SpraExpo.0 Program descrpton SpraExpo has been developed b Fraunhofer Insttut für Toxkologe und Expermentelle Medzn Nkola-Fuchs-Straße 1 D-3065 Hannover on behalf of the Bundesanstalt für Arbetsschutz und Arbetsmedzn Fachgruppe 4.1 Expostonsszenaren Fredrch-Henkel-Weg 1-5 D-44149 Dortmund
1 Executve Summar... 3 Model Assumptons and Model Descrpton... 4.1 Relevant quanttes and scenaros... 4. Phscal mechansms of droplet dsperson... 6..1 Evaporaton... 6.. Droplet settlng... 8..3 Turbulent transport... 9.3 Transport equatons... 10.4 Droplet mpacton module... 13.5 Program descrpton... 15.5.1 eneral remarks... 15.5. lobal model parameters... 16.5.3 Input forms for dfferent applcaton pattern... 19.5.4 Use of standard scenaros....5.5 Report....6 Use of standard scenaros 3 References... 5 Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de
1 Executve Summar The model calculates the arborne concentraton of the resprable, the thoracc and the nhalable, or an other meanngful sze fracton of aerosols generated durng workng processes. Specal attenton s drected to aerosols contanng bocdal substances n ndoor envronments orgnatng from the release of lqud bocdal spras. From the calculated concentraton the nhalaton as well as the dermal exposure s determned. Long term emssons of vapors from walls and other surfaces are not ncluded. It s assumed that the spraed product s composed of a non volatle substance dssolved n a solvent wth known volatlt. The model s based on a smulaton of the moton of released droplets takng nto account gravtatonal settlng, turbulent mxng wth the surroundng ar, and droplet evaporaton. In the model contnuous spatal release patterns can be smulated. No artfcal dstrbuton volumes need to be defned. In the calculaton of the nhaled dose and the dermal dose the spatal dstrbuton of the concentraton s explctl taken nto account. The man nput parameters are: the released droplet spectrum, the release rate, the concentraton of the non volatle substance, the spatal and temporal pattern of the release process surface sprang aganst floor, celng, wall; room sprang), the vapor pressure of the lqud, the sze of the room and the ventlaton rate. The path of the spraer can be explctl ncluded nto the model. For surface treatment b sprang, a droplet deposton module s ncorporated n the program package. Ths module calculates the fracton of non-mpactng droplets whch are relevant for human exposure. The mproved verson takes nto account the entranment of ar nto the spra jet accordng to Bernoull s prncple. Ths leads to a decrease n the droplet deceleraton that s due to ar frcton, resultng n an ncreased operatng dstance of the spra compared to njecton of the droplets nto stll ar. To facltate the use of the SpraExpo model an MS EXCEL worksheet was developed that can be executed under Mcrosoft Excel 003 or later usng Mcrosoft Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 3
Wndows 000 Servce Pack 3 or later, or Wndows XP or later recommended). The man nput parameters are: the released droplet spectrum, the release rate, the concentraton of the non volatle substance, the spatal and temporal pattern of the release process, the vapor pressure of the lqud, the sze of the room and the ventlaton rate. The user can select standard scenaros wth predefned default values or can select these nput parameters freel. The frst level s an nput form for the defnton of general data such as room sze, room ventlaton rate, turbulent ntenst, nozzle and spra parameters as well as relevant parameters of the spra lqud. The second level allows for the defnton of the spra path and the release rate. It also provdes an adjustable 3D mage of the room ncludng the spra pattern. The thrd level s the report level that contans the calculated values lsted n an EXCEL spreadsheet, a concentraton vs. tme dagram and the tme ntegrated nhaled and deposted dose of non volatle substance. Model Assumptons and Model Descrpton.1 Relevant quanttes and scenaros The model s amed at calculatng the nhaled and dermal dose the workers are experencng durng the release of a non volatle substance b a spra process. The spra lqud s characterzed b a non volatle substance dssolved or dspersed n a volatle solvent. The volume concentraton of the solute s c W. Dependng upon the tme hstor of the spra process the non volatle substance wll be ether ncorporated n lqud droplets or wll preval as dr aerosol partcles after complete evaporaton of the solvent. The man results of the model calculatons are the nhaled and the dermal dose ntegrated over the tme perod of contact of the worker to the spra aerosol.e. the release tme and eventuall an addtonal resdence tme nsde the room. The exposure to the volatle solvent s not calculated. The determnaton of the nhaled dose s based on the Internatonal Conventons on Health Related Partcle Samplng defned for example n CEN481 CEN, 199). Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 4
These are: the resprable, the thoracc and the nhalable fracton of the TSP total suspended partculate matter) the concentraton of whch s also calculated. A room wth dmensons A, B, H s defned n a cartesan coordnate sstem x,, z. The actual source pont.e. the pont where the spra s released s P S. The receptor s nomnated b P R. A tpcal spra operaton s then characterzed b a spra path, R S t), assocated wth a tme dependent source strength release rate), Q t) see Fg..1). The source strength, Q t), s gven n unts of kg/s. A B H P R Rt) s z P S x Fg..1 eometrc defntons of the smulaton model The possble release patterns of the model are: sprang of a wall along a lne, treatment of defned areas of the walls, the celng or the floor, and, room sprang. The coordnates of source and receptor are not ndependent from each other snce the spra operator s dentcal wth the exposed person. For a wall spra process n - drecton the followng coordnates appl see Fg...): Source x 0, t), z z t) S Receptor xr, R R t), z R z R, 0 S S S S The source s located at the wall x 0) whch s the orgn of the overspra. The two remanng coordnates are tme dependent followng the spra path. The receptor s Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 5
located at a constant dstance,, n front of the wall. The dstance of the spra nozzle s path. d. The receptor heght s assumed to be constant durng one spra room sprang P R P R P S d P S z area treatment x Fg.. Coordnates of the source and the receptor. For room sprang a constant dstance between release pont and receptor pont s assumed end of the spra cone). The release heght s varable and equvalent to the center of the spra cone.. Phscal mechansms of droplet dsperson Three phscal mechansms were consdered to control droplet moton n the ar: evaporaton, settlng and turbulent dffuson...1 Evaporaton In droplet evaporaton vapor molecules dffuse awa from the droplet surface. The vapor flux depends on the vapor pressure of the solvent, the saturaton rato n the vapor phase and the droplet dameter. The droplet dameter ntal dameter, d 0) ) changes wth tme accordng to Eq..1 Hnds, 1999): Tr Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 6
Eq..1: 1/ d ) 0) Tr t d t Tr wth 4Dp s R pteff Eq.. S 1 D dffuson constant of the vapor molecules, p S saturaton vapor pressure, R gas constant, p denst of the lqud, T eff effectve droplet temperature, S saturaton rato). Due to the consumed heat of evaporaton the effectve temperature s lower than the ar temperature. Evaporaton of the droplets contnues untl the have reached a mnmum dameter, d g, of the remanng dr aerosol of the non-volatle compounds. Ths dameter s determned b the volume concentraton, c W the lqud., of these compounds n Eq..3 d g c 1/ 3 W dtr. For a concentraton of the non volatle substance of 0.1 %, a 100 µm droplet shrnks to a dameter of 10 µm. The droplet evaporaton tme, t ev s proportonal to the ntal dameter, d Tr 0), squared. Eq..4. tev d Tr 0) 1 c / 3. W Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 7
.. Droplet settlng The determnstc vertcal moton of the droplets and ther deposton onto surfaces s determned b settlng n the earth s gravt feld. It s characterzed b the settlng veloct, v sed. Assumng Stoke s frcton law the settlng veloct s gven b: Eq..5 v t) sed d p Tr t) 18 g g gravtatonal constant, ar vscost). Ths formula apples to droplets wth dameters up to 50 µm. For larger droplets a correcton s necessar Hnds, 1999). The changng droplet dameter due to evaporaton makes the settlng veloct a tme dependent quantt decreasng wth ncreasng resdence tme. The total dstance, L sed, that a droplet settles untl t has shrunk to ts resdual aerosol partcle sze can be calculated b ntegratng Eq..5 and usng Eq..1: g Eq..6 4 Lsed d Tr 0). 18 The droppng dstance s proportonal to the fourth power of the dameter of the the released droplet. Tab..1 shows values calculated for lqud droplets and a concentraton of the non volatle substance of 0.1 %. For a tpcal room heght of 3 m the droplets wth dameters larger than appr. 160 µm are not relevant for nhalaton snce the have reached the floor well before the are evaporated and, thus, do not partcpate n the turbulent ar moton. Smaller partcle wll follow the turbulence and wll dsperse wthn the room. Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 8
Tab..1 veloctes. Drop dstance of droplets durng ther evaporaton and settlng d Tr 0) d g [µm] t ev [s] v sed 0) v sed t ev ) L sed [m] [µm] [m/s] [m/s] 0 5.8 0.38 0.01 0.0009 0.0030 40 11.7 1.51 0.049 0.0045 0.046 80 3.4 6.94 0.17 0.019 0.64 160 46.7 4.18 0.518 0.073 7.86 30 93.6 96.71 1.60 0.3 81.8..3 Turbulent transport In analog to the Brownan moton of molecules the turbulent transport s descrbed b Fck s law relatng the flux, j turb, to the concentraton gradent, c : Eq..7 jturb K c Here, K, s the edd dffusvt analog to the molecular dffuson constant D ). The turbulent moton cause an homogenzaton of the concentraton nsde the room. Ar turbulence s generated b the momentum flux of the ventlaton ar and thermal convecton. Tpcal values range from 0.0 to 0.1 m²/s, three orders of magntude above the values of the molecular dffuson. Thus mxng s determned exclusvel b edd dffuson. A pont source develops accordng to a auß-functon n three dmensons. The wdth, x b, n x -drecton) ncreases accordng to: Eq..8 xb 6Kt For K 0. 0 m²/s homogenzaton nsde a room of 5x5 m² s acheved wthn 5 mnutes whch compares rather well wth the values obtaned n the lterature Baughmann et al., 1994; Drescher et al., 1995). Tpcal fluctuatng veloctes are of the order of a few centmeters per second. Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 9
Fg..3 shows the processes nvolved n the droplet moton. Besdes these mechansms a contnuous ar exchange rate, [1/h], s also taken nto account n the model. Ths mechansm s actvated n the program when the cloud has nearl flled up the room. turb. mxng release heght L sed settlng L sed Fg..3 The mechansms of droplet moton...3 Transport equatons The smulaton s based on the soluton of nstatonar transport equatons for the droplets takng nto account the above mentoned mechansms. The spra s released along a spra path, t), see Fg..1) wth a tme dependent source r S strength, Q t). The quantt, Q, s the mass flux of released droplets of sze, d Tr, 0). There are N sze classes. The functon x) s the Drac functon. The release functon takes the followng mathematcal form: Q rs Q xs S S Eq..9. S r; t) t) r t) t) x ) ) z z ). Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 10
We frst consder the specal release functon t) t x' ' z' Q and denote the correspondng concentraton feld wth x,, z, x,, z; t). s the concentraton of droplets of ntal dameter d 0). The droplets shrnk accordng to Eq..1. tr, The transport equaton for s Eq..10 t v, d, t)) sed Tr z K x K K z, wth the ntal condton Eq..11 x,, z, x', ', z', t 0) x x') ') z z' ), and the boundar condton Eq..1 x z 0 0 0 x 0, x A 0, B z H. z 0) 0 The total concentraton C at tme t s obtaned b ntegraton: Eq..13. C x,, z, t) A 0 dx' B 0 d' H 0 dz' t 0 dt' N 1 x,, z, x', ', z'; t t') S x', ', z, t') Ths ntegral can be smplfed consderabl usng Eq..9: Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 11
t N xs S zs Q. 0 1 Eq..14 C x,, z, t) dt' x t), t), z t), t' ), t' ), t' ), t t' t' ) The health related sub-fractons of the total suspended droplets are of specal k Tr nterest. The are defned b weghng functons d ) k 1 nhalable, thoracc, 3 resprable). The concentratons of these sub-fractons are gven b: Eq..15 Ck t N x,, z, t) dt' k dtr, t t' )) xs S zs Q t 0 1 x,, z, t' ), t' ), t' ), t t' ') The deposton flux, j, due to settlng on horzontal surfaces s calculated usng the sze and tme dependent settlng veloct as weghng functon:. Eq..16 t N j x,, z, t) dt' vdep dtr, t t' )) xs S zs Q t 0 1 x,, z, t' ), t' ), t' ), t t' ') Eq..15 and Eq..16 requre the soluton of Eq..10 obtaned b the methods of separaton of varables: Eq..17 1 3 x,, z, xs, S, zs ; t) x, xs ; t'), S ; t') z, zs ; t') Here, the three functons are solutons of the followng dfferental equatons: Eq..18 1 t 1 K, x 1 x, x S ;0) x x S ) 1 x 0, t) x 0, 1 x x A, t) 0 Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 1
Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 13 Eq..19 0 ), 0, ) 0, ), ;0),, t B t S S K t and Eq..0 0 ), 3 0, ) 0, 3 ), ;0), 3 3 3 ), 3 t H t z zs z zs z z K z t dtr vsed t. Eq..18 and Eq..19 descrbe the horzontal dsperson of spra droplets due to turbulence. The functons 1 and are ndependent of the droplet dameter. The correspondng solutons are obtaned analtcall: Eq..1 t K A n Exp A xs n n A x n A t xs x cos 0 cos 1 ) ;, 1 Eq.. t K B n Exp B S n n B n B t S cos 0 cos 1 ) ;, The soluton of Eq..0 s obtaned numercall usng a fnte volume method. The calculatons are carred out for a representatve set of realstc model parameters. The solutons are stored n correspondng data fles. These data are used b the Wndows program SpraExpo to carr out the ntegratons Eq..15 - Eq..16..4 Droplet mpacton module Redesgn of the droplet mpacton module: For the surface sprang scenaros, the model calculates the overspra,.e. the fracton of droplets that are not deposted onto the surface. The ntal model
approach for calculaton of the overspra used a droplet trajector model for stll ar. The mproved model now takes nto account the entranment of ar nto the spra jet accordng to Bernoull s prncple. Ths leads to a decrease n the droplet deceleraton that s due to ar frcton, resultng n an ncreased operatng dstance of the spra compared to njecton of the droplets nto stll ar. For the calculaton of the deposton probablt as a functon of droplet sze, droplet veloct, and dstance from the wall, the algorthms descrbed n FLYNN et al. 1999) and SAZHIN et al. 001) were used. Accordngl, the ar veloct, vl, n the spra cone cone angle θ ) at a dstance x from the nozzle nozzle dameter d) can be computed usng the followng equaton: Eq..3. wth beng the flud veloct n the sprang nozzle, and beng the ar denst and water denst, respectvel. The deposton of droplets takes place b mpacton va a vrtual mpactor shown n Fg..7. The dameter of the dspatchng nozzle of ths vrtual mpactor can be computed usng the followng equaton: Eq..4 Partcle veloct equals the ar veloct v L. Based on the nozzle dameter D I, the partcle veloct at z I, and the partcle relaxaton tme ρ p beng the materal denst of the droplets, μ the ar vscost), the Stokes number can be computed. The parameter β s assgned a value of 1 for a round nozzle and a value of 1.5 for a flat fan nozzle. If the Stokes number exceeds the crtcal value of 0., the droplets wll be deposted; otherwse the wll be released nto the ar as overspra. The tme that the droplets take to travel from the nozzle to the wall s normall so short and the local water concentraton so hgh that droplet evaporaton does not have to be taken nto account for the deposton calculatons. The program performs the calculatons for each sze range. The start condtons depend on the nozzle parameters and the lqud mass flow of the sprang nozzle. Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 14
Fg..4 Vrtual mpactor accordng to FLYNN et al., 1999)..5 Program descrpton.5.1 eneral remarks To facltate the use of the SpraExpo model an MS EXCEL worksheet was developed that can be executed under Mcrosoft Excel 003 or later usng Mcrosoft Wndows 000 Servce Pack 3 or later, or Wndows XP or later recommended). After callng the worksheet a start wndow opens that allows the selecton of predefned standard scenaros. If the user wants to select the model parameters freel the contnue button should be clcked s. fgure.5). The man nput parameters are: the released droplet spectrum, the release rate, the concentraton of the non volatle substance, the spatal and temporal pattern of the release process, the vapor pressure of the lqud, the sze of the room and the ventlaton rate. The frst level s an nput form for the defnton of general data such as room sze, room ventlaton rate, turbulent ntenst, nozzle and spra parameters as well as relevant parameters of the spra lqud. The second level allows for the defnton of the spra path and the release rate. It also provdes an adjustable 3D mage of the room ncludng the spra pattern. The thrd level s the report level that contans the calculated values lsted n an EXCEL spreadsheet, a concentraton vs. tme dagram and the tme ntegrated Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 15
nhaled and deposted dose skn) of non volatle substance. The contents of the report dagram, calculated values) can be exchanged wth other MS applcatons or can be prnted f desred. Fgure.5 Start wndow.5. lobal model parameters After clckng the contnue button n the openng wndow an nput form appears for global parameters see Fg.6). lobal parameters are to be entered n ths form, for example the room dmensons: length n x-drecton), wdth n -drecton) and heght. The values for A and B can be chosen arbtrarl. For the room heght, onl 4 fxed values are allowed n the program. The ar exchange rate represents the global fresh ar flux nto the room. Ths mechansm becomes relevant after the aerosol cloud has nearl flled up the room. Ths wll be the case when the wdth of a cloud released n the center of the room has reached values of the order of the room dagonal. A small red trangle ndcates that help nformaton s avalable for a parameter. The help text s nvoked f the user shfts the cursor to the red trangle. Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 16
Fgure.6 Input form for global parameter The second group of nput parameters s related to the spra pattern. We dstngush between the followng patterns: Sprang along a lne for example along a base board. Treatng a certan area of the walls, the celng, respectvel the floor. Treatng the room volume. The thrd group of nput parameters addresses the droplet spectrum of the spra. The program subdvdes the droplet spectrum nto the dscrete sze ranges 0-5, 5-10, 10-0, 0-40, 40-80, 80-160, and 160-30 μm. There are now four dfferent possbltes avalable to enter the data Fg..7): 1. Manual nput of the percentages of droplet mass n the 7 sze ranges.. Use of a fle of measurement values, generated b the laser dffracton spectrometer HELOS of the compan Smpatec n Clausthal-Zellerfeld, erman. For some sprang technques, ths analtcal nstrument can be Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 17
used to drectl measure the droplet sze dstrbuton. 3. Input of the parameters medan value of the droplet dameter of the mass sze dstrbuton and geometrc standard devaton. A lognormal dstrbuton of the droplet mass over the droplet dameter s assumed. 4. Selecton of a common applcaton technque used for bocdal treatment of surfaces and rooms. Eght technques are at present mplemented Fg..10). The frst two of these assume the use of pressure-drven sngle-substance flat fan and hollow cone nozzles. When an of these s selected, the operatng pressure and correspondng lqud throughput have to be specfed n addton. The followng three devces are cold foggers, followed b two thermal foggers. At the end of the lst, a propellant-based spra formulaton s offered. The cold and thermal foggers as well as the pressurzed spra can have fxed droplet dstrbutons ndependent of the operatng parameters. The correspondng droplet dstrbutons have been determned n model experments. Fg..7 Droplet spectrum The substance data are the mass concentraton of the non volatle chemcal n the lqud < 100%) and the vapor pressure of the solvent. The overspra model requres values for the angle of the spra cone as well as the ext veloct of the droplets. Ths value can be nserted drectl or t wll be calculated Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 18
va nozzle dameter, respectvel nozzle area and the mass flux whch wll be specfed n subsequent nput forms..5.3 Input forms for dfferent applcaton pattern B pressng the Contnue button one proceeds to the respectve form for specfcaton of the applcaton pattern. Dependng on the selecton of the applcaton pattern n the global parameter form fve nput forms are provded: wall lne, wall area, celng, floor, room. The room and the correspondng spra path ndcated b thck lnes) are represented n an adjustable usng slders) 3D graphc. Fgure.8 shows the nput form wall lne as an example. These forms also comprse the selecton of the quanttes to be calculated as well as the calculaton of the results. Input form room The form permts to defne 4 ponts nsde the room. The spra length can be defned. It takes the same value for all droplet sze fractons. The local release pattern s a crcle wth the radus of the spra length. For each spra pont the release heght, the release tme and the release rate can be ndvduall defned. Input form wall lne The nput group Release data allows the specfcaton of a spra path along a lne at each of the four walls of the room b defnng begn and end of the path and the release heght. In addton, each path s characterzed b a release tme and a release rate. The spra paths are ndcated b thck lnes n the 3D representaton of the room. Further nput parameters are the dstance between the nozzle and the wall, respectvel between the receptor and the wall. These parameters appl to all spra patterns defned. When pressng Read spra path the program calculates the path of the source, x t ), t ), z t )), and the path of the receptor, x t ), t ), z ), for S S S dscrete tme ponts, t 0 50 ). R The nput feld Calculaton defnes the quantt to be calculated: ether the concentraton of one of the health related sze fractons accordng to CEN481, or of the total suspended amount of non volatle substance, or the dermal deposton flux. The control feld Tme resoluton defnes the number of dscrete tme ponts Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 19
coverng the total exposure tme: 50 for hgh and 50 for low. For exposure tmes smaller than 1800 s the low tme resoluton s often suffcent. B pressng Calculate the evaluaton of Eq..15, respectvel, Eq..16 s started. For nhalatve exposure the result s presented n graphcal form as a concentraton curve n the report. For dermal exposure the -axes represents the deposton rate Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 0
Fg..8 Input form for specfcaton of the release pattern wall lne. onto the total bod surface area. A total area of 1.9 m² and a horzontal fracton of 10 % was assumed USEPA, 1995). The partcle flux to the horzontal surfaces s b settlng. Deposton on the other parts of the bod surface s b turbulent dffuson wth an assumed deposton veloct, v dep, of 0.01 cm/s. The nhaled dose s calculated b: R Eq..5. Dnh Qresp dt CxR t), R t), zr t 0 Here, Q resp, s the resprator mnute volume 10 l/mn). The total dermal dose s gven b: Eq..6. t R D derm dt R t) 0 R t) v sed A hor v dep A vert C Inhaled and dermal dose as well as average concentraton, respectvel deposton rate are dsplaed n the report. Input form wall area The spra release heght extends from 0 to 4 m. The wall segment selected for treatment s dvded nto 4 sub-segments. Each of these segments wll be spraed from bottom to top. The spra paths are ndcated b thck lnes n the 3D representaton of the room. Due to the complext of the spra pattern the smulaton should be restrcted to the treatment of two wall segments. The treatment tmes of these two segments must be the same. Input form celng / floor Ths form can onl be actvated when the room heght s 3 or 4 m. The endponts of the dagonal of the area to be treated are defned b P1 and P. The area s devded nto 10 equal strpes whch wll be treated n sequental order. The spra paths are ndcated b thck lnes n the 3D representaton of the room. Receptor-nozzle Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 1
defnes the horzontal dstance between source and receptor n x -drecton. Ths s also the mnmum dstance of the receptor to all walls. Input form room The form permts to defne 4 ponts nsde the room. The spra length can be defned. It takes the same value for all droplet sze fractons. The local release pattern s a crcle wth the radus of the spra length. For each spra pont the release heght, the release tme and the release rate can be ndvduall defned..5.4 Use of standard scenaros SpraExpo.0 offers the opportunt to use 3 dfferent standard scenaros preflled scenaros) that can be selected n the openng wndow of the EXCEL worksheet.. The standard scenaros could be used n the evaluaton of bocdes for dfferent product tpes PT), for example PT 1 Antfoulngs), PT 3 Veternar hgene bocdal products), or PT 18 Insectcdes). Ths approach facltates the extrapolaton of exposure data avalable for certan products to other products and other scenaros for whch specfc data are not avalable. In addton, prelmnar specfed default values for the varous model parameters ensure a hgh degree of consstenc n the assessments. The estmaton of default parameter values should result n a reasonable worst-case scenaro whch covers the frequent use of a certan product under less favourable crcumstances. However, the default parameters should not result n an accumulaton of worst-case assumptons that would represent unrealstc values. Therefore, the default parameters have been chosen such that a relatvel hgh but stll realstc exposure and uptake are calculated. The result s a reasonable worst case estmate. The proposed default values should be chosen, determned, and mproved wth cauton. Takng nto account these prncples the user can defne ts own standard scenaros. The new scenaro can be stored n a fle b pressng the SaveAs button provded n the report form s. below). Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de
.5.5 Report The report summarses all parameters entered through the prevous forms s. Fg..9). A dagram plots the calculated concentratons aganst the tme. Below the dagram the calculated values nhaled dose or dermal dose ) and the average concentraton are gven. The tme dependent concentraton values are also provded n a table. When pressng Return the prevous nput form s shown. The current scenaro can be stored n a fle b pressng the SaveAs button. When pressng Export to EXCEL the results are stored n an EXCEL fle, usng the template sheet export_vorlage. When pressng Prnt the entre report s prnted. Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 3
Fg..9 Report Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 4
3 References Baughman, A.V., adgl, A.J., Nazaroff, W.W., Mxng of a pont source pollutant b natural convecton flow wthn a room, Indoor Ar, 4. 114-1, 1994 Comté Européen de Normalsaton CEN) 199). Workplace Atmospheres: Sze Fracton Defntons for Measurement of Arborne Partcles n the Workplace, CEN Standard EN 481 Drescher, A.C., Lobasco, C., adgl, A.J., Nazaroff, W.W., Mxng of a pont source ndoor pollutant b forced convecton, Indoor Ar, 5: 04-14, 1995 Hnds, W.C. Aerosol Technolog, John Wle, New York, 1999 US EPA Exposure factors handbook, 1995 Koch, W., Behnke, W., Berger-Preß, E., Kock, H., erlng, S., Hahn, S., Schröder, K., Valdaton of an EDP-asssted model for assessng nhalaton exposure and dermal exposure durng sprang processes. 1. edton. Dortmund: Bundesanstalt für Arbetsschutz und Arbetsmedzn 01, 115 pages, BAuA Research Project F137 Bundesanstalt für Arbetsschutz und Arbetsmedzn BAuA) - www.baua.de 5