S0380.193: suspended-floor (12) sealed rule fires only on a SUPPLIED U-value

RdSAP 10 §5 (PDF p.29) "Floor infiltration (suspended timber ground
floor only)", age band A-E, splits on whether a floor U-value is
supplied:
  a) [U-value supplied] if floor U-value < 0.5 → "sealed", (12) = 0.1
  b) [no U-value supplied] retro-fitted insulation → "sealed" 0.1;
     otherwise "unsealed", (12) = 0.2

`_has_suspended_timber_floor_per_spec` fed the cascade's COMPUTED default
U into rule (a), so an as-built/uninsulated suspended-timber floor whose
default U happens to be < 0.5 was marked "sealed" (0.1) where Elmhurst
uses "unsealed" (0.2). That dropped (18) infiltration 0.85 → 0.75, (25)
effective ACH, HTC, and understated space heating ~450 kWh.

Fix: gate rule (a) on `floor_u_value_known` — a computed default U is not
a supplied value, so it falls through to (b). Verified against the
cert 001431 sim-case-2 worksheet: floor "As built", U=0.43 (matches the
worksheet's (28a) 0.4300 exactly), (12)=0.2 unsealed. Golden cert 6035
(also a suspended uninsulated floor) is unaffected — its U=0.63 ≥ 0.5
already routed to unsealed.

Promotes sim case 2 to the e2e harness as `001431_rr` (Main + Extension
+ Simplified room-in-roof — the 6035 archetype). All 11 Block-1 line
refs pin at abs=1e-4, locking BOTH this fix and S0380.192 (Simplified-RR
remaining area) end-to-end: SAP 69, cost 920.5046, CO2 4566.7090, space
15269.8593, main fuel 18178.4039. 2319 passed (+11), 0 failed; pyright
net-zero.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

domain/sap10_calculator/rdsap/cert_to_inputs.py

@@ -4103,13 +4103,27 @@ def _has_suspended_timber_floor_per_spec(
     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))
+        # (a) a SUPPLIED floor U-value < 0.5 → sealed. RdSAP 10 §5 (PDF
+        # p.29) splits (a)/(b) on whether a U-value is supplied: (a) is
+        # the "U-value supplied" branch, (b) the "no U-value is supplied"
+        # branch. A computed default U (an assumed / as-built uninsulated
+        # floor) is NOT a supplied value, so it must NOT trigger (a) — it
+        # falls through to (b). Without this gate the cascade marked an
+        # as-built suspended-timber floor with default U=0.43 "sealed"
+        # (0.1) where Elmhurst uses "unsealed" (0.2) — cert 001431 sim
+        # case 2 worksheet (12)=0.2, dropping (25) effective ACH and
+        # understating space heating ~450 kWh.
+        main_floor_u = _main_floor_u_value(epc)
+        if (
+            u_value_known
+            and main_floor_u is not None
+            and main_floor_u < _FLOOR_U_SEALED_THRESHOLD
+        ):
+            return True, True
+        # (b) no U-value supplied: retro-fitted insulation → sealed;
+        # otherwise unsealed.
+        ins_type_str = (main.floor_insulation_type_str or "").strip().lower()
         if "retro" in ins_type_str and not u_value_known:
             return True, True
         # otherwise → unsealed

tests/domain/sap10_calculator/worksheet/_elmhurst_worksheet_001431_rr.py

@@ -0,0 +1,124 @@
+"""Mapper-driven cascade pin against the Elmhurst P960-0001-001431
+"simulated case 2" worksheet — a Main + Extension dwelling with a
+Simplified room-in-roof (the 6035 archetype, more complete than sim
+case 1).
+
+Like 000565 / sim case 1, this fixture does NOT hand-build the
+EpcPropertyData: it routes the Summary PDF through
+ElmhurstSiteNotesExtractor + from_elmhurst_site_notes so the SAP-result
+pin grid exercises the WHOLE extractor + mapper + calculator pipeline.
+
+This cert surfaced two real cascade bugs (both fixed; this fixture pins
+them end-to-end at 1e-4):
+
+  S0380.192 — Simplified room-in-roof. The Summary lodges placeholder
+    slope/ceiling Length/Height cells (a 40 m ceiling height, a 32 m
+    slope on a 4.65 m gable). RdSAP 10 §3.9.1 derives one timber-framed
+    "remaining area" from the floor area instead
+    (A_RR = 12.5√(A_floor/1.5) − Σgables = 32.89 m²). Emitting the
+    placeholders as detailed_surfaces billed 1024 + 160 m² of explicit
+    roof area → a 7.5× fabric-heat-loss explosion (SAP −14.6). Fixed by
+    dropping roof-going surfaces for Simplified assessments so the
+    cascade's residual formula fires.
+
+  S0380.193 — Suspended-timber-floor "sealed/unsealed" infiltration.
+    RdSAP 10 §5 (PDF p.29) line (12): rule (a) ("U-value < 0.5 → sealed
+    0.1") applies only when a floor U-value is SUPPLIED. This cert's
+    floor is as-built/uninsulated (default U=0.43, not supplied), so it
+    falls to rule (b) → unsealed 0.2. The cascade was feeding the
+    computed default U into rule (a) → sealed 0.1 → (25) effective ACH
+    dropped → space heating understated ~450 kWh.
+
+Source: user-simulated PDFs at `sap worksheets/golden fixture
+debugging/simulated case 2/`. The Summary is mirrored into the tracked
+`backend/documents_parser/tests/fixtures/Summary_001431_rr_ext.pdf`
+(distinct name — the corpus reuses cert 001431; sim case 1 is the
+single-part gas-combi variant) so the test runs without depending on
+the unstaged workspace.
+
+Cert shape: Main + Extension 1, both solid brick WITH internal
+insulation (Main) / as-built (Ext1), 3 storeys, Simplified room-in-roof
+on the Main (floor 29.75 m², exposed + party gables), suspended
+uninsulated ground floors, gas-combi SAP code 104, no PV.
+
+Worksheet pin targets (P960-0001-001431, Block 1 — energy rating):
+- SAP rating 69 (line 258), ECF 2.2395 (line 257)
+- Total fuel cost £920.5046 (line 255)
+- CO2 4566.7090 kg/year (line 272)
+- Space heating 15269.8593 kWh/year (Σ monthly (98))
+- Main 1 fuel 18178.4039 kWh/year (line 211)
+- Secondary fuel 0.0 (line 215)
+- Hot water fuel 3308.6172 kWh/year (line 219)
+- Lighting 282.6414 kWh/year (line 232)
+- Pumps/fans 86.0 kWh/year (line 231)
+
+Per [[feedback-zero-error-strict]] + [[feedback-e2e-validation-
+philosophy]]: pins are abs=1e-4 against the worksheet PDF.
+"""
+
+from __future__ import annotations
+
+import re
+import subprocess
+from pathlib import Path
+from typing import Final
+
+from backend.documents_parser.elmhurst_extractor import ElmhurstSiteNotesExtractor
+from datatypes.epc.domain.epc_property_data import EpcPropertyData
+from datatypes.epc.domain.mapper import EpcPropertyDataMapper
+
+
+# parents[0]=worksheet/, [1]=sap10_calculator/, [2]=domain/, [3]=tests/,
+# [4]=repo root.
+_SUMMARY_PDF: Final[Path] = (
+    Path(__file__).resolve().parents[4]
+    / "backend" / "documents_parser" / "tests" / "fixtures"
+    / "Summary_001431_rr_ext.pdf"
+)
+
+
+def _summary_pdf_to_textract_style_pages(pdf_path: Path) -> list[str]:
+    """Convert a Summary PDF into the per-page text format the
+    ElmhurstSiteNotesExtractor expects (label\\nvalue sequences).
+
+    Mirror of the helper in `test_summary_pdf_mapper_chain.py` /
+    `_elmhurst_worksheet_000565.py`.
+    """
+    info = subprocess.run(
+        ["pdfinfo", str(pdf_path)], capture_output=True, text=True, check=True,
+    ).stdout
+    m = re.search(r"Pages:\s+(\d+)", info)
+    if m is None:
+        raise RuntimeError(f"Could not parse page count from {pdf_path}")
+    page_count = int(m.group(1))
+
+    pages: list[str] = []
+    for i in range(1, page_count + 1):
+        layout = subprocess.run(
+            [
+                "pdftotext", "-layout", "-f", str(i), "-l", str(i),
+                str(pdf_path), "-",
+            ],
+            capture_output=True, text=True, check=True,
+        ).stdout
+        tokens: list[str] = []
+        for line in layout.splitlines():
+            if not line.strip():
+                tokens.append("")
+                continue
+            parts = [p for p in re.split(r"\s{2,}", line.strip()) if p]
+            tokens.extend(parts)
+        pages.append("\n".join(tokens))
+    return pages
+
+
+def build_epc() -> EpcPropertyData:
+    """Route the simulated case-2 Summary through extractor + mapper.
+
+    No hand-built EpcPropertyData — the extractor and mapper are part of
+    the test target. Exercises the S0380.192 Simplified-RR fix and the
+    S0380.193 suspended-floor sealed-rule fix.
+    """
+    pages = _summary_pdf_to_textract_style_pages(_SUMMARY_PDF)
+    site_notes = ElmhurstSiteNotesExtractor(pages).extract()
+    return EpcPropertyDataMapper.from_elmhurst_site_notes(site_notes)

tests/domain/sap10_calculator/worksheet/test_e2e_elmhurst_sap_score.py

@@ -38,6 +38,7 @@ from tests.domain.sap10_calculator.worksheet import (
     _elmhurst_worksheet_000516 as _w000516,
     _elmhurst_worksheet_000565 as _w000565,
     _elmhurst_worksheet_001431 as _w001431,
+    _elmhurst_worksheet_001431_rr as _w001431_rr,
 )
 from tests.domain.sap10_calculator.worksheet._elmhurst_fixtures import (
     ALL_FIXTURES as _ELMHURST_FIXTURES,
@@ -167,6 +168,21 @@ _FIXTURE_PINS: Final[dict[str, FixtureCascadePins]] = {
         lighting_kwh_per_yr=283.2229,
         pumps_fans_kwh_per_yr=86.0,
     ),
+    # Mapper-driven cohort entry — Summary_001431_rr_ext.pdf → extractor
+    # → mapper → calculator. Main + Extension, Simplified room-in-roof,
+    # suspended uninsulated floors (the 6035 archetype). Surfaced + pins
+    # S0380.192 (Simplified-RR remaining area) and S0380.193 (suspended-
+    # floor sealed/unsealed rule). Pins are worksheet Block 1 line refs.
+    "001431_rr": FixtureCascadePins(
+        sap_score=69, sap_score_continuous=68.7584, ecf=2.2395,
+        total_fuel_cost_gbp=920.5046, co2_kg_per_yr=4566.7090,
+        space_heating_kwh_per_yr=15269.8593,
+        main_heating_fuel_kwh_per_yr=18178.4039,
+        secondary_heating_fuel_kwh_per_yr=0.0,
+        hot_water_kwh_per_yr=3308.6172,
+        lighting_kwh_per_yr=282.6414,
+        pumps_fans_kwh_per_yr=86.0,
+    ),
 }
 
 
@@ -179,6 +195,7 @@ _FIXTURE_MODULES: Final[dict[str, ModuleType]] = {
     "000516": _w000516,
     "000565": _w000565,
     "001431": _w001431,
+    "001431_rr": _w001431_rr,
 }