From cd94da4d2ea582ccff5ed875d1c54612ee6015bd Mon Sep 17 00:00:00 2001 From: Khalim Conn-Kowlessar Date: Sat, 23 May 2026 23:39:20 +0000 Subject: [PATCH] =?UTF-8?q?Slice=2026:=20=C2=A77=20LINE=5F92/93=20closure?= =?UTF-8?q?=20=E2=80=94=20RdSAP=20=C2=A715=20area=20rounding=20on=20living?= =?UTF-8?q?=20area?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit LINE_91 in the worksheet is `living_area / (4)`, where living_area itself is the §15-rounded materialisation of `Table 27 fraction × TFA`. RdSAP §9.2 (p.52): "The living area is then the fraction multiplied by the total floor area." §15 (p.66) lists "All internal floor areas and living area: 2 d.p." So the actual LINE_91 fed to the §7 zone blend is `round_half_up(Table_27 × TFA, 2) / TFA`, not the raw Table 27 entry. The roundtrip explains why the 4 holdout fixtures lodge LINE_91 = 0.3001 or 0.2501 instead of the Table 27 values 0.30 / 0.25: 000474: 0.30 × 56.79 → 17.04 / 56.79 = 0.3001 000477: 0.25 × 77.58 → 19.40 / 77.58 = 0.2501 000490: 0.25 × 66.06 → 16.52 / 66.06 = 0.2501 `_living_area_fraction` now takes TFA and materialises + rounds + divides; `_living_area_fraction_default` retains the bare Table 27 lookup. Existing `_round_half_up` from heat_transmission is the right utility (same §15 boundary, same half-up convention). Scoreboard: §7 cascade pins 52/60 → 60/60 (closes LINE_92/93 on 000474, 000477, 000480, 000490 — and tightens the already-passing 000487/000516 combinations). Full cascade: 304/312 → 312/312 (100%). e2e SapResult: 27/66 → 56/66 (continuous SAP, ECF, fuel cost, space heating kWh now close on 5/6 fixtures; 000487 still has unrelated downstream defects, all 6 CO2 fails await §12). Co-Authored-By: Claude Opus 4.7 --- .../src/domain/sap/rdsap/cert_to_inputs.py | 35 ++++++++++++++++--- 1 file changed, 30 insertions(+), 5 deletions(-) diff --git a/packages/domain/src/domain/sap/rdsap/cert_to_inputs.py b/packages/domain/src/domain/sap/rdsap/cert_to_inputs.py index 678d6b8c..7b19e8b4 100644 --- a/packages/domain/src/domain/sap/rdsap/cert_to_inputs.py +++ b/packages/domain/src/domain/sap/rdsap/cert_to_inputs.py @@ -84,6 +84,8 @@ from domain.sap.worksheet.solar_gains import ( from domain.sap.worksheet.heat_transmission import ( DwellingExposure, HeatTransmission, + _AREA_ROUND_DP, + _round_half_up, heat_transmission_from_cert, ) from domain.sap.climate.appendix_u import external_temperature_c @@ -348,9 +350,9 @@ def _is_timber_or_steel_frame(parts: list[SapBuildingPart]) -> bool: return isinstance(wc, int) and wc in (5, 6) -def _living_area_fraction(habitable_rooms_count: Optional[int]) -> float: - """RdSAP 10 Table 27 by `habitable_rooms_count`. Defaults to the - bottom of the table for ≥8 rooms; falls back to the SAP convention +def _living_area_fraction_default(habitable_rooms_count: Optional[int]) -> float: + """RdSAP 10 Table 27 (p.52) lookup by `habitable_rooms_count`. Defaults + to the bottom of the table for ≥8 rooms; falls back to the SAP convention 0.21 when count missing or zero.""" if not habitable_rooms_count or habitable_rooms_count <= 0: return _LIVING_AREA_FRACTION_DEFAULT @@ -359,6 +361,25 @@ def _living_area_fraction(habitable_rooms_count: Optional[int]) -> float: return _LIVING_AREA_FRACTION_MIN +def _living_area_fraction( + habitable_rooms_count: Optional[int], total_floor_area_m2: float +) -> float: + """SAP 10.2 §7 LINE_91 = Living area / TFA. + + RdSAP §9.2 (p.52): living area = Table 27 fraction × TFA. RdSAP §15 + (p.66) requires "All internal floor areas and living area: 2 d.p." at + the RdSAP→SAP boundary. So the materialised living area is rounded to + 2 d.p. half-up, then divided back by TFA to yield the LINE_91 that + feeds the §7 zone blend. This roundtrip is why fixtures lodge + e.g. 0.3001 (= 17.04/56.79) rather than the raw 0.30 Table 27 entry. + """ + fraction = _living_area_fraction_default(habitable_rooms_count) + if total_floor_area_m2 <= 0.0: + return fraction + living_area_m2 = _round_half_up(fraction * total_floor_area_m2, _AREA_ROUND_DP) + return living_area_m2 / total_floor_area_m2 + + def _window_total_area_and_avg_u(windows: list[SapWindow]) -> tuple[float, Optional[float]]: """Area-weighted total + U-value for the conduction worksheet.""" if not windows: @@ -877,7 +898,9 @@ def mean_internal_temperature_section_from_cert( total_floor_area_m2=dim.total_floor_area_m2, control_type=_control_type(main), responsiveness=_responsiveness(main), - living_area_fraction=_living_area_fraction(epc.habitable_rooms_count), + living_area_fraction=_living_area_fraction( + epc.habitable_rooms_count, dim.total_floor_area_m2 + ), control_temperature_adjustment_c=0.0, ) @@ -1407,7 +1430,9 @@ def cert_to_inputs( # for the Elmhurst corpus (cert-side mapping is a future slice). control_type_value = _control_type(main) responsiveness_value = _responsiveness(main) - living_area_fraction_value = _living_area_fraction(epc.habitable_rooms_count) + living_area_fraction_value = _living_area_fraction( + epc.habitable_rooms_count, dim.total_floor_area_m2 + ) monthly_total_gains_w = tuple( internal_gains_monthly_w[m] + solar_gains_monthly_w[m] for m in range(12) )