SIST EN 15665:2009
(Main)Ventilation in buildings - Determining performance criteria for design of residential ventilation systems
Ventilation in buildings - Determining performance criteria for design of residential ventilation systems
Standard for residential ventilation to include design and dimensioning of systems
This European Standard sets out criteria to assess the performance of residential ventilation systems (for new, existing and refurbished buildings) which serve single family, multi family and apartment type dwellings throughout the year. This European Standard specifies ways to determine performance criteria to be used for design levels in regulations and/or standards. These criteria are meant to be applied to, in particular: - mechanically ventilated building (mechanical exhaust, mechanical supply or balanced system); - natural ventilation with stack effect for passive ducts; - hybrid system switching between mechanical and natural modes; - windows opening by manual operation for airing or summer comfort issues. This European Standard considers aspects of hygiene and indoor air quality. Health risk from exposure to tobacco smoke is excluded from this European Standard.
Lüftung von Gebäuden - Bestimmung von Leistungskriterien für die Auslegung von Lüftungssystemen in Wohngebäuden
Dieses Dokument legt Kriterien zur Bewertung der Leistung von Lüftungssystemen fest, die Einfamilien , Mehrfamilien und Mietswohnhäuser das gesamte Jahr über versorgen.
Dieses Dokument beschreibt Wege zur Bestimmung von Kriterien, die für die Auslegungsgrade in Vorschriften genutzt werden können.
Diese Kriterien sind vorgesehen für die Anwendung bei:
Gebäuden mit maschineller Lüftung (ventilatorgestützte Abluft, ventilatorgestützte Zuluft oder Zu- und Abluft);
Luftschächten;
Hybridsystemen, die zwischen maschineller und freier Lüftung schalten;
manuell zu öffnende Fenster, zur Lüftung oder für komfortable Bedingungen im Sommer.
Dieses Dokument berücksichtigt Aspekte der Hygiene und der Raumluftqualität.
Dieses Dokument gilt für Lüftungssysteme in Neubauten, in Bestandsbauten und in sanierten Gebäuden.
Gesundheitsrisiken, die sich aufgrund von Tabakrauch ergeben, sind in diesem Dokument nicht behandelt.
Ventilation des bâtiments - Détermination des criteres de performance pour la conception des systemes de ventilation résidentielle
La présente Norme européenne définit les critères d'évaluation des performances des systèmes de ventilation
résidentielle (dans les bâtiments neufs, existants ou rénovés) équipant les logements unifamiliaux,
multifamiliaux et les appartements tout au long de l'année.
La présente Norme européenne spécifie les manières de déterminer les critères de performance à utiliser
pour les niveaux de conception dans les réglementations et/ou les normes.
Ces critères sont destinés à s'appliquer, en particulier :
⎯ aux bâtiments à ventilation mécanique (rejet mécanique, apport mécanique ou système double flux) ;
⎯ aux bâtiments ventilés par tirage thermique ou ventilation naturelle;
⎯ au système hybride assurant la commutation entre le mode mécanique et le mode naturel ;
⎯ aux fenêtres s'ouvrant à la main pour aérer ou améliorer le confort estival.
La présente Norme européenne tient compte des aspects liés à la santé et à la qualité de l'air intérieur.
Les risques sanitaires liés à l'exposition aux fumées du tabac sont exclus de la présente Norme européenne.
Prezračevanje stavb - Ugotavljanje karakterističnih izhodišč za zasnovo prezračevalnih sistemov za stanovanja
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.DVQRYRLüftung von Gebäuden - Bestimmung von Leistungskriterien für die Auslegung von Lüftungssystemen in WohngebäudenVentilation des bâtiments - Détermination des criteres de performance pour la conception des systemes de ventilation résidentielleVentilation in buildings - Determining performance criteria for design of residential ventilation systems91.140.30VLVWHPLVentilation and air-conditioningICS:Ta slovenski standard je istoveten z:EN 15665:2009SIST EN 15665:2009en,fr,de01-julij-2009SIST EN 15665:2009SLOVENSKI
STANDARD
SIST EN 15665:2009
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15665March 2009ICS 91.140.30 English VersionVentilation for buildings - Determining performance criteria forresidential ventilation systemsVentilation des bâtiments - Détermination des critères deperformance pour les systèmes de ventilation résidentielleLüftung von Gebäuden - Bestimmung vonLeistungskriterien für Lüftungssysteme in WohngebäudenThis European Standard was approved by CEN on 7 February 2009.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre:
Avenue Marnix 17,
B-1000 Brussels© 2009 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15665:2009: ESIST EN 15665:2009
EN 15665:2009 (E) 2 Contents Page Foreword . 3Introduction . 41Scope. 52Normative references . 53Terms and definitions . 54Symbols and units . 65Needs for residential ventilation: main issues . 65.1General . 65.2General sources of pollutants . 65.3Consequences of this pollution inside a dwelling . 75.4Expectations about ventilation . 76General approach . 76.1Questions, assumptions and way of proceeding . 76.2Requirements for designing a ventilation system . 96.2.1General . 96.2.2Assumptions and criteria chosen for ventilation airflow rates values (level 1) . 96.2.3Assumptions and criteria chosen for a single calculation representing point (level 2) . 106.2.4Assumptions and criteria chosen for a yearly calculation done for design days (level 3)127Criteria . 157.1General . 157.2Threshold or limit of the level . 157.3Weighted average concentration . 177.4Average concentration above a threshold with limited compensation . 187.5Average concentration above a limit . 197.6Dose above a given value . 207.7Decay criteria . 217.8Use of criteria depending on pollutant . 217.8.1General . 217.8.2Criteria for humidity . 217.8.3Criteria for specific activities . 227.8.4Criteria for background pollutant . 22Annex A (informative)
Example of general requirements (from Switzerland) . 23A.1General requirements for all ventilation systems . 23A.2Exhaust ventilation systems . 23A.2.1General . 23A.2.2Requirements for devices (only for exhaust ventilation systems) . 23A.2.3Mechanical Ventilation (with supply and exhaust fans) . 23A.3Assumptions and criteria chosen for ventilation airflow rates values (level 1) . 27A.3.1Exhaust ventilation systems . 27A.3.2Mechanical ventilation (with supply and exhaust fans) . 27Annex B (informative)
Example of occupancy scenario . 29 SIST EN 15665:2009
EN 15665:2009 (E) 3 Foreword This document (EN 15665:2009) has been prepared by Technical Committee CEN/TC 156 “Ventilation for buildings”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 2009, and conflicting national standards shall be withdrawn at the latest by September 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 15665:2009
EN 15665:2009 (E) 4 Introduction Nowadays most ventilation requirements either in regulations or in standards are based on required airflow rates. Also, there is relatively limited knowledge about the basis for ventilation flow rates. Airflow rates are however probably the easiest way to express ventilation requirements. Nevertheless it is worthwhile to consider in a more detailed way the influence of the dilution due to air change on human exposure, in order to understand the ventilation requirements expressed in terms of flow rates. Figure 1 explains the process from pollutant to health risk. This European Standard does not deal with health effects, health risks (linked to noise, tobacco), dose and energy impact. This European Standard is not intended to design and/or dimension a ventilation system.
This European Standard is intended to support any regulation or standard. This European Standard is intended to give guidance to those with responsibility for producing requirements and standards for residential ventilation systems.
It is recommended that future revisions of relevant regulations and standards should consider the content of this European Standard.
Figure 1 — Pollutant process SIST EN 15665:2009
EN 15665:2009 (E) 5 1 Scope This European Standard sets out criteria to assess the performance of residential ventilation systems (for new, existing and refurbished buildings) which serve single family, multi family and apartment type dwellings throughout the year. This European Standard specifies ways to determine performance criteria to be used for design levels in regulations and/or standards.
These criteria are meant to be applied to, in particular: mechanically ventilated building (mechanical exhaust, mechanical supply or balanced system); natural ventilation with stack effect for passive ducts; hybrid system switching between mechanical and natural modes; windows opening by manual operation for airing or summer comfort issues. This European Standard considers aspects of hygiene and indoor air quality.
Health risk from exposure to tobacco smoke is excluded from this European Standard. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 12792:2003, Ventilation for buildings – Symbols, terminology and graphical symbols EN 15242:2007, Ventilation for buildings – Calculation methods for the determination of air flow rates in buildings including infiltration 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12792:2003 and the following apply. 3.1 background pollutants group of indoor pollutants which are continuous and diffuse NOTE 1 These pollutants are represented by materials, furnishings and products used in the dwelling. NOTE 2 These pollutants also include those resulting from human occupation such as water vapour and carbon dioxide from respiration. 3.2 specific pollutants group of indoor pollutants which are of short duration, and in specific locations in the dwelling NOTE These pollutants are mainly represented by water vapour, carbon dioxide and odours, whose production is related to specific human activities in the dwelling (such as cooking, washing, bathing). SIST EN 15665:2009
EN 15665:2009 (E) 6 3.3 parameter pollutant or marker that is used in the expression of a requirement NOTE 1 More than one parameter may be used at the same time and combined. NOTE 2 Relative humidity, odours, CO2 are examples of parameters. 3.4 criteria way (method) to express the required performance NOTE Criteria can be, for example, numbers of hours above 70 % RH in living room calculated on a standard week basis, number of minutes to reach 25 % of the initial pollution concentration based on a standard pollutant emission in a toilet, average level of CO2 above outside in bedroom on a 10 hours night with two standard persons. 3.5 requirement level of required performance
NOTE Requirements can be, for example, "maximum of 100 hours above 70 % in living room", "less than 10 minutes to reach 25 % of initial ", "less than 800 10-6 CO2 (generally named ppm) as an average", "minimum of 8 l/s in toilet", "35 l/s for global ventilation in standard inside/outside conditions". 4 Symbols and units For the purposes of this document, the symbols and units given in EN 12792:2003 apply. 5 Needs for residential ventilation: main issues 5.1 General There shall be adequate means of ventilation provided for the building and its occupants.
5.2 General sources of pollutants The following sources of pollutants influencing the ventilation in dwelling shall be considered:
Outside environment, such as climate, earth (which can provide radon);
Human respiration, odours; Human behaviour, such as cooking, bathing, drying machine, cleaning; Emissions of building materials and furniture; Emissions of cleaning material; Combustion appliance. Each of these sources can produce pollutants.
SIST EN 15665:2009
EN 15665:2009 (E) 7 5.3 Consequences of this pollution inside a dwelling
Depending on the pollutant sources given in 5.2, the following consequences can be observed: a) For the building: risk of condensation, risk of dryness, mould growth, fungi’s, dust mites, interstitial condensation; b) For human health and comfort: carbon monoxide, CO2 level and water vapour, temperature, air velocity, germs, microorganisms, formaldehydes, VOC (volatile organic compounds), “volatile organic compound, odours, noise from outside. 5.4 Expectations about ventilation Considering the pollutant sources and their consequences, the adequate means of ventilation should be provided for one or more of the following purposes: a) Dilution and/or removal of background pollutants such as substances emitted by furnishings and building materials and cleaning materials used in the building, odours, metabolic CO2 and water vapour; b) Dilution and/or removal of specific pollutants from identifiable local sources such as toilet odours, cooking odours, water vapour from cooking or bathing, combustion products; c) Provision of outdoor air for occupants;
d) Provision of control of temperature effects (over heating and draught);
e) Provision of air for combustion appliances. All these purposes shall be considered with regard to the health and comfort of the occupants and integrity of the building.
NOTE 1 Ventilation is primarily concerned with the first three purposes (a) to c)) but it is linked to the last two (d and e)).
NOTE 2 When providing ventilation, other aspects of performance including thermal comfort, durability, fire safety, noise and energy use should be considered. 6 General approach 6.1 Questions, assumptions and way of proceeding
Before designing a ventilation system, the people involved in regulations and/or standards shall answer lots of questions and assumptions that have to be taken into account for calculation. The result of this calculation can be expressed by a continuous explicit airflow rate (e.g. mechanical ventilation with constant airflow rate) or an equivalent airflow in terms of air quality according to conventional assumptions applicable in each country (e.g. Technical Approvals). The following way of proceeding shall be used in order to determine airflow rates (see Figure 2): a) Step 1: verify if there is any applicable regulation
(health, fire protection, noise, gas, etc.) in the country that leads to certain limit in airflows; b) Step 2: identify the parameters which are taken into account or which are considered as relevant; c) Step 3: at this step of the procedure, take into account the 3 following points: SIST EN 15665:2009
EN 15665:2009 (E) 8 1) for each parameter, a detailed description shall be made of the nature, sources, distribution and time dependence; 2) for each parameter, the appropriate criteria shall be chosen as described in Clause 7; 3) assumptions for buildings, ventilation systems, outdoor conditions and occupancy patterns shall be described corresponding to the table at the chosen level described in 6.2; d) Step 4: use the appropriate calculation method able to handle the chosen criteria and assumptions; e) Step 5: make requirements on the chosen criteria and verify the performance of the calculation results with other applicable requirements (health, fire protection, noise, gas, etc.); f) Step 6: give results which can be expressed as an equivalent airflow.
Figure 2 — Way of proceeding for the determination of airflow rates
NOTE The process remains the same but the level of the assumption can be fitted to level 1 to 3; see 6.2. SIST EN 15665:2009
EN 15665:2009 (E) 9 6.2 Requirements for designing a ventilation system 6.2.1 General Depending on the parameter taken into account together with the criteria and the building, the appropriate level of calculation method shall be used:
ventilation airflow rates values (level 1); calculation done for one point (level 2); yearly calculation done for design days (daily pattern) (level 3). At each level, different tables shall be completed. At each corresponding level, criteria shall be chosen between the different ways developed in Clause 7 to explain how parameters are taken into account. For each level, the number of cases could vary from one case to many (statistical approach), depending on the size of the building, the number of habitants, etc. NOTE The local ventilation effectiveness may affect the calculation of exposure level.
6.2.2 Assumptions and criteria chosen for ventilation airflow rates values (level 1) The design regulation or standard shall describe the following relevant items:
a) Type of room: 1) Type of process for extract and supply air (natural or mechanical); 2) Floor level. b) Regime: 1) Continuous (min, max); 2) Intermittent (min, max, time schedule); 3) Closable or not (air inlets). c) Airflow rate expressed in one of the following expression in Table 1: 1) l/s per m2 2) l/s per person 3) l/s per room d) Global airflow rates (including infiltrations). e) Global air infiltration. At the level of component (externally and internally mounted air transfer devices, exhaust and supply air terminal devices, etc.) requirements can be expressed in equivalent area mm2, in airflow at a certain pressure difference ∆P, etc.
SIST EN 15665:2009
EN 15665:2009 (E) 10 Pressure loss due to doors between air inlets and air exhaust shall be taken into account. Table 1 – Design airflow rates for level 1
Airflow rate in l/s Room or space Airflow rate (Normal value) Airflow rate (Increased value) Kitchen
Bathroom
WC
Living room
Bedroom 1
Bedroom n
All dwelling
An example is given in Annex A. 6.2.3 Assumptions and criteria chosen for a single calculation representing point (level 2) The requirements considered at level 2 are for a single calculation representing point, for example, for an average point in winter to roughly design a shaft natural ventilation airflow.
NOTE A shaft natural ventilation system relies on pressure differences without the aid of powered air movement components. Assumptions for the case under consideration are given in Table 2. The size of the dwelling under consideration shall be defined as assumptions for the case under consideration.
In case of no specific assumptions, default value shall be used for the calculation, as specified in Table 2. Table 2 — Assumptions for level 2 Assumptions Case under consideration Default value Unit Indoor temperature
19 °C Outdoor temperature
8 °C Wind speed
1 m/s Wind directiona
60° windward - Shieldinga
shielded - Air leakage classes
n50 = 1
1/h Air leakage splitting
See Table 4. - Outdoor humidity (optional)
% RH a According to EN 15242.
SIST EN 15665:2009
EN 15665:2009 (E) 11 Clause 6 of EN 15242:2007 shall be used to calculate airflow rates, considering the building and ventilation system characteristics and the distribution of air leakage for each air leakage class as specified in Table 4 and Figure 3. The designer shall specify criteria for the case under consideration as proposed in Table 3. Table 3 — Criteria for level 2 Parametersa Case under consideration Default value Airflow (l/s or m3/h)
Minimum continuous airflow
a Additional parameters and corresponding assumption should be added if necessary.
Table 4 — Distribution of air leakage (default values) Distribution single family Air leakage class, n50
< 1 1 to 3 3 to 6 > 6 Floor and other leakages for instance adjacent buildings 20 % 25 % 30 % 35 % Roof 30 % 35 % 40 % 45 % Facade (at 1/3 height) 25 % 20 % 15 % 10 % Facade (at 2/3 height) 25 % 20 % 15 % 10 %
SIST EN 15665:2009
EN 15665:2009 (E) 12
Key 1 Leakage to crawlspace and other dwellings mainly penetrations for plumbing and waste water 2 Leakage through roof and joint roof/wall including penetrations for exhaust 3 Façade leakage cracks and joints between construction parts such as window-frame and walls, but also joints between movable parts concentrated on 1/3 of the height of the facade 4 Façade leakage cracks and joints between construction parts such as window-frame and walls, but also joints between movable parts concentrated on 2/3 of the height of the facade
Figure 3 — Distribution of air leakage 6.2.4 Assumptions and criteria chosen for a yearly calculation done for design days (level 3) For level 3, assumptions shall be made for one day, at a suitable frequency for all patterns concerning occupancy, outside conditions, ventilation system use or pollutant sources. NOTE Calculations lead to relationship between airflows and pollutant concentration.
Requirements shall be used in one of the different frames defined in Clause 7. This level 3 shall be used for daily calculations or for yearly calculations. Each day can have the same or different patterns if needed, e.g. week-end patterns are often used and are different from week patterns. Airflow rates shall be calculated according to Clause 6 of EN 15242:2007. Assumptions for the type of the building, the size of the room, occupancy, activity pattern, and human behaviour shall be specified as shown in Table 5. In case no such values are available, the default values given in Table 5 shall be used.
A mean (typical) schedule of human occupancy shall be provided (see example in Annex B). Humidity, absorption and desorption shall be specified. Humidity and pollutant data shall be available before calculations. The following assumptions are taken into account in Table 5:
washing/drying: 1200 g/machine (100g/h for 2 h and 50 g/h for 20 h) (default set frame for drying inside and default value); SIST EN 15665:2009
EN 15665:2009 (E) 13 nothing is taken into account for room cleaning; for meals: emission during 1 h including dish washing. water: 350 g/day for gas cooking for average consumption in the year of 800 kWh for one family. CO2 emissions due to combustion: (g/h) shall not be mixed up with metabolic emissions for determining criteria; the two emissions shall be considered separately. SIST EN 15665:2009
EN 15665:2009 (E) 14 Table 5 — Assumptions for level 3
Assumptions Case under consideration Default valuec Unit Thermal and meteorological assumptions Indoor temperature
°C Outdoor temperature
°C Wind speed
1
m/s Wind directiona
60° windward - Shieldinga
shielded - Outdoor humidity (optional)
% RH Building assumptions Air leakage classes
n50 = 1
1/h Air leakage splitting
See Table 4.
Occupancy pattern
Ventilation assumptions Ventilation system use pattern
Pollutant emissionb
(Water) Water vapour awake
55 g/h per person Water vapour sleeping
40 g/h per person Breakfast
50 g/pers Lunch
75 (150 WE) g/pers Dinner
300 g/pers Natural gas cooking
350
g/day Showerd
300 g/shower Washing/drying inside
1200 g/washing Frequency of shower/pers
1 shower/pers per day Frequency of washing/pers
1 washing/pers per week Pollutant emissionb (Metabolic CO2) CO2 awake
16 l/h per person CO2 sleeping
10 l/h per person
a According to EN 15242. b In case of calculations, assumptions of one pollutant (or more) is needed, in relation with the criteria chosen for requirements. c If the parameter is used. d Drying towels is included in the shower (default value): it is a 6 minutes shower.
SIST EN 15665:2009
EN 15665:2009 (E) 15 7 Criteria 7.1 General The starting point for the calculation method is to define the most important, or key, pollutant in each type of room in the dwelling. It is assumed that if the key pollutant is adequately controlled, then other pollutants in that room are also adequately controlled. For some rooms, it may not be clear which the key pollutant is, until some calculations have been made.
The following key pollutants shall be taken into account according to the schedule: CO2 (metabolic) or water vapour in low pollution rooms; water vapour, odours and CO2 (from combustion of fuels) in kitchens; water vapour in bathrooms and laundry/utility room; odours in WC. Pollutant emission rates shall be calculated for each room separately based on either known emission rates or data given as assumptions in the standard frame defined in Clause 6. This may require assumptions about the number of occupants in the dwelling, the type and rating of combustion appliances, and occupant habits (clothes washing, cooking, bathing, etc). Humidity is taken into account in separate way due to the fact that it impacts on building independently of occupancy and external value is varying in large proportion. Other particularity is that both too high level and too low level can induce discomfort or impact building. Criteria shall be chosen among criteria specified in 7.2 to 7.7. These criteria can be associated. 7.2 Threshold or limit of the level The chosen criteria can be a threshold of the pollutant concentration.
It shall be associated with one or more of the following:
Time above this threshold during a reference period; a particular value of this time can be zero; Maximum continuous duration above this threshold during a reference period; Occurence of pollutant concentration has exceeded the threshold value; Occurence of pollutant concentration has exceeded the threshold value for a given time during the reference period. Reference period can be for example, the occupied period, the whole year.
The evolution of concentration pollutant at threshold is illustrated in Figure 4. SIST EN 15665:2009
EN 15665:2009 (E) 16
Key X time, in hours
Y concentrations in ppm 1 threshold Figure 4 — Example of evolution of maximum concentration pollutant at threshold Criteria can be the average concentration during a reference period. In this case higher values are compensated by lower values. The evolution of concentration of pollutant at average exposure is illustrated in Figure 5. SIST EN 15665:2009
EN 15665:2009 (E) 17
Key X time, in hours
Y concentrations in ppm 1 average
Figure 5 — Example of evolution of concentration of pollutant at average exposure 7.3
Weighted average concentration
The different contributions are weighted (continuous function or discrete values): In the following example in Figure 6, C is the original concentration. A discrete weighting can be applied, for example: C < 1000 : no change
: C’ = C 1000 < C < 1500: multiplied by 2
: C’ = 2xC 1500 < C < 2000: multiplied by 3
: C’ = 3xC 20000 < C : multiplied by 4
: C’ = 4xC A continuous weighting can be applied, for example: C’’ = Cx(C/500): SIST EN 15665:2009
EN 15665:2009 (E) 18
Key X time, in hours
Y concentrations in ppm C the lower curve which is the original concentration
C' the doted line which is the result of the discrete weighting process
C'' the continuous line which is the result of the continuous weighting process
The straight lines are the corresponding average values. Figure 6 — Example of evolution of weighted concentrations and average weighted concentration NOTE The level of acceptance should be adapted from the weighting method. The interest of this criterion is to permit a penalisation of high values; any weighting is possible, giving the possibility to choose the levels.
The drawback is to be far from any physical reality and to give arbitrary coefficients that could be discussed. 7.4 Average concentration above a threshold with limited compensation To calculate the compensated average above a given threshold, one takes equal to the value threshold all the values lower than the threshold. On this basis, the average concentration is calculated. The interest is to limit the compensation of higher level with lower level. The evolution of concentration of pollutant at average exposure above a threshold is illustrated in Figure 7. SIST EN 15665:2009
EN 15665:2009 (E) 19
Key X time, in hours
Y concentrations in ppm 1 average above a limit Figure 7 — Example of evolution of concentration of pollutant at average exposure above a limit 7.5 Average concentration above a limit The chosen criteria can be the average concentration above a limit value, calculated with the ti
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.