Model/datatypes/epc
Khalim Conn-Kowlessar 9cb98344fa S0380.192: drop placeholder roof surfaces from Simplified room-in-roof (Elmhurst)
A Simplified room-in-roof (RdSAP 10 §3.9.1, PDF p.21) does NOT measure
its slope / flat-ceiling / stud-wall surfaces — the Elmhurst Summary
lodges placeholder Length/Height cells (a 40 m flat-ceiling height, a
32 m slope on a 4.65 m-wide gable). The spec instead derives one
timber-framed "remaining area" from the floor area:
    A_RR       = 12.5 × √(A_RR_floor / 1.5)            §3.9.1(d)
    A_RR_final = A_RR − ΣA_RR_gable/other              §3.9.1(e)

The cascade already computes A_RR_final itself (heat_transmission.py:
`12.5 × √(A_RR_floor/1.5) − rr_walls_in_a_rr_area` residual), but only
when `detailed_surfaces` carries no roof-going kind (`has_roof_lodgement`
gate). `_map_elmhurst_rir_surface` emitted the placeholder slope/ceiling
rows as raw L×H for every assessment type, flipping that gate and billing
1024 m² + 160 m² of explicit roof area — a 7.5× fabric-heat-loss
explosion (cert 001431 sim case 2: SAP −14.6 vs worksheet 69, space
heating 114 378 vs ~15 000 kWh).

Fix: for a Simplified assessment, drop the roof-going surfaces in the
mapper so the cascade's residual formula fires. This matches how the API
path already (correctly) handles the same Simplified RR — scalar gable
fields, no roof-going detailed_surfaces (golden cert 6035) — and the
gables-only cert 000565. Detailed (§3.10) assessments still measure these
surfaces and keep them.

With the fix, sim case 2 total external area = 232.94 (worksheet exact),
roof 78.33 (was 2725.89), SAP 69.29 → worksheet integer 69. A small
residual (~450 kWh main fuel) remains — a separate fabric gap to walk
next. 2308 passed (+2), 0 failed; pyright net-zero.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-03 08:57:16 +00:00
..
domain S0380.192: drop placeholder roof surfaces from Simplified room-in-roof (Elmhurst) 2026-06-03 08:57:16 +00:00
loaders demo generated for use in address2uprn 2026-05-08 14:48:15 +00:00
schema Merge remote-tracking branch 'origin/main' into feature/landlord_data 2026-06-01 17:02:20 +00:00
search bolstering testing 2026-04-28 13:46:09 +00:00
surveys Slice S0380.170: Community heating mapper unblock (Table 12 dispatch) 2026-06-02 10:50:21 +00:00
__init__.py testing out rebaselining 2026-02-12 22:25:03 +00:00
construction_age_band.py testing out rebaselining 2026-02-12 22:25:03 +00:00
efficiency.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
floor.py preparing partiy class 2026-02-05 08:54:27 +00:00
fuel.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
heating_controls.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
hotwater.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
main_heating.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
property_type_built_form.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
roof.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
walls.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
windows.py testing out rebaselining 2026-02-12 22:25:03 +00:00