32+ years of composite engineering
Thermoset Poly Products (I) Pvt. Ltd. is an ISO 9001:2015 design & manufacturing company in Navi Mumbai, making the THERMODRAIN range of FRP/GRP/composite covers, gratings, gully covers, chambers and drain channels since 1993.
Backed by a strong design, R&D and technical team, we engineer covers and gratings for sewerage, electrical, telecom and cable networks, built to outperform cast iron, ductile iron and RCC in strength-to-weight, corrosion resistance and service life.
Our in-house testing facility runs one of the largest load-testing machines in the segment, rated up to 90 tons, and every product is tested to BS EN 124, IS 1726 and AASHTO M306. A 250-strong team and a 40,000 sq ft manufacturing facility (over a 1,60,000 sq ft factory area) support a growing export presence worldwide.
Beyond drainage, our R&D has produced FRP windmill nacelle covers for the wind-power industry and MECHWOOD, a man-made artificial wood with zero wooden ingredients. An in-house CNC machining shop and stringent third-party testing keep quality consistent across the range.
Inside our factory
A look inside our ISO 9001:2015 manufacturing facility in Navi Mumbai: moulding, curing, load-testing and export packing under one roof.
Built to outlast iron & concrete
FRP is a thermoset composite: flexible, corrosion-free and non-reprocessable, engineered for the harshest drainage and utility environments.
Theft-proof
No metal and no scrap value, and a non-reprocessable thermoset, so covers are never stolen for resale.
Non-brittle, high impact
Flexible under excess load, so covers don't shatter like cast iron, and chambers stay closed and roads stay safe.
Corrosion-free
No effect from sea water, sewage or chemical water. No rust, no algae, no protective GRP plate needed.
High strength-to-weight
Far lighter than iron or concrete, easy to handle, with lower freight and installation cost.
UV-stabilized & self-pigmented
UV-stabilized granite finish moulded in, so it never needs painting and won't fade or absorb heat.
Double seal & closed keyholes
Double-seal arrangement with bottom-closed lifting sockets, so no foul smell and no mosquito breeding in chambers.
High-abrasion surface
A 7 mm high-abrasion top layer with stainless / HSPA lifting inserts resists traffic wear and repeated lifting.
Tested up to F900 (90 T)
Load-tested to BS EN 124, IS 1726 & AASHTO from 2.5 T up to F900, with zero permanent set.
Thermoset chemistry
Cures at a 175 °C exothermic temperature into a thermoset that is non-reversible and can't be melted or reprocessed. It's anti-theft, won't soften under extreme sun, and performs in extreme hot & cold conditions.
The THERMODRAIN keyhole
Every cover lifts via a rod-type or keyhole-type arrangement, with lifting sockets moulded in High-Strength Plastic Alloy (HSPA) or stainless steel, and every keyhole is closed at the bottom, not through-and-through.
THERMODRAIN socket keyhole, with insert
- HSPA / stainless-steel socket protects the FRP from wear during repeated lifting.
- Bottom-closed, so no foul smells escape from the chamber.
- Foreign particles can't drop into the chamber.
- No standing water, so no mosquito breeding inside the chamber.
- Keyhole area stays intact after many lifting operations.
Ordinary keyhole, no insert
- Bare FRP wears and cracks around the keyhole under repeated lifting.
- Open / through keyholes let foul smells escape.
- Debris and foreign particles fall into the chamber.
- Standing water in open holes invites mosquito breeding.
Rated from 2.5T to F900
Every THERMODRAIN product is load-tested to BS EN 124, IS 1726 & AASHTO M306, from 2.5 tons up to F900 (90 tons), including a permanent-set (multiple-loading) test.
| Class | Load | Installation areas | Example |
|---|---|---|---|
| 2.5T | 2.5 T · 25 kN | Pedestrian & pedal-cyclist areas | Footpaths, cycle tracks |
| 5T | 5 T · 50 kN | Two-wheeler & light-vehicle areas | Two-wheeler parking, light driveways |
| B125 | 12.5 T · 125 kN | Footways, pedestrian areas, light duty | Car parking areas |
| C250 | 25 T · 250 kN | Kerbside channels & high wheel-load zones | Kerbside parking areas |
| D400 | 40 T · 400 kN | Carriageways & parking for all road vehicles | Roadways, vehicle traffic |
| E600 | 60 T · 600 kN | Heavy-duty & high wheel-load zones | Sea ports, docks |
| F900 | 90 T · 900 kN | Extreme wheel-load zones | Airport aprons, runways |
Do's
- Install the frame correctly with complete civil support.
- Apply load on the frame only after grouting is completed.
- Handle the cover with care during transport and fitting.
Don'ts
- Don't apply load before the grouting has fully set.
- Don't throw or drop the material.
- Don't skip the civil support around the frame.
Where THERMODRAIN is installed
From pedestrian pathways to airport aprons, matched to the right load class and product.
Thermodrain Product
The complete FRP/GRP/composite range: covers, gratings, gully & tank covers, chambers, drain channels and accessories. Tap any product for its salient features and sizes.
01Solid Top Manhole Covers
Tested to BS EN 124, IS 1726 & AASHTO M306, better performing than cast iron, ductile iron and RCC.
- Self-pigmented & non-brittle, so no painting required.
- Key locking or bolt locking arrangement available.
- HSPA / stainless-steel socket keyholes with closed bottoms (not through-and-through).
- Zero permanent set across all sizes & load bearings.
Circular Ø400–Ø1400 · Square 300×300–1500×1500 · Rectangular up to 990×1220 mm. Full list in the Product Configurator tab.
02Multiple Covers with Frame
Designed and manufactured to the existing chamber size, ideal for odd-size chambers. An industrial revolution over CI, DI and RCC.
- MS frame, epoxy-painted, with removable supports.
- Optional bolt-locking arrangement.
- HSPA / stainless-steel closed-bottom keyholes.
- Self-pigmented, non-brittle, zero permanent set.
03Recess (Fill-in) Covers
65 mm depth is provided for fixing cement, blocks, tiles or other materials so the cover blends into the surrounding floor.
- Lighter and easier to use than conventional materials.
- Closed-bottom keyholes; zero permanent set in all sizes & load bearings.
Circular Ø500–Ø1000 · Square 300×300–1500×1500 · Rectangular up to 990×1220 mm. Full list in the Product Configurator tab.
04Air & Water Tight Covers
Tested to BS EN 124, IS 1726 & AASHTO M306, better than CI, DI and RCC.
- Available without bolting.
- Locally-found replaceable gasket in case of damage.
- No foul smell or seepage.
Circular Ø400–Ø1000 · Square 300×300–1500×1500 · Rectangular up to 990×1220 mm. Full list in the Product Configurator tab.
05Gratings
- ZERO filler content, so no air pockets, no painting or coating required.
- High impact resistance vs. filled gratings.
- Self-pigmented, not painted.
- One-piece moulded, jointless interwoven construction.
Swimming pools · industrial plants · podiums · basement car parks · storm-water drain trenches · cable trenches.
06Tree Gratings
- Self-pigmented, non-painted.
- Available in two-piece or four-piece for easy installation.
- Protect the soil and let pedestrians walk near the tree without compacting it.
- Allow rainwater to penetrate the soil.
- Artistic designs improve landscaping and aesthetics.
07Water Gully Covers (with / without frame)
- Minimum opening is more than 30% of the clear opening for smooth water flow.
- Zero permanent set in all sizes & load bearings; self-pigmented / non-painted.
Industrial plants · podiums · basement car parks · storm-water drain trenches.
Square 300×300–900×900 · Ø600 round · Rectangular incl. 335×930, 500×600, 900×600 mm. Full list in the Product Configurator tab.
08Hinged Overhead & U.G. Water Tank Covers
180° opening with hinge & locking arrangement.
- Provision for gasket fitting; self-pigmented / non-painted.
- 550 kg covers have locking as a standard feature.
- No moss or algae formation.
Ø600 · Ø750 · 600×600 · 750×750 mm.
09L-Angles
- Corrosion & chemical resistant; self-pigmented (no painting).
- Non-conductive (thermally & electrically), non-magnetic, EM-transparent.
- Lightweight, high-strength & durable, impact resistant.
- Dimensional stability, long life cycle, low maintenance.
10Chambers
- High-strength chambers from specially-prepared resin; UV stabilized.
- Take any type of traffic load and withstand earth vibrations from traffic.
- Completely leak-proof and relocatable; can be used as inspection chambers.
- Readily mounted by digging, concreting the bottom & fixing.
11Drain Channels with Grating / Gully Cover
- Prepare a trench 200 mm wider than the channel; check soil compaction (add a concrete bed if needed, sloped 1 mm/m for gravity flow).
- Lay the channel from the starting point towards the exit; silicone-seal the joints and connectors (90° bend, tee, four-way tee).
- Backfill around the network with concrete & soil, compact to the grating level, then place the gratings / gully covers.
Fast to install · minimal manpower & labour cost · no water-proofing · no separate MS/FRP angles for gratings · no hidden cost.
12Lifting Accessories
Lifters ensure manhole covers are lifted with ease and without damage, for circular, square or rectangular covers.
Square / Rectangular: all sizes 300×300 to 1500×1500 · Circular: all sizes Ø300 to Ø900 mm.
THERMODRAIN FRP vs traditional materials
How composite covers and gratings stack up against cast iron, ductile iron and concrete.
 THERMODRAIN FRP / GRP |
 Cast / Ductile Iron |
 Concrete |
|
|---|---|---|---|
| Strength-to-weight | High | Low | Low |
| Theft risk | None, no scrap value | High | Present (internal steel) |
| Weight & handling | Light, easy to handle | Heavy, needs manpower | Heavy, needs manpower |
| Impact behaviour | Flexible, won't shatter | Brittle, cracks on impact | Poor abrasion resistance |
| Corrosion (sea / sewage) | Immune | Corrodes | Erodes |
| Painting | Never, self-pigmented | Regular intervals | — |
| Service life | 20–30 years | Corrosion-limited | 2–3 years |
| Freight cost | Low | High | High |
THERMODRAIN FRP / GRP gratings vs mild-steel gratings
 THERMODRAIN FRP / GRP grating |
 Mild-steel grating |
|
|---|---|---|
| Strength-to-weight | High | Low |
| Theft risk | None, no scrap value | High |
| Weight & handling | Light, easy to handle | Heavy, needs manpower |
| Under moving vehicles | Doesn't permanently bend | Permanently bends |
| Corrosion (sea / sewage) | Immune | Corrodes |
| Algae formation | None | Forms easily on metal |
| Finish | Dark grey or any colour | Standard appearance |
| Painting | Never, self-pigmented | Periodic, to prevent rust |
| Maintenance | None | Regular |
Choose your product, size & load class
Pick a product and its size, then the load class. The photo and specification update to match. Full range on frpmanholecover.com.
Product photo
Specification
We'll include your selected product, size, load class & quantity automatically.
Grating size configurator
Type any length and width, or use −/+ to change the size 1 mm at a time. An off-size edge fills in as open teeth until it reaches the next standard size and turns flush. Switch bar height too; the panel redraws live at true proportions.
Configure your grating
A standard moulded size has flush edges. Between two standards the edge is cut through the bars and shows open teeth: a partial row that grows as the size increases, until it completes the next flush row.
How to choose your size
- Set the Length and Width: type an exact size (48–2430 mm), or use −/+ to change the size 1 mm at a time. An in-between size is cut to fit and shows open teeth on the growing edge until it reaches the next standard size.
- Set the bar height (30 mm or 40 mm); taller bars carry heavier loads and longer spans.
- The edges are finished to your size. A standard moulded size gives a closed / flush edge; an in-between size is cut through the bars, so that edge shows an open / tooth edge that grows a little at a time until the next standard row completes. The preview redraws so you can see the exact edge for your size.
- Note your Overall size and Edge finish from the summary, then send them with your enquiry.