Model/domain/sap10_calculator/worksheet
Khalim Conn-Kowlessar 781efd75c0 fix(heat-transmission): apply dry-lining Table 14 R=0.17 to the main wall
The main-wall `u_wall(...)` call dropped the `dry_lined` kwarg, so the RdSAP 10
§5.7/§5.8 (PDF p.40-41) Table 14 dry-lining adjustment — U_adj = 1/(1/U₀ +
0.17) for a dry-lined (incl. lath-and-plaster) uninsulated wall — was never
applied to any main wall, even when the cert lodged `wall_dry_lined=Y`. The
ALTERNATIVE-wall path already passes `dry_lined` (line 1367); this one-sided
omission billed every dry-lined main wall at the un-adjusted (too-high) U →
wall heat loss too high → SAP under-rated.

Per-cert: a solid-brick (construction 3) band-A 230 mm main wall computes
U₀=1.70; dry-lined it is 1/(1/1.70+0.17)=1.32 — we were 22% too high. Across
the API gov-EPC sample the dry-lined `wall_construction=3` (solid brick)
sub-cohort sat at 10% within-0.5 / signed -1.33.

Fix: pass `dry_lined=bool(part.wall_dry_lined)` to the main-wall `u_wall`
call, mirroring the alt-wall path. `part.wall_dry_lined` is already plumbed
(Optional[bool], None → False). The three dry-lining branches in `u_wall`
(stone §5.6, solid-brick-by-thickness §5.7, generic uninsulated bucket §5.8)
are all spec-correct and already worksheet-validated (the bucket-0 cavity
case against cert 7700 age-C → 1.20).

Worksheet harness UNAFFECTED (47/47, 0 divergers): the Elmhurst/Summary
extractor only captures dry-lining for ALTERNATIVE walls (Summary §7), never
the main wall, so `part.wall_dry_lined` stays None on that path — this is a
pure API-path improvement. API gauge: within-0.5 60.1% -> 64.4% (mean|err|
1.163 -> 1.085, signed -0.097 -> +0.049). Both affected buckets improved
with no overshoot: solid brick (wc=3) 50% -> 57% within-0.5; cavity (wc=4,
dry-lined via the §5.8 bucket-0 path) 68% -> 72%.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-11 09:43:50 +00:00
..
__init__.py refactor: lift-and-shift packages/domain/src/domain/sap → domain/sap10_calculator 2026-05-26 12:22:37 +00:00
appendix_h_solar.py Slice S0380.74: Appendix H (H7) U3.3 monthly-integrated convention closes 1.81× over-count 2026-05-29 18:02:35 +00:00
dimensions.py refactor: lift-and-shift packages/domain/src/domain/sap → domain/sap10_calculator 2026-05-26 12:22:37 +00:00
energy_requirements.py S0380.200: SAP 10.2 §9a two-main-heating split (203)/(205)/(207)/(213) 2026-06-03 13:09:43 +00:00
fabric_energy_efficiency.py refactor: lift-and-shift packages/domain/src/domain/sap → domain/sap10_calculator 2026-05-26 12:22:37 +00:00
fuel_cost.py Slice S0380.47: wire β-split into cost cascade per SAP 10.2 Appendix M1 §6 2026-05-28 19:01:38 +00:00
heat_transmission.py fix(heat-transmission): apply dry-lining Table 14 R=0.17 to the main wall 2026-06-11 09:43:50 +00:00
internal_gains.py S0380.202: SAP 10.2 Table 5a note a) second main-system pump gain (70) 2026-06-03 14:35:08 +00:00
mean_internal_temperature.py S0380.205: SAP 10.2 p.186 two-systems-different-parts MIT (weighted R + elsewhere blend) 2026-06-03 16:02:56 +00:00
mev.py Slice S0380.100: MEV SFPav + (230a) cascade helpers (SAP 10.2 §2.6.4 + Table 4f) 2026-05-30 15:28:59 +00:00
photovoltaic.py Slice S0380.44: SAP 10.2 Appendix M1 §3-4 PV β-factor calculator (no wiring) 2026-05-28 18:11:56 +00:00
rating.py refactor: lift-and-shift packages/domain/src/domain/sap → domain/sap10_calculator 2026-05-26 12:22:37 +00:00
solar_gains.py Slice S0380.42: Decimal HALF_UP per-window areas per RdSAP10 §15 — closes cert 1536 2026-05-28 17:11:39 +00:00
space_cooling.py refactor: lift-and-shift packages/domain/src/domain/sap → domain/sap10_calculator 2026-05-26 12:22:37 +00:00
space_heating.py refactor: lift-and-shift packages/domain/src/domain/sap → domain/sap10_calculator 2026-05-26 12:22:37 +00:00
utilisation_factor.py refactor: lift-and-shift packages/domain/src/domain/sap → domain/sap10_calculator 2026-05-26 12:22:37 +00:00
ventilation.py refactor: lift-and-shift packages/domain/src/domain/sap → domain/sap10_calculator 2026-05-26 12:22:37 +00:00
water_heating.py fix(water-heating): heat-network primary loss uses Table 3 h=3 all months 2026-06-10 20:12:49 +00:00