Fosroc Nitoseal PU220PF
Two-part, pitch-free polyurethane gun-grade joint sealant engineered for water-retaining, sewage, petrochemical and marine structures exposed to immersion, chemical attack and tidal scour.
What is it?
A two-component (base + hardener) gun-grade polyurethane joint sealant from Fosroc. It is the pitch-free variant of Nitoseal PU220, curing to a tough, elastomeric, biodegradation-resistant seal designed for aggressive water and petrochemical environments.
Where is it used?
Movement and expansion joints in sewage treatment works, sludge digestion / aeration / filtration tanks, raw water reservoirs, culverts, petrochem storage tank bunds, sea walls, sea-water intakes and tidal marine defences across India.
Why use it?
It resists bacteriological attack, hydrocarbon fuels, chemical spillage and tidal abrasion while staying flexible and watertight under permanent immersion – conditions that defeat conventional bituminous or general-purpose sealants. Being pitch-free, it suits ISO 14001 environmental policies.
How is it applied?
Gun-applied into a primed joint over a bond-breaker / backer rod, tooled off, with movement accommodation up to 25% of joint width. A separate accelerator component is available to speed the initial cure for tidal windows.
About Fosroc Nitoseal PU220PF
Fosroc Nitoseal PU220PF is a high-performance, two-part polyurethane joint sealant developed for the most demanding water-engineering and petrochemical structures. It is the pitch-free (“PF”) version of the well-established Nitoseal PU220: where PU220 is blended with high-grade pitch, the PF grade delivers the same durable, elastomeric performance without coal-tar pitch, making it the preferred choice for projects governed by ISO 14001 environmental management policies and for clients who want to avoid pitch-based products in potable-adjacent or sensitive water assets.
Supplied as a gun-grade (non-sag) sealant, PU220PF is mixed on site from a base and a hardener and cures chemically to form a tough, highly resilient rubber-like seal. Unlike traditional bitumen or tar compounds, it does not embrittle, suffer cold flow or behave thermoplastically over time, so joints stay sealed and serviceable through years of wetting, drying and movement cycles. Its defining strengths are resistance to bacteriological (biological) attack in sewage and effluent, resistance to hydrocarbon fuels and chemical spillage in petrochem bunds, and outstanding abrasion resistance that lets it survive tidal scour on sea defences and intakes. It also maintains adhesion under permanent immersion, which is where many general-purpose sealants fail.
For Indian contractors and consultants, Nitoseal PU220PF sits in the specialist end of the Fosroc Nitoseal joint-sealant range, reserved for water-retaining and aggressive-chemical structures rather than ordinary building expansion joints. Space Arc Engineering supplies and supports it Pan-India as an authorised Fosroc distributor and applicator.
The technical insight
Nitoseal PU220PF is a chemically-curing (moisture-independent) two-part polyurethane, so unlike single-component PU sealants it cures reliably at depth and in immersed or poorly-ventilated joints where atmospheric moisture cure would stall. The PU220 family is formulated to a movement accommodation factor (MAF) of 25%, meeting the performance intent of ISO 9047 and US Federal Specification TT-S-00227E Type 2 Class A; in practice this means a correctly designed joint can absorb cyclic movement up to a quarter of its installed width without losing its seal. Cured hardness is in the order of 15-25 Shore A (DIN 53505 at 7 days, 25 C), giving a seal soft enough to flex with the joint yet tough enough to resist the abrasive action of moving water and grit. The chemistry is deliberately tuned for biodegradation resistance: the cured polymer is not a food source for the bacteria found in sewage and digestion tanks, which is why it holds up where organic sealants would be consumed or softened. A key practical feature is the separate accelerator component – dosed into the mix to shorten the initial cure – which lets applicators seal between tides on marine and coastal works, a window of only a few hours. Adhesion is primer-dependent: Fosroc specifies the appropriate Nitoseal/Fosroc primer for the substrate (concrete and other porous faces versus metals and non-porous faces), and the system can be made to bond even to damp concrete with the correct primer selection.
Where it is used
- Expansion and movement joints in sewage treatment works and effluent channels
- Sludge digestion tanks, aeration tanks and filtration tanks
- Raw water reservoirs, service reservoirs and culverts
- Petrochemical storage tank farms and chemical bund / containment joints
- Sea walls, sea-water intakes and coastal sea-defence works subject to tidal action
- Joints in water-retaining and below-ground civil structures exposed to immersion
- Joints requiring resistance to hydrocarbon fuels, chemical spillage and abrasion
Key advantages
- Pitch-free formulation – suits ISO 14001 policies and avoids coal-tar pitch in sensitive water assets
- Resistant to bacteriological / biodegradation attack in sewage and effluent environments
- Resistant to hydrocarbon fuels and chemical spillage for petrochem bund joints
- High abrasion resistance – withstands tidal scour and grit-laden moving water
- Maintains adhesion and flexibility under permanent immersion
- 25% movement accommodation factor with excellent elastomeric recovery
- Does not embrittle, cold-flow or behave thermoplastically like bituminous compounds
- Optional separate accelerator for rapid initial cure between tides
- User-friendly gun-grade application and tooling for vertical and horizontal joints
Limitations & considerations
- Two-part product – requires accurate on-site mixing of base and hardener; no part-pack use without re-proportioning
- Specialist sealant aimed at water/petrochem/marine joints, not a general-purpose facade or glazing sealant
- Primer is mandatory for reliable adhesion; the correct primer must be matched to the substrate
- Limited pot life once mixed (around 1-2 hours at 20 C), shortening at higher temperatures and with accelerator
- Joint must be correctly designed (width:depth, backer rod / bond breaker) or movement performance is compromised
- Typically supplied black/dark – not intended for decorative colour-matched joints
- Not a structural adhesive, a waterstop or a trafficked floor-joint sealant (use Nitoseal PU280 / Colpor grades for heavy floor traffic)
Selection & best practice
Design the joint before specifying the sealant. For Nitoseal PU220PF, keep movement within the 25% MAF: the installed sealant width must be large enough that cyclic movement never exceeds a quarter of it. Follow the Fosroc width-to-depth guidance for the PU220 family – for typical joints a sealant width in the 10-25 mm range with depth roughly equal to width (and a minimum sealing depth of about 10 mm) works well; very wide joints should still respect the family limits up to around 50 mm. Always install a closed-cell backer rod or bond-breaker (debonding) tape at the joint base so the sealant bonds only to the two joint faces and is free to extend and compress – never three-sided adhesion. Clean joint arrises to sound, dry, laitance-free concrete, then apply the correct Fosroc primer for the substrate (porous concrete versus non-porous metal), respecting the primer’s open time. Mix the full base and hardener thoroughly to a uniform colour; do not split packs by eye. On tidal or coastal work, add the separate accelerator component at the specified dosage to gain a tooled, tack-free skin before the water returns. Gun the sealant in firmly to exclude air, tool to a slightly concave profile, and protect from immersion and traffic until the manufacturer’s cure time is reached. Allow concrete to cure adequately before sealing and avoid application onto frozen, contaminated or actively wet faces unless a damp-tolerant primer is specified.
Specifications
| Product type | Two-part (2K) polyurethane joint sealant, pitch-free |
| Grade / consistency | Gun-grade, non-sag (suitable for vertical and horizontal joints) |
| Base chemistry | Chemically-curing polyurethane (base + hardener) |
| Colour | Black / dark grey (typical) |
| Movement accommodation factor (MAF) | 25% (ISO 9047 / TT-S-00227E Type 2 Class A intent, per PU220 family) |
| Hardness | 15-25 Shore A (DIN 53505, 7 days at 25 C) |
| Pot life | Approx. 1-2 hours at 20 C (shorter at higher temperature / with accelerator) |
| Accelerator | Separate accelerator component available for rapid initial cure (tidal use) |
| Joint width range | Approx. 6-50 mm (per Nitoseal PU220 base data) |
| Joint depth | Depth approximately equal to width; minimum sealing depth ~10 mm |
| Coverage | Approx. 100 m of 10 mm-deep joint per litre (profile dependent) |
| Primer | Fosroc primer required, selected for porous vs non-porous substrate |
| Key resistances | Biodegradation / bacteriological attack, hydrocarbon fuels, chemical spillage, abrasion, immersion |
| Pack sizes | 1 litre and 4 litre packs (base + hardener); accelerator supplied separately |
Industry use cases
Municipal water & wastewater
Sealing expansion and construction-movement joints in sewage treatment plants, sludge digestion and aeration tanks, and service reservoirs where biological attack and permanent immersion would degrade ordinary sealants.
Petrochemical & chemical storage
Joints in tank-farm bunds and chemical containment areas that must resist hydrocarbon fuels and chemical spillage without softening or losing seal.
Marine & coastal infrastructure
Sea walls, sea-water intakes and tidal defence works where abrasion resistance to scour and the accelerator’s fast cure between tides are decisive.
Water-conveyance civil works
Culverts, channels and raw water reservoirs requiring a durable, flexible, watertight movement joint under wet/dry cycling.
Industrial & process plants
Below-ground and water-retaining structures in process facilities needing chemical and immersion resistance in their movement joints.
Frequently asked questions
What is the difference between Nitoseal PU220PF and Nitoseal PU220?
What movement can Nitoseal PU220PF accommodate?
Do I need a primer with Nitoseal PU220PF?
Can it be used in tidal and underwater marine joints?
What pack sizes and pot life should I plan for?
Where does Nitoseal PU220PF fit versus other Fosroc sealants?
How we position Fosroc Nitoseal PU220PF
Within the Fosroc joint-sealant portfolio, Nitoseal PU220PF is the specialist, pitch-free polyurethane for aggressive water, sewage, petrochemical and marine movement joints – distinct from the general-purpose Nitoseal PU40, the trafficked floor-joint grades Nitoseal PU280 and the Colpor 200 / Colpor 200PF range, the polysulphide Thioflex 600, and the MS-polymer Nitoseal MS600 used for immersed engineering joints. Its closest sibling is Nitoseal PU220 itself, which is the same product blended with pitch; PU220PF is chosen when pitch must be avoided for environmental (ISO 14001) or client reasons. Among credible alternatives an Indian specifier may evaluate, Sika offers the Sikaflex polyurethane sealant family (and Sikadur/Sikaflex combination systems) for chemical and immersion-exposed joints; MBCC/Master Builders Solutions offers the MasterSeal range (e.g. MasterSeal NP/PU grades) for movement and water-retaining joints; and STP / Choksey supply polysulphide and PU joint sealants used in Indian water and infrastructure projects. Space Arc Engineering, as an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India, recommends Nitoseal PU220PF where biodegradation resistance, hydrocarbon and chemical resistance, immersion adhesion and tidal abrasion resistance are all required in one specification – and will advise on joint design, primer selection and the correct sister product when the application falls outside PU220PF’s intended scope.
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