EN ISO 10211 & 13788 calculation verification

28/28 EN ISO 10211:2017 — 2D FEM basic correctness (Test reference case 1)

Validates fundamental FEM solver correctness — meshing, stiffness assembly, and boundary condition handling — against the standard's simplest published case: a homogeneous square column, split by symmetry, with fixed temperatures on three edges and an adiabatic symmetry plane on the fourth. All 28 published reference grid-point temperatures must match within 0.1°C.

Modules: fem_solver: 2.1.0, thermoplot: 10.1.0

10/10 EN ISO 10211:2017 — 2D FEM thermal bridge (Test reference case 2)

Validates the 2D finite element solver used for ψ-value junction calculations and 2D assembly thermal bridges. This is the standard's own published test case: a concrete slab penetrated by an aluminium bracket, insulated on one side — a realistic thermal bridge geometry with four different materials. All 9 published reference point temperatures and the total heat flow rate must match within the standard's required tolerances (0.1°C, 0.1 W/m).

Modules: fem_solver: 2.1.0, thermoplot: 10.1.0

4/4 2D interstitial condensation (vapour FEM) — cross-check against 1D Glaser

Validates the genuinely-2D interstitial condensation method against this app's own EN ISO 13788-validated 1D Glaser method, for a flat construction where both should agree exactly — the appropriate reference for a steady-state method generalised from 1D to 2D, not a transient/HAM benchmark built for different physics (see this function's own docstring).

Modules: fem_solver: 2.1.0, glaser: 1.1.0, interstitial_condensation: 1.1.0, uvalue_from_fem: 1.2.0, vapour_from_fem: 1.3.0

6/6 Magnus formula — saturation vapour pressure

The Magnus formula calculates the pressure at which water vapour saturates at a given temperature. This is the foundation of every Glaser condensation check — if the vapour pressure in the assembly exceeds the saturation pressure at any interface, condensation occurs. The reference values come directly from EN ISO 13788:2012 Annex C, where the standard itself publishes expected boundary condition pressures.

Modules: glaser: 1.1.0

9/9 Glaser method — EN ISO 13788:2012 Annex C.2, normal occupancy

The Glaser method checks whether water vapour will condense at any interface within a building assembly. This verifies the steady-state single-month implementation against the flat roof construction in EN ISO 13788:2012 Annex C.2 under normal occupancy conditions. The construction has an impermeable weatherproofing layer over insulation, which traps vapour and causes condensation in winter months. Reference values from EN13788_RESULTS.xlsx, table C.3 EN 13788.

Modules: glaser: 1.1.0

8/8 Glaser annual cycle — EN ISO 13788:2012 Annex C.2, normal occupancy

The full annual cycle tracks moisture accumulation and drying over 12 months. This verifies the monthly condensation rates and accumulated moisture content against the published reference values in EN ISO 13788:2012 table C.3. The assembly must dry out completely by end of year to pass. Tolerance ±0.00003 kg/m² — the published table rounds to 5 decimal places.

Modules: glaser_annual: 1.3.0

9/9 Glaser — EN ISO 13788:2012 Annex C.5, warm humid climate

Annex C.5 analyses a timber-framed wall in a warm humid climate — conditions where condensation risk occurs in summer rather than winter, as warm moist external air drives vapour inward through the brick outer leaf. This tests that the implementation correctly handles reversed vapour drive. Reference values from EN13788_RESULTS.xlsx, table C.3 EN 13788. Tolerance ±0.005 kg/m² — this table's own values are published to only 4 decimal places, a coarser source precision than Annex C.2's.

Modules: glaser: 1.1.0, glaser_annual: 1.3.0

7/7 Glaser — EN ISO 13788:2012 Annex C.6, layer subdivision

Annex C.6 demonstrates the layer subdivision requirement in ISO 13788 section 6.4.1 — any layer with thermal resistance R > 0.25 m²K/W must be subdivided to locate condensation accurately within the layer. This blockwork wall requires the blockwork (R=2.5 m²K/W) to be divided into 10 sublayers and the insulation (R=0.5 m²K/W) into 2. The climate is a harsh continental winter (−10°C/95% RH January) from the TRISCO project file C6_HUMID.trc. Note: our interface-only method gives gc≈78% of the TRISCO reference. Unlike Annex C.2/C.5 above, this isn't a numeric tolerance on the same quantity — TRISCO is a fully subdivided-layer reference solution, and this method's own condensation-rate figure is expected to differ from it by up to roughly 30% while still correctly identifying WHETHER condensation occurs each month, which is what the checks below verify. Reference values from EN13788_RESULTS.xlsx, table C.12 EN 13788.

Modules: glaser_annual: 1.3.0

6/6 ISO 6946:2017 — U-value, wall (horizontal heat flow)

ISO 6946:2017 defines the simple summation method for calculating thermal transmittance (U-value) of uniform building assemblies: U = 1 / (Rsi + ΣR + Rse), where each layer's resistance R = thickness / thermal conductivity. For walls, Rsi=0.13 m²K/W and Rse=0.04 m²K/W per ISO 6946:2017 Table 1 (horizontal heat flow). All expected values are derived from first principles — independently verifiable with a calculator.

Modules: uvalue_base: 2.0.0, uvalue_wall: 1.0.0

3/3 ISO 6946:2017 — U-value, roof (upward heat flow)

Roofs use upward heat flow boundary conditions: Rsi=0.10 m²K/W and Rse=0.04 m²K/W per ISO 6946:2017 Table 1. The lower internal surface resistance (0.10 vs 0.13 for walls) reflects the reduced convective resistance when heat flows upward. This means a roof with identical insulation to a wall will have a slightly higher U-value.

Modules: uvalue_base: 2.0.0, uvalue_roof: 1.0.0, uvalue_wall: 1.0.0

3/3 ISO 6946:2017 — U-value, exposed floor (downward heat flow)

Exposed suspended floors use downward heat flow boundary conditions: Rsi=0.17 m²K/W and Rse=0.04 m²K/W per ISO 6946:2017 Table 1. Downward heat flow has the highest internal surface resistance because warm air rises — convection does not assist heat transfer through a floor in the downward direction. This means an exposed floor with identical insulation to a wall will have a lower U-value.

Modules: uvalue_base: 2.0.0, uvalue_floor: 1.0.0, uvalue_wall: 1.0.0

5/5 ISO 13370:2017 — U-value, ground floor (slab-on-ground)

Ground floors cannot use the simple ISO 6946 summation because heat flows laterally through the ground before reaching the external environment. ISO 13370:2017 uses an 'equivalent thickness' method: B' = A/(0.5P) is the characteristic floor dimension, dt = w + λg(Rsi+Rf+Rse) is the equivalent thickness, and the U-value formula depends on whether dt < B' (shallow — equation 5) or dt ≥ B' (deep — equation 6). All expected values derived from first principles using the published equations.

Modules: uvalue_ground: 2.0.0

6/6 ISO 13370 Annex G — suspended ground floor (Tu, ventilation)

The underfloor space temperature Tu is ISO 13370 Annex G equation G.1 — a weighted heat-balance average of Ti/Tve/Te. Checked directly against Physibel's own official reference spreadsheet's worked example, not derived from first principles alone.

Modules: uvalue_ground: 2.0.0

15/15 BR 497 Appendix B — Worked Example 3 (E1 steel lintel with perforated base-plate)

The published worked example that exercises the most conventions at once. The perforated base-plate's equivalent conductivity is solved from its own repeat model per §2.3.1 rather than quoted; the three lintel air spaces keep their real drawn shapes, per §2.4.3, carrying their Table B3b equivalent conductivities — themselves resolved by Psiclops rather than transcribed, and checked here against Table B3b; surface resistances follow Table B3a. Checked against the standard's own declared psi = 0.42 W/m·K and fRsi = 0.75, and against its flanking wall U-value of 0.330 W/m²K.

Modules: fem_solver: 2.1.0, frsi_from_fem: 2.1.0, psi_from_fem: 1.12.0, uvalue_from_fem: 1.2.0