PBI SAS SUPER IAQ - Page 26

“SAS Super IAQ” Rev. 1 Pg. 22
ENGLISH
Example of calculation of results
Pr x 1000
X =----------------------
V
Where:
V = Volume of sampled air = 200 litres of air
r = Colony Forming Units counted on “ 55 mm Contact Plates” = 67
Pr = Probable count obtained by positive hole correction = 80
x = Colony Forming Units per 1000 litres (= 1 cubic metre) of air
80 x 1000
x = ------------------------- = 400 CFU per 1000 litres of air (1000 litres=1m
3
)
200
To express the final result in CFU/ft
3
multiply the CFU/m
3
value by 0,02832