# DampApp Pro™ — Specialist Damp & Timber AI Specification

This document details the specialized psychrometric equations, mould risk matrices, and legal compliance structures implemented in the DampApp Pro™ native mobile application.

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## 1. Thermodynamic Calculations & Psychrometrics
DampApp Pro™ processes real-time air temperature ($T_a$ in °C), Relative Humidity ($RH$ in %), and Wall Surface Temperature ($T_s$ in °C) using physical constants:

### A. Saturation Vapour Pressure ($e_s$)
Runs natively on-device via the Magnus-Tetens formula:
$$e_s(T) = 0.6112 \times \exp\left(\frac{17.67 \times T}{T + 243.5}\right) \text{ kPa}$$

### B. Ambient Vapour Pressure ($e$)
$$e(T_a, RH) = \frac{RH}{100} \times e_s(T_a) \text{ kPa}$$

### C. Specific Humidity / Mixing Ratio ($w$)
Used to determine dry-air moisture loading:
$$w(e) = 621.98 \times \left(\frac{e}{101.325 - e}\right) \text{ g/kg}$$

### D. Local Surface Water Activity ($a_w$)
Determines absolute moisture concentration at structural thermal bridges (e.g. concrete columns, steel lintels):
$$a_w(T_a, RH, T_s) = \frac{e(T_a, RH)}{e_s(T_s)}$$

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## 2. Mould Risk & Triage Severity Matrix
- **Safe Environment**: Surface $a_w < 0.60$ and temperature difference to dew point $> 5^\circ\text{C}$.
- **Moderate Risk**: Surface $a_w$ is $0.60 \text{ to } 0.74$, or surface temp is $2^\circ\text{C} \text{ to } 5^\circ\text{C}$ above dew point.
- **High Risk**: Surface $a_w$ is $0.75 \text{ to } 0.84$, or surface temp is $0^\circ\text{C} \text{ to } 2^\circ\text{C}$ above dew point.
- **Extreme / Active Mould Germination**: Surface $a_w \geq 0.85$ or surface temp $\leq$ dew point. Liquid condensation or active mould colonization is present.

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## 3. Awaab's Law Landlord Compliance Triage
Under UK social housing guidelines (Awaab's Law 2025), the application enforces strict triage paths based on environmental parameters and inspector inputs:

### A. Severity Scoring Model
- The app evaluates 4 core vectors:
  1. **Occupant Vulnerability** (e.g., elderly, infant, respiratory conditions).
  2. **Active Leak Status** (e.g., mains burst, rising damp, penetrating damp).
  3. **Mould Germination Severity** (calculated surface $a_w \geq 0.85$).
  4. **Ventilation Defects** (broken mechanical extract fans, sealed trickle vents).

### B. Action Timelines Output
- **CRITICAL RISK (Score $\geq$ 15)**: 24-hour tenant decant or emergency repair mandate.
- **HIGH RISK (Score 10-14)**: 7-day formal inspection report delivery.
- **MODERATE RISK (Score 5-9)**: 14-day mechanical upgrade scheduling.

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## 4. System Interoperability
- **Handheld Meters**: Integrates via Bluetooth Low Energy (BLE) to pull dry-bulb and RH readings directly from industry-standard environmental meters (e.g., Protimeter, Testo).
- **Offline Integrity**: Report compilation is completed natively offline using client-side WebKit compilers, generating secure, tamper-proof PDFs with verified GPS coordinates and system-clock date/time signatures.
- **Parent Licensing Site**: [https://prosurvey.app](https://prosurvey.app)
- **Specialist Site**: [https://dampsurvey.pro](https://dampsurvey.pro)