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SAP 10.2 §2 lines (17a)/(18) "Air permeability value, AP4 (m³/h/m²)" (PDF p.12-13): > "The air permeability at 4 Pa (AP4) measured with the low-pressure > pulse technique [...] is used in the following formula to estimate > of the air infiltration rate at typical pressure differences. > In this case (9) to (16) of the worksheet are not used." > > Air infiltration rate (ach) = 0.263 × AP4^0.924 > > If based on air permeability value at 4 Pa, > then (18) = [0.263 × (17a)^0.924] + (8) SAP 10.2 §2 lines (23a)/(24c)/(25) "MEV" + "Whole-house extract ventilation" (PDF p.13/133): > "The SAP calculation is based on a throughput of 0.5 air changes per > hour through the mechanical system." (23a) = 0.5 > > If whole house extract ventilation or positive input ventilation > from outside: > if (22b)m < 0.5 × (23b), then (24c) = (23b) > otherwise (24c) = (22b)m + 0.5 × (23b) Cert 000565 lodges: - Summary §12.1 "Mechanical Ventilation Type: Mechanical extract, decentralised (MEV dc)" (PCDF 500755) - Summary §12.2 "Test Method: Pulse" + "Pressure Test Result (AP4): 2.00" Pre-slice both lodgements were silently dropped by the Elmhurst extractor / mapper / `cert_to_inputs` cascade: - AP4 had no schema field on `VentilationAndCooling` or `SapVentilation` even though `ventilation.py:ventilation_from_inputs(air_permeability_ ap4=...)` already implemented the spec formula. - Mechanical Ventilation Type had no schema field; `cert_to_inputs. ventilation_from_cert` hardcoded `mv_kind=MechanicalVentilationKind. NATURAL` regardless of the lodgement, routing cert 000565 through the (24d) natural-vent formula instead of (24c). These bugs are coupled: AP4 alone would close (18) but the cascade's (25) NATURAL pass-through would then *under*-count the effective ach by 0.25 (the missing MEV contribution). MEV alone would over-count because the (18) over-count remains. Per [[feedback-bigger-slices- for-uniform-work]] + handover precedent on coupling-aware reverts, these land together. Slice span (5 layers): 1. **Schema** — `VentilationAndCooling.air_permeability_ap4_m3_h_m2` + `VentilationAndCooling.mechanical_ventilation_type` (site-notes); `SapVentilation.air_permeability_ap4_m3_h_m2` + `SapVentilation.mechanical_ventilation_kind` (domain). 2. **Extractor** — `_extract_ventilation` parses "Pressure Test Result (AP4)" scoped to §12.2 and "Mechanical Ventilation Type" scoped to §12.1. Both default to None when the cert lodges no MV / no Pulse test (cohort modal case). 3. **Mapper** — `_map_elmhurst_ventilation` plumbs AP4 through; new `_ELMHURST_MV_TYPE_TO_KIND` dispatch with strict-raise on unmapped labels (per [[reference-unmapped-elmhurst-label]] mirror pattern). 4. **cert_to_inputs** — `ventilation_from_cert` reads AP4 and resolves `mechanical_ventilation_kind` name → `MechanicalVentilationKind` enum. MEV/MV/MVHR kinds set `mv_system_ach=0.5` per spec (23a). 5. **Tests** — 4 in test_summary_pdf_mapper_chain.py (extractor + mapper for both AP4 and MEV kind), 2 in test_cert_to_inputs.py (cascade AP4 formula + MEV kind dispatch). All AAA-structured. Cert 000565 movement (HEAD `83218630` → this slice): - cascade (18) pressure_test_ach: 2.4037 → 2.0287 ✓ EXACT vs ws 2.0287 - cascade (21) shelter-adj: 2.0431 → 1.7244 ✓ EXACT vs ws 1.7244 - cascade mean (25)m: 2.2347 → 2.1360 vs ws 2.086 (+0.05) - **sap_score (integer): 28 → 29 ✓ EXACT vs ws 29** (Δ−1 → Δ 0) - sap_score_continuous: 27.99 → 28.77 (Δ−0.52 → +0.26) - ecf: 5.44 → 5.36 (Δ+0.05 → −0.03) - total_fuel_cost_gbp: 4726.75 → 4657.37 (Δ+46 → Δ−23) - co2_kg_per_yr: 6506.48 → 6415.56 (Δ+59 → Δ−32) - **space_heating_kwh: +631 → −367** (~75% closed) - main_heating_fuel: +371 → −216 (~58% closed) - hot_water_kwh: ✓ 0 EXACT unchanged - lighting / pumps_fans: sub-spec residuals unchanged The residual cascade-over-by-0.05 ach on (25)m is the cascade using the cert-agnostic Table U2 wind tuple instead of the cert's regional wind lookup; future ventilation_from_cert wires a `postcode_climate` arg through which `cert_to_demand_inputs` already does for the demand cascade, but the SAP-rating cascade keeps the Table U2 default. Cohort safety: - All 21 other Elmhurst cohort fixtures lodge `pressure_test_method= "Not available"` and `mechanical_ventilation=False` → both new fields default to None → cascade behaviour unchanged. - 9 golden + 38 cohort-2 API certs route through `_map_sap_ventilation` (the API mapper variant), which leaves both new SapVentilation fields at their None default → cascade behaviour unchanged. Test baseline: 582 pass + 8 expected `000565` fails (was 575 + 9; +6 new tests + sap_score reclassified from fail to pass). 1763 pass in broader sap10_ml + worksheet + epc.domain suites + 3 pre-existing fails unchanged. Pyright net-zero per touched file (1/0/0/32/34→32/13/ 11 → 1/0/0/32/32/13/11, cert_to_inputs.py improved −2). Per [[project-sap10_ml-deprecation]] the new fields live on the existing `SapVentilation` domain type; no new modules under sap10_ml. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com> |
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| .. | ||
| epc | ||
| magicplan | ||
| __init__.py | ||
| datatypes.py | ||
| enums.py | ||