Six-Stage and Two-Stage Viable Andersen
Contents
1. can be determined by collecting intermittent samples at the same location Agar plates containing more than 300 colonies may be counted by a positive hole method which is less accurate than optically counting each colony and is rarely used today However since some people still use this technique the following discussion is included The positive hole method is essentially a count of the jets which delivered viable particles to the Petri plates and the conversion of this count to a particle count by use of the positive hole conversion table Table I This table is based upon the principle that as the number of viable particles being impinged on a given plate increases the probability of the next particle going into an empty hole 22 decreases For example when 9 10 of the holes have each received one or more particles the next particle has but one chance in ten of going into an empty hole Thus at this point on the average ten additional particles would be required to increase the number of positive holes by one and before all the holes become positive some holes will receive a number of particles The p N IL IL re l r N Nel N 2 N r l where Pr is the expected number of viable particles to produce r positive holes and N is the total number of holes per stage 400 The above formula assumes that the flow of particles stops at th2. 5 93 135 1 6 9 143 251 0 157 193 670 8 66 9 4 497 2 6 94 127 0 7 0 144 2546 16 0 194 7018 725 45 51 0 2 6 95 1288 7 2 145 2582 163 195 7384 79 6 46 52 2 2 7 96 1308 7 3 146 2618 166 196 7834 889 47 53 6 2 8 97 132 7 7 4 147 2656 168 197 841 8 101 7 48 54 8 2 8 98 134 7 75 148 2694 17 2 198 925 1 121 3 49 56 2 2 9 99 136 6 7 6 149 273 3 17 5 199 1075 1 156 9 50 57 6 3 0 100 138 6 7 8 150 277 3 17 8 200 1175 6 253 8 i the observed number of colony forming units cfu Bii the expected number of cfu corrected for coincidence iii the standard deviation of ii see text for a further explanation Am Ind Hyg Assoc J 50 25 VI INSTRUCTIONS FOR 12 VOLT VACUUM PUMP Pump and motor require no lubrication Do not use rubber tubing of smaller diameter or length than that supplied with the unit unless the flow rate is checked and readjusted The pump is equipped with an adjustable valve Always tighten the lock nut on the adjustment valve after the flow rate has been set To adjust flow turn screw in to increase the flow and out to decrease the flow It is important the unit always operate at 1 cfm The unit should be periodically recalibrated To calibrate attach a 1 I D hose with approximately a 1 4 wall to the inlet nozzle of the sampler and the other end to the outlet of a flow meter Continue to adjust the valve until you are pulling 1 cfm over a three minute test period determin
3. ACFM For this reason the unit should be periodically recalibrated and whenever non standard temperatures and pressures ar ncountered calibration should be performed at the sampling conditions Do not use rubber 15 tubing of smaller diameter or length different than that supplied with the impactor unless the flow rate is readjusted Each ACI pump is equipped with an adjustable valve Always tighten the lock nut on the adjustment valve after the flow rate has been set To adjust the flow turn the screw in to increase flow and out to decrease flow Each ACI pump impactor assembly is calibrated before shipment to deliver 1 ACFM at ambient temperature and pressure levels in Franklin MA In order to recalibrate at your sampling environment the following procedure is recommended Place a calibrated flow meter upstream from the ACI Attach a short 1 I D hose with approximately 1 4 wall to the inlet cone of the impactor and the other end to the outlet of the flow meter Adjust the pump valve until you are pulling 1 ACFM over a three minute test period as determined with an accurate stop watch After maintaining 1 ACFM for three minutes tighten the lock nut on the adjustment valve Because of the 1 4 ACFM free flow rating of the motor and pump up to 50 feet of tubing can be used between the Sampler and pump while still maintaining 1 ACFM through the ACI The pump and motor are guarantee
4. follows the air stream around the edge of the Petri dish to the next stage Each stage contains 400 orifices with diameters ranging from 1 81 mm on the first stage to 0 25 mm on the sixth stage Each stage has a removable glass Petri dish with metal cover The exhaust section of each stage is approximately 19 mm larger in diameter than the Petri dish which allows unimpacted particles to go around the dish and into the next stage Figure 3 The ACI and Vacuum pump include their own carrying cases for ease of portability Figure 4 Case dimensions are 9 3 8 wide x 8 3 4 high x 5 deep Complete sampler and vacuum pump weights including carrying cases are 6 pounds and 12 pounds respectively A constant air sample flow of 1 ACFM is provided by a continuous duty vacuum pump Flow rate is controlled by an adjustable valve on the pump and periodic calibration is recommended Requirements for flow rate adjustments can be found in Section VI 11 Figure 2 TFS ACI Six Stage Viable Sampler 12 2 Assembly The orifice stages should be cleaned and disinfected each time the instrument is used A mild pH neutral detergent and warm water are sufficient for cleaning The soap can be removed by holding the stages under hot running water or immersing them in clean water in an ultrasonic cleaner Each stage should be examined for any material in the jet holes If holes are pl
5. pump is turned on and a sample stream of 1 ACFM will flow through the sampler Figure 5 shows how impaction occurs at the orifice collector interfaces Normal sampling periods for viable aerosols will vary from a few minutes up to 30 minutes depending on the purpose for which the sample is collected and the type of air environment being sampled It is important to collect sufficient viable particles in each sample to be statistically significant and representative however difficulty is encountered in counting agar plates which contain more than 250 300 colonies The flow of high velocity sample air across the agar plates also tends to dehydrate and perhaps damage the viable particles which have already been collected Thus extended sampling periods over 30 minutes are not recommended If a larger sample volume is required it is better to use two sampling instruments in parallel or to remove the agar plates representing one sample and insert fresh plates for a second sample 14 G JET EXIT ANNS TRAJECTORY OF PARTICLE TOQ SMALL TO Su TRAJECTORY OF 5 IMPACTED PARTICLE IMPACTION DISC Figure 5 Schematic of Impactor Stage After the sampling has been completed the ACI is disassembled and the covers are replaced on each of the Petri dishes 4 Calibration Since the size fraction for each stage is determined by the orifice velocities it is important that the ACI be operated at 1
6. since a single viable particle may contain more than one cell If the sample plates have been incubated aerobically all the colonies must be considered as aerobic or facultative anaerobic bacteria The percentage of viable particles in each size range can be determined by dividing the number of colonies on a given stage by the total number of colonies on all the stages Percent of Colonies on Stage 1 of the Six Stage Sampler X 100 Viable Particles Total Number of Colonies from all Sample Plates Over 7 0 Microns In Diameter The site of deposition of these particles in the human respiratory tract can be predicted from this data The approximate settling rate in air of the 21 particles collected can also be calculated from the particle size data Settling Rates of Airborne Particles Diameter of Particles Velocity of Settling microns feet per minute 0 8 0 005 1 0 0 007 4 0 0 095 10 0 0 59 40 0 9 25 100 0 59 2 Condensed from Size and characteristics of airborne solids W G Frank in the Smithsonian Meteorological Tables Rates are for particles in the shape of spheres with a specific gravity of 1 0 settling in air at 70 F It is not possible to determine the exact density or shape of viable particles which are collected with any cascade impactor including the Six and Two Stage Viable Cascade Impactors The variation in concentration of viable airborne particles with time
7. time set forth in the product documentation published specifications or package inserts If a period of time is not specified in Seller s product documentation published specifications or package inserts the warranty period shall be one 1 year from the date of shipment to Buyer for equipment and ninety 90 days for all other products the Warranty Period Seller agrees during the Warranty Period to repair or replace at Seller s option defective Products so as to cause the same to operate in substantial conformance with said published specifications provided that a Buyer shall promptly notify Seller in writing upon the discovery of any defect which notice shall include the product model and serial number if applicable and details of the warranty claim b after Seller s review Seller will provide Buyer with service data and or a Return Material Authorization RMA which may include biohazard decontamination procedures and other product specific handling instructions and c then if applicable Buyer may return the defective Products to Seller with all costs prepaid by Buyer Replacement parts may be new or refurbished at the election of Seller All replaced parts shall become the property of Seller Shipment to Buyer of repaired or replacement Products shall be made in accordance with the Delivery provisions of the Seller s Terms and Conditions of Sale Consumables including but not limited to lamps fuses batteries b
8. 42 115 171 2 9 9 165 3486 24 1 16 16 6 0 8 66 80 0 4 2 116 173 5 10 1 166 354 4 24 7 17 17 8 0 9 67 816 4 3 117 175 9 10 2 167 360 4 25 2 18 18 8 0 9 68 83 1 4 4 118 178 3 10 4 168 366 6 25 8 19 20 0 1 0 69 84 6 45 119 1808 105 169 3729 265 20 210 1 0 70 86 2 46 120 183 2 107 170 379 4 271 21 22 2 1 1 71 87 7 4 7 121 1858 109 171 386 2 27 8 22 233 1 2 72 892 4 8 122 188 3 111 172 393 2 28 5 23 24 4 1 2 73 908 4 9 123 1909 11 2 173 4005 29 3 24 25 6 1 3 74 924 5 0 124 193 5 11 4 174 408 0 30 1 25 26 7 1 3 75 94 0 5 1 125 196 2 11 6 175 415 9 309 26 278 1 4 76 956 5 1 126 198 8 118 176 4240 318 27 29 0 1 5 77 972 5 2 127 201 6 12 0 177 4326 32 8 28 30 2 1 5 78 988 5 3 128 2043 12 2 178 441 4 33 8 29 313 1 6 79 100 5 5 4 129 207 1 12 4 179 4508 34 8 30 32 5 1 6 80 102 2 5 5 130 2100 126 180 4606 36 0 31 33 7 1 7 81 103 8 5 6 131 2128 128 181 4708 37 2 32 349 1 8 82 105 6 5 7 132 2158 13 0 182 4816 38 5 3 36 1 1 8 83 107 2 5 8 133 2187 132 183 493 1 40 0 34 37 3 1 9 84 109 0 5 9 134 2218 13 5 184 5052 415 35 38 5 2 0 85 110 6 6 0 135 2248 13 7 185 5182 43 2 36 39 7 2 0 86 112 4 6 1 136 2279 139 186 532 0 45 1 37 409 2 1 87 114 2 6 3 137 231 0 142 187 5468 47 1 38 422 2 2 88 116 0 6 4 138 2342 144 188 5628 49 4 39 43 4 2 2 89 117 8 6 5 139 2375 146 189 580 2 520 40 446 2 3 90 119 6 6 6 140 2408 149 190 5993 549 41 45 9 2 4 91 121 4 6 7 141 244 2 15 2 191 6204 58 3 42 47 2 2 4 92 123 2 6 8 142 2476 15 4 192 6440 62 2 43 48 4 2
9. 5 17 377 1142 18 378 1160 19 379 1179 20 380 1198 21 381 1219 22 382 1241 23 383 1263 24 384 1288 25 385 1314 26 386 1341 27 387 1371 28 388 1403 29 389 1438 30 390 1476 31 391 1518 32 392 1565 33 393 1619 34 394 1681 35 395 1754 36 396 1844 37 397 1961 38 398 2127 39 399 2427 40 400 All holes must be clean and open Indicates quantitative limit of state approximately 2628 particles is exceeded CADocuments and Settings wjones 000 Local Settings Temp Draft single stage doc jwj 7 16 2003 24 TABLE Il Positive Hole Correction Table to Adjust Colony Counts from a 200 Hole Impactor for the Possibility of Collecting Multiple Particles through a Hole i u ini i ii iii i ii iii i ii iii 1 1 0 0 0 51 58 8 3 1 101 140 6 7 9 151 281 3 181 2 2 0 0 1 52 60 2 3 1 102 142 7 8 0 152 285 4 185 3 3 0 0 1 53 61 6 3 2 103 144 8 8 2 153 289 6 18 8 4 4 0 0 2 54 63 0 33 104 146 8 8 3 154 294 0 19 2 5 5 1 0 2 55 643 3 4 105 148 8 8 4 155 298 4 19 6 6 6 1 0 3 56 65 7 3 4 106 151 0 8 6 156 302 8 20 0 7 7 1 0 3 57 671 3 5 107 153 2 8 7 157 307 4 20 4 8 8 2 0 4 58 685 3 6 108 155 3 8 8 158 3122 208 9 9 2 0 4 59 69 9 3 7 109 157 5 9 0 159 317 0 212 10 10 2 0 5 60 71 3 3 8 110 159 7 9 1 160 321 9 21 6 11 11 3 0 5 61 72 8 3 8 111 162 0 9 3 161 327 0 22 1 12 12 4 0 6 62 74 2 3 9 112 164 2 9 4 162 332 2 226 13 13 4 0 7 63 75 6 4 0 113 166 4 9 6 163 337 5 23 1 14 14 6 0 7 64 772 4 1 114 168 8 9 7 164 3430 23 6 15 15 6 0 8 65 78 6
10. E PARTICLE SAMPLER 16 1 DESCRIPTION 16 2 ASSEMBLY 17 3 SAMPLING 17 4 CALIBRATION 18 v ANALYSIS AND INTERPRETATION OF DATA 20 VL INSTRUCTIONS FOR THE VACUUM PUMP 25 LIST OF TABLES TABLE TITLE PAGE NO 1 POSITIVE HOLE CONVERSION TABLE 400 23 2 POSITIVE HOLE CONVERSION TABLE 200 24 LIST OF FIGUR zal n PAGE FIGURE TITLE NO 1 SAMPLER STIMULATES 8 HUMAN RESPIRATORY SYSTEM t 2 SIX STAGE VIABLE SAMPLER 1 1 I PREFACE The assay of the microbial content of the air has become increasingly more significant in the past decade as the need for contamination free environments has become more apparent The treatment of hospital patients medical as well as surgical who are high risk candidates for infection the manufacture and processing of sterile materials and pharmaceuticals and the increased use of these products the massive production and wide distribution of convenience foods and the growing emphasis on consumer protection have all contributed to the need for controlled environments Biological aerosols have been defined as viable biological contaminants occurring as solid or liquid particles in the air These particles can vary in size from viruses less than 0 1 micron in diameter to fungal spores 100 or more microns in diameter They may occur as single unattached organisms or as aggregates
11. For the ACI containing round jets and flat collection surfaces the 50 effective cutoff diameter would yield a value of 0 14 for the inertial impaction parameter K The Cunningham slip C 1 5 0316 amp factor corrects for free path length of molecules mor flow stream lines the gas molecules asily and ar Th correction factor is equal To 10 D for normal temperatures and pressures This the fact that as particle diameters approach the mean therefore they tend to slip between gas ulk than would be predicted by inertial on the order of 1 or stages minimized in these samplers by design a particle passes through a jet of the factors that determines whet impaction surface rectangular jets in each stage Travel of the particle is average distance of the particles from the axis in other impactors sharper cutoffs than theoretical basis which is natural Ranz and Wong more easily able to cross the b collection efficiency is therefore slightly greater impaction theory for particle diameters 2 microns i the ACI thus confined 1952 rectangular jets The overlapping of particl Lly inherent in all cascade impaction devices Ranz and Wong ts nearness to the axis of The ACI sampler size betw is 1952 stated that as the jet is one ther or not the particle will reach the
12. In contrast to competitive samplers which have larger sampler has 400 small round jets near the axis of the jets The of the jets is less than also stated that round jets have therefore on a should have a sharper cutoff Another inherent advantage of the ACI over its competitors is that single circular orifice and multiple rectangular orifice impactors by design must operate with higher orifice velocities turbulent flow great distribution toward t being smaller than it This results in more ter re entrainment the lower end i e really is and a skewing of the size the indicated size distribution 10 VIMPACTORS T SIX STAGE VIABLE CASCADE IMPACTOR 1 Description The Six Stage ACI is constructed with six aluminum stages that are held together by three spring clamps and sealed with O ring gaskets Figure 2 Each impactor stage contains multiple precision drilled orifices When air is drawn through the sampler multiple jets of air in each stage direct any airborne particles toward the surface of the agar collection surface for that stage The size of the jet orifices is constant within each stage but are smaller in each succeeding stage The range of particle sizes collected on each stage depends on the jet velocity of the stage and the cutoff of the previous stage Any particle not collected on the first stage
13. Series 10 800 Instruction Manual Six and Two Stage Viable Samplers Part Number 100072 00 290ct2009 2007 Thermo Fisher Scientific Inc All rights reserved Specifications terms and pricing are subject to change Not all products are available in all countries Please consult your local sales representative for details Thermo Fisher Scientific Air Quality Instruments 27 Forge Parkway Franklin MA 02038 1 508 520 0430 www thermo com aqi Thermo Fisher Scientific WEEE Compliance This product is required to comply with the European Union s Waste Electrical amp Electronic Equipment WEEE Directive 2002 96 EC It is marked with the following symbol Thermo Fisher Scientific has contracted with one or more recycling disposal companies in each EU Member State and this product should be disposed of or recycled through them Further information on Thermo Fisher Scientific s compliance with these Directives the recyclers in your country and information on Thermo Fisher Scientific products which may assist the detection of substances subject to the ROHS Directive are available at www thermo com WEEERoHS WEEE Compliance Warranty Warranty Seller warrants that the Products will operate or perform substantially in conformance with Seller s published specifications and be free from defects in material and workmanship when subjected to normal proper and intended usage by properly trained personnel for the period of
14. Viable particle samplers have been generally used to collect and assay aerobic species of bacteria and fungi Even though many viable samplers including the Thermo Fisher Scientific Andersen Viable Cascade Impactor ACI will collect some virus particles there is no convenient practical method for the cultivation and enumeration of these particles There are two constraints on all viable particle samplers for which there is no analog in the assay of nonbiological aerosols First the particle must be separated from the air for any viability assay and second the ability to reproduce viability must be demonstrated The purpose of this manual is to outline proper methods for the assay of biological aerosols using the Andersen Viable Cascade Impactor ACI INTRODUCTION SIX STAGE VIABLE CASCADE IMPACTOR T The Six Stage ACI is a multi orifice cascade impactor which is normally used to measure the concentration and particle size distribution of aerobic bacteria and fungi in the intramural or ambient air This instrument has been widely used as a standard for enumerating the viable particles in a microbial aerosol Viable particles can be collected on a variety of bacteriological agar and incubated in situ for colony counting and identification This sampler was calibrated so that all particles collected regardless of physical size sha
15. action for each stage is determined by the orifice velocities it is important that the ACI be operated at 1 ACFM For this reason the unit should be periodically recalibrated and whenever non standard temperatures and pressures ar ncountered calibration should be performed at the sampling conditions Do not use rubber tubing of smaller diameter or length different than that supplied with the impactor unless the flow rate is readjusted Each ACI pump is equipped with an adjustable valve Always tighten the lock nut on the adjustment valve after the flow rate has been set To adjust the flow turn the screw in to increase flow and out to decrease flow 19 Each ACI pump impactor assembly is calibrated before shipment to deliver 1 ACFM at ambient temperature and pressure levels in Franklin MA In order to recalibrate at your sampling environment the following procedure is recommended Place a calibrated flow meter upstream from the ACI Attach a short 1 I D hose with approximately 1 4 wall to the inlet cone of the impactor and the other end to the outlet of the flow meter Adjust the pump valve until you are pulling 1 ACFM over a three minute test period as determined with an accurate stop watch After maintaining 1 ACFM for three minutes tighten the lock nut on the adjustment valve Because of the 1 4 ACFM free flow rating of the motor and pump up to 50 feet of tubing can be used between the Sampler and pu
16. air and growth of injured or stressed cells One collection plate with the cover removed is inserted on each stage of the sampling instrument The air to be sampled enters the jet orifices of Stage I and cascades through the jet orifices of Stage II with a higher orifice velocity through Stage II than Stage I Smaller particles are inertially impacted on the agar plate in Stage II than in Stage I Viable particles are retained on the agar plates and the exhaust air is carried through the outlet in the base of the instrument and the vacuum hose to the vacuum source pump or in house vacuum system For maximum collection efficiency a constant air sample flow of 1 ACFM must be provided After sampling is completed the sampling time is recorded the agar collection plates are removed from the sampling instrument and the cover is replaced on each Petri dish Identify each plate as to sample and stage number i e 1 1 1 2 Place both agar plates inverted to prevent condensation drip in an incubator at 35 C for 18 to 24 hours Plates can be incubated at room temperature if the user is most interested in environmental bacteria whose optimum growth temperature is lower than body temperature or at 20 25 C for maximum recovery of fungi After incubation the number of colonies on each plate are counted using a standard bacterial colony counter Knowing the air sample flow r
17. ate and the sampling time the mean number of viable particles aerobic bacteria and or fungi per unit volume of air can be calculated and the percent of particles in the respirable Stage II and nonrespirable Stage I size ranges can be estimated 71 III AERODYNAMIC PARTICLE SIZING The design concept of the ACI evolved from the following information The human respiratory tract is an aerodynamic classifying system for airborne particles A sampling device can be used as a substitute for the respiratory tract as a collector of viable airborne particles and as such it should reproduce to a reasonable degree the lung penetration by these particles The fraction of inhaled particles retained in the respiratory system and the site of deposition vary with all the physical properties size shape density of the particles which make up the aerodynamic dimensions Figure 1 Because the lung penetrability of unit density particles is known and since the particle sizes that are collected on each stage of the ACI have been determined if a standard model of these samplers is used according to standard operating procedure the stage distribution of the collected material will indicate the extent to which the sample would have penetrated th respiratory system Numerous small round jets improve collection impaction efficiency and provide a sharper cutoff of particle s
18. containing 20 ml of agar medium is correctly placed on the support posts of each stage the correct distance between the jet orifices and the agar surface is maintained 3 Sampling when ready to sample the vacuum source is turned on A constant sample flow rate of 1 ACFM 28 3 liters min must be maintained Accurately time the length of the sampling period Normal sampling periods for viable aerosols will vary from a few minutes up to 30 minutes depending on the purpose for which the sample 18 is collected and the type of air environment being sampled It is important to collect sufficient viable particles in each sample to be statistically significant and representative However difficulty is encountered in counting agar plates which contain more than 250 300 colonies The flow of high velocity sample air across the agar plates also tends to dehydrate and perhaps damage the viable particles which have already been collected If a larger sample volume or a longer sampling time over 30 minutes is required it is better to use two or more sampling instruments in parallel or to sample sequentially After the sampling has been completed the Sampler is disassembled This is accomplished by unscrewing the Teflon caps Remove Stage I and the Petri dish on Stage I and replace its cover Remove Stage II and the Petri dish on Stage II and replace its cover 4 Calibration Since the size fr
19. d by the original manufacturer and should not be disassembled for any reason The pump and motor require no lubrication The pump rate of the 12 volt DC pump will vary with voltage One ACFM can be drawn through the impactor if the voltage is maintained near 12 volts Refer to the attached supplementary titled Instructions For 12 Volt Pump for detailed 12 volt DC pump operation 16 T T T B TWO STAGE ALUMINUM VIABLE CASCADE IMPACTOR 1 Description The ACI is constructed of aluminum with two stages which are held together with three dowel pins and three Teflon caps Each impactor stage contains multiple precision drilled orifices When air is drawn through the ACI multiple jets of air in each stage direct any airborne particles toward the surface of the agar collection surface for that stage The size of the jet orifices is the same on each of the two stages but are smaller on the second stage The range of particle sizes collected on each stage depends on the jet velocity of the stage and the cutoff of the previous stage Any particle not collected on the first stage follows the air stream around the edge of the Petri dish to the second stage Each stage contains 200 tapered orifices The diameter of the orifices on the first stage are 1 5 mm and 0 4 mm on the second stage Standard 100 x 15 mm petri dishes are used for collecting surfaces on each stage T
20. e instant a particle enters the rth hole Since in the actual case of sampling the flow of particles stops at random the expected number of particles present if r positive holes are observed would be equal to or greater than P but less than P and the average would be P P t 1 2 This correction has been applied in the construction of the table In using the positive hole conversion table the number of positive holes must be precisely determined A colony out of the hole pattern is not counted as a positive hole By this method counts up to 1 200 or 1 500 particles per stage are quite reliable If higher counts are to be encountered the microscope method is employed with this method the number of viable particles per stage is determined after a short incubation period by counting with the aid of a microscope the micro colonies in a number of deposit areas and calculating the total for the plate A deposit area is that area which receives particles from one jet or hole The micro 53 counted By this method total sampler counts as high as 40 000 or 50 000 can be made Table 1 Positive hole conversion table Positive hole counts r and corresponding correct particle counts P BOB Ba EIER r_P 1 1 361 931 2 2 362 942 3 3 363 952 4 4 364 963 5 5 365 974 6 6 366 986 T 367 998 8 8 368 1010 g 9Y 369 1023 10 10 370 1036 11 371 1050 12 372 1064 13 373 1078 14 374 1093 15 375 1109 16 376 112
21. e soy agar or blood agar can be used for the collection plates Selective media are not recommended since they inhibit the repair and growth of injured or stressed cells c One collection plate with the cover removed is inserted on each stage of the sampling instrument d The air to be sampled enters the inlet cone and cascades through the succeeding orifice stages with successively higher orifice velocities from Stage 1 to Stage 6 Successively smaller particles are inertially impacted onto the agar collection surfaces es 4 Viable particles are retained on the agar plates and the exhaust air is carried through the vacuum hose to the vacuum source pump or in house vacuum system For maximum collection efficiency a constant air sampler flow of 1 ACFM must be provided This constant flow is provided with a continuous duty carbon vane vacuum pump and is controlled by an adjustable valve on the pump Periodic calibration is recommended See Section VI Another method of assuring a constant flow would be to insert an airflow meter not provided with a minimum capacity of 1 ACFM 28 3 liters min in the vacuum hose between the Sampler and the vacuum source This flowmeter should be properly calibrated After sampling is completed the sampling time is recorded th agar collection plates are removed from the sampling instrument and the cover is re
22. ed by an accurate stop watch After this has been achieved tighten the lock nut on the adjustment valve The pump and motor should not be disassembled for any reason Due to the 1 4 cfm rating of the motor and pump up to 50 feet of hose can be used between the sampler and the motor and still pull 1 cfm 12 VOLT PUMP OPERATION Battery required 12 volt automotive type minimum 69 amp hour capacity TO OPERATE 1 Connect clip of red shielded pump wire to positive or Red battery terminal 2 6 2 Connect clip of black shielded wire to negative terminal pump should start immediately 3 If pump does not start check battery voltage should be not less than 12 volts under light load 13 volts no load 4 If pump does not operate with fully charged battery check battery clip connections and wires for poor connections 5 Should pump fail to operate after Steps 1 4 are completed refer to manufacturer s instructions attached 6 Pumping rate of the 12V DC unit will vary with voltage Normal pump operation requires a current draw of approximately 11 amps Continuous running in excess of 3 hours may result in reduced battery voltage and lower CFM through the ACI 7 Fully recharge battery between uses SERVICE LOCATIONS For additional assistance worldwide service is available from Thermo Fisher Scientific Contact one of the phone numbers below for product support and tech
23. he exhaust section of each stage is approximately 19 mm larger in diameter than the Petri dish which allows unimpacted particles to go around the dish and into the next stage Figure 3 A continuous duty carbon vane vacuum pump is available which will provide a constant sample flow of 1 ACFM The 50 effective cutoff diameter of Stage I of this Sampler is 8 0 microns for spherical particles of unit density or their aerodynamic equivalent A reasonable working interpretation would 17 conclude that non respirable particles do not penetrate the lower human respiratory tract are collected on Stage I and respirable size particles will penetrate the lower human respiratory tract are collected on Stage II 2 Assembly The complete impactor assembly consists of a base two stages and three threaded Teflon caps Figure 7 The assembly of the two stage impactor begins by placing an agar collection plate uncovered on the base so that the Petri dish rests on the three post supports Place Stage II carefully over the thr dowel pins and slide into position over the Petri dish Place the second Petri dish on the top of Stage II and carefully cover with Stage I Screw the thr caps onto the dowel pins and tighten by hand Connect a vacuum hose not supplied to the nipple on the base of the instrument Connect the vacuum hose to a vacuum source when a 100 x 15 mm Petri dish
24. izes on each stage of inertial impactors Thus the Six Stage ACI with 400 small round jets per stage and the Two Stage ACI with 200 tapered round jets per stage meet all the criteria for the efficient collection of airborne viable particles Recent reports have discussed a reduced efficiency in cascade impactors when particles bounce off the impaction surface are reintrained and lost in the exhaust air This effect is minimized when a sticky agar surface is used as the collection medium Stage 1 7 0 Microns and above Nasal Cavity Stage 2 4 7 7 0 Microns Pharynx Stage 3 3 3 4 7 Microns Trachea and Primary Bronchi Stage 4 2 1 3 3 Microns Secondary Bronch Stage 5 1 1 2 1 Microns Terminal Bronchi Stage 6 0 6 1 1 Microns Alveoli Figure 1 Six Stage ACI Sampler Simulates Human Respiratory System The earliest and most fundamental work in inertial impaction theory was conducted in the early 1950 s by Ranz and Wong In this work Ranz and Wong showed that the collection of a particle by an obstacle is a function of what is defined as the inertial impaction parameter K CpUDp 183uD where U is the relative velocity p is the particle density Dp is the particle diameter wis the gas viscosity Dc is the diameter of the round jet and C is the Cunningham slip correction factor Data from inertial impactors are normally presented as 50 effective cutoff diameters
25. mp while still maintaining 1 ACFM through the ACI The pump and motor are guaranteed by the original manufacturer and should not be disassembled for any reason The pump and motor require no lubrication The pump rate of the 12 volt DC pump will vary with voltage One ACFM can be drawn through the impactor if the voltage is maintained near 12 volts Refer to the attached supplementary titled Instructions For 12 Volt Pump for detailed 12 volt DC pump operation 20 V ANALYSIS AND INTERPRETATION OF DATA The number of viable aerobic particles per unit volume of air sampled is easily computed After incubation count the number of bacterial colonies accepted microbiological theory assumes that each colony represents a single particle on each sample plate Sum the number of colonies on each plate to give a grand total for that particular sample Divide this total by the total volume of air sampled in cubic feet if a constant flow rate of 1 ACFM is maintained the volume of air sampled is equal to the number of minutes sampled to give the mean number of viable particles per cubic foot of air in the sample Mean Number of Viable Particles per Cubic Foot of Air Sampled Total Number of Colonies from all Sample Plates Total Sampling Time in Minutes 1 ACFM Note that the number of viable particles in the air sample is not equal to the number of bacterial cells in the sample
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27. pe or density are sized aerodynamically and can be directly related to human lung deposition TWO STAGE ALUMINUM VIABLE CASCADE IMPACTOR T T The Two Stage ACI is also a multi orifice cascade impactor This unit is used whenever a size distribution is not required and only respirable nonrespirable segregation or total counts are needed Ninety five to one hundred percent of the viable particles above 0 8 microns in an aerosol can be collected on a variety of bacteriological agar This impactor separates viable particles into two size ranges with the 50 cut off diameter of Stage 1 at 8 0 microns for spherical particles of unit density The impactor is fabricated of aluminum and is reusable A brief description of the operation of the viable particle samplers follows 1 Six Stage Viable Particle Sampler a Collection plates are prepared by aseptically pipetting 27ml of sterile bacteriological agar 45 50 C into each of six glass Petri dishes supplied with the instrument The Petri dishes must be sterilized prior to filling Petri dishes other than those supplied cannot be used since this would alter the distance between the jet orifice and the collection surface of each stage Plastic Petri dishes should not be used because the static charge generated reduces the collection efficiency b Any general purpose solid bacteriological medium such as trypticas
28. placed on each Petri dish Identify each plate as to sample and stage number i e 1 1 1 2 1 3 etc Place all agar plates inverted to prevent condensation drip in an incubator at 35 C for 18 to 24 hours Plates can be incubated at room temperature if the user is most interested in environmental bacteria whose optimum growth temperature is lower than body temperature or at 20 to 25 C for maximum recovery of fungi After incubation the number of colonies on each plate are counted using a standard bacterial colony counter Knowing the air sample flow rate and the sampling time the mean number of viable particles aerobic bacteria and or fungi per unit volume of air can be calculated and the percent of particles in each size range can be estimated 5 Two Stage Viable Particle Samplers a Collection plates are prepared by aseptically pipetting 20ml of sterile bacteriological agar 45 50 C into each of two sterile 100x15mm plastic disposable Petri dishes An anti static chemical has been incorporated into the plastic used to fabricate the disposable sampler Commercially available agar plates 20 ml agar can be substituted for user prepared collection plates Any general purpose solid bacteriological medium such as trypticase soy agar or blood agar can be used for the collection plates Selective media are not recommended since they inhibit the rep
29. r replacement parts that are not covered by the warranty provided in this warranty Buyer shall pay Seller therefor at Seller s then prevailing time and materials rates ANY INSTALLATION MAINTENANCE REPAIR SERVICE RELOCATION OR ALTERATION TO OR OF OR OTHER TAMPERING WITH THE PRODUCTS PERFORMED BY ANY PERSON OR ENTITY OTHER THAN SELLER WITHOUT SELLER S PRIOR WRITTEN APPROVAL OR ANY USE OF REPLACEMENT PARTS NOT SUPPLIED BY SELLER SHALL IMMEDIATELY VOID AND CANCEL ALL WARRANTIES WITH RESPECT TO THE AFFECTED PRODUCTS THE OBLIGATIONS CREATED BY THIS WARRANTY STATEMENT TO REPAIR OR REPLACE A DEFECTIVE PRODUCT SHALL BE THE SOLE REMEDY OF BUYER IN THE EVENT OF A DEFECTIVE PRODUCT EXCEPT AS EXPRESSLY PROVIDED IN THIS WARRANTY STATEMENT SELLER DISCLAIMS ALL OTHER WARRANTIES WHETHER EXPRESS OR IMPLIED ORAL OR WRITTEN WITH RESPECT TO THE PRODUCTS INCLUDING WITHOUT LIMITATION ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE SELLER DOES NOT WARRANT THAT THE PRODUCTS ARE ERROR FREE OR WILL ACCOMPLISH ANY PARTICULAR RESULT Warranty TABLE OF CONTENTS ECTION TITLE PAGE NO Tr PREFACE 1 Th INTRODUCTION 2 Trt AERODYNAMIC PARTICLE SIZING 7 IV IMPACTORS 10 A SIX STAGE VIABLE PARTICLE SAMPLER 10 1 DESCRIPTION 10 2 ASSEMBLY 12 3 SAMPLING 13 4 CALIBRATION 14 B TWO STAGE ALUMINUM VIABL
30. ugged or partially plugged a jet blast of dry air is effective in cleaning them Just before use wipe all surfaces with 70 isopropyl alcohol using a lint free gauze pad The complete impactor assembly consists of an inlet cone six stages and 12 glass petri dishes includes 6 spare dishes The stages are inscribed 1 2 3 4 5 and 6 Each stage contains an O ring for sealing These O rings should be checked regularly and replaced when they no longer provide an airtight seal The assembly of the Six Stage ACI begins by placing an agar collection plate uncovered on the base plate so that the Petri dish rest on three raised metal pins Insert Stage 6 over the Petri dish Place a second Petri dish on the top of Stage 6 and continue this manner until all six agar collection plates have been positioned in the ACI The inlet cone is placed on top of Stage 1 All the agar plates should be at room temperature before they are inserted into the sampling instrument When the Petri dishes supplied with the sampler are used and 27ml of agar medium is placed in each Petri dish the three metal pins on each stage position the collection surface for the correct distance between the jet orifices and the agar surface 13 After the ACI has been assembled connect the outlet nipple on the base plate to the vacuum pump or other vacuum source 3 Sampling When ready to sample the vacuum
31. ulbs and other such expendable items are expressly excluded from the warranty under this warranty Notwithstanding the foregoing Products supplied by Seller that are obtained by Seller from an original manufacturer or third party supplier are not warranted by Seller but Seller agrees to assign to Buyer any warranty rights in such Product that Seller may have from the original manufacturer or third party supplier to the extent such assignment is allowed by such original manufacturer or third party supplier In no event shall Seller have any obligation to make repairs replacements or corrections required in whole or in part as the result of i normal wear and tear ii accident disaster or event of force majeure iii misuse fault or negligence of or by Buyer iv use of the Products in a manner for which they were not designed v causes external to the Products such as but not limited to power failure or electrical power surges vi improper storage and handling of the Products or vii use of the Products in combination with equipment or software not supplied by Seller If Seller determines that Products for which Buyer has requested warranty services are not Thermo Fisher Scientific Thermo Fisher Scientific covered by the warranty hereunder Buyer shall pay or reimburse Seller for all costs of investigating and responding to such request at Seller s then prevailing time and materials rates If Seller provides repair services o
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