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
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.