Kan indeklimaet forbedres og risikoen for smittespredning sænkes uden forøget energiforbrug?

Transcription

1 Kan indeklimaet forbedres og risikoen for smittespredning sænkes uden forøget energiforbrug? Arsen K. Melikov De nye Danske sygehus byggerier, SWEGON Air Academy Seminar, 14 April 2011 International Centre for Indoor Environment and Energy Department of Civil Engineering, Technical University of Denmark 1

2 50000 years ago. 2

3 Buildings Today Dubai Burj Khalifa Blg. Height 828 m 162 floors 3

4 Buildings in the Future Sky City (Japan) 1000 m tall & 300 m diameter at basis 4

5 Hospitals: Past and Present 5

6 Hospitals of the future: Requirements good indoor climate flexibility energy efficient patient-centred care universal (adaptable) patient care rooms 6

7 Indoor Environment is important! Ventilation & Health, Comfort, Performance 7

8 Ventilation and Health 8 Fisk et al. 2003

9 Ventilation and Health The ALLHOME study 5 4 Asthma, Sofia Asthma, Burgas region Prevalence [%] Years Naydenov 2008 Ventilated, energy inefficient buildings Tight, more energy efficient but less ventilated buildings 9

10 Ventilation and PAQ 10

11 Ventilation & Performance Office productivity R 2 = Ventilation rate (L/s per person) 11 Wargocki, et al. 2004

12 Ventilation & Performance Decrement in performance, % Temperature, C Wargocki Seppänen et al

13 Influenza Measles Bird-flu Airborne Transmission of Infectious Agents Swine flu Smallpox Varicella 13 Tuberculosis

14 Transmission of Infection Agents In USA Communicable Respiratory Infectious (influenza, cold, TB) amount to: $ 10 billion in health care costs $ 19 billion in costs arising from absence due to illness $ 3 billion in other performance losses In USA alone is assessed that: 52 million cases of influenza and common cold a year 10-14% (5-7 million cases) could be prevented resulting in a saving of $ 3 to 4 billion 14

15 Global Human Pandemic of Bird Flu World Health Organisation: it is only matter of time United Nations: global worst case is 60 million deaths and 2% fall in global output economy World Bank: cost to wealthy nations alone $550,000,000,000 15

16 Prevention from Cross-Infection strict hygiene disinfection strict isolation reduced contact medicine??? ventilation!! 16

17 Airborne Transmission of Viruses Sneezing, coughing, talking Droplets ( m) with viruses Breathing - Exhalation Airborne aerosols (< 1 m) with attached viruses (0.003 to 0.06 m) settling, evaporation, inhalation Inhaled by occupants 17

18 Ventilation Principles Total Volume Ventilation Supply of Clean and Cool air to Nobody Advanced Ventilation Supply of Clean and Cool air to Everybody 18

19 Protection by Ventilation R A0 - reproductive number of secondary infections that arise when a single infectious case is introduced into a population where everyone is susceptible [Rudnick and Milton, 2003] Reproductive number Influenza 10 L/s per person 40 L/s per person Transmission likely unlikely Mixing PV Cermak Cermak & Melikov and Melikov (2007)

20 ASHRAE Standard Function of space Operating room Recovery room Trauma room Waiting room Minimum Outdoor air h -1 Minimum total air change Relative humidity % h Design temperature C Max

21 Airborne Cross-Infection in Hospitals High risk of cross-infection Ventilation: minimum 12 h -1 Problems: More energy use Increased draught discomfort Large AHU and duct system Does it always protect? 21

22 Airborne Cross-Infection in Hospital Wards Total volume ventilation case Mixing Ventilation: 3, 6, 12 ACH Room temperature: 22 C Coughing & Breathing patient: lying on side & back 1. Source patient (Coughing manikin) 2. Doctor (breathing thermal manikin) 3. Second patient (breathing thermal manikin) 4. Air supply diffuser 5. Air Exhaust diffuser 22

23 Airborne Cross-Infection due to Coughing Doctor: 0.55 m from coughing patient lying on side 23 Melikov et al. 2009

24 Pettenkofer (1858): If there is a pile of manure in a space, do not try to remove the odor by ventilation. Remove the pile of manure. 24

25 Advanced Air Distribution in Hospitals The cleansed filtered air is moved upwards creating two air curtains and/or a horizontal air curtain preventing airborne spread of pathogens among patients and health care staff Exhaust Cleansed air Sensors Polluted air 25

26 Advanced Air Distribution in Hospitals Hospital bed integrated ventilation and cleaning unit HBIVCU A sensor registers which side of bed the head is facing, and starts the fan to exhaust the exhaled pathogen laden air. The captured air passes through a HEPA/ULPA filter able to retain very small particles and bacteria. Cleansed air Polluted air System of honeycomb air straightener and a direction latch move the air either upwards towards or back to the patient. UV-C light is used to kill the remaining pathogens. Reflective material covers the inside of the box to enhance the germicidal effect. 26

27 Airborne Cross-Infection in Hospital Wards 1-Source patient (Coughing manikin); 2- Doctor (breathing thermal manikin); 3-Exposed patient (breathin thermal manikin); 4-Exhaust;5-HBIVCB Mixing Ventilation:3,6,12 ACH; Room temperature: 22 C 27 Coughing & Breathing patient: lying on side & back

28 Performance of HBIVCU Doctor: 0.55 m from coughing patient lying on side 28

29 Advanced Air Distribution in Hospitals The cleansed filtered air is moved upwards creating two air curtains and/or a horizontal air curtain preventing airborne spread of pathogens among patients and health care staff Exhaust Cleansed air Sensors Polluted air 29

30 Head-Set Incorporated PV Independent of occupant s movement Minimal ventilation rate ( L/s) PEE [%] cm (M/N) 2 cm (N/M) 6 cm (M/N) 6 cm (N/M) 0 0,1 0,2 0,3 0,4 0,5 Flow rate [l/s] Bolashikov et al

31 ASHRAE Standard Function of space Operating room Recovery room Trauma room Waiting room Minimum Outdoor air h -1 Minimum total air change Relative humidity % h Design temperature C Max

32 Indoor Environment Design Total Volume Heating, Cooling & Ventilatioon Clean air is supplied far from occupants Uniform environment Limited control Large differences between occupants! Clothing insulation: clo Metabolic rate: 1 2 met Preferred temperature: 10 C Preferred velocity: 4 times 32

33 Personalized Ventilation 33

34 Personalized Heating and Cooling Naturally & mechanically ventilated chairs/seats Clothing integrated ventilation, cooling &heating 34

35 Bed Integrated Micro-Environment System 35

36 Thank you! 36