50W High-Density Spray Foam | Rigid SPF with Declared Compressive Strength
Contents
- What is 50W spray polyurethane foam and when should you specify it?
- Water blowing agent and make-up of 50W spray polyurethane foam
- Applied foam properties: density, compressive strength, λ, μ, water absorption and fire
- 50W spray foam aged thermal performance table (thickness / λ / R)
- Mix ratios and site application conditions
- Component properties and laboratory reactivity
- Safety, storage, equipment cleaning and empty containers
- 50W spray polyurethane foam vs other Rayston grades: which one to choose?
- 50W spray polyurethane foam: FAQ
- Engineering summary
- Related links
Rayston Spray Foam 50W by Krypton Chemical: the high-density spray foam of the water-blown line (48–56 kg/m³), λ = 0.030 W/m·K, declared compressive strength 280 at level CS(10/Y)200, free of HFCs and HCFCs — figures from the technical datasheet.
- Product: Rayston Spray Foam 50W
- Grade: 50W · high-density water-blown
- Application: spray-applied thermal insulation
50W spray polyurethane foam (Rayston Spray Foam 50W) is a two-component rigid SPF system from Krypton Chemical, S.L. and the highest-density grade in Rayston’s water-blown line. The blowing agent is water, and the system is free of HFCs, HCFCs and VOCs. Key figures: applied density 48–56 kg/m³, declared thermal conductivity λ = 0.030 W/m·K, declared compressive strength 280 at level ≥ 200 (CS(10/Y)200), closed-cell content < 70% and μ ≥ 70, according to the official technical datasheet (last revised 02/06/2026).
This article covers a single grade of the Rayston Spray Foam range (the water-blown W line). For a full comparison of all seven grades, see the general guide: spray polyurethane foam. For a direct comparison, see the lighter 40W spray foam and HFO 50 spray foam, a closed-cell grade of similar density.
01
What is 50W spray polyurethane foam and when should you specify it?
50W spray foam (Rayston Spray Foam 50W) is a rigid polyurethane foam made from a two-component system (polyol + isocyanate). Sprayed directly onto the substrate, it forms a continuous, fully adhered insulation layer that limits thermal bridging at corners and junctions.
Use declared in the datasheet:
- Spray-applied thermal insulation on surfaces not subject to permanent loads, such as vertical walls and ceilings from the inside.
- On façades: repels water while still allowing the construction to breathe to some degree.
At 48–56 kg/m³, 50W is the heaviest grade of the W line and the only one whose sheet declares a numerical compressive strength (280, with a declared level of ≥ 200). Even so, the use stated in the datasheet remains surfaces not subject to permanent loads, so the declared compressive strength should not be read as approval for permanent loading.
According to the datasheet, the product contains no fibres and no biohazardous materials, nor any substances classed as hazardous construction and demolition waste. It is for industrial and professional use only and not suitable for DIY. The cured foam is 100% recyclable by environmentally friendly mechanical means, with no gas capture needed for recycling or disposal.
Manufacturer: kryptonchemical.com.
Internal links: Knowledge base · Products · Documents.
02
Water blowing agent and make-up of 50W spray polyurethane foam
50W spray foam uses water as its blowing agent, within Rayston’s water-blown line (30W / 40W / 50W), as opposed to the HFO family (HFO 35 / HFO 40 / HFO 50) and the 8W open-cell grade.
According to the datasheet, the system is free of ozone-depleting substances and fluorinated greenhouse gases: it contains no HFCs, HCFCs or VOCs, and thermal conductivity λ remains stable from application throughout the life of the product.
Designation code as given in the foam property table:
PU EN 14315-1-CCC2-CT3 (20)-TFT18(20)-FRB35(20)-W0,2-MU70 – CS (10/Y)200
Reference standard for use as thermal insulation in buildings (ThIB): EN 14315-1:2013, together with guidance document NB-CPR/SG19-17/167r2 dated 24/01/18. Note for specifiers: the CE marking block in the same sheet gives a different designation code (CT4 / GT18 / TFT11 / FRB30) without a CS element, so confirm the applicable code with the manufacturer before writing it into the project specification.
03
Applied foam properties: density, compressive strength, λ, μ, water absorption and fire
Applied density
48–56 kg/m³
UNE-EN 1602
Compressive strength
280 (declared level ≥ 200)
CS (10/Y)200 in designation code
Closed-cell content
< 70%
— (row notes “does not allow water through”)
Reaction to fire
Euroclass E (all thicknesses)
UNE-EN 13823:2002
| Property | Value | Standard / TDS reference |
|---|---|---|
| Applied density | 48–56 kg/m³ | UNE-EN 1602 |
| Free-rise density (lab) | 45 g/L | EN 14315-1:2013 |
| Compressive strength | 280 (declared level ≥ 200) | CS (10/Y)200 in designation code |
| Closed-cell content | < 70% | — (row notes “does not allow water through”) |
| Declared thermal conductivity λ | 0.030 W/m·K | UNE-EN 12667 |
| Reaction to fire | Euroclass E (all thicknesses) | UNE-EN 13823:2002 |
| Short-term water absorption | ≤ 0.2 kg/m² | EN 14315-1:2013 |
| Water vapour diffusion resistance factor μ | ≥ 70 | EN 14315-1:2013 |
Brief engineering notes:
- 50W is the only grade in the W line that declares a numerical compressive strength: 280, with a declared level of ≥ 200 and code CS(10/Y)200.
- λ = 0.030 is slightly lower than 30W and 40W (0.031), which shows in the R values of the ageing table.
- Closed-cell content is declared as < 70%, lower than 30W and 40W (< 80%), and the designation code carries CCC2.
- Reaction to fire is Euroclass E for all thicknesses; according to the CE marking block, neither reaction to fire nor compressive strength deteriorates over time.
04
50W spray foam aged thermal performance table (thickness / λ / R)
Base the thermal calculation on the target-thickness row of the aged performance table, not on the general λ value alone. For 50W spray foam, λ = 0.030 stays constant from 30 to 200 mm, and thermal resistance R increases with thickness.
R (m²·K/W)
Aged λ (W/m·K) 0.030 · thickness 30–200 mm
30 mm
1.05
35 mm
1.20
40 mm
1.40
45 mm
1.55
50 mm
1.70
55 mm
1.90
60 mm
2.10
65 mm
2.25
70 mm
2.40
75 mm
2.60
80 mm
2.75
85 mm
2.90
90 mm
3.10
95 mm
3.25
100 mm
3.40
105 mm
3.60
110 mm
3.80
115 mm
4.00
120 mm
4.20
125 mm
4.30
130 mm
4.50
135 mm
4.65
140 mm
4.80
145 mm
5.00
150 mm
5.20
155 mm
5.35
160 mm
5.50
165 mm
5.70
170 mm
5.85
175 mm
6.00
180 mm
6.20
185 mm
6.40
190 mm
6.55
195 mm
6.70
200 mm
6.90
Worked example: at 50 mm, R = 1.70 m²·K/W; at 100 mm, R = 3.40; and at 200 mm, R = 6.90 — with λ = 0.030 in every declared row.
| Thickness (mm) | Aged λ (W/m·K) | R (m²·K/W) |
|---|---|---|
| 30 | 0.030 | 1.05 |
| 35 | 0.030 | 1.20 |
| 40 | 0.030 | 1.40 |
| 45 | 0.030 | 1.55 |
| 50 | 0.030 | 1.70 |
| 55 | 0.030 | 1.90 |
| 60 | 0.030 | 2.10 |
| 65 | 0.030 | 2.25 |
| 70 | 0.030 | 2.40 |
| 75 | 0.030 | 2.60 |
| 80 | 0.030 | 2.75 |
| 85 | 0.030 | 2.90 |
| 90 | 0.030 | 3.10 |
| 95 | 0.030 | 3.25 |
| 100 | 0.030 | 3.40 |
| 105 | 0.030 | 3.60 |
| 110 | 0.030 | 3.80 |
| 115 | 0.030 | 4.00 |
| 120 | 0.030 | 4.20 |
| 125 | 0.030 | 4.30 |
| 130 | 0.030 | 4.50 |
| 135 | 0.030 | 4.65 |
| 140 | 0.030 | 4.80 |
| 145 | 0.030 | 5.00 |
| 150 | 0.030 | 5.20 |
| 155 | 0.030 | 5.35 |
| 160 | 0.030 | 5.50 |
| 165 | 0.030 | 5.70 |
| 170 | 0.030 | 5.85 |
| 175 | 0.030 | 6.00 |
| 180 | 0.030 | 6.20 |
| 185 | 0.030 | 6.40 |
| 190 | 0.030 | 6.55 |
| 195 | 0.030 | 6.70 |
| 200 | 0.030 | 6.90 |
05
Mix ratios and site application conditions
Mix ratio by volume (polyol : isocyanate)
100:100
Mix ratio by weight
100:107
Component temperature
30–60 °C
Working pressure
60–120 bar
Ambient temperature
0 to 40 °C
Relative air humidity
< 90%
Wind speed
< 30 km/h
Substrate temperature
0–40 °C
Substrate moisture
No surface condensation
| Condition | Value in the 50W datasheet |
|---|---|
| Mix ratio by volume (polyol : isocyanate) | 100:100 |
| Mix ratio by weight | 100:107 |
| Component temperature | 30–60 °C |
| Working pressure | 60–120 bar |
| Ambient temperature | 0 to 40 °C |
| Relative air humidity | < 90% |
| Wind speed | < 30 km/h |
| Substrate temperature | 0–40 °C |
| Substrate moisture | No surface condensation |
Apply the system with dedicated spray equipment at the mix ratios above. Note that the substrate temperature in the 50W sheet starts at 0 °C, whereas it starts at 5 °C for 30W and 40W. The manufacturer’s recommendations do not relieve the applicator of reviewing the application method and running on-site trials whenever there is doubt about the system’s suitability for the project conditions.
06
Component properties and laboratory reactivity
The following values are given at 20 °C in the datasheet section on supplementary component information and reactivity:
Hydroxyl value
Polyol: 180–220 mg KOH
DIN-53240-2
Water content
Polyol: 2.4–2.6%
ISO 14897
Viscosity
Polyol: 420–650 mPa·s
Isocyanate: 180–250 mPa·s
INT-IT-17
NCO content
Isocyanate: 30–32%
UNE-92120-1
| Property | Polyol | Isocyanate | Standard |
|---|---|---|---|
| Hydroxyl value | 180–220 mg KOH | — | DIN-53240-2 |
| Water content | 2.4–2.6% | — | ISO 14897 |
| Viscosity | 420–650 mPa·s | 180–250 mPa·s | INT-IT-17 |
| NCO content | — | 30–32% | UNE-92120-1 |
| Cream time | 4 ± 1 s | EN 14315-1:2013 | |
| Thread (string) time | 11 ± 1 s | EN 14315-1:2013 | |
| Free-rise density | 45 g/L | EN 14315-1:2013 |
These are reference laboratory times; working times on site depend on component temperature, working pressure and ambient conditions within the declared ranges. The 50W sheet does not give a drying time.
07
Safety, storage, equipment cleaning and empty containers
Occupational safety
Component B of 50W spray foam contains isocyanates, so always follow the safety data sheet (MSDS): good ventilation and/or respiratory protection (combined organic vapour and particulate filters) together with protective clothing. Use the product only for the applications described in the datasheet; it is intended for industrial and professional use and is not suitable for DIY.
Storage
Store both components between 10 and 25 °C, always protected from moisture ingress. Under suitable storage conditions and in the original packaging, the maximum shelf life is 6 months from the date of manufacture.
Equipment cleaning
After application, clean the machine carefully to avoid contaminating the next system used on the same rig. Solvents are not recommended for cleaning machine parts; a plasticiser-based cleaning fluid such as Rayston Fluid is preferred. Remove component B completely from all parts exposed to air and replace it with cleaning fluid.
Empty containers and environment
Handle empty containers with the same precautions as full ones and hand them over as hazardous waste to a licensed waste manager. A and B can be mixed 1/1 to obtain an inert material, provided the quantity does not exceed 5 litres, to avoid a dangerous build-up of heat. Never mix residues with any other product without knowing the possible reactions.
08
50W spray polyurethane foam vs other Rayston grades: which one to choose?
Choosing a grade is a design decision governed by the application, density, λ, μ and any declared compressive requirements — not by the trade name alone. Within the 50W datasheet figures:
1
Water-blown with a numerically declared compressive strength, 48–56 kg/m³ density, λ = 0.030 → 50W is the direct candidate.
2
Closed cells > 90% with a stated compressive strength greater than 200 kPa and 48–55 kg/m³ density → see HFO 50.
3
5
Declared sound insulation with lightweight open cells → 8W, not 50W.
This section does not replace the building’s thermal calculation or the technical datasheet of the selected grade. For a side-by-side comparison of all seven grades, see the spray polyurethane foam guide.
09
50W spray polyurethane foam: FAQ
What is 50W spray foam, in short?
A two-component rigid polyurethane foam system (Rayston Spray Foam 50W) from Krypton Chemical, water-blown, with an applied density of 48–56 kg/m³ and a declared compressive strength, for spray-applied thermal insulation.
What is the declared thermal conductivity of 50W spray foam?
λ = 0.030 W/m·K to UNE-EN 12667, constant in the ageing table from 30 to 200 mm; use the R value in the target-thickness row.
What is the declared compressive strength?
The datasheet gives a value of 280 with a declared level of ≥ 200, and the designation code carries CS (10/Y)200. The declared use remains surfaces not subject to permanent loads.
Is 50W spray foam closed-cell?
Closed-cell content is declared as < 70% (with the note “does not allow water through”), and the designation code carries CCC2. For closed cells > 90%, see the HFO grades.
What is the correct mix ratio?
100:100 by volume and 100:107 by weight (polyol : isocyanate), with a component temperature of 30–60 °C and a working pressure of 60–120 bar.
What is the difference between 50W and HFO 50 spray foam?
Both are high-density grades (48–56 and 48–55 kg/m³), but 50W is water-blown with closed cells < 70% and λ = 0.030, while HFO 50 has closed cells > 90% and aged λ values between 0.028 and 0.025 depending on thickness.
What is the reaction-to-fire classification?
Euroclass E for all thicknesses, tested to UNE-EN 13823:2002; according to the CE marking block, reaction-to-fire performance does not deteriorate over time.
What is the shelf life and how should the components be stored?
Up to 6 months from the date of manufacture in the original packaging, with both components stored between 10 and 25 °C and fully protected from moisture.
10
Engineering summary
50W spray polyurethane foam (Rayston Spray Foam 50W) is the highest-density grade of Krypton Chemical’s water-blown line: applied density 48–56 kg/m³, declared λ of 0.030, constant in the ageing table from 30 to 200 mm, declared compressive strength 280 at level CS(10/Y)200, closed cells < 70%, μ ≥ 70, short-term water absorption ≤ 0.2 kg/m² and reaction to fire Euroclass E. Its declared use is spray-applied thermal insulation on surfaces not subject to permanent loads. Settle the final choice against the datasheet figures and the project thickness, and refer to the general guide to compare it with the other grades.
11
Related links
General guide
Grade articles
50W
Rayston Spray Foam 50W
| Grade | Trade name | Article |
|---|---|---|
| 8W | Rayston Spray Foam 8W | 8W spray foam |
| 30W | Rayston Spray Foam 30W | 30W spray foam |
| 40W | Rayston Spray Foam 40W | 40W spray foam |
| 50W | Rayston Spray Foam 50W | This article |
| HFO 35 | Rayston Spray Foam HFO 35 | HFO 35 spray foam |
| HFO 40 | Rayston Spray Foam HFO 40 | HFO 40 spray foam |
| HFO 50 | Rayston Spray Foam HFO 50 | HFO 50 spray foam |
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