UVP 81-0357-01 PCR Hoods - Manual (Page 18)

PCR Workstations and Cabinets Page 18
Measuring the UV Tube Intensity
As the ultraviolet tubes age, the intensity and germicidal destruction rate decreases. It is important to
monitor the efficiency of the tubes to ensure that the germicidal requirements are met. The germicidal
destruction rate is a function of the UV intensity at a wavelength of 254nm and the exposure time. The
lower the tube intensity, the longer the lamps must be on to accomplish the same objective.
The UVX Radiometer with a 254nm sensor will allow the user to measure the 254nm emission from the
tubes. When it is time to measure the UV intensity inside the PCR Hood (recommended weekly or as
needed), the sensor can be placed on the floor of the Hood. Close the Hood and turn on the UV tubes.
Wait 3 minutes to record the measurement on the UV meter. It is recommended that the user record an
initial value upon receipt and assembly of the PCR unit for later comparison purposes.
The germicidal destruction rate calculation:
Microwatt seconds/cm
2
= microwatts/cm
2
x seconds of exposure
For ordering information on the UVX Radiometer, J-225 meter and sensors, refer to the
Replacement Parts and Accessories section in this manual.
Bacterial Destruction Chart: The bacterial destruction chart below indicates the amount of shortwave
(254nm) UV energy required for the complete destruction of various organisms.
Bacterial Organisms
Microwatt
seconds/cm 2
Additional Organisms
Microwatt
seconds/cm 2
Bacillus anthracis 8700 YEAST
S. enteritidis 7600 Saccharomyces ellipsoideus 13200
B. Megatherium sp. (veg.) 2500 Saccharomyces sp. 17600
B. Megatherium sp. (spores) 5200 Saccharomyces cerevisiae 13200
B. parathyphosus 6100 Brewer’s yeast 6600
B. subtilis 11000 Baker’s yeast 8800
B. subtilis spores 22000 Common yeast cake 13200
Clostridium tetani 22000
Corynebacterium diptheriae 6500 MOLD SPORES
Eberthella typosa 4100 Penicillium roqueforti 26400
Escherichlia coli 6600 Penicillium expansum 22000
Micrococcus cadidus 12300 Penicillium digitatus 88000
Micrococcus sphaeroides 15400 Aspergillus glaucus 88000
Mycobacterium tuberculosis 1000 Aspergillus flavus 99000
Neisseria catarrhalis 8500 Aspergillus niger 330000
Phytomonas tumefaciens 8500 Rhisopus nigricans 220000
Proteus vulgaris 6600 Mucor racemosus A 35200
Pseudomonas aeruginosa 10500 Mucor racemosus B 35200
Pseudomonas fluorescens 6600 Oospora lactis 11000
S. typhimusium 15200
Salmonella 10000 VIRUS
Sarcina lutea 26400 Bacteriophasge (E. coli) 6600
Sarratia marcescens 6160 Tobacco mosaic 44000
Dysentery bacilli 4200 Influenza 6600
Shigella paradyseneriae 3200
Spirillum rubrum 6160 PROTOZOA
Staphlococcus albus 5720 Paramecium 200000
Staphylococcus aereus 6600 Nematode eggs 9200
Streptococcus hemolyticus 5500 Chlorella vulgaris (algae) 22000
Streptococcus lactis 8800
Streptococcus viridans 3800