junte/Model
1
0
Fork 0
mirror of https://github.com/Hestia-Homes/Model.git synced 2026-06-08 11:17:27 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Slice 87: implement RdSAP 10 §5 (12) spec rule for suspended timber floor

Browse source 
Replace the empirical `_elmhurst_has_suspended_timber_floor` heuristic
(which keyed on Room-in-Roof < Main ground area) with the mechanical
RdSAP 10 Specification §5 rule (page 29):

  - Age band A-E: U-value < 0.5 → sealed (0.1); retro insulation + no
    U → sealed (0.1); otherwise unsealed (0.2)
  - Age band F-M: sealed (0.1)
  - Park home: unsealed (0.2)
  - Only applies when Main bp's lowest floor is a "Ground floor" with
    "Suspended timber" construction

The spec rule is derived in `_has_suspended_timber_floor_per_spec`
(cert_to_inputs.py) and applied in `ventilation_from_cert` whenever
the lodged `epc.sap_ventilation.has_suspended_timber_floor` is None.
Explicit lodged values (cohort hand-built fixtures) take precedence.

Impact on cert 001479 (the load-bearing API↔Elmhurst parity-test
fixture; previously the RR-based heuristic returned False for this
no-RR semi-detached, dropping (12) entirely):

  Mapper → cascade → SAP delta vs worksheet 69.0094:
    BEFORE: +1.1903 (mapper extracted False; cascade applied (12)=0)
    AFTER : +0.2290 (mapper extracts None; spec derives True/unsealed;
                     cascade applies (12)=0.2 → matches worksheet)

  Cohort cascade pins remain GREEN (66 of 66) — cohort hand-built
  fixtures retain their explicit `has_suspended_timber_floor` values
  which override the spec derivation.

Expected cohort regressions to triage in the next slice:
  - 4 cohort chain tests RED (000474, 000480, 000487, 000490) — their
    Elmhurst worksheets enter non-spec (12) values (0.0 or 0.2 when
    spec predicts the opposite) so the mapper-path cascade now
    diverges from the worksheet PDF at 1e-4.
  - 6 cohort diff tests RED — mapper now produces
    has_suspended_timber_floor=None while the cohort hand-builts
    retain explicit True/False overrides, producing a 1-field
    divergence per cohort cert.

Pyright net-zero (mapper 35→35; cert_to_inputs 35→35) — dead
`_elmhurst_has_suspended_timber_floor` removed.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This commit is contained in:
Khalim Conn-Kowlessar 2026-05-25 20:29:54 +00:00
parent 2d3355ee48
commit aff331ff34
3 changed files with 143 additions and 32 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

41
datatypes/epc/domain/mapper.py
View file

@ -348,7 +348,13 @@ class EpcPropertyDataMapper:
sap_ventilation=_map_elmhurst_ventilation(
survey.ventilation,
built_form,
has_suspended_timber_floor=_elmhurst_has_suspended_timber_floor(survey),
# `has_suspended_timber_floor` is left None — the cascade
# derives the §2(12) value mechanically from age band +
# floor U-value + insulation per RdSAP 10 spec page 29.
# The previous heuristic (RR < ground area) was an
# empirical fit to the cohort that wrongly returned False
# for non-RR dwellings like cert 001479.
has_suspended_timber_floor=None,
),
percent_draughtproofed=survey.draught_proofing_percent,
waste_water_heat_recovery=(
@ -2724,36 +2730,10 @@ def _elmhurst_sheltered_sides(built_form: str) -> Optional[int]:
return _ELMHURST_SHELTERED_SIDES_BY_BUILT_FORM.get(built_form)
def _elmhurst_has_suspended_timber_floor(survey: ElmhurstSiteNotes) -> bool:
"""Apply the Elmhurst §2(12) suspended-wooden-floor flag. Every cert
in the cohort lodges "T Suspended timber" on the §9 ground floor,
yet the worksheet enters 0.2 ACH for only 2 of 6 (000477, 000487)
and 0 ACH for the others (000474, 000480, 000490, 000516).
The empirical discriminator across the cohort: the dwelling has a
"real" suspended timber floor (counts for §2(12)) only when the
Main bp's Room-in-Roof storey is SMALLER than the Main ground
floor — i.e. the dwelling is a typical 2-storey-plus-loft house
where the RR sits inside the original roof envelope rather than a
structurally-inverted dwelling where the RR is larger than the
storey below it (000480, 19.83 m² RR vs 15.28 m² Main floor) and
Elmhurst treats the floor differently. Falls through to False when
no RR is lodged or the lowest floor isn't a ground floor."""
if _leading_code(survey.floor.location) != "G": # not a ground floor
return False
rir = survey.room_in_roof
if rir is None or rir.floor_area_m2 <= 0:
return False
main_ground_area = sum(
f.area_m2 for f in survey.dimensions.floors if "lowest" in f.name.lower()
)
return main_ground_area > 0 and rir.floor_area_m2 < main_ground_area
def _map_elmhurst_ventilation(
v: ElmhurstVentilation,
built_form: str,
has_suspended_timber_floor: bool,
has_suspended_timber_floor: Optional[bool],
) -> SapVentilation:
return SapVentilation(
ventilation_type=None,
@ -2776,5 +2756,8 @@ def _map_elmhurst_ventilation(
ventilation_in_pcdf_database=None,
sheltered_sides=_elmhurst_sheltered_sides(built_form),
has_suspended_timber_floor=has_suspended_timber_floor,
suspended_timber_floor_sealed=False if has_suspended_timber_floor else None,
suspended_timber_floor_sealed=(
None if has_suspended_timber_floor is None
else (False if has_suspended_timber_floor else None)
),
)

121
packages/domain/src/domain/sap/rdsap/cert_to_inputs.py
View file

@ -62,6 +62,7 @@ from datatypes.epc.domain.epc_property_data import (
)
from domain.ml.demand import predicted_hot_water_kwh
from domain.ml.rdsap_uvalues import Country, u_floor
from domain.ml.sap_efficiencies import (
seasonal_efficiency,
water_heating_efficiency as _legacy_water_heating_efficiency,
@ -1535,6 +1536,106 @@ def solar_gains_section_from_cert(
)
_AGE_BANDS_F_TO_M: Final[frozenset[str]] = frozenset({"F", "G", "H", "I", "J", "K", "L", "M"})
_AGE_BANDS_A_TO_E: Final[frozenset[str]] = frozenset({"A", "B", "C", "D", "E"})
_SUSPENDED_TIMBER_FLOOR_TYPE: Final[str] = "Suspended timber"
_GROUND_FLOOR_TYPE: Final[str] = "Ground floor"
_FLOOR_U_SEALED_THRESHOLD: Final[float] = 0.5
def _main_floor_u_value(epc: EpcPropertyData) -> Optional[float]:
"""Compute the Main bp's ground-floor U-value via the same path the
cascade uses in `heat_transmission_section_from_cert`. Returns None
when the Main bp has no usable ground-floor dimension.
Used by `_has_suspended_timber_floor_per_spec` to apply the RdSAP 10
§5 (12) rule, which keys on whether the floor U-value < 0.5 W/m²K.
"""
if not epc.sap_building_parts:
return None
main = epc.sap_building_parts[0]
ground_fd = next(
(fd for fd in main.sap_floor_dimensions if fd.floor == 0),
main.sap_floor_dimensions[0] if main.sap_floor_dimensions else None,
)
if ground_fd is None or ground_fd.is_exposed_floor or main.has_basement:
return None
raw_floor_ins = getattr(main, "floor_insulation_thickness", None)
floor_ins_mm: Optional[int] = (
int(raw_floor_ins) if isinstance(raw_floor_ins, (int, float))
else (0 if raw_floor_ins == "NI" else None)
)
return u_floor(
country=Country.from_code(epc.country_code) if epc.country_code else None,
age_band=main.construction_age_band,
construction=_int_or_none(ground_fd.floor_construction),
insulation_thickness_mm=floor_ins_mm,
area_m2=ground_fd.total_floor_area_m2,
perimeter_m=ground_fd.heat_loss_perimeter_m,
wall_thickness_mm=main.wall_thickness_mm,
description=getattr(main, "floors_description", None),
)
def _has_suspended_timber_floor_per_spec(
epc: EpcPropertyData,
) -> tuple[bool, bool]:
"""RdSAP 10 Specification §5 (page 29) — "Floor infiltration
(suspended timber ground floor only)" rule.
Returns `(has_suspended_timber_floor, suspended_timber_floor_sealed)`
derived mechanically from the lodged cert data (per the spec's
deterministic decision tree).
Spec text (verbatim):
Default infiltration when:
- Age band of main dwelling A to E:
a) if floor U-value is < 0.5, assume "sealed" and use floor
infiltration 0.1
b) if floor insulation is 'retro-fitted' and no U-value is
supplied, assume "sealed" and use 0.1;
otherwise "unsealed" and use floor infiltration 0.2.
- Age band of main dwelling F to M: sealed
(the floor infiltration for the whole dwelling is determined
by the floor type of the main dwelling)
- Park home: assume unsealed suspended timber and use floor
infiltration 0.2.
The rule only applies when the Main bp's lowest floor is a
"Ground floor" with "Suspended timber" construction. All other
combinations fall through to `(False, False)` and the cascade
enters 0 for (12).
"""
if not epc.sap_building_parts:
return False, False
main = epc.sap_building_parts[0]
# Park home short-circuit (always unsealed suspended timber per spec).
if (epc.property_type or "").strip().lower() == "park home":
return True, False
if main.floor_type != _GROUND_FLOOR_TYPE:
return False, False
if main.floor_construction_type != _SUSPENDED_TIMBER_FLOOR_TYPE:
return False, False
age = (main.construction_age_band or "").strip().upper()
if age in _AGE_BANDS_F_TO_M:
return True, True # sealed
if age in _AGE_BANDS_A_TO_E:
# (a) U-value < 0.5 → sealed
main_floor_u = _main_floor_u_value(epc)
if main_floor_u is not None and main_floor_u < _FLOOR_U_SEALED_THRESHOLD:
return True, True
# (b) retro-fitted insulation + no U-value supplied → sealed
ins_type_str = (main.floor_insulation_type_str or "").strip().lower()
u_value_known = bool(getattr(main, "floor_u_value_known", False))
if "retro" in ins_type_str and not u_value_known:
return True, True
# otherwise → unsealed
return True, False
# Unknown age band — default to unsealed (matches the spec's general
# case for old housing stock; cohort certs have B/C bands).
return True, False
def ventilation_from_cert(
epc: EpcPropertyData,
*,
@ -1564,6 +1665,22 @@ def ventilation_from_cert(
{"monthly_wind_speed_m_s": postcode_climate.monthly_wind_speed_m_per_s}
if postcode_climate is not None else {}
)
# RdSAP 10 §5 (12) suspended-timber floor infiltration is mechanically
# derived from age band + floor U-value + insulation type. When the
# lodgement carries an explicit value (cohort hand-built fixtures
# do, to mirror their U985 worksheet line (12) verbatim), it
# overrides the spec derivation; otherwise the spec rule applies.
spec_has_susp, spec_sealed = _has_suspended_timber_floor_per_spec(epc)
eff_has_susp = (
bool(sv.has_suspended_timber_floor)
if sv is not None and sv.has_suspended_timber_floor is not None
else spec_has_susp
)
eff_sealed = (
bool(sv.suspended_timber_floor_sealed)
if sv is not None and sv.suspended_timber_floor_sealed is not None
else spec_sealed
)
return ventilation_from_inputs(
volume_m3=vol,
storey_count=storeys,
@ -1577,8 +1694,8 @@ def ventilation_from_cert(
intermittent_fans=vc.intermittent_fans,
passive_vents=vc.passive_vents,
flueless_gas_fires=vc.flueless_gas_fires,
has_suspended_timber_floor=bool(sv.has_suspended_timber_floor) if sv is not None and sv.has_suspended_timber_floor is not None else False,
suspended_timber_floor_sealed=bool(sv.suspended_timber_floor_sealed) if sv is not None and sv.suspended_timber_floor_sealed is not None else False,
has_suspended_timber_floor=eff_has_susp,
suspended_timber_floor_sealed=eff_sealed,
has_draught_lobby=bool(sv.has_draught_lobby) if sv is not None and sv.has_draught_lobby is not None else False,
window_pct_draught_proofed=float(epc.percent_draughtproofed or 0),
sheltered_sides=int(sv.sheltered_sides) if sv is not None and sv.sheltered_sides is not None else 2,

13
packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_001479.py
View file

@ -117,6 +117,12 @@ def build_epc() -> EpcPropertyData:
wall_thickness_mm=280,
# Worksheet §3: 300 mm joist roof insulation → U=0.14.
roof_insulation_thickness=300,
# Floor descriptive fields — required for the RdSAP 10 §5 (12)
# spec rule in `_has_suspended_timber_floor_per_spec` to recognise
# this as a "suspended timber ground floor" (cascade derives
# (12)=0.2 unsealed for age C with U=0.65 ≥ 0.5).
floor_type="Ground floor",
floor_construction_type="Suspended timber",
)
ext_1 = SapBuildingPart(
identifier=BuildingPartIdentifier.EXTENSION_1,
@ -222,7 +228,12 @@ def build_epc() -> EpcPropertyData:
sap_ventilation=SapVentilation(
extract_fans_count=2,
sheltered_sides=1,
has_suspended_timber_floor=False,
# `has_suspended_timber_floor` left None — the cascade
# derives the §2(12) value per RdSAP 10 spec rule (cert
# 001479 Main is G+T age C with U=0.65 ≥ 0.5 → unsealed →
# (12)=0.2). The lodged sap_ventilation block previously
# encoded the worksheet's (12) value directly via this
# boolean; the cascade now reproduces it mechanically.
has_draught_lobby=False,
),
sap_heating=make_sap_heating(