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Relative bactericidal effectiveness

There are several types of uphymeter. The instructions on using the automatic UVR dosimeter ДАУ-81 (DAU-81) for measuring the intensity of the UVR and radiation dose are given below.

A dosimeter measures an energy (band to 500 W/m²) and dose (band from 10 J/m² to 15 MJ/m²) of radiation at the exposure angles between +80° and - 80° from the artificial sources: bacteridcidal diapason UVR-DB from 0.22 to 0.28 mcm (region C); lamps LUV-40, LUV-80 with band from 0.32 to 0.40 mcm (optical region).

A dosimeter ДАУ-81 (DAU-81) consists of a measuring block and converters – primary (UV-C) with F-29 photoelement for wave length 0.22 – 0.28 nm (region C); primary (UV-A) with F-26 photoelement and UV and C2C23 color filters for wave length 0.32 – 0.40 mcm (region A); primary (FAR) with F-25 photoelement and C3C25 and ZC4 color filters for wave length 0.38 – 0.71mcm (optical region).

Dosimeter setup. Connect the primary converter for the selected region (C, A or optical region) to the measuring block and a cable of radiation source (UV lamp) to a control system.

Plug the device into the electrical supply network. Press the “Power” button. The device is ready when the pointer is not at 0 immediately after that.

Order of testing. Press “Power” and switch on the dosimeter.

Press the radiation wave band of energetic illumination switch button (“10”) (the primary converter is closed), after that press the “Уст. 0” (Set 0) button to set the microampermeter pointer to zero.

Press the “500” button. Take the deck off the primary converter. Check the data of the ampermeter. Select a more sensitive mode if the pointer shows less than 1/5 of the scale.

Set necessary dose of irradiation according to the sensor.

Press the “Reset” button. The counter has to show zero.

A chime will make a sound and the radiation source (UV lamp) will be switched off when the necessary dose has been reached.

Write down the data, and press “Reset”. The counter has to show zero.

Dosimeter is ready again after a necessary dose of radiation is set according to the sensor.

2.5. Calculation methods of determination of the UV radiation intensity.

2.5.1. The following formula is used for the calculation of erythemal flow from a movable source of the UVR

ℱ_{source of radiation} = 5.4 × S × H/t,

where:

ℱ is the general (integral) flow of irradiation device, ;

5.4 – safety factor;

S – area of the room, m²;

t – the duration of the irradiation source work, min;

H – dose of the preventive UV irradiation, .

Values of H: - if 1 MЕD = 800 mcer (mcW/cm²) = 5000 ;

- if ¹/₂ MЕD = 400 mcer (mcW/cm²)=2500 ;

- if ¹/₄ MЕD = 200 mcer (mcW/cm²) = 1250 ;

- if ¹/₈ MЕD = 100 mcer (mcW/cm²) = 625 .

Comment: The calculation of the preventive UVR dose during the exposure to the sun or the open air with the tables is shown in the topic #3 - “Usage of the UV radiation for disease prevention and air sanation”.