1. Monitoring of Air Infiltration in Museums, Case study: The National Museum of Fine Arts, Stockholm, Sweden. Contribution to The 6 th Indoor Air Quality Meeting, Padova, November 10 - 12, 2004. CarlAxel Boman, Pentiaq AB, Gavle, Sweden. Jan Holmberg, The Royal Institute of Technology, Stockholm, Sweden Hans Stymne, University of Gavle, Sweden

3. ground floor 2 nd floor 1 st floor entrancr

4. entrance hallstair well The stair wells in 1866. Picture by Ny Illustrerad Tidning 1866.

5. ground floor 2 nd floor 1 st floor entrance ? ventilation by infiltration ?? ?

6. ground floor 2 nd floor 1 st floor entrancr zone A zone B 2-zone-set up

7. tracer gas sourcesampler

8.  p = the local mean age of air C p = local tracer concentration S = the tracer gas emission rate V = the zone volume ACH = air changes rate  = the local mean age of air Ventilation measurement technique, the homogeneous emission technique

9. four measurement cases 1. normal position, ventilation off 2. stairwell sealed, ventilation off 4. normal position, ventilation on3. entrance sealed, ventilation off

10. caseventsealing infitration entrance net flow to 2 nd floor off/onentrance stair- well [m 3 /h]ACH[m 3 /h][%] 1off22700.76181080 2offseald15800.5361040 3offseald13400.4166050 4on94002.7-- Air flow infiltration results with different cases

11. ground floor 2 nd floor 1 st floor Case 1. Air flows, [m 3 /h], ventilation system off 2270 460 1840 30 2160 350

12. ground floor 2 nd floor 1 st floor Case 2. Air flows, [m 3 /h], ventilation system off 1580 970 1920 1310 690 80

13. ground floor 2 nd floor 1 st floor Case 3. Air flows, [m 3 /h], ventilation system off 1340 680 1640 980 860 200

14. ground floor 2 nd floor 1 st floor Case 4. Air flows, [m 3 /h], ventilation system on 9400

15. Indoor climate and wether conditions during the measurements Indoors: temperature: 19.4 – 20.8 °C relative air hunidity: 22 – 26 %RH Outdoors: temperature: - 1.4 – 2.6 °C relative air hunidity: 72 – 92 %RH

16. Conclusions To improve indoor climate in historic buildings: it is necessary to keep the air infiltration rate under control it is of great importance to know the air infiltration the homogeneous tracer gas method is suitable and reliable For the National Museum of Fine Arts to get good indoor air quality condirions, it is possible to reduce the uncontrolled air infiltration