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 there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2011 SAE International All rights reserved. No part of this publication m
3、ay be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside U
4、SA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visit http:/www.sae.org/technical/standards/J2773_201102SURFACEVEHICLESTANDARDJ2773 FEB2011 Issued 2011-02 Standard for Refrigerant Risk An
5、alysis for Mobile Air Conditioning Systems RATIONALE This standard is necessary due to introduction of new alternative refrigerants for mobile air conditioning. New requirements for the proper handling of these refrigerants are required. FOREWORD The potential impact of unintended refrigerant discha
6、rges resulting in high refrigerant concentrations shall be investigated and considered. All reasonable hazards affecting persons inside the vehicle and in the close proximity of the vehicle, as well as the effects of long-term exposure shall be considered. Possible failure scenarios and safety targe
7、ts shall also be considered. 1. SCOPE This Standard describes methods to understand the risks associated with vehicle mobile air conditioning MAC systems in all aspects of a vehicles lifecycle including design, production, assembly, operation and end of life. Information for inputto the risk assessm
8、ent is provided in the Appendices of this document. This information should not be considered to be complete, but only a reference of some of the data needed for a complete analysis of the risk associated with the use of refrigerants in MAC systems. 2. REFERENCES 2.1 Applicable Publications The foll
9、owing publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA
10、 and Canada) or 724-776-4970 (outside USA), www.sae.org.SAE J639 Safety Standards for Motor Vehicle Vapor Compression Refrigerant Systems SAE J1739 Potential Failure Mode and Effects Analysis in Design (Design FMEA), Potential Failure Mode and Effects Analysis in Manufacturing and Assembly Process F
11、MEA) SAE J2683 Refrigerant Purity and Container Requirements for Carbon Dioxide (CO2 R-744) Used in Mobile Air-Conditioning Systems Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2773 Issued FE
12、B2011 Page 2 of 6SAE J2772 Measurement of Passenger Compartment Refrigerant Concentrations Under A/C System Refrigerant Leakage Conditions SAE J2844 R-1234yf New Refrigerant Purity and Container Requirements Used in Mobile Air-Conditioning Systems 2.1.2 Other Publications ISO 13043 Road vehicles - R
13、efrigerant systems used in Mobile Air Conditioning systems (MAC) - Safety requirements 3. GENERAL DEFINITIONS Safety is the absence of non-acceptable risk. Non-acceptable risk are those that are higher than those already accepted by the general population today (e.g., risks involved with riding in a
14、n airplane are considered acceptable by general public today).Risk: Combination of probability of a harm occurring during an event and the severity of it.OEM - Original Equipment Manufacturer - unless otherwise stated in this document, this refers to the vehicle manufacturer. FTA is a methodology th
15、at graphically presents the sequences and combinations of failures that lead to a particular outcome. It utilizes a “top-down“ approach, starting with the undesired effect as the top event of a tree of logic. Each situation that could cause that effect is added to the tree as a series of logic expre
16、ssions. This technique analyzes the potential combinations or sequences of events by which an undesired event may occur. FTA can consider such causal effects as human error, equipment failure, and operating and maintenance procedures, though it cannot cover those causes of system failure that cannot
17、 be envisioned by risk analysts (Blackwell et al., 2006). FTAs consist of various event “boxes“, which reflect the probability or frequency of key events leading up to a system failure. The event boxes are linked by connectors (“gates“) which describe how the contributing events may combine to produ
18、ce the failure. General Safety Process Requirements - Proper design practices for the application of a refrigerant to MAC systems are required. The following or other equivalent methods shall be used to assess the risks associated with the use of a new refrigerant proposed for use in mobile air cond
19、itioning systems. SAE J1739 - Potential Failure Mode and Effects Analysis in Design (Design FMEA), Potential Failure Mode and Effects Analysis in Manufacturing and Assembly Processes (Process FMEA), or equivalent shall be applied to the design and development of mobile air conditioning refrigerant s
20、ystems. FTA - Fault Tree Analysis methods.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2773 Issued FEB2011 Page 3 of 64. SAFETY ASSESSMENT This standard provides the guidelines for an assessm
21、ent of safety with the refrigerants referenced in this standard for mobile air-conditioning systems. The management of functional safety shall include the following from the concept phase through the lifetime of the vehicle 1. Concept phase 2. Product development phase 3. Production and assembly 4.
22、Operation 5. Service 6. End of life and scrapping 5. RISK ASSESSMENT Risk characterization represents the step in the analysis where data on acute and chronic toxicity, flammability and anticipated air concentrations are brought together to quantify the potential risks of the refrigerant system. The
23、 results of the risk characterization contribute to the FTA and/or DFMEA and allow an estimate of the impact of adverse events that may result from use of the refrigerant. Risk assessment shall be established for all relevant situations. 5.1 At a minimum, the following scenarios shall be considered
24、in the risk assessment for R-744 CO2: Inhalation exposure to CO2 concentration above health limits due to a small or large refrigerant leak into the passenger compartment Inhalation exposure to CO2 concentration above health limits during vehicle service Liquid or fragment projectiles resulting from
25、 high pressure system burst Liquid or fragment projection during vehicle service Potential startling of the vehicle driver due to rupture of the high pressure system, resulting in a possible accident Manufacturers should design systems cognizant of CO2 concentration peak level concentrations that co
26、uld impact driver performance during vehicle operation, and shall measure the interior concentrations as outlined in SAE J2772. Background levels of CO2 that may exist in the vehicle need to be considered. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproductio
27、n or networking permitted without license from IHS-,-,-SAE J2773 Issued FEB2011 Page 4 of 65.2 At a minimum, the following scenarios shall be considered in the risk assessment for R-1234yf HFO-1234yf: Inhalation exposure to R-1234yf concentration above health limits due to a small or large leak in t
28、he passenger compartment Inhalation exposure to R-1234yf concentration above health limits during vehicle service Ignition event associated with large leak in the passenger compartment Ignition event due to R-1234yf release during vehicle service Inhalation exposure to HF concentration above health
29、limits AEGL2 resulting from refrigerant thermal decomposition in the event of a refrigerant release Manufacturers should design systems cognizant of the flammable properties of R-1234yf and the potential for ignition sources that could ignite the refrigerant. 5.3 All other refrigerants considered fo
30、r MAC usage shall comprehend similar scenarios and the appropriate refrigerant properties in the risk assessment. 6. NOTES 6.1 Marginal Indicia A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been
31、 made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY SAE
32、 INTERIOR CLIMATE CONTROL STANDARDS COMMITTEE Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2773 Issued FEB2011 Page 5 of 6APPENDIX A - EXAMPLE RISK ASSESSMENT INPUTS A.1 TOXICITY INPUTS LC50o
33、r ALC studies in rats Tabulae Biologicae studies Repeated dose studies Genotoxicity in vitro studies Ames tests Teratogenicity in multiple species AIHA WEEL committee TWA values NOAEL values A.2 CARDIAC SENSITIZATION Cardiac sensitization studies A.3 ANESTHETIC EFFECT Studies of anesthetic effects A
34、.4 OTHER ESCAPE-IMPAIRING EFFECTS AND PERMANENT INJURY Occupational Safety and Health (NIOSH) IDLH Immediately Dangerous to Life and Health limits A.5 OTHER FACTORS Pressures during operation and service of vehicles shall be considered. Flammability properties including those shown in the table belo
35、w Other properties available in the current published MSDS sheets TABLE A1 - FLAMMABILITY PROPERTIESUpper Flammability Limit, Vol. % in air (21C, ASTM E681) Lower Flammability Limit, Vol. % in air (21C, ASTM E681) Minimum Ignition Energy, mJ at 20C and 1 atm (per IEC 79-3, 3rd ed., 1990) Autoignitio
36、n Temperature, C (EC Physico/Chemical Test A15) Heat of Combustion, MJ/kg per ASHRAE Standard 34 Fundamental burning velocity, cm/s (per ISO 817) Minimum Ignition Current (per IEC 79-3, 3rded., 1990) Minimum Ignition Current Ratio (per IEC 79-3, 3rded., 1990) Copyright SAE International Provided by
37、IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2773 Issued FEB2011 Page 6 of 6APPENDIX B - HEALTH BASED LIMITS FOR HYDROGEN FLUORIDE (HF) B.1 AEGL: ACUTE EXPOSURE GUIDELINE LIMIT AEGLs have been developed primarily to provide guidanc
38、e in situations where there can be a rare, typically accidental exposure to a particular chemical that can involve the general public. They, therefore, differ from other exposure guideline values in that they are based primarily on acute toxicology data and not sub -chronic or chronic data. The guid
39、ance therefore does not reflect the effects that could result from frequent exposure. Also, they are designed to protect the general population including the elderly and children, groups that are generally not considered in the development of workplace exposure levels. AEGLs consist of three specifi
40、c values for a chemical of interest, corresponding to increasing severity of health effects with increases in exposure time (10 min to 8 h). AEGL-1: Exposures below this value will result in no adverse health effects. AEGL-2: Exposures below this value may result in mild and reversible effects, such
41、 as irritation or discomfort, but will not impair the ability to escape or result in permanent health effects. This value shall be used in assessing the risk of exposure to HF AEGL-3: Exposures below this level are not lethal, but could result in long-term health effects. Hydrogen fluoride (HF) is a
42、 potential decomposition product for any fluorine containing refrigerant product, (R-152a, R-134a and R-1234yf). Refrigerant is not expected to come into contact with open flames or red hot surfaces during normal usage. However, in the unlikely event that R-1234yf should come into contact with an op
43、en flame or red hot surface (possibly from an accident) there is a possibility that the refrigerant may decompose into HF. Hydrogen fluoride (HF) is a noxious and irritant gas. The odor threshold for HF varies among individuals but has been reported to be 0.02 to 0.13 ppm (NRC, 2004). Appropriate gu
44、idelines for assessing acute exposures to HF in an emergency situation include the Emergency Planning Response Guideline (EPRG) values published by the American Industrial Hygiene Association (AIHA) and the Acute Exposure Guideline Limits (AEGLs) established by the U.S. National Advisory Council for
45、 AEGLs and National Research Council (NRC).1Occupational exposure values such as the U.S. Occupational Health and Safety Administrations (OSHA) Short Term Exposure Limit (STEL) or the National Institutes of Occupational Health and Safety (NIOSH) shall be used. Recommended Exposure Limits (REL) are n
46、ot appropriate values for consideration because these values are intended for workers who may be exposed repeatedly to these values over the course of their job tenure (i.e., multiple brief exposures per work week or even per day). Such a value would not be consistent with the emergency-type situati
47、on envisioned by release and ignition of a refrigerant. The AEGL-2 values represent reasonable health-based limits for use in this risk assessment. The key concern should be to prevent situations in which the individual is unable to safety operate the vehicle or take action (e.g., stopping, opening
48、windows) in order to avoid significant and permanent injury. AEGL-1 values, which represent a threshold for minor discomfort, would be overly restrictive for evaluating scenarios which by their very nature involve other hazards such as collision-related trauma, exposures to smoke or flames in car fires, etc. AEGL-2 value for HF is 95 ppm for 10 min AEGL-2 value for HF is 34 ppm for 30 min AEGL-2 value for HF is 24 ppm for 60 min 1Provisional AEGLs are developed and proposed by the U.S. National Advisory Council fo
