Built to Last: IPX8 Seal, A4-80 Bolt & Fire Safety
Every SolVe Mount carries a 20-year warranty. Behind that promise is a verified engineering case — drawn from the SolVe Mount Design Report (SOL-DO-P2301-300-2) and the IPX8 Test Report (SOL-DO-P2301-300-4). Every figure below traces to one of those documents, to the applicable standard, or to basic physics.
Key Takeaways
tested to IPX8 — submerged 1 m under water for an extended period with no leakage observed
8.2× pressure margin — the IPX8 seal withstands 8.2 times the dynamic wind pressure of a 50-year return-period UK storm
VMQ silicone rated −50 °C to +200 °C, UV stable, fire resistant, and watertight under mechanical compression
A4-80 bolt — 33% higher proof strength and 14% higher tensile strength than A2-70 (common solar mounting grade), plus superior corrosion resistance
Eurocode 5 verified — meets strength and serviceability requirements with adequate safety margins
MCS 012 3.0 certified — does not reduce the fire rating of the roof
Table of Contents
1. What IPX8 Really Means
IEC 60529 defines the IP (Ingress Protection) rating system. The "X" in IPX8 means the dust rating is unspecified; the "8" is the highest standard liquid-ingress protection level in the code.
To achieve IPX8, a product must be suitable for continuous immersion in water at a depth and duration agreed between manufacturer and user — with a minimum depth of 1 m. This is not a splash-proof or rain-proof rating: it is full submersion protection.
The SolVe Mount is tested to IPX8 (Design Report, Product Overview). The internal test performed to procedure SOL-DO-P2301-100-6 confirmed this:
IPX8 Test Results (SOL-DO-P2301-300-4)
1-Hour Continuous Immersion — PASSED
No leakage, seepage, or signs of moisture ingress were observed.
1-Month Continuous Immersion — PASSED
Throughout the extended duration, no leakage or degradation of sealing performance was observed.
The test conclusion states: "The sealing system demonstrated effective and sustained resistance to water ingress. The test therefore meets the acceptance criteria and is deemed to have PASSED."
2. The Pressure Comparison
To understand what IPX8 means in practical roofing terms, compare the water pressure the seal withstands during the test with the dynamic wind pressure it faces in a severe UK storm.
Scenario
Pressure
Source / Basis
IPX8 test — 1 m water depth
≈ 9.8 kPa
ρgh = 1,000 × 9.81 × 1 m (IEC 60529 minimum test depth)
Wind-driven rain at 100 mph (50-year return period)
The SolVe seal would need to lose approximately 88% of its sealing force before wind-driven rain at the 50-year return-period extreme — 100 mph, the structural design wind defined in BS EN 1991-1-4 Section 4.2 (annual exceedance probability 0.02) — could pose any risk of ingress. The seal has been immersion-tested for a full month at this pressure level and passed with no degradation observed.
Note: The 9.8 kPa and 1.2 kPa figures are derived from physics (hydrostatic and Bernoulli equations). The 100 mph reference wind speed corresponds to the 50-year return period defined in BS EN 1991-1-4 §4.2 for UK structural wind loading.
3. The VMQ Silicone Seal
The seal material is VMQ — Vinyl-Methyl Silicone Rubber, designated per ISO 1629 (Design Report, Material Mechanical Properties). The specific compound is proprietary and its formulation is not disclosed (Design Report).
The Design Report (Material Durability section) documents the following properties:
VMQ Silicone Properties (Design Report)
Temperature Range
−50 °C to +200 °C
UV Stability
Resistant to UV degradation
Fire Resistance
Fire resistant (see Section 6)
Watertight Sealing
Watertight sealing under mechanical compression
The seal achieves its waterproof performance mechanically — by expanding under compression to fill the cored hole from the inside — rather than relying on site-applied sealants. This is a key architectural decision documented in the Design Report.
4. A4-80 Marine-Grade Stainless Steel
The hanger bolt is the single structural connection between the solar rail above and the roof rafter below. SolVe specifies a single bolt — the A4-80, 200 mm hanger bolt (Design Report, Material Mechanical Properties, ISO 3506-1):
Bolt
Length
Grade
Proof Strength (fy)
Tensile Strength (fu)
SolVe Hanger Bolt
200 mm
A4-80
600 MPa
800 MPa
A2-70 (typical solar mounting grade)
—
A2-70
450 MPa
700 MPa
Properties per ISO 3506-1. A2-70 shown for comparison only; not specified in the SolVe Design Report.
Compared with A2-70 (the grade commonly used in standard solar mounting hardware), the SolVe A4-80 bolt offers:
33% higher proof strength — 600 MPa vs 450 MPa
14% higher tensile strength — 800 MPa vs 700 MPa
Beyond raw strength, the grade difference matters for corrosion. The A4 designation means the alloy is 316 stainless steel, which contains molybdenum. A2 (304 stainless) does not. Molybdenum significantly improves resistance to chloride-induced pitting — the dominant corrosion mechanism in coastal and marine environments.
Corrosion Category: C3–C5
All metallic components are fully corrosion-resistant under atmospheric and coastal exposure conditions, compliant with EN 1993-1-4 Table A.3 (corrosion category C3–C5 — urban to coastal/marine atmospheric environments). (Design Report, Material Durability)
Dissimilar metal contact — a common source of galvanic corrosion in roof penetrations — is mitigated by eliminating dissimilar metals throughout the assembly (Design Report, Material Durability).
5. Structural Verification
The hanger bolt-to-rafter connection has been analytically verified to the following framework (Design Report, Calculations & Analysis):
Design code: EN 1995-1-1 (Eurocode 5) for timber fasteners
Timber grade: C24 structural timber
Service class: Service Class 2 (covered, but exposed to occasional wetting)
Wind loads: EN 1991-1-4; dead loads: EN 1991-1-1
Analysis method: Hand calculations supplemented by Finite Element Analysis (FEA)
Fastener properties: Based on ISO 3506-1 and ISO 3506-2 characteristic yield and tensile strengths for A4-80 grade
Design Report Conclusion — Verbatim
"The results presented in this section demonstrate that the hanger bolt-to-timber connection meets the strength and serviceability requirements of the relevant Eurocodes, with adequate safety margins against withdrawal, shear failure, and timber crushing under the most adverse loading combinations."
6. Fire Safety
The SolVe Mount creates an airtight VMQ seal — no open air void is left in the roof covering. Because the seal is fully airtight, the fire performance of the roof is not compromised, and the fire rating is preserved in full.
The SolVe Mount is MCS 012 3.0 certified. The VMQ silicone compound also carries a fire resistance property as documented in the Design Report (Material Durability section).
Building Regulations Approved Document B — Section B4 (External Fire Spread)
Does Not Lower the Fire Rating of the Roof
UK Building Regulations Approved Document B, Section B4 requires that roof coverings adequately resist external fire spread, classified under BS EN 13501-5 (BRoof(t4) being the required performance class for residential roofs). MCS 012 3.0 — the certification standard for solar mounting systems — explicitly requires that the fire performance of the roof is not compromised by the installation.
The airtight VMQ seal leaves no air void in the roof covering. The mount does not penetrate or degrade the fire-rated layer, and the fire classification of the roof is fully preserved.
✓ Installers can fit SolVe Mount without any fire rating caveats to declare on handover.
Per UK Building Regulations 2010, Approved Document B (2025 ed.); BS EN 13501-5:2016; MCS 012 3.0.
7. The 20-Year Warranty
The 20-year SolVe Mount warranty is backed by the verified engineering properties described above: an IPX8-rated seal that has passed a full month of continuous immersion testing; a marine-grade A4-80 bolt rated for coastal environments (C3–C5); a VMQ silicone compound resistant to UV, thermal cycling, and fire; and a structural connection verified to Eurocode 5 with adequate safety margins.
The SolVe Promise
Fit & Forget Reliability
A roof penetration rated to IPX8. Verified to Eurocode 5. Certified to MCS 012 3.0. Fire-safe to Approved Document B. Install it once — no maintenance, no revisits, no callbacks.
Watertight
IPX8 — passed 30 days continuous immersion
Structural
Eurocode 5 verified with adequate safety margins
Fire Safe
Does not lower the fire rating of the roof
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