## Grating panel size shall be limited so that any panel intended for manual handling does not exceed 50 lb; heavier panels shall be split into multiple sections or detailed for mechanical lifting.
+### Where a panel is welded, it shall be welded to the support at not fewer than four points, with a weld at each corner and at intermediate supports as the clip spacing above requires, and the weld shall be repaired on galvanized panels in accordance with ASTM A780.
+### Panels over equipment, valves, instruments, sumps, or any service that requires access from above shall be fastened with a removable method, not welded, regardless of the method selected above.
+
+### A panel welded shut over a valve is cut out the first time the valve is serviced and is never put back as well as it was fabricated. The clip costs a few dollars a panel and the cut-out costs a change order, and the access below the panel is foreseeable from the plans. {note}
+
+### Fasteners for grating shall be of the material indicated in the datasheet.
+
```datasheet
−label: Maximum manual-handling panel weight
+label: Grating Fastener Material
+type: select
+options:
+ - "Hot-dip galvanized steel"
+ - "Stainless steel Type 304"
+ - "Stainless steel Type 316"
+ - "Aluminum"
+derived: "the grating material and finish selected and the corrosion exposure of the location"
+default: derived
+```
+
+### Fasteners shall be galvanized steel on galvanized carbon steel grating, stainless steel of the same type on stainless grating, stainless steel Type 304 on aluminum grating and on FRP grating, stainless steel Type 316 on any grating in a chloride or a chemical exposure, and stainless bolts shall conform to ASTM F593.
+
+### A fastener of a different metal from the panel it holds corrodes one or the other at the contact, and the clip is the one piece of hardware a maintenance crew removes and loses, so it is matched to the panel by rule rather than by selection. Stainless on aluminum is the exception that works, because the couple is small and the aluminum is isolated at the clip. {note}
+
+## Removable Panels and Handling {toc}
+
+### The panels designated removable shall be as indicated on [[drawing: the platform plans]].
+
+### A panel designated removable, or any cover over a trench, pit, or sump, shall not exceed the handling weight indicated in the datasheet, and a panel that would exceed it shall be split into panels that do not or shall be furnished with lifting provisions for mechanical lifting.
+
+```datasheet
+label: Maximum Handling Weight of a Removable Panel
type: range
+unit: lb
min: 30
−max: 80
+max: 150
step: 5
−unit: lb
−default: 50
```
−## A panel designed only for its full structural capacity often exceeds a safe two-person manual lift, which produces field RFIs to split it. Setting a handling weight limit up front, or calling out mechanical lifting, avoids that rework and keeps maintenance access practical. {note}
+### A panel engineered to its full structural capacity is often heavier than two people can lift from a crouch at the edge of a trench, and the panel that is too heavy to lift is lifted anyway, with a back injury or a dropped panel into the trench. The limit follows the Owner's lifting policy and the crew that will lift it; a one-person lift ends near 50 lb, a two-person lift near 100 lb, and a panel above that is lifted by a hoist with provisions built in. {note}
−# Edge and Opening Conditions {toc}
+### The lifting provisions furnished on removable panels shall be as indicated in the datasheet.
−## Where grating abuts an open-sided platform edge, a toe board (kick plate) of the height required by the governing building code shall be provided; the code minimum is 3-1/2 in.
+```datasheet
+label: Removable Panel Lifting Provisions
+type: select
+options:
+ - "Lift-out handles recessed flush with the surface"
+ - "Lifting holes for a hook"
+ - "Lifting lugs for mechanical lifting"
+```
−## The toe board prevents tools and debris from being kicked off the platform edge onto workers below and closes the gap between the walking surface and the guardrail. The 3-1/2 in. minimum is the common code value; confirm against the adopted code edition. The toe board and guardrail assembly itself is furnished under [[sync/metal-stairs-and-railings]], but the grating edge must be detailed to receive it. {note}
+### A recessed handle lies flush in the surface so nothing stands up to trip on, and it lifts a hand-handled panel by hand. A lifting hole takes a hook or a bar and leaves nothing in the panel to break, and it is the stock provision on a bar grating cover. A lifting lug is a welded eye for a sling and is the provision on a panel above the hand-lifting weight. {note}
−## Bearing bar depth shall be held uniform across adjoining panels within a continuous walking area so that adjacent panel surfaces are flush.
+### Every removable panel shall be marked with its panel mark and its handling weight on the underside or on an edge where the marking is read when the panel is lifted.
−## Mixing bearing bar depths across a continuous floor produces a step-up at the joint between panels, which is a trip hazard. Where different depths are unavoidable (different spans), the supports shall be set at different elevations so the walking surfaces remain flush.
+# Trench, Pit, and Sump Covers {toc}
−## Openings, penetrations, and trim at grating edges shall be banded and shall maintain the governing opening-size limit at the trimmed edge.
+## Grating and plate covers over trenches, pits, sumps, and equipment wells shall be furnished in panels whose bearing bars span across the opening in its shorter direction, bearing on the seat angle or frame furnished under the standard that governs the frame.
+## Cover panels shall bear on the frame for the full bearing length required under Installation, and the frame seat depth shall be coordinated so that the cover top is flush with the adjacent floor within the flush and gap limits of this standard.
+
+## Cover panels shall be fastened to the frame by the removable method selected, and no cover panel shall be welded to its frame.
+
+## Cover panels in a wheel path shall be sized to the wheel load basis selected and shall be fastened at every corner so that a wheel at the panel edge does not rock or lift the panel.
+
+## A trench cover that rocks under a cart wheel is the cover that lifts at the far edge and drops a wheel into the trench. Four corner clips, full bearing on both sides, and a seat set to the panel depth are what hold a cover flat. {note}
+
+## Where a cover carries a process liquid or a drainage function, the openings of a grating cover shall satisfy the opening-size limit of this standard where the cover lies on an accessible route or in the means of egress, and the grating of a plumbing trench drain or a floor drain is furnished under [[sync/trench-drains-and-interceptors]].
+
# Installation {toc}
−## Grating shall be installed in accordance with the manufacturer's instructions and ANSI/NAAMM MBG 531.
+## Grating and floor plate shall be installed in accordance with the approved shop drawings, the fabricator's instructions, and ANSI/NAAMM MBG 531 or MBG 532 as applicable.
−## Support framing for grating panels shall be coordinated with the grating load table so that the support spacing does not exceed the allowable span of the selected bearing bar.
+## The bearing length of every panel on its support shall be not less than 1 in. for bearing bar depths up to and including 2-1/4 in., and not less than 2 in. for bearing bar depths of 2-1/2 in. and greater, and floor plate shall bear not less than 1 in. on every supported edge.
−## Support framing is frequently laid out independently of the grating it carries, which can leave a panel spanning farther than its load table allows. {note}
+## A panel end that bears 1/2 in. on a flange rolls off the flange under an eccentric load at the edge or an impact at the end, and the deeper bars of a heavy-duty panel carry larger end reactions that a short seat crushes. The seat lengths follow NAAMM practice for the depth. {note}
−## The grating supplier's allowable span shall be confirmed against the as-detailed support spacing before fabrication, and any over-span condition shall be resolved by adding intermediate support or deepening the bearing bar.
+## Panels shall be set with full bearing on every support and shall not rock, and where shimming is required to seat a panel, the shim shall be of the same material family as the panel, or of the isolation material where the panel is aluminum, and shall be secured so that it cannot work out.
−## Panels shall be set with full bearing on their supports and shall not rock; shims, where required, shall be of the same material family as the grating or an approved isolation material.
+## Panels shall be set to the flush and gap limits of this standard, and a panel that cannot be set within them without cutting shall be reported to the Engineer of Record before it is cut.
−## Field cuts shall be banded after cutting.
+## Field cutting of metal grating shall be done with a saw or an abrasive wheel, every field-cut end shall be banded, and the cut and the band shall be repaired in accordance with ASTM A780 on galvanized panels before the panel is set.
−## Galvanized panels shall receive ASTM A780 touch-up at all field cuts and field welds.
+## Field welding of grating to supports, where welded fastening is selected, shall be performed under the project welding program of [[sync/welding-requirements]] and shall be repaired in accordance with ASTM A780 on galvanized panels.
−## Field welding of grating to supports shall be performed only where welded fastening is scheduled and shall conform to AWS D1.1, with coating repair per ASTM A780 at every field weld.
+## Stainless steel and aluminum panels shall not be cut, drilled, or ground with a tool or an abrasive that has been used on carbon steel, and shall not be stored or handled in contact with carbon steel.
−## Aluminum and stainless panels shall not be cut, drilled, or ground with tools or abrasives previously used on carbon steel.
+## A carbon steel particle embedded in a stainless or an aluminum surface rusts in place and starts a pit that looks like a flaw in the base metal; a saw blade that cut steel yesterday carries those particles into every cut it makes today. {note}
−## Embedded carbon steel particles rust on a stainless or aluminum surface and create a corrosion site that looks like a defect in the base metal. Dedicated, non-contaminated tooling preserves the corrosion resistance the material was selected for. {note}
+## Aluminum panels shall be set on the isolation this standard requires at every bearing and at every fastener, and the isolation shall be in place before the panel is fastened.
+## Clips shall be installed with the bolt torque the clip manufacturer publishes, and a wedge clip shall be driven to the manufacturer's engagement.
+
+## Fastening into concrete, where a seat angle or a cover frame is anchored in the field, shall be with the post-installed anchors governed by [[sync/post-installed-anchors]].
+
+# Field Verification {toc}
+
+## Before any walking surface is turned over for use, the Contractor shall walk every panel and shall verify and record that each panel bears fully, does not rock, is fastened with the number of fasteners this standard requires, and is within the flush and gap limits of this standard.
+
+## The Contractor shall verify and record that every panel designated removable lifts freely with the lifting provisions furnished, that its handling weight is marked, and that no panel over a service requiring access is welded.
+
+## The Contractor shall verify and record that the bearing bar spacing of every panel on an accessible route and in the means of egress satisfies the opening-size limit of this standard, measured in the direction of travel.
+
+## Where a panel fails any verification, the Contractor shall correct it at the Contractor's cost and shall re-verify it before the surface is turned over.
+
+## The field verification record shall list every panel by mark with the result of each check and shall be submitted with the closeout submittals.
+
# Delivery, Storage, and Handling {toc}
−## Grating and floor plate shall be delivered bundled and marked with the panel marks shown on the approved shop drawings.
+## Panels shall be delivered bundled by panel mark, with each panel marked to match the approved shop drawings, and the bundles shall be handled so that the bearing bars are not bent and the banding is not sprung.
−## Panels shall be stored off the ground on dunnage, sloped to drain, and protected from standing water and mud.
+## Panels shall be stored off the ground on dunnage, sloped to drain, with spacers between galvanized panels, and shall be protected from standing water, mud, and construction debris.
−## Galvanized and FRP panels stacked flat in standing water develop wet-storage staining (white rust on zinc) and trapped grit; sloped, dunnaged storage keeps the surfaces drained and clean until installation. {note}
+## Galvanized panels stacked flat and wet grow a white zinc hydroxide bloom at every contact that stains the coating and, left long enough, consumes it; sloped stacking with spacers lets the stack dry. {note}
−## Aluminum panels shall be stored separated from carbon steel and away from sources of alkaline runoff such as fresh concrete.
+## Aluminum panels shall be stored separately from carbon steel, off concrete, and away from fresh concrete, mortar, and alkaline runoff.
+## FRP panels shall be stored out of direct sunlight until installed, shall not be dragged across abrasive surfaces, and shall be lifted so that the grit surface is not ground against another panel.
+
# Warranty {toc}
−## The Contractor shall warrant grating and floor plate materials and installation against defects in material and workmanship for a period of not less than one year from Substantial Completion.
+## The Contractor shall warrant the grating, the floor plate, their finish, and their installation against defects in material and workmanship for the period indicated in the datasheet, beginning at Substantial Completion.
```datasheet
−label: Warranty period
−type: radio
−options:
− - 1 year (project standard)
− - 2 years
− - 5 years (extended coating warranty)
−default: 1 year (project standard)
+label: Warranty Period
+type: range
+unit: years
+min: 1
+max: 5
+setpoints: [1, 2, 5]
+default: 1
```
−## The one-year correction period is the project-standard floor for fabricated metal work. Coating systems may carry a longer manufacturer warranty where scheduled. {note}
+## The one-year correction period is the term the construction contract applies to fabricated metal work, and a longer term is bought where the finish carries a manufacturer's coating warranty or the Owner wants the installation covered through a first full season of plant operation. {note}
+## A panel, a band, a clip, or a finish replaced or repaired under the warranty shall be warranted for the remainder of the original term or for one year from the date of the repair, whichever is longer.
+
+## Warranty repair of a finish shall include the surface preparation and the coating repair under ASTM A780 or the coating system furnished, and the Contractor shall bear the cost of removing and resetting any panel the repair requires.
+
# Spare Parts {toc}
−## The Contractor shall furnish spare saddle clips and fasteners equal to 5 percent of the installed quantity, and not fewer than one box of each clip type used.
+## The Contractor shall furnish spare clips, bolts, and fasteners of each type used on removable panels in the quantity indicated in the datasheet, and not fewer than ten of each type, delivered to the Owner against a signed receipt before the work is accepted.
```datasheet
−label: Spare fasteners furnished
+label: Spare Clips and Fasteners
type: range
+unit: percent of installed quantity
min: 0
max: 10
step: 1
−unit: percent of installed
−default: 5
```
−## Removable grating loses clips during maintenance access; a small clip stock lets the owner re-secure lifted panels without a procurement cycle. Spare full panels are furnished only where called out for high-traffic or impact-prone areas. {note}
+## Clips are lost at every lift of a removable panel, and a panel re-set with two clips instead of four is the panel that lifts under a cart. A small stock of the clip actually used, in the plant and not on order, is what keeps lifted panels re-secured. {note}
+
+## Spare clips and fasteners shall be identical to those installed, of the same material and finish, and shall be delivered in labeled containers that name the panel type they fit.