Measuring the uv tube intensity – UVP Ultraviolet PCR User Manual

Page 11

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Ultraviolet PCR Cabinets and Workstations

Page 11

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 the germicidal requirements are met. The germicidal
destruction rate is a function of the UV intensity at wavelength 254nm and exposure time. The
lower the tube intensity, the longer the lamps must be on to accomplish the same objective.

The UVX Radiometer using a 254nm sensor will allow the user to measure the 254nm emissions
from the tubes. When it is time to measure the UV intensity inside the PCR workstation
(recommended weekly or as needed), the sensors can be placed on the floor of the PCR. Close the
hood and turn on the UV tubes. Wait three 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.

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.

The bacterial destruction chart below indicates the amount of shortwave (254nm) UV energy
required for 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

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