STP ShaliDCT 102
STP’s solvent-free processed dehydrated coal tar (Grade 102) for durable anti-corrosive protection of buried steel and concrete surfaces.
What is it?
A solvent-free, processed dehydrated coal tar coating (Grade 102) from STP Limited, formerly sold as ShaliKote CT 102, used as an anti-corrosive protective barrier.
Where is it used?
Buried and embedded steel and concrete — pipelines, tanks, foundations, structural steel, and other surfaces exposed to soil moisture and corrosive ground conditions.
Why use it?
It lays down a tough, water-repellent film that shields metal and concrete from moisture-driven corrosion, with a smoother finish than raw, unprocessed coal tar.
How is it applied?
Applied by brush or as a hot-applied barrier over a cleaned, primed surface; grade 102 gives the viscosity and penetration suited to general protective duty.
About STP ShaliDCT 102
STP Limited’s ShaliDCT 102 sits in a category of products that Indian contractors have relied on for decades: coal tar barrier coatings for the parts of a structure nobody sees. It is a processed, dehydrated coal tar refined to Grade 102 — the dehydration step drives off free moisture and lighter fractions, which is what gives the cured film its density, its water resistance, and the cleaner surface finish that sets it apart from crude, unprocessed tar. STP markets it as a solvent-free protective material, so what goes onto the substrate is essentially the tar itself rather than a thinned solution that shrinks back as solvent flashes off. The product was previously catalogued as ShaliKote CT 102, a name still remembered on many older drawings and BOQs.\n\nIts job is corrosion control by exclusion. Buried steel and concrete fail when soil moisture, dissolved salts and oxygen reach the surface and drive electrochemical corrosion; ShaliDCT 102 answers that by forming a continuous, hydrophobic membrane that keeps water and its dissolved aggressors off the metal or off the concrete pore network. Within STP’s ShaliDCT range — which spans grades 101 through 105 plus specialised variants like the PU-compatible 105 — the 102 grade is positioned as the general-purpose protective coat where a better surface finish is wanted, making it a familiar specification for pipeline exteriors, embedded steelwork and below-ground concrete faces across Indian infrastructure and industrial work.
The technical insight
Corrosion of buried metal is an electrochemical process: it needs an electrolyte (moisture carrying dissolved salts) in contact with the steel to move ions between anodic and cathodic sites. Break that contact and the reaction starves. ShaliDCT 102 works purely as a barrier — the dehydrated coal tar cures to a dense, continuous film with very low water permeability, so soil moisture, chlorides and sulphates cannot reach the substrate to sustain the cell. The dehydration during manufacture matters here: by removing free water and volatile light ends, STP produces a film that is less porous and less prone to blistering than crude tar, and being solvent-free there is no solvent evaporation to leave pinholes or voids as the coating sets. On concrete the same film blocks the ingress path for the carbonation and chloride attack that would otherwise depassivate embedded reinforcement. The protection is entirely dependent on film continuity, so surface preparation and full, holiday-free coverage are what actually determine service life.
Where it is used
- Anti-corrosive protective coating on the exterior of buried steel pipelines and ducts
- Protection of embedded and below-ground structural steelwork against soil-side corrosion
- Barrier coating on below-ground concrete faces — foundations, retaining walls and tank exteriors
- Damp-proof protective film on concrete surfaces in contact with soil or backfill
- Coating of steel tanks, chambers and fittings before burial or backfilling
- General industrial anti-corrosive duty where a smoother tar finish is preferred over raw coal tar
- Protection of concrete and steel in effluent, drainage and services trenches
- Refurbishment re-coating of previously tar-protected buried assets during maintenance
Key advantages
- Solvent-free formulation, so the film does not shrink back or leave solvent pinholes as it sets
- Processed and dehydrated for a denser, lower-porosity film than crude, unprocessed coal tar
- Delivers a better, smoother surface finish where appearance or overcoating matters
- Strongly hydrophobic barrier that resists soil moisture and dissolved salts
- Protects both steel and concrete substrates from one product family
- Grade 102 offers viscosity and penetration tuned to general protective coating duty
- Long-established STP chemistry with proven field history on Indian buried assets
- Backed by a documented TDS and MSDS for specification and site compliance
Limitations & considerations
- Coal tar coatings carry health and environmental concerns (PAH content); many specifiers now restrict or phase them out in favour of modern coatings
- Not UV-stable — unsuitable as a final coat on permanently sun-exposed surfaces, where it will degrade
- Purely a barrier: performance depends entirely on film continuity, so any holiday, pinhole or damage becomes a corrosion initiation point
- Hot-applied or high-viscosity use needs correct heating and handling, with attendant fume and safety precautions
- Not a structural, crack-bridging or trafficable membrane — it protects, it does not span moving cracks or take foot traffic
- Public TDS does not publish coverage, softening point or viscosity figures; project dosage must be confirmed against STP’s current data sheet
Selection & best practice
Success with ShaliDCT 102 is decided at the surface, not in the pot. Prepare steel to a clean, dry, rust- and scale-free condition and concrete to a sound, dry, laitance-free surface before coating; any grease, moisture or loose material will undermine adhesion. Apply STP’s recommended primer where the TDS calls for one, then build the coating to a continuous, holiday-free film — inspect for pinholes and missed edges, since these are where corrosion starts. Where the grade is heated to reduce viscosity for application, control the temperature per the TDS and observe fume, ventilation and PPE precautions, as coal tar products require careful handling. Avoid application over damp substrates or in the rain, protect the fresh film until set, and keep the coating out of permanent UV exposure. Always confirm number of coats, film thickness and consumption against the current STP technical data sheet for your specific structure and exposure.
Specifications
| Product Type | Processed dehydrated coal tar, Grade 102 |
| Brand | STP Limited |
| Former Name | ShaliKote CT 102 |
| Chemistry | Solvent-free processed, dehydrated coal tar |
| Function | Anti-corrosive protective barrier coating |
| Suitable Substrates | Steel and concrete |
| Finish | Improved surface finish vs. unprocessed coal tar |
| Documentation | TDS and MSDS available from STP Limited |
Industry use cases
Oil, Gas & Water Pipelines
Exterior anti-corrosive coating on buried steel pipelines and ducts, keeping soil moisture and dissolved salts off the metal wall.
Industrial Plants & Utilities
Protection of embedded steelwork, buried tanks and below-ground concrete in plants, effluent systems and services trenches.
Infrastructure & Foundations
Damp-proof barrier on below-ground concrete faces, foundations and retaining walls exposed to aggressive backfill and groundwater.
Maintenance & Rehabilitation
Re-coating of previously tar-protected buried assets during planned maintenance, restoring the barrier film on ageing infrastructure.
Frequently asked questions
What exactly is ShaliDCT 102 and how is it different from ordinary coal tar?
Is ShaliDCT 102 the same as the old ShaliKote CT 102?
Can it be used on both steel and concrete?
How is ShaliDCT 102 applied?
Should I still specify coal tar coatings today?
Does Space Arc supply ShaliDCT 102 across India?
How we position STP ShaliDCT 102
ShaliDCT 102 is the general-purpose grade in STP’s coal tar family. Where a project needs a different profile, the same ShaliDCT range offers close relatives: ShaliDCT 101, 103 and 104 as alternative processed dehydrated grades, and ShaliDCT 105 as a PU-compatible saturated processed tar with waterproofing properties for jobs that must be overcoated with polyurethane systems. For pitch-based and low-odour requirements, STP also offers ShaliPitch and the low-smell ShaliModulate LS. Because coal tar is a legacy chemistry, many of our clients now pair or replace it with modern protective coatings from our other brands — Fosroc concrete protection and Dr. Fixit or Sika barrier systems — particularly on exposed, above-ground or UV-facing surfaces where coal tar is unsuitable. We help specifiers choose honestly between the traditional tar route and a contemporary coating based on the actual exposure.
Fosroc Dekguard S — Choose Dekguard S when the surface is above-ground or exposed concrete rather than buried steel — it is a modern, low-toxicity silane-siloxane protective impregnation that avoids coal tar’s PAH and UV limitations while guarding against carbonation and chloride ingress.
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