Model/datatypes
Khalim Conn-Kowlessar c144d444e2 Slice S0380.26: RdSAP10 §5.8 dry-lining adjustment on alt walls — closes cert 7700 -0.44 → +5e-5
Per RdSAP10 §5.8 final note + Table 14 page 41:

  "For drylining including laths and plaster use Rinsulation = 0.17 m²K/W."

Applied additively to the base U-value of an otherwise-uninsulated wall:

  U_adjusted = 1 / (1/U_base + 0.17)  — rounded to 2 d.p. half-up.

Closed form for the cohort fixture (cavity-as-built age C, U_base=1.5):

  1 / (1/1.5 + 0.17) = 1.19522... → 1.20 ✓ matches worksheet

Cert 7700-3362-0922-7022-3563 (Summary_000905.pdf / dr87-0001-000905.pdf)
is an End-Terrace house age C lodging:
  - Main wall: CavityWallDensePlasterDenseBlock, Filled Cavity, U=0.70
  - Alt wall 1: 14.44 m² Cavity As-Built, Dry-lining: Yes (worksheet
    `CavityWallPlasterOnDabsDenseBlock`, U=1.20)

Pre-slice the Elmhurst alt-wall mapper hard-coded `wall_dry_lined="N"`
and the cascade ignored the field everywhere — alt-wall U routed to the
cavity-as-built default (1.50), giving fabric (33) 148.72 W/K vs
worksheet 144.38 (Δ +4.33 W/K = ~+0.44 SAP). Worksheet "SAP value" line
lodges unrounded SAP 63.4425.

Implementation:
  1. `AlternativeWall.dry_lined: bool = False` on the Elmhurst surveys
     dataclass.
  2. Elmhurst extractor reads "Alternative Wall N Dry-lining: Yes/No"
     into the new field.
  3. `_map_elmhurst_alternative_wall` propagates `wall_dry_lined="Y"`
     instead of the hard-coded "N".
  4. `u_wall` gains a `dry_lined: bool = False` kwarg and a single
     §5.8 adjustment site at the as-built bucket (bucket=0). Insulated
     buckets already absorb the dry-lining R via Table 14.
  5. `_alt_wall_w_per_k` passes `dry_lined=alt_wall.wall_dry_lined == "Y"`.

Scope is the alt-wall path only — main BPs in the corpus all lodge
`wall_dry_lined="N"` (or the Summary PDF omits the field for the main
wall), so the main-wall call site is untouched. Conservative regression
posture per the user's strict cohort-pin convention.

Cohort-2 outcome (38 certs, Summary path):
  exact (<1e-4): 22 → **23**  (+1: cert 7700 -0.44 → +4.87e-05)
  0.07..0.5:      1 → **0**   (-1: cert 7700 closes out)
  0.5..1:         1 → 1       (cert 9796 unchanged — MIT precision floor)
  RAISES:         0 → 0

Cohort-1 ASHP cohort untouched: all certs lodge wall_dry_lined="N", so
the alt-wall call site short-circuits to the original cascade. Verified
no regressions across the 22 previously-exact cohort-2 certs either.

Pyright net-zero on all 8 touched files (183 → 183).

Tests: 704 → 708 pass (+4 new: u_wall §5.8 adjustment fires
correctly; cavity-as-built unchanged without flag; insulated bucket
unaffected by flag; heat_transmission alt-wall delta = 14.44 × 0.30
W/K; cert 7700 full chain hits worksheet 63.4425 at < 1e-4),
10 expected fails unchanged.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-28 10:56:11 +00:00
..
epc Slice S0380.26: RdSAP10 §5.8 dry-lining adjustment on alt walls — closes cert 7700 -0.44 → +5e-5 2026-05-28 10:56:11 +00:00
magicplan typing and renaming 🟪 2026-05-07 13:26:49 +00:00
__init__.py further breaking up code 2023-07-20 12:24:34 +01:00
datatypes.py further breaking up code 2023-07-20 12:24:34 +01:00
enums.py completed build of new demo portfolio - some fixed required still 2023-11-20 14:42:16 +00:00