We respect regional rating schemes and the push they’ve given practice—more shade, higher SR/SRI, better baselines. They’re better than nothing. But they don’t guarantee how a place feels. Most schemes don’t set UTCI-by-programme targets, don’t pair results with NEN 8100 wind comfort, and don’t ask for a reliability metric showing how often comfort is achieved across real seasons—which is odd, because the tools to measure these are common.
If we were a client, we’d brief for outcomes: define use windows and shoulder seasons; set clear UTCI targets by programme; pair with NEN 8100; require a simple reliability KPI and ask for tree-canopy performance assurance so modelled shade is actually delivered.
We haven’t yet seen an RFP that asks for these robust, impactful services—so we wrote one ourselves.
1. Objective
To quantify outdoor thermal comfort for podium and public-realm areas and to evidence the uplift delivered by landscape design. The study must support decision-making and accountability with measurable KPIs.
2. Scope of services
2.1 Standards & metrics
Thermal comfort: UTCI at 1.5 m AGL.
Wind comfort coupling: classify to NEN 8100 (A–E + safety). Use as boundary condition or declare assumptions.
UTCI KPI: Comfort Days (80/80) — count of calendar days per year on which ≥80% of use-window hours meet the UTCI target in ≥80% of years over a ≥10-year climate record. Report Baseline vs With-Design and the season extension (earlier start, later finish).
2.2 Program targets
Seating / cafés / play (in shade): UTCI ≤ 32 °C during use windows.
Entrances / queue lines: UTCI ≤ 32 °C during use windows.
Promenades / primary walks (short exposure): UTCI ≤ 38 °C during use windows. (Adjust in consultation with the Client if required.)
2.3 When to assess
Focus on shoulder seasons and actual use windows per programme area (to be confirmed by Client).
Provide a method to set actual dates (see 4.3).
2.4 What to deliver (minimum)
UTCI maps (Baseline and With-Design) at 09:00 / 12:00 / 15:00 on representative days inside each shoulder period.
Shade duration / sun-hours maps for the same hours.
MRT (Tmrt) maps at 1.5 m AGL. If not available, provide surface-temperature maps and method notes.
Wind comfort coupling: either (a) use PLW/Comfort outputs supplied by the wind consultant, or (b) state wind assumptions and include a short sensitivity check.
Programme pass/fail table against targets.
KPI report: Comfort Days (80/80) and season extension for each programme area; Baseline vs With-Design.
Methods statement: datasets, processing, assumptions, and limitations.
Digital outputs: georeferenced rasters (GeoTIFF) and vector layers (SHP/GeoPackage), plus layered PDFs (A1/A3).
3. Tree canopy assurance
Provide a second layer of evidence to demonstrate that the modelled canopy is achievable within agreed certainty.
3.1 Tree Growth & Canopy Performance Certificate (TGCP)
For each tree species/zone: expected canopy diameter, height, clear trunk height, leaf-area density at years 1, 3, 5, 10 (and maturity), with P50 and P80 intervals.
Basis of estimate: soil volumes, soil specification, irrigation water source/quality, irrigation regime, exposure/wind, heat load, and nursery stock quality, tree species characteristics include form modification due to planting design.
Cite data sources (regional trials, nursery records, literature) and any calibration used.
3.2 Model geometry alignment
Supply two canopy sets for simulation: Establishment (years 1–3) and Design Condition (years 5–10). Confirm these match the TGCP values.
3.3 Arboricultural sign-off
TGCP to be signed by a qualified arboriculturist (ISA or equivalent) independent from the modelling team.
4. Method Requirements
4.1 Datasets
Meteorology: ≥10 years of hourly data for locality (station ID and period stated). Apply directional weighting.
Terrain/urban context: current massing within agreed radius.
Materials: SR/SRI values as provided by Client/Design Team.
4.2 Wind coupling
Prefer use of PLW/Wind Comfort results (NEN 8100) from the wind package. If unavailable at the time of analysis, assume conservative wind (state values) and include a sensitivity note; update once PLW is issued.
4.3 Deriving shoulder dates (simple rule)
For each programme area: compute, for every day of the climate record, the fraction of use-window hours meeting the UTCI target (Baseline and With-Design).
Apply a 7-day moving average. Define shoulder start as the first spring date the average falls below threshold T; shoulder end as the first autumn date it rises above T. Default T: Seating 0.40; Promenades/Entrances 0.60. Propose alternates if footfall data is supplied.
5. Inputs to be provided by client
General arrangement (GA) with levels and programme areas.
Digital 3D model(s) (Baseline and With-Design): RVT/3DM/IFC with separate layers for geometry, trees (two canopy sets), shade elements (open/closed states), and material SR/SRI.
Use windows by programme area; any relevant operational constraints.
PLW/Wind Comfort package (if available) and contact for coordination.
6. Meetings and re-checks
One coordination meeting to confirm inputs and targets.
One re-check after each agreed design changes (same scope, same representative days).
Additional iterations to be instructed separately.
7. Acceptance criteria
Completeness of deliverables in 2.4 and 3.
Reproducibility: all assumptions and datasets documented; outputs georeferenced.
Logical consistency between TGCP canopy geometry and model layers.
KPI results clearly reported and traceable (tables + calendar graphic).
8. Programme and submissions
Issue Draft (all maps, TGCP, KPI) for review; allow one consolidated comment round.
Issue Final package and data after comments closure.
File naming and drawing registers to be agreed at kick-off.
9. Intellectual property and data
- Model scripts and processed climate series to be archived with the project. The Client receives a perpetual, non-exclusive licence to use all deliverables for the project.
Model scripts and processed climate series to be archived with the project. The Client receives a perpetual, non-exclusive licence to use all deliverables for the project.
10. Team credentials and relevant Gulf projects.
Proposed datasets, tools, and any constraints (e.g., MRT export).
Clarifications to targets, thresholds T, and use windows if suggested.
Fee, programme, and list of assumptions/exclusions.
