Hensotherm 820KS Intumescent for Concrete (Available to order)
What is this product?
HENSOTHERM 820 KS requires a primer of BETON-CARBONSPERRE (available separately), applied at 2 × 140 g/m² and dried thoroughly before the fire protection coating.
Fire protection coating for concrete
HENSOTHERM 820 KS is a water-based, single-component fire protection coating for concrete structural members in indoor use. In a fire it forms a heat-insulating barrier of carbon foam, which keeps the concrete from heating up and stops it flaking off the steel reinforcement (European Patent EP 2686391 B1).
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Fire resistance
- Flat concrete ceilings and walls: up to 240 minutes (R240)
- Reinforced concrete beams and supports: up to 150 minutes (R150)
- Prestressed concrete hollow ceilings: up to 120 minutes (R120)
- Ribbed ceilings: on request, with project-specific expertise
- Tested to EN 13381-3:2015. Warringtonfire EWCL Certificate No. ME 5119
Product characteristics
- Free of halogens, APEO, borates and plasticisers
- Low VOC (below 6 g/l), VOC emission class A+, LEED confirmation, AgBB tested
- Imposes little structural load, no loss of headroom
- Maintenance-free
- Colour: white (approx. RAL 9010)
Technical data
- Consumption: 2 kg/m² per 1.0 mm dry film (1.4 mm wet)
- First pass max. 700 µm wet film, max. 1,500 µm wet per operation
- Recoatable after 24 hours at the earliest (+20°C, 65% relative humidity, approx. 1.0 mm dry film), after a successful fingernail test
- Airless spray: 200 to 250 bar, nozzle 0.017 to 0.025 inch, output above 4.5 l/min. Thin with up to 5% water
- At least +10°C, relative humidity below 80%, surface at least 5°C above dew point
- Optional top coat: HENSOTOP WB Green, for colour in dry indoor areas
- Supplied in 25 kg pails
Information required for quotation
- Required fire protection duration (e.g. 60, 120, 240 minutes)
- Total concrete thickness (mm)
- Depth of reinforcement steel bars in the concrete
- Total surface area to protect (m²)
Documents
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Up to 240 minutes fire resistance for concrete
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Tested to EN 13381-3:2015
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Prevents concrete spalling off the reinforcement
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Low VOC (below 6 g/l), emission class A+
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Maintenance-free with no loss of headroom
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European Patent EP 2686391 B1
Specifications & Documents
Full technical data and downloadable certification for compliance records.
| Product Code | CKS25 |
| Finish | White (approx. RAL 9010) |
| Use | Indoor |
| Application Method | Airless spray (200 to 250 bar, nozzle 0.017 to 0.025 inch), brush or roller |
| Fire Classification | Tested to EN 13381-3:2015. Up to R240 flat ceilings and walls, R150 beams and supports, R120 prestressed hollow ceilings. |
| VOC Content | Below 6 g/l, VOC emission class A+ |
| Shelf Life | 12 months unopened |
How to Apply
Simple application with standard tools — no specialist equipment required.
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1Prepare concrete for HENSOTHERM 820 KSThe surface must be rough, clean and free of dust, cement laitance, efflorescence, oil and grease. Concrete dry per ASTM D 4263 and/or residual moisture max. 4% (CM method). Remove old coatings completely.
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2Prime before HENSOTHERM 820 KSApply BETON-CARBONSPERRE at 2 × 140 g/m² and let it dry thoroughly.
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3Check conditions for HENSOTHERM 820 KSAt least +10°C, relative humidity below 80%, surface at least 5°C above dew point and always above 0°C.
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4Apply HENSOTHERM 820 KSAirless spray at 200 to 250 bar, nozzle 0.017 to 0.025 inch, output above 4.5 l/min, intake hose detached. Thin with up to 5% water. First pass max. 700 µm wet, max. 1,500 µm wet per operation. Check with a wet film gauge.
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5Allow HENSOTHERM 820 KS to dry between coatsRecoat at the earliest after 24 hours at +20°C and 65% relative humidity (approx. 1.0 mm dry film), after a successful fingernail test.
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6Inspect HENSOTHERM 820 KSVisually inspect at least every two years. Damage must be documented and repaired promptly.
Coverage Guide
Frequently Asked Questions
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HENSOTHERM 820 KS is a water-based fire protection coating for concrete structural members in indoor use, including hollow core slabs, flat ceilings, walls, beams and columns.
Up to 240 minutes for flat concrete ceilings and walls, 150 minutes for reinforced concrete beams and supports, and 120 minutes for prestressed concrete hollow ceilings. Tested to EN 13381-3:2015.
In a fire it forms a heat-insulating barrier of carbon foam, which stops the concrete heating up and flaking off the steel reinforcement.
Yes. BETON-CARBONSPERRE is the mandatory primer, applied at 2 × 140 g/m². Betongrund AQ is an alternative only in dry indoor areas where CO₂/SO₂ infiltration does not need to be prevented.
2 kg/m² per 1.0 mm dry film. The required thickness depends on the element and fire resistance needed.
At the earliest after 24 hours at +20°C and 65% relative humidity (approx. 1.0 mm dry film), after a successful fingernail test.
No. It is for indoor use only.
The required fire protection duration, total concrete thickness, depth of the reinforcement steel bars, and the total surface area to protect.
What Our Customers Say
Verified reviews collected via eKomi — independently moderated and genuine.
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★★★★★
Gave them a ring to ask for some advice, was pointed to exactly what I needed and how much. Arrived promptly and has performed perfectly.
Verified purchase · 2 weeks ago -
★★★★★
Very quick response to query and fast delivery. Easy to use product with good instructions. Great company. Will use again.
Verified purchase · 1 month ago -
★★★★★
Excellent product with swift delivery. Easy to top up fire retardancy after the deck was cleaned. Looks completely untreated which was exactly what we wanted.
Verified purchase · 1 month ago