Galvanized Welded Wire Trench Drainage Grating and Stainless Steel Trench Cover Grating for Heavy Duty Drainage

• Factory floors and process areas — oil, water, scale
• Loading docks, warehouse and forklift aisles
• Municipal sidewalks and kerb drains
• Parking decks and petrol station forecourts
• Port aprons, container yards, airport service roads
• Pump stations and wastewater decks

Pedestrian zones need heel safety and a clean appearance; factory floors need drainage area and forklift resistance; ports need wheel-load rating and corrosion resistance. One grate type does not serve all applications — drawings should show the clear opening, depth and frame material, not just “supply grating”.

A grate that lifts under traffic is a hazard. Specify the load class to EN 1433 (or AASHTO M306 / AS 3996 locally) and confirm the channel body matches. A D400 grate on a C250 channel fails at the wall, not the grate — the most common retrofit issue we see.

Open area — the percentage of the grate open to water — comes from bearing bar pitch, not depth. Standard 19-W-4 is approximately 75–80% open; 15-W-4 is approximately 70–75%; 11-W-4 is approximately 65%. For parking and loading bays, target 70–80% open. For kerb drains in leaf-fall areas, drop to approximately 60% and add a silt bucket upstream.

Heel-safe design requires an aperture of ≤13 mm transverse to travel (AS 1428.2, EU codes). Public walkways fall under this requirement; factory floors above pedestrian areas usually do not. The material and load class stay the same — only the pitch changes.

Do not jump to D400 by default. A rarely-driven staff sidewalk is A15 and costs a third as much. A forklift aisle is D400 minimum — and solid tires push the requirement higher.

Solid-tire forklifts concentrate load on a smaller patch than pneumatic tires, so they defeat under-rated grates that would otherwise handle trucks. Three rules for a forklift aisle:

• Pick the class one step above the duty forklift’s nominal wheel load.
• State the wheel load, tire type (solid or pneumatic) and travel direction at the trench.
• Lock the grate — bolt-down or four-point clip is mandatory from D400 up.

1. Width and depth measured outside the frame, not the clear opening.
2. Frame material omitted — defaults to mild steel when stainless was needed.
3. Load class not stated — the quote comes back pedestrian-only.
4. Open area target omitted — heel-safe is quoted when capacity was the priority.
5. Pipe or column cut-out not dimensioned.
6. Grade or fall missing — grate supplied level on a sloped slab, causing water to pond.

19-W-4. Heel-safe pitches reduce open area by 5–10 points absolute.

Yes on load class (D400 covers both); specify pedestrian pitch where heel-safe is needed.

In dry service, mill finish is often sufficient. For wash-down, chemical or outdoor environments, HDG pays back in reduced repainting.

Send the checklist and a sketch (hand-drawn is fine) via our contact page. We return size, open area, load class match, finish and full quantity pricing within one working day, with a drawing for approval on non-standard specifications.