2. The Drying of Heritage Properties Nigel Hewitt Technical Manager

3. Communication Establish good lines of communication –Project Managers –Insured –All other relevant parties

4. Goals What are trying to achieve What was pre loss condition –Indoor Atmosphere 18ºC - 22ºC 40% - 60% Relative Humidity Can we find a “Dry Standard” –How “Dry” was the property pre-incident

5. Goals Where is the moisture located –Moisture Meters Moisture sensors Penetrating Non-penetrating Thermal Hygrometers Thermography Boroscopes

6. Goals What’s Wet –What kind of materials –Structural or decorative How Wet is it –Which is the most appropriate drying system Open Closed Combination

7. The Drying Process Water is present in one of three forms –Surface Water Very easy to dry –Free Water Easy to dry –Bound Water Harder to dry

8. What Effects The Drying TEMP AIRFLOW Humidity

9. Surface Free Water Bound Water Temperature Humidity Airflow

10. Moisture Movement Moisture movement occurs when there is a vapour pressure imbalance between materials and environments Moisture movement ceases when there is vapour pressure equilibrium

11. Permeance Ability of moisture to pass through materials Based on: –Vapour Pressure –Temperature –Relative Humidity –Pore size

12. Considerations Permeability of different materials –Connected materials with different rates of permeability Vapour Barriers –Where are they located –Can they be perforated –Can they be removed Hidden cavities

13. Considerations Secondary Damage –Moulds –Dry Rot –Wet Rot

14. Drying Equipment Airmovers –Essential part of drying process –Velocity, pressure and placement effect performance Airmover Types –Carpet dryers –Inter-air dryers –Axial fans –High volume airmovers

15. Dehumidifers Types of dehumidifier –Domestic refrigerant –Commercial Refrigerant –LGR –Desiccants Humididstats

16. Alternatives Heat drying systems –Is it safe Low level back ground heat Controlled Ventilation Dry Slowly

17. Considerations Surface finishes –Limewash –Paints –Wood panelling –Fabric –Leather

18. Areas of Concern

20. Target Drying Ducting –Simple way to improve drying

21. Target Drying

25. Drying Hardwood Floors –Apply positive air pressure one side –Negative pressure on the other –Greatly increases drying efficiency

26. Target Drying

29. Injection Drying –Dries voids and cavities –Use positive and negative pressure –Reduce claim duration –Equipment can be expensive

30. Secondary Damage

33. Contents

34. Monitoring Where is the moisture located –Moisture Meters Moisture sensors Penetrating Non-penetrating Thermal Hygrometers Thermography –Data Loggers –Remote Monitoring –Calcium Carbide

35. Data Loggers

37. Remote Monitoring Continual Monitoring –Temp –Rh –Specific Humidity –Dew Point –Set Thresholds –Alarms

38. Calcium Carbide Measures moisture content in materials A weighed sample is added with calcium carbide into the pressure vessel Chemical reaction produces acetylene gas The increase in pressure can be read directly from a calibrated pressure gauge

39. In Summary Determine what’s wet and how wet it is Check all unaffected items Select appropriate drying system Monitor frequently and accurately Flood Prevention

40. Thank You Any Questions