A r a ş t ı r m a irritation, therefore an acceptable perceived indoor air quality would be relatively casy to obtain. Another example is tobacco smoke which has been listed asa carcinogen byt he U.S. Environmental Protection Agency (EPA). This means it might not be possible to reach an "acceptable indoor air quality', because ofthe health risk; but it might be possible to reach an "acceptable perceived indoor air quality' in a smoking environment. in the CIBSE proposal, this definition is found in the text: "lndoor air quality may be said to be acceptable if less than 50 % of the occupants can detect any odor, less than 20 % experience discomfort, less than 1 O % suffer from mucosal irritation, and less than 5 % experience annoyance tor less than 2 % of the time". Howewer, the CIBSE draft also states that this comfortrelated definition of "acceptable indoor air quality' does not take into account substances such as radon which potent ially affect health but are odorless. AIIof the proposed standards deal with the health issue and not just with the comfort issue. CIBSE refers of the World Health Organization defınition of good health as ... "a state of complete physical, mental and social well-being, not merely the absence of disease and infırmity." According to this definition, "comfort equates to well-being" and, therefore, is a component of health. Because the committees which have developed these documents are dominated by members with engineering backgrounds, the have avoided setting new criteria tor health, but refer to recommendations from international authorities such as the World Health Organization (WHO, 1987) or national authorities such as EPA, NIOSH, OSHA and ACGIH; which are involved in establishing Threshold Limit Values (TLV, fılıAJ<) or similar criteria. Prescriptive procedure with table values ASHRAE 62-1989R has two prescriptive procedures: The Simple System Procedure may only be used for single zone systems and 100 % outdoor air systems. Using this procedure, assumptions are made for occupant density, ventilation effectiveness and fılter efficiency. The minimum ventilation rates for both prescriptive procedures are listed in a table. The method ofcalculation is shown in Table 3. Values tor four typical spaces (single office, landseaped offıce, conference room and classroom) are shown in Table 4. in addition to the minimum ventilation requirement, ASHRAE 621989R also requires that the total amount of supply air (outside + recirculated) must be at least 7.5 Vs (15 cfm) per person. Simple systems Prescriptive procedure procedures Minimum ı.entilation rate : Design Ventilation Rate for each space : v,. = .E � Us DVR = Rı,PoD + RıAo Us R., = Outdoor air Rp = Outdoor air per Person (fable 4), (fable 4), Us.mı Us. Person Ab = Floor area, m ı Po = Design accupancy per mı D = Occupant Diı.ersity factor Rb = Outdoor air requirement per mı (fable 4), Us.mı Ab = Floor area, mı Minimum supply air Minimum supply air MSR = RssAo Us MSR ;;>; DVRJE,.,and;;,, 7,5P0DIE.c R,. = Supply air (fable 4) E., = air change effectiı.enes Us.mı Table 3. Calculations for the two procedures. People B.Jildina Area related R>om Standard Class � Low Rı flbt low Roe Us.oerson 1 oollutina 1polluting Us mı prB'N 1752 (93) A 10 1.0 2D B 7 0.7 1.4 C 4 0.4 0.8 □N19461941 11 1.11 The CEN document operates with ventilation requirements in there categories, representing satisfaction levSing!e office AS-E62 (reıı.93) 30 0.35 0.66 els of 85 % 80 % and 70 %. The analytical method presented in an appendixofASHRAE 62-1 989R also includes a method tor establishing requirements at different levels of satisfaction. Estimating Minimum Ventilation in each of the documents, more than one procedure for estimating minimum ventilation is included. Each includes a prescriptive method where the minimum ventilation rates can be found in a table listing values for different type of spaces. Analytical procedures tor calculating the minimum ventilation rate are also included. Using the analytical procedure, ventilation rates are calculated on the basis of pollutanttype, emission rate and acceptable concentration. A-E62-89 10 i'J<B-61 191' 35 0.7 OBS&G..ide A treıı. 93' 8 prB'N 1752 A 10 1.0 2.0 B 7 0.7 1.4 C 4 0.4 0.8 laıdscaped □N1946 16.6 1.67 office A-E621reıı.93' 3.0 0.35 0.65 AS-E62-89 10 i'J<B-61I91' 3.5 0.7 OBSE-G..ideA lreıı. 931 8 prB'N 1752 A 10 1.0 2.0 B 7 0.7 1.4 C 4 0.4 0.8 Qrıfererce □N1946 5.6 2.7- 5.6 room A-E62Ireıı.93\ 25 A-E62-89 10 i'J<B-61 191' 3.5 OBS&G..ide A lreıı. 93\ 8 General prB'N 1752 A 10 classrocm B 7 C 4 □N1946 8.3 A-E62 1reıı.93\ 3.0 A-E62-89 8 i'J<B-61I911 3.5 OBSE-G..ide A treıı. 931 8 flbtes : prB'N 1752 : �le ancı Buldinga-eadded. □ N 1946 : Hgıest value are used. 0.35 1.0 2.0 0.7 1.4 0.4 0.8 055 A-E-62 : �le and Buldngareadded <K SirrpleSystems (RS8) is used. f<K unadapted people, 5 Us person is added ta ttıe � value. 1.6 0.7 42 1.8 0.7 111<8-61 : Feople and Building are added, but total outside a:r m.ıst be >7 Us person. Tablo 4. Minimum requirements for ventilation. 105 1 1 - '-- � • • 1 "i 1 j 1 1 1 1 1 1 1 = -
RkJQdWJsaXNoZXIy MTcyMTY=