Air disinfection calculator

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Air disinfection tool

This calculation tool for Air disinfection is based on a theoretical calculation. Once lamps are designed in equipment of any kind, the UVC efficiency should be measured as the equipment design will have an effect on the UVC intensity profile in the irradiated space and consequently on the UVC dose.

In the calculation following is taken into account:

System preferably on 24h, 7 days a week. Cycling (for instance in office buildings) is possible but should be taken into account when designing the application.
Reduction rate selection is based on design of application:
High -> optimized design with reflection, optimized air flow etc..
Low -> minimal design without reflection, optimized air flow etc.
As air speed in HVAC systems is typically very high (1 to 3 m/sec) a log 1 reduction can only be reached with optimized systems, placed in the best way in the system or in the room. Total solution needs to be optimized.
This tool has been designed to provide indicative calculations for air disinfection of moving air.
Calculations are based on Keitz formula for UV-C irradiance*. Dose is calculated: Irradiance*exposure time.
In design-in phase reflection, optical design, switches, temperature, humidity should be taken into account**
This calculation and outcome are to be used to get a first estimate of the number of lamps needed. The final number should be based on measurements in the final equipment. It is the final equipment manufacturer or installers’ responsibility to release a well performing product to the market.
For design-in support, please go through ** documents below.

Philips UV-C lamp systems are a safe, reliable and proven choice for use in ventilation air ducts, air disinfection units and stand-alone air purifiers. This calculator provides a rough indication of how many UV lamps you need in your in-duct air disinfection system. Detailed information about air disinfection is available here ›

This tool gives you a rough indication of how many UV lamps you need in your in-duct air disinfection system:

Detailed information about lamps are available in our e-catalogue ›

Air flow

The calculation is based on 70% reduction of micro-organisms taking various parameters into account, such as the effect of air moving in an open space, speed of air and cycles in a room.**

Required reduction rate of organisms

Please select the reduction rate you want to reach, which in most cases will be the combination of lamp selection and application design.

High can only be reached with a good design, reflector and correct amount of lamps. Therefore this should only be selected when installing the lamps in such a design.

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Your Result

The results are based on the following selections:

Product:

AirFlow: m³/minute

Reduction rate:

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UV output from the selected lamp: UVC 100h

Depreciation: % (at useful lifetime)

Number of lamps required to obtain effective dose: lamps

This is an indication only. Actual reduction rates will depend on equipment design. Please contact us for further information.

*IES Lighting Handbook, Application volume, 1987, 14-19;
Keitz. H.A.E. 1971. Light Calculations and Measurements, Macmillan and Co. Ltd., London, UK.
Legan, LW. UV disinfection Cahmbers, Water and Sewage works R56-R61;
Groocock, NH, Disinfection of Drinking Water by UV Light. J. Inst. Water Engineers and Scientists 38 (2) 163-172, 1984;
Antopol, SC. Susceptibility of Legionella pneumophila to UV Radiation. Applied and Environmental Microbioligy 38, 347-348. 1979;
Wilson, B. Coliphage MS-2 as UV Water Disinfection Efficacy Test. Surrogate for Bacterial and Viral Pathogens (AWWA/WQT conference 1992);
Wolfe, RL. Ultraviolet Disinfection of Potable Water; Current Technology and Research. Environmental Sci. Technology 24 (6), 768-773, 1990;

** https://www.ashrae.org/file%20library/technical%20resources/covid-19/i-p_a19_ch62_uvairandsurfacetreatment.pdf
Ultraviolet purification application information, perfection preserved by the purest of light, Philips, 2006.

Please Choose:

Please type in the air flow:

** https://www.ashrae.org/file%20library/technical%20resources/covid-19/i-p_a19_ch62_uvairandsurfacetreatment.pdf

Please indicate required reduction rate:

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The speed of the air streams and the air temperature influence the temperature of the bulb wall, and as a result the UVC lamp output. UV lamps have an optimal output at a bulb wall temperature of 40C.

If the airflow is fast (e.g. 3 to 4 meter per second), the bulb wall temperature will become equal to the temperature of the air. As a temperature of 20C, the UV output is decreased to 50%. This means that twice the amount of lamps is required to obtain the same effect.

At a low air speed (e.g. 0.5 to 1 meter per second), the bulb wall temperature is less affected.

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Temperature dependence of mercury lamp*:

* Ultraviolet purification application information, perfection preserved by the purest of light, Philips, 2006.

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Reflection of the walls influences the disinfection rate.

The higher the UVC reflection, the less UV power is required for the same effect, or a higher reduction of microorganisms is obtained.

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The required UV power also depends on type of organism that needs to be inactivated.*

For bacteria: 20 - 50 J/m²
For viruses: 50 - 100 J/m²
For mould: 100 - 1000 J/m²

* Ultraviolet purification application information, perfection preserved by the purest of light, Philips, 2006.

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The humidity influences the growth rate of microorganisms. An increase of UVC power is required if the humidity is more than 50%.***

***ASHRAE handbook

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