1、 _ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising ther
2、efrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2016 SAE International All rights reserved. No part of this
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4、70 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/standards.sae.org/ARP4259A AEROSPACE RECOMMENDED PRACTICE ARP4259 REV. A Issued 1991-04 Revised 1996-07 Reaffirm
5、ed 2016-11 Superseding ARP4259 Metabolic Simulator Testing Systems for Aviation Breathing Equipment RATIONALE ARP4259A has been reaffirmed to comply woth the SAE five-year review policy. 1. SCOPE:This Aerospace Recommended Practice (ARP) describes test equipment and methods used for testing closed c
6、ycle or semiclosed cycle breathing devices of short duration that are designed to operate with a high partial pressure of oxygen in the breathing circuit. It is intended to supplement ARP1109 and ARP1398 for applications involving closed cycle or semiclosed cycle breathing equipment which may be eva
7、luated to the requirements of AS8031 and/or AS8047.1.1 Purpose:This ARP recommends performance requirements for test equipment used to simulate human respiration in the testing of aviation protective breathing equipment (PBE). This ARP does not, however, preclude the need for human testing.2. REFERE
8、NCES:The applicable sections of the following documents shall be considered as integral parts of this recommended practice.SAE:AIR825 Oxygen Equipment for AircraftARP1109 Dynamic Testing Systems for Oxygen Breathing EquipmentAIR1176 Oxygen System and Component Cleaning and PackagingARP1398 Testing o
9、f Oxygen EquipmentAS8010 Aviators Breathing Oxygen Purity StandardAS8031 Minimum Performance Standard for Personal Protective Devices for Toxic and Irritating Atmospheres, Air Transport Crew MembersAS8047 Performance Standard for Cabin Crew Portable Protective Breathing Equipment for Use During Airc
10、raft Emergencies2. (Continued):Others:MIL-O-27210 Oxygen Aviators Breathing (ABO)MIL-P-27401 Nitrogen, Type IMIL-G-27617 Oxygen LubricantsTSO C99 Protective Breathing EquipmentTSO C116 Crewmember Protective Breathing Equipment3. GENERAL:3.1 Human Respiration Simulation:There are two primary requirem
11、ents for simulation:a. A breathing simulator with control of ventilation rate , respiratory frequency (f) and desirably, breathing waveform shape controlb. Gas-exchange metabolism simulation with control of the oxygen consumption , carbon dioxide elimination , and temperature-humidity of the exhaled
12、 gas3.2 Test Conditions Pertaining to Short Duration Breathing Devices of Rebreather Type:As described in B.9, very elaborate respiration simulators with computerized monitoring of the different parameters have been designed to accurately simulate metabolic processes. Oxygen consumption is simulated
13、 by continuous gas removal sufficient to effect the desired rate of oxygen consumption, and replacement of the balance composition of the other gases. These systems allow accurate testing of any type of closed circuit breathing device and are particularly well suited to equipment which operates with
14、 oxygen concentrations that are less than 50%.For breathing devices that operate with a high partial pressure of oxygen in the breathing circuit and are of short duration, much simpler simulators can allow reasonably accurate testing. Most of these breathing devices generally deliver an oxygen flow
15、to the user largely in excess of the average metabolic O2 consumption which results in a high O2 concentration in the rebreather reservoir. Therefore the simulated O2 consumption can be effectively achieved by direct volumetric removal of the breathing gas and a more complicated subsystem is not nec
16、essary. B.5 and B.10 describe functional installations of these simpler systems.V E( )V O2( )V CO2( )V IO2V O2( )SAE INTERNATIONAL ARP4259A 1 of 13_4. REQUIREMENTS:Typical schematic diagrams of metabolic simulators are given in Figures 1 and 2.4.1 Breathing Simulator or Artificial Lung:It will be a
17、mechanical breathing simulator of Type I or II, Class A as defined by ARP1109.Use of a sinusoidal breathing waveform is acceptable.Since high concentrations of oxygen will be encountered during testing, it is recommended that the equipment be cleaned for oxygen service in accordance with AIR1176. Te
18、st gases of the appropriate referenced standard are recommended to avoid contamination of the equipment.For each workload to be simulated, the artificial lung will be set to a given ventilation rate (minute volume ) for a given respiratory frequency (f) in breaths per minute (BPM) according to the p
19、rocedures described in Section 5.4.2 Metabolic Simulation:4.2.1 Body CO2 Simulated Production ( ): A steady flow of CO2 simulating will be injected into the simulator, preferably directly into the artificial lung for better mixing of the breathing gases. will be in accordance with the values determi
20、ned in Section 5 for the given workload. Note that expiratory must be the sum of and of inspiratory residual CO2 leaving the breathing device.A CO2 analyzer will allow measuring the CO2 contents in expired gases prior to their entry into the breathing device.Accurate control of the CO2 flow is essen
21、tial to establish the proper loading on the breathing device CO2 scrubbing component. CO2 average input can be manually adjusted by means of a needle valve and an appropriate rotameter or equivalent, with a flexible bag and a check-valve upstream of the artificial lung to allow for cyclic discharge
22、into the upper chamber of the lung.4.2.2 Body O2 Simulated Consumption ( ): A metered flow of inspired gas will be withdrawn from the inspired gas circuit to simulate O2 consumption. A length of withdrawal tubing will isolate the withdrawal gas stream from the circuit as it is diverted to a series o
23、f analyzers (O2, CO2, CO, etc.) and then discharged to ambient. This will allow for measuring the mean gas concentrations in the mixture.An auxiliary lung synchronized with the artificial lung can be used to simulate cyclic withdrawal of the gases. Alternatively, a small volumetric pump can be used
24、in a continuous mode.V EV CO2 V CO2V CO2CO2 V ECO2( ) V CO2V O2SAE INTERNATIONAL ARP4259A 2 of 13_4.2.2 (Continued):For simplicity, the volume/time of gas withdrawn to simulate may be set equal to , establishing a respiratory quotient (RQ) of 1. This will have the advantage of maintaining a constant
25、 mass balance within the simulator and the breathing device. If more accurate volumetric control of the gas exchange is desired, a detailed procedure is described in Annex 1.4.2.3 Temperature and Humidity Control: Expired gases from the simulator shall be water saturated at body temperature (37 C or
26、 98 F).Humidification can be achieved by means of an appropriate humidifier located between the artificial lung and the expired gases interface to the breathing device.An alternate method is to circulate water at 37 C into the upper chamber of the breathing simulator by means of a small volumetric p
27、ump.Temperature control of the gas within the simulator, or volumetric compensation, is required to prevent gas volume changes in resulting from changing temperatures in the output of the device under test. Subsequent rewarming of the gases to body temperature prior to entering the breathing device
28、during expiration phase is required. This rewarming can also be achieved at the same time as humidification.A water trap may be needed to remove condensation in the tubing circuits.4.2.4 Simulator Dead Volume: A metabolic simulator and human anatomy will never be identical. However it is essential t
29、hat:a. The dead volume above the breathing simulator piston and that of the different hoses and accessories up to simulator/device interface should not exceed the average human functional residual capacity (FRP), i.e., 2.3 to 2.4 L.b. The simulated tracheal dead volume should not exceed 150 cm3.c. I
30、f it is necessary to extend the functional interface of the simulator for remote operation within an altitude or environmental chamber, separation of inspiration and expiration circuits shall be maintained to minimize the dead volume effects.V O2 V CO2V ESAE INTERNATIONAL ARP4259A 3 of 13_4.2.5 Brea
31、thing Device/Simulator Interface: Protective Breathing Equipment (PBE) for Air Transport Cabin Crew to the requirements of AS8047 generally consists of closed cycle breathing hoods sealing around the neck of the user.The hood will interface with the simulator by means of a dummy head (medium size) p
32、rovided with a smooth neck surface compatible with the device neck seal. The dummy head will be equipped with a pipe connecting the mouth area with the simulator. An alternative is shown in Figures 2 and 3 with a concentric pipe connector separating the inhaled gases from the exhaled gases. Each bra
33、nch of this connector is alternatively isolated from the simulator by means of a check valve or solenoid valve activated by the artificial lung. Solenoid A opens at the beginning of the inspiration phase and closes at the end of this phase. Solenoid B opens at the beginning of the expiration phase a
34、nd closes at the end of this phase. The advantages of this system are:a. Reduction of the dead volume simulating the tracheab. Reduction of the rebreathing between inhaled and exhaled gases4.2.6 Directional Valves: A set of directional valves (C and D Figure 2) located at the lung outlet will allow
35、for proper transfer of the breathing gases throughout the simulator.5. OPERATING PARAMETERS:Simulator set point parameters for different workloads may be empirically derived from equivalent human subject testing, or calculated from physiological relationships. A sample sequence for calculating param
36、eters for a known workload is discussed in this section.5.1 Determination of :The relationship of to work is well defined and is generally considered linear for submaximal work. B.7 details methods for relating external workload to oxygen equivalents. For purposes of this derivation, the external wo
37、rkload of a bicycle ergometer is used. Referring to the procedures of AS8047 to determine the external workload from the subject weight, a 95th percentile 220 lb (100 kg) male exercising at a workload of 0.5 w/lb is chosen for illustration.External workload requirement:(Eq. 1)V O2V O2220 lb 0.5 w/lb
38、 110 w100 kg 1.1 w/kg 110 w=( )=SAE INTERNATIONAL ARP4259A 4 of 13_5.1 (Continued):For a bicycle ergometer, the total oxygen uptake includes a resting basal metabolism component dependent upon the individuals body weight, plus the external work requirement that is independent of body weight. This is
39、 frequently expressed by the following equation (where w = power in kilopond meter/minute (kpm/min), wt = subject weight in kg, and = ml/min):(Eq. 2)Applying the conversion factor of 1 w = 6.12 kpm/min(Eq. 3)5.2 Determination of :Although is normally a function of , it is significantly altered by in
40、creased inspiratory levels of CO2. These effects over the range of 0 to 40 mmHg PICO2 are documented in B.6 and shown graphically in Figure 4 for male subjects of average 71 kg bodyweight. Accordingly, the equation closest to the known, or anticipated, inspiratory CO2 level should be chosen for dete
41、rmination of .PICO2 = 0 mmHg (0 kPa)(Eq. 4)PICO2 = 10 mmHg (1.3 kPa)(Eq. 5)PICO2 = 20 mmHg (2.7 kPa)(Eq. 6)PICO2 = 30 mmHg (4.0 kPa)(Eq. 7)PICO2 = 40 mmHg (5.3 kPa)(Eq. 8)V O2V O2 3.5 wt 2 w+=V O2 3.5 220 lb 2.2 lb/kg( ) 2 110 6.12( )+=V O2 3.5 110 kg 2 110 6.12( )+=( )V O2 1,696 ml/min 1.696 lpm= =
42、V EV E V O2V EV E 6.588 10.72 V O2 6.226 V O22+ +=V E 6.277 20.60 V O2 4.923 V O22+ +=V E 6.680 33.95 V O2 1.744 V O22+ +=V E 12.20 50.71 V O2 2.532 V O22+=V E 26.99 59.60 V O2 5.879 V O22+=SAE INTERNATIONAL ARP4259A 5 of 13_5.2 (Continued):For this example, an inspiratory PICO2 = 20 mmHg (2.7 kPa)
43、will be assumed(Eq. 9)5.3 Determination of Respiratory Frequency (f):Although there is a high degree of individual variation in f, B.8 establishes a general relationship to that is useful for obtaining a guide to anticipated values.(Eq. 10)For this example,f = (6.7 1.696) + 17.4f = 28.85.4 Determina
44、tion of Tidal Volume (VT):(Eq. 11)For this example,VT = 69.3 lpm/28.8 bpmVT = 2.4 LV E 6.680 33.95 V O2 1.744 V O22+ +=V E 6.680 33.95 1.696( ) 1.744 1.696 1.696( )+ +=V E 69.3 lpm=V O2f 6.7 V O2 17.4+=VT V E f=SAE INTERNATIONAL ARP4259A 6 of 13_5.5 Alternative Procedures for Fixed Tidal Volume:As a
45、n alternative simplification, a specific midrange tidal volume may be chosen for a test sequence, and changes in ventilation ( ) achieved by adjusting the breathing frequency (f) to obtain desired values. Because of the wide range in individual tidal volumes and breathing frequencies, this simplific
46、ation has little impact on the accuracy of the test set up. The following Table 1 summarizes the calculations of 6.2 to determine for a 220 lb (100 kg) subject:TABLE 15.6 Summary of Calculated Parameters:For this example, simulating a 220 lb (100 kg) subject exercising at 110 w external workload with PICO2 = 20 mmHg (2.7 kPa).a. VENTILATION ( ) = 69.3 lpmb. FREQUENCY (f) = 28.8 bpmc. TIDAL VOLUME (VT) = 2.40 Ld. O2 CONSUMPTION = 1.696 Le. CO2 PRODUCTION = 1.696 L (RQ = 1 assumed)V EV EV ESAE INTERNATIONAL ARP4259A 7 of 13_6. TESTING AT ALTITUDE:It may be necessary to run alti
