Application of global service to air filtering systems

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1

SCUOLA DI INGEGNERIA INDUSTRIALE E

DELL’INFORMAZIONE

MASTER OF SCIENCE

MECHANICAL ENGINEERING

MASTER THESIS

ACADEMIC YEAR 2015/2016

APPLICATION OF GLOBAL SERVICE TO

AIR FILTERING SYSTEMS

SUPERVISOR CANDIDATE

ING. LUCA LEONARDO

FUMAGALLI

CAMBIOTTI

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RINGRAZIAMENTI

La laurea è una di quelle occasioni considerate importanti nella vita di una persona. Il Dr. Perry Cox l’ha elencata come primo grande avvenimento per ognuno di noi e insieme a matrimonio, divorzio e funerale forma i cosiddetti “big four”, gli eventi importanti a cui è necessaria la presenza di parenti e amici. Per questo mi prendo qualche riga in questa occasione per ringraziare coloro che ci sono veramente sempre stati per me, a partire dai miei genitori che mi hanno supportato incondizionatamente in tutto ciò che ho intrapreso, a mia sorella Elena per la quale credo di essere stato un buon monello da imitare, ai nonni Franco, Giulia e Annetta con i quali ho sempre “creato” qualcosa, a Glenda che oltre ad essere un’ottima compagna di vita mi ha sempre tenuto focalizzato sugli obiettivi importanti. Un ringraziamento è d’obbligo anche per la Zia Doni e Alberto sui quali ho potuto sempre contare e per Diego e Cecilia con i quali ogni volta ritorno ad essere ancor più bambino.

Per il supporto durante la stesura di questa tesi devo ringraziare l’Ing. Luca Fumagalli e l’Ing. Irene Roda, insegnati del Politecnico di Milano, per l’indirizzamento e il supporto e l’Ing. Michele Acerenza, l’Ing Marco Fiori, Eliana Solcia e Carlo Ferri per avermi iniziato e insegnato molto durante la mia esperienza in Camfil.

Non posso non citare gli amici che hanno sempre rappresentato un punto fermo e con cui ho passato alcuni dei più belli e significanti momenti della mia vita. Quindi per essere arrivato fin qui devo per forza ringraziare gli amici di sempre Matteo, Michele, Mattia, Bisca, Alessio T, Giorgio, Alessio e gli amici di scuola Gianluca e Andrea.

In ultimo un ringraziamento va a chi ha condiviso con me l’avventura universitaria dai miei primi momenti qui a Milano, in particolare Seba, Matteo e Massimo.

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Table of Contents 3

TABLE INDEX

Chapter I: Indoor Air Quality

Tab 1.1 Guide values for each substance based on effects different from cancer

or from unpleasant odors (WHO guidelines 2000)... 23

Tab 1.2 Estimated cancer risk based on human studies to exposures concentrations of 1 μg/ 3 (WHO Guidelines 2000)... 23

Tab 1.3 Estimated risk for asbestos (WHO Guidelines 2000)... 24

Tab 1.4 Estimated risk and recommended action level for radon (WHO Guidelines 2000)... 24

Tab 1.5 Guide values for individual substances based on the effects on vegetation (WHO Guidelines 2000)... 24

Tab 1.6 Values for PM short term exposition from WHO guidelines 2005... 29

Tab 1.7 Values for PM long term exposition from WHO guidelines 2005... 29

Tab 1.8 Minimum risk levels for exposition to PM... 30

Chapter II: Air filtering systems Tab 2.1: Performance Values to be measured after each increase of dust load... 42

Tab 2.2 Filter classification in accordance with EN 779:2012... 42

Tab 2.3 Example of the standardized particle size distribution qv in ambient air for the particle size channels... 47

Tab 2.4 Filter classification in accordance with the ISO-16890... 47

Tab 2.5 Example filter data of Filter... 48

Tab 2.6 Example for the calculation of PM-efficiencies... 49

Tab 2.7 Filter classification for EPA, HEPA, ULPA... 53

Tab 2.8 Buildings classification on the basis of cleaning level... 55

Tab 2.9 Inspection intervals suggested by the EN 15780:2011... 56

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Table of Contents

6 Tab 2.11 Acceptable levels of dust accumulation in the ducts... 56

Tab 2.12 Classification of outdoor air quality in accordance with the

standard... 57 Tab 2.13 Concentration levels of outdoor air... 58 Tab 2.14 Classification of indoor air quality in accordance with the

standar... 59 Tab 2.15 Minimum recommended class for filtering section... 60

Chapter III: Total Cost of Ownership of Global Service

Tab 3.1 Assumptions recap... 86

Chapter IV: Test on a reference case

Chapter V: Final considerations from Camfil

Chapter VI: Conclusions

Chapter VII: Bibliography

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Figure index

7

FIGURES INDEX

Chapter I: Indoor Air Quality

Fig 1.1 Camfil Logo... 17

Fig 1.2 Camfil filter solution... 19

Fig 1.3 Filter for power sector... 20

Fig 1.4 Dust, mist and fume control solutions... 21

Fig 1.5 Dust penetration in respiratory system... 27

Fig 1.6 Relative dimentions of PMs... 30

Chapter II: Air filtering systems Fig 2.1 UTA block scheme... 35

Fig 2.2 Collecting global efficiency variation in function of the particulate diameter... 38

Fig 2.3 Unit collectiong efficiency variation in function of the particulate diameter and collecting technique... 39

Fig 2.4 Example filter data of Filter... 48

Fig 2.5 Comparison between EN 779 and ISO 16890... 50

Chapter III: Fig 3.1 Example of TCO components standardization (IEC 60300-3-3 1996)... 62

Fig 3.2 Possible costs distributions... 63

Fig 3.3 Determination and generation TCO... 64

Fig 3.4 TCO equation... 64

Fig 3.5 Cost voices for TCO evaluation... 65

Fig 3.6 Role distribution in Global Service... 67

Fig 3.7 Advantages of Global Service... 68

Fig 3.8 LCC external sight... 71

Fig 3.9 LCC’s Running Condition section... 72

Fig 3.10 LCC’s cost rates section... 74

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Figure index

8

Fig 3.12 Example of different substitution policies... 75

Fig 3.13 Camfil’s actual business areas... 78

Fig 3.14 Camfil’s spread worldwide... 79

Fig 3.15 Europe detail... 80

Fig 3.16 Maintenance cost distribution... 81

Fig 3.17 Examples of cost distribution in air filtering systems... 84

Fig 3.18 Pressure gauges... 84

Fig 3.19 Fiat Ducato van... 89

Fig 3.20 Fan system poor condition... 92

Fig 3.21 UTA conditions with no maintenance... 93

Fig 3.22 Detail of no maintenance... 93

Fig 3.23 Project data first part... 97

Fig 3.24 Project data second part... 97

Fig 3.25 Project data third part... 98

Fig 3.26 Fixed cost section... 100

Fig 3.27 Variable cost first part... 101

Fig 3.28 Variable cost second part... 101

Fig 3.29 Results section... 103

Chapter IV: Fig 4.1 Running condition... 106

Fig 4.2 LCC costs... 106

Fig 4.3 LCC cost voice... 106

Fig 4.4 G4 prefilter degradation... 107

Fig 4.5 F7 compact filter degradation... 107

Fig 4.6 Model output in the as-is situation... 109

Fig 4.7 Running condition of the improved situation... 110

Fig 4.8 Improved situation LCC costs... 111

Fig 4.9 30/30 life in reference case condition... 111

Fig 4.10 Model results for improved case... 112

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Figure index

9 Fig 4.12 LCC cost with FOG replacement every 3 months... 113

Chapter V: Final considerations from Camfil

Chapter VI: Conclusions

Chapter VI: Bibliography

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Abstact

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ABSTRACT

Storicamente il settore dell’air filtering è stato, e in alcuni casi è ancora, caratterizzato dalla fornitura dei nuovi filtri in sostituzione degli esausti. Camfil ed alcune altre aziende hanno un approccio più generale, cercano infatti di proporre soluzioni che possano portare dei benefici ai clienti in termini energetici e ambientali. Lo scopo di questo lavoro è quello di studiare, inseme all’azienda, la fattibilità di un ulteriore passo avanti nelle relazioni tra cliente e fornitore, sempre tenendo presenti i benefici sopra citati. La novità che la società produttrice di filtri vuole studiare è rappresentata dalla applicazione del Global Service, un'offerta che copre tutte le necessità richieste dal sistema di ventilazione, dall'installazione iniziale allo smaltimento a fine vita. Attualmente sul mercato italiano non ci sono produttori che forniscono l'intero servizio sui sistemi di areazione, l'unica soluzione possibile è di incaricare una società di manutenzione. Queste aziende però non sono dedicate alla sola filtrazione dell’aria e solitamente la loro attività è quella di fornire la manutenzione su tutto l’impianto. In questo lavoro di tesi si studia una metodologia per passare il compito direttamente a Camfil, che conosce bene le proprie soluzioni ed è in grado di fornire le migliori performances, in quanto i suoi prodotti sono riconosciuti tra i best in class per le prestazioni di filtrazione e il consumo energetico.

Analizzeremo quindi le basi di filtrazione dell'aria, le norme da seguire e le condizioni necessarie per erogare un Global Service. In particolare un modello per valutare il costo totale di Global Service offerto da Camfil ai propri clienti è stato sviluppato, applicando la metodologia del Total Cost of Ownership. Una volta definite le modalità e i costi del servizio potremo capire, insieme a Camfil, se il tipo di proposta può essere economicamente sostenibile per le parti interessate e se poter andare a proporla ai clienti.

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Abstact

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ABSTRACT

Historically the air filtering sector was, and in some cases still is, characterized by the provision of new filters in replacement of the exhausted. Camfil and some other companies have a more general approach, in fact, they try to propose solutions that can bring benefits to customers in energy and environmental terms. The purpose of this work is to study, together with the company, the feasibility of a further step in the relationship between customer and supplier, always having in mind the benefits stated above. The news that the manufacturer of filters wants to study is represented by the application of the Global Service to this sector, an offer that covers all the necessities required by the ventilation system, from initial installation to disposal at end of life. Currently on the Italian market, there are no manufacturers that provide the whole service on ventilation systems, the only possible solution is to hire a maintenance company. These companies, however, are not dedicated only to air filtration and usually their activity is to provide the maintenance of the entire system. In this thesis we study a methodology to move the task directly to Camfil, who is familiar with their own solutions, and can provide the best performance, in that its products are recognized among the best in class for filtration performances and energy consumption. Then we will analyze the air filtration basics, the standards to follow and the conditions required to provide a global service. In particular a model for assessing the total cost of Global Service offered by Camfil to its customers has been developed, applying the methodology of the Total Cost of Ownership. After defining the modalities and the cost of services we can understand, along with Camfil, if the type of proposal can be economically viable for the parties involved and if we can offer it to customers.

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Introduzione in italiano

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INTRODUZIONE IN ITALIANO

Il lavoro di tesi svolto in collaborazione con Camfil ha avuto come scopo lo studio di un nuovo servizio da introdurre nel mercato degli air filtering system, il Global Service. L’idea dietro questa proposta sta nel far avvicinare di più manufacturer e client. L’approccio classico vede il cliente contattare, nel momento in cui ritiene di dover sostenere la manutenzione, il fornitore con il quale si accorderà per avere dei filtri di ricambio. I sistemi di ventilazione richiedono diversi interventi manutentivi, alcuni di semplice sostituzione filtri mentre altri di controllo, manutenibilità e pulizia delle UTA (Unità di Trattamento Aria). Con il Global Service che andremo a studiare si valuterà la possibilità da parte di Camfil di farsi carico di tutte queste attività, la quale si occuperà di svolgerle nel miglior modo possibile, essendo specializzata nella filtrazione di aria da più di mezzo secolo, permettendo al cliente di concentrarsi sulle attività che rappresentano il proprio core business.

Il lavoro di tesi è stato articolato in quattro capitoli principali, il primo introduce alle problematiche e alle necessità della filtrazione dell’aria, il secondo espone i principali standard del settore che devono essere rispettati, il terzo mostra un modello di implementazione del servizio e l’ultimo testa il modello costruito in un contesto reale. Gli altri capitoli inseriti sono di supporto in quanto comprendo bibliografia e conclusioni.

In breve il servizio che dovremo offrire al cliente deve includere tutte le azioni necessarie al sistema di areazione, si parte con la fase di discussione contrattuale e scelta dei filtri da installare più le varie azione manutentive da svolgere sul sistema. Una volta concordato il tutto con il cliente starà al fornitore trasportare i filtri a destinazione, rimuovere i vecchi, smaltirli ed installare i nuovi. Per tutta la durata del contratto, dovrà provvedere alle necessarie sostituzioni e alla manutenzione del sistema filtrante, che tipicamente è svolta con cadenza annuale.

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Introduzione in italiano

13 Tutte queste azioni ad oggi sono dei costi sia in termine di tempo che di denaro,

il modello che è stato sviluppato punta proprio a stimare tutte queste cost voices in modo da poter capire il Total Cost of Ownership del sistema di areazione.

Una volta che Camfil è in possesso dei vari costi sarà in grado di proporre ai propri clienti, in alternativa alla semplice fornitura di filtri, un servizio completo per la gestione delle UTA.

Le simulazioni svolte su un caso preso come riferimento mostrano come la richiesta di applicazione di global service comporti un aumento dei costi di un 15% rispetto alla sola spesa di acquisizione ed energia. La componente energia merita un approfondimento in quanto solitamente rappresenta il 70% del costo totale di gestione delle UTA quindi, una cattiva gestione degli elementi filtranti con conseguente aumento delle perdite di carico, comporta immediatamente una importante perdita economica.

Il Global Service è quindi volto anche a “curare” gli impianti affetti da cattiva gestione e proporre al cliente un risparmio considerevole in termini economici per l’energia risparmiata e ambientale per l’ottimizzazione nell’utilizzo dei filtri. In conclusione in questo lavoro si mostrano, dopo aver analizzato le fondamenta del problema dell’indoor air quality e le varie norme da rispettare, le modalità di esecuzione del Global Service con le relative complicazioni e le potenzialità che può avere, sia per il cliente che per Camfil, una volta implementato.

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Chapter I Indoor Air Quality

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INDOOR AIR QUALITY

1.1 Introduction

Why is so important to filter air? The answer is basically made of two aspects: to protect people from pollutions and to protect industrial processes.

Example of this practices are very common, in industrial sector a lot of items as electronic devices, pharmaceutical products or food require clean air to be processed safely. The clean air is also mandatory to ensure a good health, every day we see lots of people going around the cities wearing anti-pollution masks. This is the probe that the air around us is not so good the way it is.

After some years researchers showed that air pollution in confined environments can be potentially more dangerous than atmospheric. This has taken some time to came out because the effects on human body is mostly chronic and requires some time to show.

Today people of industrialized cities spend 90% of their time in confined environment and, always for industrialized cities, the measured outdoor air quality exceeds the regulation limits for 60% of the year.

From the combination of the two aspects is easy to understand the importance of a good Indoor Air Quality for our offices and houses.

Usually, for Indoor Air Quality it is meant that form of pollution affecting the air in closed places, such as homes, offices and community facilities, where there are the most human activities.

Currently we don’t have a universally shared definition of “good air quality”, the most successful is the one proposed by 'American Society of Heating, Refrigerating, and Air-Conditioning Engineers - ASHRAE (ASHRAE, 2010):

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16 "air quality is considered acceptable when there are no known pollutants in

concentrations harmful to health, as determined by the competent authorities, and when a large percentage of people (80% or more) does not express dissatisfaction with it".

In the definition we find the concept of cleanness and comfort. So the good air must be safe and enjoyable for people who breath it.

In fact, it has been shown that an air is unpleasant because of the "sick building syndrome", syndrome described as a situation in which the occupants of a building to have an acute phenomena effects that appear related to the time spent in a building, but which can not be identified as specific diseases or causes.

Today the practice of improving air quality is carried out by adding in the ambient fresh and filtered air, this means a dilution of pollutant concentration.

1.1.1 Air Contaminants

In the air that we breath every single day are present contaminants. We can found it in confined environment because or they come from outside or are produced inside the same environment. Among the main pollutants with chemical mechanism of action, there are carbon monoxide, nitrogen dioxide, sulphur dioxide, benzene, ozone and aero-dispersed particulate. To the category of biological pollutants belong pollens and microorganisms (mold, bacteria, fungi). While between pollutants with the mechanism of action of physical type there are asbestos and radon.

The effects that the pollutants can induce on people are generally grouped into three categories:

 Olfactory stress, sometimes combined with headaches, sore throat and eyes;

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17  Biological effects on some organs, that manifest themselves in the form

of irritation and allergic reactions;  Carcinogenic effects.

Of course the effects on human health are very dependent on exposure time, type of contaminant and its concentration, so it is common that the effects of the same pollutant come out with different entities.

In confined environments the presence of contaminants can be increased by the presence of following factors:

 Man, which generates pollution for the normal metabolic processes (carbon dioxide, water vapour and bioeffluents), pets, tobacco smoke, cooking food and the use of detergents and cleaning agents;

 The building materials and furnishings, which can be sources of harmful substances (formaldehyde, asbestos, radon, VOC);

 The technical systems of air conditioning, combustion and the different equipment, household or office (microorganisms, VOC, combustion products).

1.2 The company

Fig 1.1 Company logo

The company that allowed me to study the air filtering sector is Camfil. Form its site we can have some direct informations on who are this people and what they do, so I simply quote the presentation:

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18 “Camfil is a global leader in the air filtration industry with more than half a

century of experience in developing and manufacturing sustainable clean air solutions that protect people, processes and the environment against harmful airborne particles, gases and emissions. These solutions are used globally to benefit human health, increase performance and reduce energy consumption in a wide range of air filtration applications. Our 26 manufacturing plants, six R&D sites, local sales offices and 3,800 employees provide service and support to our customers around the world. Camfil is headquartered in Stockholm, Sweden. Group sales total more than SEK 6 billion per year”.

We see that they are quite experienced on air filtration and also thanks to them I could understand the subject and the problem.

The company is divided in three business area: Filters, Power Systems, Air Pollution Control.

Filters constitute the product platform for all of Camfil’s operations and the Group’s biggest core business. Filters also generate the highest percentage of Camfil’s sales. Camfil’s air filters can be as small as a matchbox and as large as a shipping container.

Their end product is clean air free of harmful or damaging pollutants, dust, dirt, allergens, contaminants, molecular gases and, in some cases, even life-threatening radiation, depending on the application.

By providing clean air, filters improve people’s health and performance, protect critical manufacturing processes, boost productivity and safeguard the environment.

Camfil offers the most energy-efficient filters for public and commercial buildings. These products deliver clean air for high indoor air quality (IAQ). At

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19 the same time, they help building owners reduce their energy consumption and

carbon footprint.

In the production world, filters and clean air solutions are crucial for protecting advanced or sensitive manufacturing processes, or for combatting airborne molecular contamination or microbiological contamination.

In the healthcare sector, hospitals use filtration systems to eliminate infectious airborne contaminants.

In the nuclear power industry, Camfil is the leader in particulate filtration, gas-phase filtration and containment, with experience from all over the world. Camfil has also leveraged this experience from containment to develop advanced biocontainment systems and filter housings for high-risk research facilities and biosafety labs.

The Filters Business Area also includes line of standalone air purifiers and air cleaners.

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20 The second business area for the company is the protection of power system by

the supplingheavy-duty filtration and noise-control equipment for gas turbines. Solutions include air inlet filtration systems, acoustic enclosures, de-icing and cooling systems, and exhaust stacks. Other specialties include plant optimization, service and refurbishment.

Fig 1.3 Filters for Power sector

The last Business Area is Air Pollution Control, it operates globally in North America, Europe and Asia under the Camfil Air Pollution Control (APC) name.

APC’s main mission is to design, manufacture and supply a full range of dust, mist and fume collectors to clean up factories, making them safer, more productive and more sustainable. APC’s collection equipment is typically used in metal, mining, pharmaceutical, chemicals, paper, seed processing, food processing and many other industries.

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Fig 1.4 Dust, mist and fume control solutions

1.3 WHO Guidelines for Air Quality

The WHO Guidelines for Air Quality1_{is the main document that aims to} guarantee a proper air quality and reduce impact of pollution on health.

The first version of Guidelines for Air Quality was published on 1987 and it was updated 10 years later, in 1997.These guidelines are based on expert evaluation of current scientific evidence.

1_{Air quality guidelines for Europe, 2nd ed. Copenhagen, World Health Organization Regional}

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22 In 2000 came out a second edition, it showed the result of many studies on

pollutants effects on health. In the document is clearly reported the scope of the work that is: “The primary aim of these guidelines is to provide a basis for protecting public health from adverse effects of air pollution and for eliminating, or reducing to a minimum, those contaminants of air that are known or likely to be hazardous to human health and wellbeing.”

The latest version on which we can refer is the 2005 update, here we find guidelines on the four most common air pollutants that are Particulate Matter (PM), ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2).

The 2005 update is just a revision and is not complete, for a deeper understanding of the problem we should take as reference the whole work from 2000.

The guidelines are a tool that help us on setting some threshold levels for tolerance exposition and understening what that can imply for human health. They also state very clearly that the reported value can not be simply used but need some revision before the application on the basis of the particular environment, the concentration of pollutant and other variable factors. The values represent level for acceptable risks, not total absence of it.

We can see from the following tables some information from guidelines on exposure times and tolerant concentration of several substances.

Tab.1.1 shows the average concentrations of certain substances, which may cause annoying effects different from cancer or from unpleasant odors, as a function of the exposure period.

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Tab 1.1 Guide values for each substance based on effects different from cancer or from unpleasant odors (WHO guidelines 2000)

Tab.1.2 shows the risk values for carcinogenic substances known as genotoxic. It should be highlighted that for carcinogens is more complicated to define a level of security, since according to the theories ofcarcinogenesis there is not a threshold value that separates the safe area from the risky one. So you have to decide whether to ban direct exposure or to restrict concentrations at a borderline level which is associated with an acceptable risk level.

Tab 1.2 Estimated cancer risk based on human studies to exposures concentrations of 1μg/ 3_{(WHO Guidelines 2000)}

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24 For asbestos and radon are provided separated tables where the level of risk is

expressed as a range, which indicates the Excess lifetime risk, which is the additional risk of developing cancer during their lifetime, due to exposure to carcinogenic agents.

Tab 1.3 Estimated risk for asbestos (WHO Guidelines 2000)

Tab 1.4 Estimated risk and recommended action level for radon (WHO Guidelines 2000)

In Tab 1.6 shows the guide values for major air pollutants.

Tab 1.5 Guide values for individual substances based on the effects on vegetation (WHO Guidelines 2000)

According with the Guidelines, the air pollutants can be divided into four major categories: organic pollutants, inorganic pollutants, classic pollutants and indoor air pollutants.

The WHO Guidelines of 2000 Guide for each category, report extensive discussion of individual pollutants, indicating their source, the average

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25 concentrations, the estimated effects on health and, where possible, the reference

threshold levels.

The categories of the research are divided in categories:

 Organic pollutants  Inorganic pollutants  Classical pollutants  Indoor air pollutants

In organic pollutant we find substances like benzene, carbon monoxide, carbon disulfide, formaldehyde, polycyclic aromatic hydrocarbons and many others.

The inorganic pollutants are for example arsenic, asbestos, fluoride, hydrogen sulfide and many metals like nickel, platinum, vanadium, mercury, cadmium and chromium.

In classical pollutants are substances like nitrogen dioxide, ozone and others photochemical oxidants, sulfur dioxide and particulate matter.

The indoor air pollutants are radon, environmental tobacco smoke and man-made vitreous fibers.

For all the pollutants the WHO guidelines give an exposure evaluation with the exposure levels for people based on the area where the presence of pollutant is higher, following we have the health risk evaluation in which the exposure time and diseases are correlated and finally the guidelines to prevent or limit the hazardous.

We don’t enter now in details of each pollutant analyzed by WHO guidelines but focus our work on the most common industrial pollutant: the particulate matter.

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1.4 Particulate matter

Particulate matter is the term for a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope_.

Particle pollution includes:

 PM10: inhalable particles, with diameters that are generally 10

micrometers and smaller

 PM2.5: fine inhalable particles, with diameters that are generally 2.5

micrometers and smaller

The PM10 are generated by mechanical processes such as construction activities,

road dust re-suspension and wind, whereas PM2,5 originates primarily from

combustion sources.

Particulate matter contains microscopic solids or liquid droplets that are so small that they can be inhaled and cause serious health problems. Particles less than 10 micrometers in diameter pose the greatest problems, because they can get deep into your lungs, and some may even get into your bloodstream. Fine particles (PM2.5) are also the main cause of reduced visibility (haze).

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Fig 1.5 Dust penetration in respiratory system.2

The WHO Guidelines 2005 warn us about the effects of particulate matter:

“The evidence on airborne particulate matter (PM) and its public health impact is consistent in showing adverse health effects at exposures that are currently experienced by urban populations in both developed and developing countries. The range of health effects is broad, but are predominantly to the respiratory and cardiovascular systems. All population is affected, but susceptibility to the pollution may vary with health or age. The risk for various outcomes has been shown to increase with exposure and there is little evidence to suggest a threshold below which no adverse health effects would be anticipated. In fact, the low end of the range of concentrations at which adverse health effects has been demonstrated is not greatly above the background concentration, which for particles smaller than 2.5 μm (PM2.5) has been estimated to be 3-5 μg/m3 in both the United States and western Europe. The epidemiological evidence

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28 shows adverse effects of PM following both short-term and long-term

exposures.

As thresholds have not been identified, and given that there is substantial inter-individual variability in exposure and in the response in a given exposure, it is unlikely that any standard or guideline value will lead to complete protection for every individual against all possible adverse health effects of particulate matter. Rather, the standard-setting process needs to aim at achieving the lowest concentrations possible in the context of local constraints, capabilities and public health priorities. Quantitative risk assessment offers one way of comparing alternative control scenarios and of estimating the residual risk associated with a particular guideline value. Both the United States Environmental Protection Agency and the European Commission have recently used this approach to revise their air quality standards for PM. Countries are encouraged to consider adopting an increasingly stringent set of standards, tracking progress through the monitoring of emission reductions and declining concentrations of PM. To assist this process, the numerical guideline and interim target values given here reflect the concentrations at which increased mortality responses due to PM air pollution are expected based on current scientific findings.”

From this extract we see that the WHO is worried about such a presence of PM in the air of America and western Europe and suggests to adopt an increasingly set of standards.

So it is really important to reduce the concentration of PM in the air in order to guarantee the comfort and health of people.

The guidelines fix the thresholds levels of exposition and we can see from the tables the values for short term and long term.

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Tab 1.6 Values for PM short term exposition from WHO guidelines 2005

Tab 1.7 Values for PM long term exposition from WHO guidelines 2005

The WHO guidelines set as security level the lowest values from the tables 1.7 and 1.8:

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Tab 1.8 Minimum risk levels for exposition to PM

We see how the 2005 guidelines tackle the PM problem defining some “tolerance exposure” to PM10 and PM2.5 but these two kinds of particulate matters are not the only to threaten our health.

1.4.1 PM

1

At the moment the 2005 version is the latest one available but in the recent years the scientific community started to investigate also another kind of PM, finer than the others, the PM1.

• PM1– particles <1 µm in size. Examples: dust, combustion particles, bacteria and viruses.

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31 As shown in Fig 1.6 the PM1 is much more fine than the other particulate and it

can reach easier the found of the lungs and enter the bloodstream in respect with PM10 or PM2,5.

As showed above in figure 1.5 our body can naturally filter the biggest particles, for example the PM10 are stopped by the noise, but we are unarmed against the smallest particles so we need some way to be safe.

So to provide a truly healthy and productive indoor air environment in areas with bad air pollution, ventilation systems need filters that are also capable of removing PM1 particles – the smallest fraction and the most harmful.

Our lungs are prey to PM1. When inhaled, PM1 particles travel to the deepest area of the lungs, where a significant part of them passes through the cell membranes of the alveoli (the millions of tiny sacs in our lungs where O2 and CO2 are exchanged), enter the bloodstream, damage the inner walls of arteries, penetrate tissue in the cardiovascular system and potentially spread to organs. At worst, PM1 can contribute to deadly diseases like heart attacks, lung cancer, dementia, emphysema, edema and other serious disease, leading to premature death.

We will see in the next chapter that starting from January 2017 a new standard for filter classification, ISO 16890, will be adopted. This new regulation will group the filter on the PM10,PM2.5 and PM1 efficiency.

Even though the WHO doesn’t mention the PM1 in the 2005 Guidelines version in another works made it refers to PM1as “…likely to be most harmful, as they penetrate deep into the human lung.3”

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32 So to ensure a good Indoor Air Quality we have to deal with the reduction of

PM1 concentration, to obtain it the new filters should be chosen checking the PM1 efficiency.

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Chapter II Air filtering systems

33

Air filtering systems

2.1 Introduction

In previous chapter we saw the main pollutants of the air and the effects that they can have on human health, now we will analyze the equipment used to filter the air and delivery clean and fresh air to confined environments.

Usually all the industrial processes have to face the problem of particulate matters in the supplying air, so we focus our work on the reduction of this particular type of pollutant in order to get a better air quality. To get this goal we can use the air filtering system, specifically filtering sections in which the air is cleaned by passing through a filter media.

The CTI (Comitato Termotecnico Italiano) stated that in design phase of a new air-conditioned building is needed to select the right air filters which can supply the desired IAQ level and reduce at the lowest possible the energy consumption, according with the 10-year strategy Europe 2020. This plan set the purpose of reducing greenhouse gas emissions by at least 20% compared to 1990 levels, increase the share of renewable energy in final energy consumption to 20%, and achieve a 20% increase in energy efficiency.

The main equipment used to achieve the purpose of filtering air is the AHU – Air Handling Unit, UTA Unità di Trattamento Aria in Italian. This tool is widely used in industrial sector and now we’ll show shortly the structure and the working principles of an UTA, then the most important standard of this sector.

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2.2 Ventilation and air conditioning systems

Ventilation and air conditioning system is the whole system made by UTA and ducts. The function of the system is to provide good quality air form outside to inside, removing pollutants if present and warm or cool it if necessary, increasing the level of IAQ.

Basically the function of air systems is to take some air from outside, filtering it and then delivery it to ambient. Through the ventilation it starts moving the air, returning the inside air with outside and diluting the pollutants.

Of course the system must be able to serve all the users, so it has to be correctly dimensioned in order to provide the right amount of fresh air. It is a good practice to consider the users to serve and the main pollutants to face already in design phase, in order to avoid some errors and to have a not proper functioning system.

Even a window can be considered a natural ventilation air system because it guarantees an air change but usually we refer to air systems which creare pressure gradient and, in these cases, we call them forced ventilation air systems.

On the market we find several typologies of air systems, they differ on function. We can have air system that just dilutes the pollutant or other that are made also for warming the air:

 Ventilation system, only makes air exchange (dilutes the pollutants);  Thermo-ventilation system, ventilation air and controls the temperature;  Cooling System, ventilates the air and controls the relative humidity

parameters and speed.

In Fig 2.2 we can see a general block scheme of an UTA. It is made by (from left to right) filtering section, fan, cold battery, humidifier, drop separator and hot battery.

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Fig 2.1 UTA block scheme

With this type of design we can both have hot and cold air as output, in fact these systems are used along the whole year, both for summer cooling and winter heating, and, with seasons changing, also the parts of UTA kept in working condition change.

The difference between the two possible configuration is made by inhibiting the humidifier for summer cooling or pumping hot water into both the battery in order to have hot air in winter.

More precisely in summer conditioning the air, after passing through the filtration stage, is pushed into the cooling battery where is cooled until the temperature t1, higher than input temperature tc. Usually the temperature control is allowed by a thermostat (T1). On the bottom of cold battery a tray collects the water that condenses on the cold tubes. In this case we don’t have the humidifier on working and the air goes to drop separator in which the drops are separated from the flow. Finally, through the heating coil, the air is brought to the desired temperature C.

In winter heating the air, after being filtered, it is thrust by the fan to pass on the first battery, which in this case behaves as hot battery due to the passing of hot water inside the tubes. The air then passes through the saturator (humidifier with ∅ = 100%) and the droplets separator. Finally, through the second heating battery that brings air to the requested tc temperature.

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36 Usually inside the UTA we find two filtration stages, the first one is coarse

filters, with poor filtration efficiency, that are supposed to retain “big” contaminants such as insects, spores, birds, larger particulates, leaves etc. and guarantee a good cleanness inside the UTA. After this first sage of filtration is placed a second stage equipped with fine filters, which have a higher efficiency and capable of retain smallest particles. In this way the system can ensure a very good air quality to the served environment.

In cases in which a further step toward extreme clean air is required a third stage of filtration is present, but this stage is not located into the UTA but at the end of the ducts, practically in contact with the ambient to serve. This is the field of application of high efficiency filters, known as absolute filters because their efficiencies are very high, tending to unit value.

The filtration mechanisms are mainly:

 Sieve, when the particles or objects have larger dimensions of the filter mesh4 and then fail to cross it;

 Interception, when a particle touches the fiber and is captured;

 Inertial impact, when a particle is so large as not to be able to follow the abrupt changes of direction of the flow lines in the vicinity of the fiber but, because of its inertia, continues to the tangent and impact the fiber. This type of mechanism is predominant while in the presence of high flow velocity and a high density of the mat;

 Brownian diffusion, when the particles are small, with diameters less than 0,1μm, and tend to have random motions caused by their collision with the gas molecules and between them. The spread is a function of flow rate and of particle size. The smaller the particles, the slower the flow, the greater the time that the particles have available for their random motion, thereby increasing the probability of hitting a fiber and be captured;

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37  Electrostatic, when the medium is loaded with opposite charge to that of

the particles.

The filtration efficiency is a very important characteristic of the filters. It represents the number of captured particles compared to the total number of particles impacting on average.

The efficiency value can vary depending on material chosen for filter media, predominant filtering technique, effective area of filtering section and degree of clogging of the filter. Indeed the maximum value of efficiency is reached when the filter is clogged ant maximum level, this is due to the material that over time deposits itself on the filter.

Of course if the filter is completely clogged the efficiency value is 1 but because nothing is passing through the section, not even air. On the other hand we face an increasing of pressure drops with the increasing of clogging level. Our task will be to choose the best time to replace the filter balancing the pressure drops, that bring with them a higher energy consumption, and the clogging level that means better filtration efficiency.

In Fig.2.3 it is shown the overall efficiency of a filter as a function of particle size.

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Fig 2.2 Collecting global efficiency variation in function of the particulate diameter

The curve "total" shown in Fig.2.3 is the result of the combination of the individual filtration mechanisms, which have different efficiencies as a function of particle size (Fig.2.4).

As can be seen from Fig.2.3, the overall efficiency curve has a minimum around 0.1-0.2 µm (order of magnitude of the MPPS particles), for which this dimension is particularly critical to treat. For this reason the rules on particulate filtration systems propose a classification of filters based on efficiency on the particles of 0.4 µm.

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Fig 2.3 Unit collecting efficiency variation in function of the particulate diameter and collecting technique

2.3 Standards

2.3.1 EN 779:2012 Particulate air filters for general ventilation -

Determination of the filtration performance

Mission: set specifics and performances of particulate filters.

This is the main European standard, used since 2002, to classify and test the filters, and it is still in use at the end of 2016.

The first standard developed to deal with the classification of the filters for ventilation was the Eurovent 4/5 in the 1980. Inside of it we find the first classification and it was pretty simple, indeed there was only two types of filters: coarse and fine. The differentiation was made on the basis of efficiency average point (for fine filters ranging from EU5 to EU9) and on arrestance (for coarse filters, from EU1 to EU4).

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40 This first definition didn’t specify neither the air flow to use nor the final

pressure drop.

More than 10 years later, in 1993 we have the Eurovent 4/9. This standard, revised in 1997, set DHES, a fine oil mist, as aerosol to perform the test and stated that the particulate range on which base the efficiency calculation was 0.2-5.0 µm.

In the same year, in 1993, the European Committee for Standardization (CEN) publish the EN 779, on the basis of Eurovent 4/5.

After passing through an update in 2002 that set as reference size the 0.4 µm, the standard received the last change in 2012. Respect the 2002 version it reports a finer categorization of filter, in fact in 2012 version we find three different major categories of filter: fine (F), medium (M) and coarse (G) instead the 2002 version had only two of them fine (F) and medium (M).

The latest version states that the efficiency calculation had to be performed on electrically discharged filters, this because many filters reach high efficiency due to the presence of charge. This effect is not durable along all the filter life and after some time is lost and the filter performance falls down, in some cases the performances are so different that is not even more in the same target class.

Inside the standard we find information about the testing procedure, it is set that the air flow rate has to be of 0.24 3/s (850 3_{/h) and 1.5} 3_{/s (5400} 3_/h).

The real usage of the standard is not to predict the exact performances of filter in working condition, this is neither so easy to obtain because in real application there are lots of different parameter to consider that are not replicable in laboratory environment. Also the condition used on test phase are quite different from reality, for example the filter are tested for very long time, until reaches 450 Pa of pressure drop. This value is higher than the final pressure drop in

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41 which the filters are changed, that is usually is 250 Pa. In this way the filter

efficiency is overestimated by the standard.

So the real utility of the standard is to provide a testing procedure in order to have quick information on different filters by giving some synthetic parameters, like as the reference class, to compare them.

For the classification of the standard filters 779: 2012 provides two types of tests:

 Test with synthetic aerosols order to measure the filtration efficiency as a function of particle size in a range from 0.2 µm to 3.0 µm;

 Testing with coarse aerosols for obtaining information on the sealing capacity against powder, and for coarse filters estimate the arrestance, i.e. the average of the efficiency as a function of the applied powder load.

The two types of test are relative to the two main filter typology. The test with synthetic aerosols is used on medium (M) and fine (F) filters, and the used technique in order to have the filtration efficiency is the particle counts5, which links the number of particles downstream of the filter to the injected particles upstream.

Test with coarse aerosols is used on gross (G) filters, here the filtering sections are subjected to gravimetric test so the efficiency is calculated as ratio between the mass of dust retained by the filter on the total injected mass, practically this is a mass efficiency.

The test procedure specified by EN779: 2012 for classifying a filter is as follows:

1. Place the filter according to the manufacturer's recommendations and check their integrity by visual inspection;

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42 2. Measure the pressure drop at the filter heads using filtered air for 4 different

flow rates (50%, 75%, 100% and 120% of the test flow);

3. Determine, using an optical particle counter, the initial efficiency to 0,4μm, through measures upstream and downstream of the filter;

4. Feed gradually with the synthetic dust filter, periodically interrupting the supplying to measure the arrestance, the efficiency, the pressure loss and the weight amount. of the particulate sent (Tab.2.1);

5. Determine the filter class according to the average recorded performance.

Tab 2.1 Performance Values to be measured after each increase of dust load

In Tab 2.2 is shown the filter classification in accordance with EN 779:2012

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43 The filters with an average efficiency value of less than 40% compared to 0.4

μm particles are classified in group G and their efficiency is reported as "<40%". The classification of Class G filters (G1 - G4) is based on their average arrestance performances.

The filters with an average efficiency of between 40% and '80%, related to particles of 0.4 µm are classified in group M (M5, M6) and the classification is based on their average efficiency (0.4 µm). The old 2002 standard didn’t have the (M) group and the transition from coarse filter to fine was direct, in fact after G4 we had F5, F6 and so on. In this version the filters F5 and F6 have been renamed in M5 and M6 but basically they remain the same filters.

The filters with an efficiency average of 80% or greater, referred to 0.4 µm, are classified in group F (F7-F9) and their classification is based on the efficiency average (0.4 µm), as in previous system, and according to the minimum efficiency measured during the test.

As Shown in Tab 2.2 the standard requires also the measure of minimum efficiency, to ensure a better transparency for final users. The cause of measuring the minimum efficiency is due to the fact that some type of filters use electrostatical effect to increase their performances, but this effects vanish in presence of oils or moisture in the air stream.

The minimum efficiency corresponds to the smallest value measured between:

• Initial Efficiency (of a new filter) with DEHS;

• Measured initial efficiency of a filter material sample after the "artificial" removal of electrostatic charges present on the filter media; • Minimum efficiency between those measured on the dirty filter.

The 2002 version didn’t give attention to the aspect but the EN 779: 2012 version, to overcome this problem and to enable users to understand the real

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44 potential of the filtration media, introduced the test to evaluate the efficiency of

electrically discharge filter.

To assess minimum performance, you must first electrically discharge the media according to the following procedure:

•Efficiency measurement of untreated media (electrically charged), with speeds of up to 100% and 50% of the rated speed of the filter;

• Neutralization of charge, by immersion of the filter media in isopropanol and subsequent drying (24h);

• Control of the total evaporation of the isopropanol for weight comparison between the average pre-treated and dried medium; • The treated media’s efficiency measure (electrically discharge).

The measures carried out at 100% of rated speed, provide the average efficiency values, while the results obtained with the 50% of the nominal speed representing an actual load loss evaluation parameter.

The main issues of this standard are the overestimation of filter efficiency and the consideration of 450 Pa as final pressure value, value never reached in real application and the partial influence of electrostatical effects on filter efficiency evaluation.

To overcome these problems and provide a finer categorization of filters ISO has developed a new standard, quite different from this one, named ISO 16890. It will be in charge starting January 2017 in parallel with 779:2012 for 18 months.

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2.3.2 ISO 16890 - Air filters for general ventilation

Mission: establishing a better standard, stopping to overestimate the filter

efficiency in working condition and considering a better end of filter life point.

This standard establishes an efficiency classification system of air filters for general ventilation based upon Particulate Matter (PM). It also provides an overview of the test procedures, and specifies general requirements for assessing and marking the filters, as well as for documenting the test results.

The test method described in this standard is applicable for air flow rates between 0,25 m3_{/s (900 m}3_{/h, 530 ft}3_{/min) and 1,5 m}3_{/s (5400 m}3_{/h, 3178 ft}3_/min), referring to a test rig with a nominal face area of 610 mm × 610 mm (24 inch × 24 inch).

The full test according to this standard consists of the steps given below, which all shall be carried out with the same filter test specimen under the same test conditions and at the same test air flow rate:

a) Measure the initial fractional efficiency curve Ei of the unloaded and unconditioned filter element as a function of the particle size in

accordance with ISO 16890;

b) Carry out an artificial conditioning step in accordance with ISO 16890;

c) Measure the fractional efficiency curve ED,i of the conditioned filter element as a function of the particle size in accordance with ISO 16890; d) Calculate the PM efficiencies

e) Load the filter with synthetic test dust in accordance with ISO 16890 to determine the initial gravimetric arrestance, the resistance to air flow versus the mass of test dust captured and the test dust capacity (optional for filters of group PM10 or higher);

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46 f) Measure the fractional efficiency curve of the conditioned filter

element after dust loading as a function of the particle size in accordance with ISO 16890.

The initial fractional efficiency curve Ei of the untreated and unloaded filter element and the fractional efficiency curves ED,i after an artificial conditioning step are used to calculate the average fractional efficiency curve EA,i using Equation:

EA,i = 0,5 · (Ei + ED,i) (1)

The procedure described in ISO 16890 quantitatively shows the extent of the electrostatic charge effect on the initial performance of the filter element without dust load. It indicates the level of efficiency obtainable with the charge effect completely removed and with no compensating increase in mechanical efficiency. Hence, the fractional efficiencies ED,i after an artificial conditioning step could under-estimate the fractional efficiencies under real service conditions. Since the real minimum fractional efficiencies encountered during service strongly depend on the operating conditions defined by numerous uncontrolled parameters, its real value will lay unpredictably between the initial and the conditioned value. For good sense, the average between the initial and the conditioned value is used to predict the real fractional efficiencies of a filter during service, as defined by Equation (1).

Therefore, it may be noted that fractional efficiencies measured in real service may differ significantly from the ones given in this standard.

To evaluate air filters according their PM-efficiencies, a standardized volume distribution of the particle size is used which globally represents the average ambient air of urban areas. Typically, in the size range of interest (> 0.3 μm), the particle sizes in ambient air are bimodal distributed with a fine and coarse mode.

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Tab 2.3 Example of the standardized particle size distribution qv in ambient air for the particle size channels

The initial gravimetric arrestance and the three efficiency values ePM1, ePM2,5 and ePM10 and the minimum efficiency values shall be used to classify a filter in one of the four groups given in Table 2.4.

Tab 2.4 Filter classification in accordance with the ISO-16890

The filter classes are reported as class reporting value in conjunction with the group name. For the reporting of the PM classes, the class values have to be rounded to the nearest multiple of 5 %. Values larger than 95 % are reported as “>95%”. Examples of reporting classes are ISO 60 % Coarse, ISO 60 % ePM10, ISO 80 % ePM2.5, ISO 85 % ePM1, or ISO > 95 % PM1. For filters of group ePM10 or higher, the dust loading to ISO 16890 and the measurement of the initial gravimetric arrestance is optional.

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48 ISO coarse filters can be classified only based on the initial gravimetric

efficiency and hence, in this case the measurement of the PM efficiencies is optional.

In a full summary report, all five PM-efficiency values shall be reported, namely the three efficiency values to the three different PM particle size ranges and the minimum efficiencies to ePM1 and ePM2.5 particle size ranges. The reporting of the initial gravimetric arrestance is optional.

The standard explains how to use the new procedure with a practical case.

Tab 2.5 Example filter data of Filter

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Tab 2.6 Example for the calculation of PM-efficiencies

We can observe that every filter has expressed 5 different indicator

performance, unlike for previous standards now it’s easier to understand the specific quality of the filter in respect to the different kind of particulate.

As showed in Fig 2.6 the new classification is more precise than the old one, indeed in EN 779 we can have two filters in the same with quite different efficiencies.

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Fig 2.5 Comparison between EN 779 and ISO 16890

For example we can have two filters, the first one with 73% of PM1 efficiency and a second one with 85%. These two filters have quite different characteristic but for EN 779 are both F8. The new standard instead classifies them in two different classes, ePM1 70% and ePM1 85%, showing to user the differences between the two solution.

I think that this aspect needs to be clearly explain to users because, starting from next month, they will be in front of different solutions, with different prices and performances, that until now were considered the same solution.

2.3.3 EN 1822

– High performances filters (EPA, HEPA, ULPA)

Mission: The standard applies to air filters, high and very high efficiency and

very low penetration (EPA, HEPA and ULPA), used in the field of ventilation and air conditioning, as well as in technological processes such as technology clean rooms or the pharma industry. It establishes a process for the determination of efficiency on the basis of a particle counting method using a liquid aerosol as test (or in an alternative solid) and allows to classify these filters as a function of their efficiency.

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51 The European standard EN 1822 "Air filters with high efficiency (EPA, HEPA

and ULPA)" applies to air filters for high and very high efficiency and very low penetration (EPA, HEPA and ULPA), used in the field of ventilation and air conditioning, as well as in technological processes such as clean room technology or the pharmaceutical industry. It establishes a process for the determination of efficiency on the basis of a particle counting method using a liquid aerosol (or in an alternative solid) test and allows the classification of these filters, in a normalized way, in function of their efficiency6.

The first draft of 1998, revised in 2009, is different from the previous one as it includes the following elements:

 an alternative test for the evaluation of losses of Group H filters, different from the panels;

 an alternative test that uses a solid rather than a liquid aerosol;

 a method of evaluation and classification of filters with membrane type filter medium;

 a method of evaluation and classification of filters with a filter medium of synthetic type.

The main difference is related to the classification of H10 - H12 filters, that have been renamed E10 - E12 to better specify the difference between Efficient Filters (EPA, also called "semi-absolute filters"), for which it is not required on the test losses, and High Efficiency filters (HEPA, also called "absolute filters"). The ULPA filters are those defined with very low penetration.

The current classification is:

 EPA (Efficient Particulate Air filter) - E10, E11 and E12;  HEPA (High Efficiency Particulate Air filter) - H13 and H14;

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52  ULPA (Ultra Low Penetration Air filter) - U15, U16 and U17.

For this filters the standard set a stringent scan test on individual base, on which every single filter is tested and the results must not be different from the target ones more than 0,01%. This is due to ensure the absence of construction errors, because the absolute filters are used in critical situations, where reliability is a must.

Also the traditional filters are subjected to scan test but not on individual basis, but on batch basis, so not all the filters are tested before the usage.

The standard is divided into five sections, each of which analyzes a portion of the problem, traces the boundaries and rules.

 Classification, performance testing, marking

 Aerosol production, measuring equipment, particle counting statistics  Tests on the sheet of filter material plane

 Determination of loss in the filter elements (scan method)  Determination of efficiency of filter elements

EN 1822-1: 2009 establishes that the filters must be designed and constructed so as to be easily installed and free of leaks along the edges.

In summary, the standard EN 1822 provides methodologies for:

 evaluate the efficiency of the filter media. Verified that each filter medium has a maximum penetration point (or minor efficiency) relatively to a specific dimension of the test particles (which can vary as a function of the flow crossing speed, the density of the filter medium and the diameter of the fibers)

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53  check the losses of the filter element. This test is performed with a probe

which produces aerosols which can be moved across the surface of the filter so as to collect a series of local data on the efficiency which will then be used to determine the overall efficiency; in this way it is possible to determine the rate of loss of specific area of the filter. The overall efficiency calculation is often referred to as the integral value, while the leak rate is defined as a local value.

 determine the filter element integral efficiency. In the first instance it is measured the pressure loss of the filter at a volumetric flow rate of air corresponding to the nominal flow, and subsequently, by means of an aerosol generator, it determines the efficiency of the filter in correspondence of the MPPS particles. Depending on the efficiency of such value, a classification according to the table below. (General Filter source)

In Tab.2.4 is the classification for the three groups of filters according to the efficiency and penetration.

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2.3.4 EN 15780 Ventilation for buildings- Ductwork - Cleanliness of

ventilation systems.

Mission: provide a European standard for ventilation system’s hygiene.

The standard was published in 2011 and it is applied to ventilation and air conditioning systems with the purpose of setting specifics for procedures cleaning-

This standard does not apply to systems serving industrial processes, which specific rule are present on the base of the kind of process.

We can use this standard to have a general idea of what is required to clean the air system, without focus our attention on a specific industrial process.

EN 15780: 2011 specifies the general requirements and procedures necessary in the evaluation and maintenance of cleanliness in ventilation ducts, it defines:

 The classification of cleaning quality;

 How to evaluate the need for cleaning (visualization, measures);  The control frequency (general guide): guidance of the inspection

system in accordance with UNI EN 15239 and UNI EN 15240, if relevant;

 Choice of cleaning method, to be in line with the delivery of the documentation according to the UNI EN 12599;

 How to evaluate the cleaning results.

The ventilation and air conditioning systems have a dual function:

 remove pollutants through extraction systems;  introduce fresh air in buildings.

Application of global service to air filtering systems

SCUOLA DI INGEGNERIA INDUSTRIALE E

DELL’INFORMAZIONE

MASTER OF SCIENCE

MECHANICAL ENGINEERING

MASTER THESIS

ACADEMIC YEAR 2015/2016

APPLICATION OF GLOBAL SERVICE TO

AIR FILTERING SYSTEMS

SUPERVISOR CANDIDATE

ING. LUCA LEONARDO

FUMAGALLI

CAMBIOTTI

RINGRAZIAMENTI

TABLE OF CONTENTS

TABLE INDEX

FIGURES INDEX

ABSTRACT

ABSTRACT

INTRODUZIONE IN ITALIANO

INDOOR AIR QUALITY

1.1 Introduction

1.1.1 Air Contaminants

1.2 The company

1.3 WHO Guidelines for Air Quality

1.4 Particulate matter

1.4.1 PM

Air filtering systems

2.1 Introduction

2.2 Ventilation and air conditioning systems

2.3 Standards

2.3.1 EN 779:2012 Particulate air filters for general ventilation -

Determination of the filtration performance

2.3.2 ISO 16890 - Air filters for general ventilation

2.3.3 EN 1822

– High performances filters (EPA, HEPA, ULPA)

2.3.4 EN 15780 Ventilation for buildings- Ductwork - Cleanliness of

ventilation systems.