MC-Bauchemie ombran MHP-SP
A C3A-free, fibre-reinforced spray mortar engineered for sewers, manholes and sulphate-laden underground structures — not a general-purpose patch repair.
What is it?
A one-component, cement-bound, polymer-modified mortar with a C3A-free binder built to resist sulphate and biogenic sulphuric-acid corrosion in sewerage systems.
Where is it used?
Concrete and masonry manholes, sewer chambers, wet wells, pump stations and water-retaining reservoirs exposed to aggressive wastewater or sulphate-bearing groundwater.
Why use it?
Meets DIN 19573’s toughest B1/B2-XWW3 mortar class and EN 1504-3 Class R3, with high early strength — at least 20 N/mm² at 24 hours — for fast return to service.
How is it applied?
Mechanically mixed, 3.2-3.5 parts water to 25 parts powder, pumped through a screw pump and applied by wet-spray or spinning technology in 10-25mm layers; hand-mixing of partial bags is not permitted.
About MC-Bauchemie ombran MHP-SP
ombran MHP-SP is a one-component, cement-bound, polymer-modified mortar from MC-Bauchemie’s ombran range, built around a C3A-free binder specifically to withstand sulphate attack and the biogenic sulphuric-acid corrosion that eats through ordinary concrete in sewer networks. Where a standard repair mortar is formulated for general above-ground structural work, ombran MHP-SP is engineered around one job: coating and re-profiling the concrete and masonry surfaces of manholes, sewer chambers, wet wells and reservoirs that sit in permanently wet, chemically aggressive underground conditions. It carries the toughest classifications the German DIN 19573 standard sets for wastewater mortars — B1-XWW3 as a coating mortar, B2-XWW3 as a repair mortar, XWW3 as a jointing mortar — plus Class R3 under EN 1504-3, and general building supervision approval in Germany.
For Indian municipal and industrial wastewater work — sewer rehabilitation under AMRUT and Smart Cities-type upgrades, STP/ETP wet-well linings, pumping-station chambers — this is a specification-grade material rather than a retail patch compound. It is fibre-reinforced for crack resistance in thin sprayed layers, machine-mixed and pumped for consistent, lump-free application, and reaches at least 20 N/mm² compressive strength within 24 hours so a rehabilitated chamber can return to service quickly. Space Arc supplies and can arrange application support for ombran MHP-SP as part of MC-Bauchemie’s underground sewer systems range, alongside the bonding agents, fine-grained variants and flexible coatings that complete a full manhole or sewer rehabilitation build-up.
The technical insight
The C3A-free formulation is what separates ombran MHP-SP from an everyday repair mortar. Tricalcium aluminate (C3A) is normally present in Portland cement and reacts with sulphates to form ettringite — an expansive compound that cracks and eventually delaminates conventional mortar coatings exposed to sulphate-rich groundwater or sewage. By formulating around a C3A-free binder, MC-Bauchemie removes that failure mode at the chemistry level rather than compensating for it with surface coatings, which is why the product is rated for exposition classes XA3, XS3 and XD3 under EN 1504-3 and EN 206 — the top tier for chloride and sulphate exposure. The fibre reinforcement matters operationally too: sprayed coatings in the 10-25mm range are prone to plastic shrinkage cracking as they lose water fast against a porous old-concrete substrate, and fibres control that cracking so the coating stays monolithic. An E-modulus of roughly 19,200 N/mm² at 28 days keeps the material’s stiffness close to the substrate concrete it is bonding to, reducing the differential-stress cracking that rigid, over-stiff repair mortars can trigger at the bond line.
Where it is used
- Spray-applied coating of concrete and masonry sewer manholes and inspection chambers
- Re-profiling of spalled, eroded or corroded sections in sewers, wet wells and pump-station chambers
- Internal lining of clarifiers, reservoirs and water-retaining structures exposed to sulphate-bearing water
- Rehabilitation of biogenic sulphuric-acid corrosion damage in wastewater infrastructure
- Jointing mortar for manhole ring joints and sewer segment joints (XWW3-rated)
- Structural re-profiling of underground concrete classified EN 1504-3 Class R3
- Base coat under subsequent coating systems (with curing-agent precautions) in sewer rehabilitation
- STP/ETP wet-well and channel lining in municipal and industrial wastewater treatment plants
Key advantages
- C3A-free binder is engineered at the chemistry level for sulphate and biogenic acid resistance, not a general repair mortar re-labelled for wastewater use.
- High early strength — at least 20 N/mm² compressive at 24 hours — lets contractors bring a manhole or chamber back into service fast.
- Machine-sprayable, one-component system gives more consistent, lump-free coating quality than hand-batched mortars.
- Fibre reinforcement resists plastic-shrinkage cracking in thin sprayed layers.
- Certified to DIN 19573’s toughest B1/B2-XWW3 classes and EN 1504-3 Class R3, backed by German general building supervision approval.
- Single material spans both a thin coating (10-25mm/layer) and a deeper re-profiling mortar (6mm+), simplifying material logistics on site.
- Water-impermeable once cured, and rated for freeze and de-icing-salt exposure as well as sulphate and chloride attack.
- Backed by MC-Bauchemie’s full ombran system — bonding agents, primers and coating variants — so the whole build-up comes from one manufacturer.
Limitations & considerations
- Purpose-built for underground sewer, manhole and wastewater exposure — not the right choice for general above-ground structural repair, where a standard EN 1504-3 repair mortar is more economical.
- Requires proper mechanical mixing (pan mixer/double stirrer) and a screw pump for spray or spinning application; MC-Bauchemie explicitly disallows hand-mixing or mixing partial bags, so it is not a small-repair, hand-trowel product.
- Demands disciplined curing — protected from water loss for a minimum 72 hours — needing real site supervision in hot, windy Indian conditions.
- Published technical data is from MC-Bauchemie’s German TDS (DIN 19573, EN standards); local availability, pricing and any India-specific datasheet should be confirmed with Space Arc/MC-Bauchemie India before finalising a specification.
- Supplied only as grey 25 kg bags — no ready-mix or bulk-silo option noted on the manufacturer’s data sheet.
- Coating build-ups beyond the per-layer thickness limits (up to 25mm coating/50mm total) need multiple passes with intermediate curing, adding programme time on large networks.
Selection & best practice
Follow MC-Bauchemie’s substrate-preparation and bond-coat guidance for manhole and sewer repair mortars before applying ombran MHP-SP; for hand application, prime with ombran HB bonding agent per its own data sheet. Mix mechanically only — major part of the water first, then the dry mortar, to a lump-free consistency for at least 3 minutes — and pump through a hose of at least 35mm internal diameter for spray or spinning application. Keep air, substrate and material temperature between 5°C and 30°C, and protect the coating from excessive water loss for at least 72 hours using a compatible curing agent, jute sacking or polythene sheeting; if a further layer or top coat is planned, avoid film-forming curing agents or remove them by blasting before recoating.
Specifications
| Binder system | Cement-bound, polymer-modified, one-component, C3A-free, fibre-reinforced mortar |
| Standards compliance | DIN 19573 (B1-XWW3 coating, B2-XWW3 repair, XWW3 jointing mortar); EN 1504-3 Class R3; EN 206 exposition class XA3 (also XS3, XD3 per EN 1504-3) |
| Compressive strength | ≥20 N/mm² (24 h), ≥40 N/mm² (7 d), ≥45 N/mm² (28 d) |
| Flexural strength | ≥4 N/mm² (24 h), ≥5 N/mm² (7 d), ≥7 N/mm² (28 d) |
| Mixing ratio | 25 : 3.2-3.5 by mass, powder to water |
| Consumption (flat) | 1.9 kg/m² per mm of factory-dried mortar |
| Layer thickness | ≥6 mm re-profiling; 10-25 mm per coating layer; 50 mm max total |
| Pack size | 25 kg bag, grey |
| Application/working conditions | Air, substrate and material 5°C-30°C; working time approx. 60 min at 20°C |
Industry use cases
Municipal sewer rehabilitation
Spray-coating and re-profiling ageing manhole chambers and sewer shafts under AMRUT/Smart Cities-type upgrade works in Delhi NCR and other metros
Wastewater treatment plants (STP/ETP)
Lining wet wells, channels and chambers exposed to continuous sulphate and hydrogen-sulphide (biogenic acid) attack
Industrial effluent infrastructure
Rehabilitating below-ground sumps and chambers in process industries where effluent carries aggressive sulphates or chlorides
Water/reservoir structures
Coating and re-profiling clarifiers and reservoirs where sulphate-bearing groundwater or process water attacks the concrete
Utility and underground chambers
Re-profiling breakouts and defects in underground utility chambers requiring EN 1504-3 Class R3 structural repair
Frequently asked questions
Can ombran MHP-SP be applied by hand, or does it need spray equipment?
What’s the difference between ombran MHP-SP and ombran MHP-SP 3000?
Is this suitable for potable/drinking water reservoirs?
How is the sulphate resistance different from an ordinary SRC-cement-based repair mortar?
What pack size does it come in, and how do I estimate quantity for a manhole?
Can it be top-coated with an epoxy or polyurethane lining afterward?
How we position MC-Bauchemie ombran MHP-SP
ombran MHP-SP sits inside MC-Bauchemie’s dedicated ombran underground sewer systems range, alongside ombran HB (the bonding agent for hand-applied areas), ombran MHP fine (a finer-grained variant for tighter tolerances), ombran IW, ombran flex (a flexible coating for manhole tapers), and ombran SC (hand lay-up reactive-resin lamination) — together these cover the full manhole and sewer rehabilitation build-up rather than being a single stand-alone patch product. There isn’t a genuine like-for-like Fosroc equivalent in Space Arc’s current catalogue: Fosroc’s Renderoc range (Renderoc HB, for instance) is a strong general-purpose polymer-modified spray/hand repair mortar, but it isn’t formulated C3A-free or classified to DIN 19573 for sewer/wastewater duty, so it’s a substitute for general concrete repair rather than a direct match for sulphate-and-biogenic-acid-rated sewer coating work. Where a project specifically calls out DIN 19573 XWW3 or EN 1504-3 Class R3 for underground sewer infrastructure, ombran MHP-SP remains the more defensible specification.
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