Inquiry On WhatsApp
+86 19031313708
Contact Via E-mail
gtofrp@gtofrp.comViews: 0 Author: Site Editor Publish Time: 2025-07-16 Origin: Site
With growing demand for corrosion-resistant, lightweight, and secure infrastructure components, FRP manhole covers are replacing traditional cast iron and concrete in cities and industries worldwide. But with so many sizes, shapes, load classes, and installation methods available, how do you choose the right cover?
This article offers a complete guide to selecting and installing fiberglass manhole covers tailored to your application needs—whether it's a residential sidewalk or a heavy-duty industrial zone.
FRP manhole covers follow the EN 124 standard, which defines load-bearing categories based on the location and expected traffic.
| Load Class | Max Load | Recommended Use |
|---|---|---|
| A15 | 1.5 Ton (15 kN) | Sidewalks, greenbelts, pedestrian zones |
| B125 | 12.5 Ton (125 kN) | Parking lots, residential roads, driveways |
| D400 | 40 Ton (400 kN) | Urban roads, logistics areas, industrial use |
Tip: Always match the class to actual use, not just expected load.
FRP covers come in a variety of standard diameters—commonly 500mm, 600mm, and 800mm—with matching frames. But you also need to consider:
Clear Opening (CO): The usable internal diameter of the access hole
Cover Diameter (d): The outer edge of the cover itself
Frame Diameter (D): The overall diameter including the support structure
Cover Thickness (H): Affects load-bearing ability
Frame Height (h): Important for flush installation
| Cover Dia | Load Class | Clear Opening | Outer Dia (d) | Frame Dia (D) | Thickness (H) | Frame Height (h) |
|---|---|---|---|---|---|---|
| 500 mm | A15 | 458 mm | 500 mm | 600 mm | 60 mm | 40 mm |
| 500 mm | B125 | 450 mm | 500 mm | 600 mm | 70 mm | 50 mm |
| 800 mm | D400 | 745 mm | 800 mm | 910–920 mm | 100 mm | 70 mm |
If unsure, ask your supplier for a size drawing or compatibility chart.
To ensure long-term performance, consider the operating environment:
Wet or humid areas: Use FRP for corrosion resistance
Chemical exposure: Choose resins with enhanced chemical resistance
High temperatures or UV: Verify UV-stabilized formulations
Electrical areas: Always use non-conductive FRP, not metal
Depending on your project, you may want:
Locking systems for added security
Non-slip surfaces (molded or serrated)
Sealing gaskets to prevent odor leakage
Color coding for identification (e.g., telecom = green, water = blue)
Custom logos or city emblems for branding
Installing FRP covers is simpler than metal or concrete, but proper method ensures performance and safety:
✅ Prepare the Surface:
Ensure the supporting structure (concrete base or ring) is level and properly cured.
✅ Use Compatible Frame & Cover:
Never mix frames from different manufacturers unless compatibility is confirmed.
✅ Apply Bedding Mortar or Adhesive:
Place a thin layer to seat the frame and absorb vibrations or traffic load.
✅ Level and Align Carefully:
Use a spirit level to ensure flush mounting with the surrounding pavement or road.
✅ Check Load Class Label:
Always verify that the installed cover meets the required load rating for the site.
❌ Using a low-load cover (A15) in a driveway
❌ Forgetting to check frame diameter compatibility
❌ Installing without leveling, causing rocking or uneven wear
❌ Assuming all covers are interchangeable—FRP designs vary widely
❌ Overlooking electrical safety where non-conductive covers are needed
Choosing the right FRP manhole cover is about more than just picking a size. By considering load class, dimensions, material performance, and installation best practices, you can ensure long-term durability, safety, and compliance.
Whether for a telecom vault, wastewater system, or urban street, GTOFRP™ provides custom-engineered covers to fit your exact needs—with decades of reliability built in.
