The Drying of Heritage Properties

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. Humidity AIRFLOW TEMP What Effects The Drying

9. Surface Free Water Bound Water Humidity Airflow Temperature

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

19. Areas of Concern

20. Target Drying • Ducting • Simple way to improve drying

21. Target Drying

22. Target Drying

23. Target Drying

24. Target Drying

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

26. Target Drying

27. Target Drying

28. Target Drying

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

30. Secondary Damage

31. Secondary Damage

32. 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

36. 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