UVGI Dosage Calculation for

Clarifier Four Lamp Systems including Alzak reflective materials

 

The calculation of the average efficacy of the ultra violet germicidal lamps is a function of the resident time of the bacteria within sight of the ultra violet light and the intensity of the light within this “Kill Zone”. Calculations are quite a complex integration; however, the basic “easy to understand” value, approach within 2 to 3% of the rigorous integrations (noted below), and is therefore, conservatively:

Resident Time              =  CFM/area/airflow path/60 seconds per minute.

                                    =  *300*/1.51 sq.ft. = 200 fpm/60 = 3.333 feet per second average speed

                                    =  Circular or twisting airflow pattern is 3.9 feet@3.333 feet per second        

=  1.17 second

 

Lamp Intensity             =  32.9 microwatts/cm squared at 1 meter (lamp mfg data)

                                    Median distance from lamp to unit wall is 3.3”

                                    Intensity multiplier at 3.3” = 39.37”/meter/3.3” = 11.93

(From N.A. Philips Lighting Handbook, light intensity varies with square of distance)

 

                                    =  11.93 squared x 32.9 microwatts/cm squared

                                    =  4682 microwatts per cm squared per lamp

 

Reflection of measured UV light is a 22% increase at cabinet surface = 1.22 increase

 

Total Efficacy   =  1.17 second x 4682 x 1.22 x 4 lamps         Adding Alzak (1.22=1.86)  

=  26,732 microwatt-seconds/cm sq’d.                 43,440                      

 

 

 

 

 

 

 

 

 

                                    Lamp life is rated at 9000 hours or 1 year.

 

NOTE:

     The Addition of Alzak reflective material ostensibly doubles the UV intensity inside the Clarifier air purifier making it much more effective on killing pathogens especially in a safe room application.