STP ShaliPoxy 400 FG
A solvent-free, food-grade two-component epoxy that lines steel and concrete pipes, tanks and vessels for potable water, applied by an ordinary single-feed airless spray gun.
What is it?
A 2K (two-component) solvent-free, food-grade epoxy coating from STP Limited, formulated for internal and external lining of steel and concrete pipes, vessels and storage tanks that carry or hold potable water.
Where is it used?
Drinking-water pipelines, water treatment plants, RCC and steel water storage tanks, and sea-water intake tunnels, wherever an inert, non-tainting barrier is needed against corrosion, abrasion and mild chemical attack.
Why use it?
It combines certified food-grade safety (BS 6920, IS 16676, AWWA C-210, NSF/ANSI 61) with a high-build, low-permeability film, and unlike the plural-feed ShaliPoxy 400 it sprays through a standard single-feed airless gun.
How is it applied?
Grit-blast steel to SA 2.5 or prime cured concrete with ShaliPrime 2E, mix Component A and B at 3:1 by volume, then spray 200-300 micron per coat at 2500-4000 psi through a 27-35 thou tip.
About STP ShaliPoxy 400 FG
ShaliPoxy 400 FG is STP Limited’s food-grade version of its well-known ShaliPoxy 400 pipe-lining system. It is a fast-setting, solvent-free, two-component epoxy engineered to seal the inside and outside of steel and concrete pipes, vessels and storage tanks that come into direct contact with drinking water. The cured film is inert and non-tainting, so it protects the substrate from corrosion and abrasion without imparting taste, odour or contaminants to the water it holds. Because it carries zero solvent, there is no VOC release during application and no risk of solvent entrapment in a thick film, which matters when you are lining a confined pipe interior or a covered reservoir.
The “FG” here signals two things at once: food-grade certification and, importantly, a reformulation for single-feed airless spray. The parent ShaliPoxy 400 is built for plural-feed (hot two-component) spray rigs that meter and mix resin and hardener at the gun; that equipment is specialised and not always available on Indian project sites. ShaliPoxy 400 FG is designed to be pre-mixed at a 3:1 ratio and pumped through a conventional single-feed airless unit, which contractors already own. You trade a slightly shorter working window for far wider equipment availability, making high-build potable-water lining practical on jobs where a plural-feed rig would be uneconomic to mobilise.
The technical insight
The performance comes from a high-solids (about 82 percent by volume), high-build epoxy chemistry that lays down a dense, cross-linked film exceeding 200 microns in a single pass. Because there is no solvent to flash off, almost the entire applied wet thickness remains as protective dry film, which is why very low permeability and a water-vapour transmission of only 0.10 g/m2 over 24 hours are achievable. That tight film is the real barrier: it keeps oxygen, moisture and dissolved salts away from the steel or concrete so corrosion and carbonation cannot start at the interface. The epoxy also develops genuine mechanical grip, with pull-off adhesion above 10 MPa on steel and above 3 MPa on concrete, plus Shore D hardness around 70 and abrasion loss under 100 mg per 1000 cycles, so it resists the scouring of flowing water and suspended grit. Food-grade safety is not a coating additive but a consequence of full cure: once the epoxy is fully reacted (7 days at RH below 75 percent) the network is chemically stable and inert, which is what lets it pass NSF/ANSI 61 long-term potable-water contact and the AWWA C-210 30-day immersion tests without blistering, peeling or leaching.
Where it is used
- Internal lining of steel and DI potable-water transmission and distribution pipelines
- External lining of buried steel pipes where abrasion and chemical attack are a concern
- Internal lining of RCC and steel potable-water storage tanks and overhead reservoirs
- Coating of pipes, vessels and equipment inside water treatment plants
- Sea-water intake tunnels and structures needing an inert, abrasion-resistant barrier
- Rehabilitation and relining of ageing concrete and steel water-carrying pipes
- Lining of clear-water sumps, break-pressure tanks and process vessels in the water sector
- High-build protective coating for structures requiring food-grade contact certification
Key advantages
- Certified food-grade and potable-water safe to BS 6920:2014, IS 16676:2017, AWWA C-210:2003 and NSF/ANSI 61
- Solvent-free with zero VOC, so it is safe to apply in confined pipe interiors and covered tanks
- Sprays through a standard single-feed airless gun instead of a specialised plural-feed rig
- High-build film exceeding 200 microns per coat, extendable with further passes
- Very low permeability with water-vapour transmission of just 0.10 g/m2/24hr
- Strong adhesion, above 10 MPa on steel and above 3 MPa on concrete
- Excellent abrasion and chemical resistance for flowing, grit-laden water
- Fast setting, touch dry in about 3 hours for quicker recoating and return to service
Limitations & considerations
- Pot life is only about 60 minutes at 27C, so mix in working quantities and use promptly
- Substrate must be blast-cleaned to SA 2.5 on steel and concrete must be at least 28 days old and primed with ShaliPrime 2E
- Full cure takes 7 days at RH below 75 percent before the tank can be filled or put into service
- Applies best between 10C and 50C substrate temperature, limiting cold or very hot site conditions
- Being pre-mixed for single-feed spray, it has a shorter working window than the plural-feed ShaliPoxy 400
- Correct DFT depends on good atomization, so tip pressure and tip size must be set and checked on site
Selection & best practice
Success with ShaliPoxy 400 FG is largely a surface-preparation exercise. On steel, grit or shot blast to SA 2.5 to a clean, angular profile and remove all dust, oil and loose scale by compressed air; on concrete, confirm the substrate is at least 28 days old, remove laitance and loose particles, and always prime with ShaliPrime 2E before coating. Stir each component thoroughly with a variable-speed drill and spiral blade at 400-600 rpm, then combine Component A and B strictly at 3:1 by volume and mix only the quantity you can spray inside the 60-minute pot life. Apply by single-feed airless spray at 2500-4000 psi through a 27-35 thou tip, adjusting pressure to get clean atomization, and build 200-300 microns per coat in even, overlapping passes. Check wet-film thickness as you go, allow the touch-dry and hard-dry intervals between coats, and let the lining reach full cure (7 days, RH below 75 percent) before filling a tank or commissioning a line. Flush tools with STP cleaner immediately after use, and always work with adequate ventilation and the recommended skin and eye protection.
Specifications
| Type | 2K solvent-free, food-grade epoxy coating |
| Mixing ratio | 3:1 (Component A : Component B) by volume |
| DFT per coat | 200-300 microns |
| Theoretical coverage | 4.2 m2/L at 200 micron DFT |
| Volume solids | 82 +/- 5 % |
| Pot life | 60 +/- 10 minutes at 27C, 55% RH |
| Drying time | Touch dry 3 hrs; hard dry 6-8 hrs; full cure 7 days (RH < 75%) |
| Adhesion (pull-off) | > 10 MPa on steel; > 3 MPa on concrete (ASTM D 4541) |
| Standards | BS 6920:2014, IS 16676:2017, AWWA C-210:2003, NSF/ANSI 61 |
| Pack size | 20 L drum (Component A 15 L + Component B 5 L) |
Industry use cases
Municipal Water Supply
Lining new and rehabilitated steel and DI mains and overhead reservoirs so treated water reaches consumers without pick-up of rust or contaminants.
Water Treatment Plants
Protecting internal surfaces of process pipes, clear-water sumps and vessels against corrosion and mild chemical exposure while staying food-grade compliant.
Infrastructure & Utilities
Coating sea-water intake tunnels and pump-house pipework where abrasion from grit-laden flow demands a hard, low-permeability epoxy barrier.
Industrial Process Water
Lining storage tanks and pipework in beverage, dairy and food-adjacent plants where the coating must be inert and non-tainting to stored liquids.
Pipeline Rehabilitation
Relining ageing concrete and steel water pipes in situ, restoring flow and extending service life without full replacement.
Frequently asked questions
Is ShaliPoxy 400 FG safe for drinking water?
How is it different from standard ShaliPoxy 400?
What thickness and coverage should I expect?
What surface preparation does it need?
What is the pot life and full cure time?
What pack size is it supplied in, and does Space Arc deliver Pan-India?
How we position STP ShaliPoxy 400 FG
Within the STP family, ShaliPoxy 400 FG sits alongside its plural-feed sibling ShaliPoxy 400 (choose that where a hot two-component spray rig is available and maximum single-pass build is wanted) and pairs with ShaliPrime 2E, the recommended primer for concrete substrates. For structures outside the food-grade scope, STP’s ShaliPoxy PC and coal-tar-free protective epoxies cover general anti-corrosion lining. Across our other brands, specifiers comparing potable-water tank linings often weigh this against Fosroc’s Nitocote EP405 and Dr. Fixit’s food-grade epoxy systems; the STP option is frequently favoured on Indian projects for its single-feed sprayability and IS 16676 conformity.
Fosroc Nitocote EP405 — Specify the Fosroc option where the project standard calls for a WRAS-listed, BS 6920 potable-water lining or where roller and brush application on tanks is preferred over airless spray.
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