The contamination of air-handling units is a widespread phenomenon in buildings with air-conditioning systems, including hospitals. The germicide capacity of UV-C rays is known and, in the air-conditioning apparatuses, the UV-C lamps are generally located inside the air ducts. Aim of the paper is to evaluate the effectiveness of UV-C lamps when they are differently placed, i.e. in a position to directly irradiate the HEPA filters surface. We built ad hoc experimental air-conditioning systems, with HEPA filters and UV-C lamps in the two described positions. The results obtained demonstrate that, for disinfection purpose, the direct irradiation of the HEPA filters by UV-C provides better results than irradiation of the air stream and the effectiveness increases when lowering the relative humidity of the air. The survival curves of the tested microorganisms (fungi) show typical tail shaped curves (two steps survival curves). Additional tests using both HEPA filters alone, and HEPA filters plus UV lamps, have been performed measuring the air pressure drop between entrance and exit the HEPA filters and collecting air samples in order to obtain total microbial and fungal count. The results obtained suggest that, at least in experimental conditions described, the radiation on filter surface reduces significantly the microbial load and the pressure drop through the filter, compared to a situation of not-irradiated HEPA filters.

Air bio-contamination control in hospital environment by UV-C rays and HEPA filters in HVAC systems / D'Orazio, A.; D'Alessandro, D.. - In: ANNALI DI IGIENE MEDICINA PREVENTIVA E DI COMUNITÀ. - ISSN 1120-9135. - 32:5(2020), pp. 449-461. [10.7416/ai.2020.2369]

Air bio-contamination control in hospital environment by UV-C rays and HEPA filters in HVAC systems

D'Orazio A.
Primo
Writing – Original Draft Preparation
;
D'Alessandro D.
Ultimo
Writing – Review & Editing
2020

Abstract

The contamination of air-handling units is a widespread phenomenon in buildings with air-conditioning systems, including hospitals. The germicide capacity of UV-C rays is known and, in the air-conditioning apparatuses, the UV-C lamps are generally located inside the air ducts. Aim of the paper is to evaluate the effectiveness of UV-C lamps when they are differently placed, i.e. in a position to directly irradiate the HEPA filters surface. We built ad hoc experimental air-conditioning systems, with HEPA filters and UV-C lamps in the two described positions. The results obtained demonstrate that, for disinfection purpose, the direct irradiation of the HEPA filters by UV-C provides better results than irradiation of the air stream and the effectiveness increases when lowering the relative humidity of the air. The survival curves of the tested microorganisms (fungi) show typical tail shaped curves (two steps survival curves). Additional tests using both HEPA filters alone, and HEPA filters plus UV lamps, have been performed measuring the air pressure drop between entrance and exit the HEPA filters and collecting air samples in order to obtain total microbial and fungal count. The results obtained suggest that, at least in experimental conditions described, the radiation on filter surface reduces significantly the microbial load and the pressure drop through the filter, compared to a situation of not-irradiated HEPA filters.
HEPA Filters; HVAC system; Indoor Air Quality; Microorganisms; UV-C Lamps
01 Pubblicazione su rivista::01a Articolo in rivista
Air bio-contamination control in hospital environment by UV-C rays and HEPA filters in HVAC systems / D'Orazio, A.; D'Alessandro, D.. - In: ANNALI DI IGIENE MEDICINA PREVENTIVA E DI COMUNITÀ. - ISSN 1120-9135. - 32:5(2020), pp. 449-461. [10.7416/ai.2020.2369]
File allegati a questo prodotto
File Dimensione Formato  
DOrazio_Air-bio-contamination_2020.pdf

accesso aperto

Note: http://www.seu-roma.it/riviste/annali_igiene/apps/autos.php?id=1337
Tipologia: Documento in Post-print (versione successiva alla peer review e accettata per la pubblicazione)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 335.83 kB
Formato Adobe PDF
335.83 kB Adobe PDF Visualizza/Apri PDF

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1449807
Citazioni
  • ???jsp.display-item.citation.pmc??? 5
  • Scopus 6
  • ???jsp.display-item.citation.isi??? 5
social impact