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International Safety Standards International Safety Standards (ISO & IEC) and Flammable (ISO & IEC) and Flammable
RefrigerantsRefrigerants
Advancing Ozone and Climate Protection Technologies: Next Steps
29-30 June 2013Bangkok
Osami KataokaJRAIA
Advancing Ozone and Climate Protection Technologies: Next Steps the technology conference
2
ContentsContents
1. Introduction
2. International Standard
3. Refrigerant Safety and Climate Change
4. Accident Statistics of Japan 4. Accident Statistics of Japan
5. What is 2L?
6. Overall Relative Risk
7. Japanese Study
8. Conclusion
3
11.. IntroductionIntroduction
Experience of presenter• More than 30 years dealing RAC technical issues• Representing Japan for following International standards
– ISO 5149 [ISO TC86 SC1 WG1 (1997- )] FDIS– ISO 817 [ISO TC86 SC8 WG5 (1998- )] FDIS– IEC60335-2-40 [IEC61D]– IEC60335-2-40 [IEC61D]
• JWG (1998-2001) Published• WG7 (2005 -2006) FDIS• WG9 (2011-2013) WD
• Worked for Natural Gas field in 1986-1989.(Methane, Volcanic gas)
2. International Standards2. International StandardsISO817 ISO5149 IEC60335-2-40(24,89)
Title Refrigerants -Designation and safety classification
Refrigerating systems and heat pumps -Safety and environmental requirements
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES -SAFETY -
Part 2-40: Particular requirements for electrical heat pumps,
4
air-conditioners and dehumidifiers
Scope Refrigerant Refrigeration System Appliance
Contents Refrigerant Flammability classificationAllowable concentration
Allowable charge amountDesign of unitInstallation siteService
Allowable charge amountDesign of unitRequirements on manual contents
Process Second FDIS Second FDIS FDIS(Joint), DC(A2L)
Publication(shortest)
End of 2013 End of 2013 End of 2013 (Joint)Summer of 2015 (A2L)
3.1 GWP and Flammability3.1 GWP and Flammability
170 161 152a 143(a) 134a 125 116
Life in Air(yr) 0.3 1.4 3.4(43) 14 29 10 000
GWP(100y) <3 12 124 330(4470) 1430 3500 12 200
5
• Lower GWP means less stable or abundant in air.• Lower GWP substances are generally less stable, so more
flammable and/or toxic than high GWP substances
HoC (MJ/kg) 46 25 16 10 6.6 4.0 2.2
C
H C F
F
F
F
HF
F
F
F
FC
H C
F
F
125134a152a
CC
C
H CEthane
H F
F
FF
1234yf
CC
C
6
3.2 Refrigerant Safety and Climate Change3.2 Refrigerant Safety and Climate Change
• Now, it is necessary to minimize GWP of refrigerants. • Precise flammability evaluation of refrigerant is mandatory. • Acceptable flammability depends on charge amount.• Precise charge limitation is necessary.
GWP
Fla
mm
abili
ty(H
oC M
J/kg
)
Allowable Amount
Fla
mm
abili
ty
Allowable Amount
GW
P
0
10
20
30
40
50
60
0 1000 2000 3000 4000
125134a32152a
Ethane
1234yf
3.3 Flammability Indices3.3 Flammability Indices• Detailed flammability evaluation was not necessary
until GWP became an issue. • Indices were not reliable.
7
LFLv LFLw HoC% kg/m3 MJ/kgHydrogenHydrogen1.8 0.003 120Iso-Butane
ISO 5149-1993 ASHRAE 34 before 2010
HydrogenMethaneEthylene PropaneIso-ButaneAmmoniaR152aCOR143aR142b
HydrogenEthyleneMethanePropaneIso-ButaneAmmoniaR152aCOR143aR32R142b R32
1.82.12.74.14.75.06.26.89.0
12.512.715.0
0.0030.0310.0330.0390.0440.1060.1290.1460.2170.2750.2850.439 R141b
12050474646
18.6161010998R141b
PropaneEthyleneHydrogenR152aMethaneR143aR142bR141bCOR32Ammonia
Iso-Butane
3.4 Flammability Indices of ISO817 FDIS3.4 Flammability Indices of ISO817 FDIS
• Burning velocity was chosen to be added from several candidates at the WG in 2002. ASHRAE 34 employed it in 2010.
• LFLv is to ensure low
8
BV (m/s)
Hydrogen 2.91
Ethylene 0.75
CO 0.11-0.43
Propane 0.43
Iso-Butane 0.38• LFLv is to ensure low probability of occurrence and consistency to EN378.
• Heat of combustion is to ensure total energy to be released and consistency to ASHRAE.
Iso-Butane 0.38
Methane 0.37
R152a 0.23
Ammonia 0.07
R143a 0.07
R32 0.07
R1234yf 0.02-0.06
R141b -
3.5 Allowable Charge 3.5 Allowable Charge –– Pooling EffectPooling Effect• Charge amount was limited to 20 or 25% of
LFL x Room Volume • Floor installation was found dangerous• Not possible to avoid flammable cloud completely• IEC/ISO Joint working group developed requirements
9
140
160Release height Release Condition
0
20
40
60
80
100
120
140
Concentration of R134a in Air [vol%]0 5 10 15 20 25 30
10cm
50cm
90cm
Release height180cm
Release Condition
Just after the End of Release
f
Gas:HFC-134a Amount:1300g Port Size: 22 cm Rate:70g/min Velocity:<0.1cm/s
Hei
ght f
rom
Flo
or (
cm)
3.6 Formula for Charge Limit3.6 Formula for Charge Limit• 4 minutes entire release with minimal velocity.• Avoid LFL at floor level and explosion.• Various tests and numerical analysis were
carried out to develop the formula.
10
• Accuracy was confirmed by experimental tests.• It was employed to IEC60335-2-40 draft in
2000, then copied to ISO5149 draft in 2004.
11
4.14.1 Accident Statistics in JapanAccident Statistics in Japan2000 2001 2002 2003 2004 2005 2006 2007 2008 2009Fuel gas facility(KHK)
Explosion NA 38 51 77 57 48 57 64 53 45
fire NA NA NA NA NA NA 19 51 60 42
Refrigeration FacilityAmmonia Installation 210 257 239 NA 111 168 154 151 132 188
FC Unit sales (CU) 141,928126,079
127,304118,627
124,387115,044
114,063100,337
83,47377,023
Refrigerant FatalityRefrigerant FatalityAmmonia 0 0 0 0 0 0 1 0 0 1Fluorocarbon 0 0 0 0 0 0 0 0 0 0
Refrigerant InjuryAmmonia 2 2 1 5 0 1 2 1 3 9Fluorocarbon 0 3(11) 0 2(39) 0 0 3 0 0 0
• Ammonia accidents did not result in fire except one case, though anti-explosion system is not required with ammonia in Japan. In the case it appears that lubricant is ignited.
Accident data: High pressure gas safety institute JapanFC unit sales data: JRAIAAmmonia sales data: JSRAE
4.2 Cause of accidents in Japan4.2 Cause of accidents in Japan
• Major cause of refrigerant sudden release accidents are human error in service.
12
18181818
20202020OperationOperationOperationOperation
FataltyFataltyFataltyFatalty InjuryInjuryInjuryInjury TotalTotalTotalTotal0000
2222
4444
6666
8888
10101010
12121212
14141414
16161616
18181818
FataltyFataltyFataltyFatalty InjuryInjuryInjuryInjury TotalTotalTotalTotal
OperationOperationOperationOperation
Wrong ServiceWrong ServiceWrong ServiceWrong Service
Wrong Service andWrong Service andWrong Service andWrong Service andInstallationInstallationInstallationInstallation
IntentionalIntentionalIntentionalIntentional
Not ClearNot ClearNot ClearNot Clear
CFC, HCFC toxicity accidents
13
4.34.3 AC appliance Accident in JapanAC appliance Accident in Japan• Current accident statistic of mini-splits over 100 million.
Cause of accidentsNumberIn 6 yr
1 Improper wiring of power supply cable 34
2 Cleaning detergent damaged electric insulation 29
3 Deterioration due to long use period 18
4 Starting fire from a parts of unit 134 Starting fire from a parts of unit 13
5 Short circuit in outdoor unit by foreign matter 10
6 Injury due to contact with fan or heat exchanger fin 5
7 Dust short circuit at power plug 5
8 Overstress on power cable 4Unknown burnout includes suspected arson cases 117Total 272
Prevention of single failure results in significant accident is required by IEC/ISO. Highly flammable/toxic refrigerants?
14
5.15.1 What is 2L?What is 2L?• Based on ammonia flammability. Does not Flash.
Flammability is less than lubricant.• IEC61D WG9 is developing requirements for 60335-2-40.
Propane R152aAmmonia R32
R32 R22+Mineral OilR32+Ether oil
55.2.2 Various test resultsVarious test results15
• Propane 30g Small Chamber• Propane 110g Large Chamber• R152a 1000 g Large Chamber• Ammonia 600g Large Chamber• R32 320g Small Chamber• R32 320g Small Chamber• R1234yf 180g Small Chamber• R32 1000g Large Chamber• Brazing 5% Oil• Brazing 50% Oil
55.3 Difference in Risk of rapid release.3 Difference in Risk of rapid release
• CFD results indicate:– If flow velocity is
considered, A2L does not generate flammable cloud in
16
R32 Propane
LFL
rapid release.– Flow speed is too
high to ignite where concentration is high enough.
LFL+speed
200 g /min release
10 m
17
5.45.4 Difference between 2L and 3Difference between 2L and 3• In 4 minutes complete charge leaks• A2L class refrigerants dilute below LFL quickly due to
heavy molecule and high LFL.
CFD results
R290(60g/min) R32 (250g/min)
5.5 Decomposition Products5.5 Decomposition Products• 800g refrigerant released into 30 m3 room with operating
combustion heater. (Tokyo university of science results.)• It can reach fatal concentration, but it smells and is slowly
generated. It appears acceptable based on ammonia experience.
18
5.6 Expected requirement5.6 Expected requirement19
0
1
2
3
4
5
6
7
8
0 20 40 60 80 100
Opening area and capacity of relayArea to propagate flame Capacity (A)
Ope
ning
(d*)
5.7 Sample of relays5.7 Sample of relays20
• Most relay is Japan appears safe for 2Ls, but relays in the States ay be dangerous.
6. Overall Relative 6. Overall Relative RRiskisk
Concentration limit Other factor
HC Flammability Limit 40g/m3Ignition source of HC is less than population, but considerably exists.
R22 Toxicity Limit 220g/m3 Ignition source density of A2L is far less than population A2L Flammability Limit 300g/m3<
21
• Human density is much higher than the density of A2L ignition sources.
• Flammability risk of A2L is less than toxicity risk of R22. So, care shall be taken for applications with toxicity accidents of R22. In Japan, about 50 kg was the minimum charge to cause such accident in statistics.
77.1 A2L Risk Study in Japan.1 A2L Risk Study in Japan22
Project
University of Tokyo
Tokyo University of Science, Suwa
Chair: Dr. Hihara (University of Tokyo)
Secretary: Fujimoto(Industry)
JAMA(Automobile Industry)
JSRAE(Academia)
JRAIA(AC/Ref Industry)
Tokyo University of Science, Suwa
AIST(National Laboratory)
Kyushu University
Observers-NEDO-METI (Government)
Project started in 2011 to share latest information of research relating A2L refrigerants.Academia and Industry supported by the government.
77.2 Research themes and sharing.2 Research themes and sharingBasic Studies• Temp. and humidity effect on combustion• Minimum ignition energy• Thermal decomposition Products• Pressurization with combustion• Thermo-physical Properties• Safety analysis of service procedure
23
Tokyo University of Science
University of Tokyo
Kyushu University• Safety analysis of service procedure
• Leakage and stagnation analysis
JRAIA
Risk Assessments
VRF
Mini-Split
Chiller
MAC at repair JAMA
AIST
IEC60335-2-40
ISO 5149ISO 817
7.3 Schedule7.3 Schedule24
2011 2012 2013 2014
CommonAnalysis
SeverityAnalysis
Influence of humidity and temperature
Leakage of refrigerant into a room
Flammability test and Condition of flame propagation
Possibility of explosion
• Excellent results are obtained. Refer http://www.jsrae.or.jp/jsrae/Eindex-2.html (Bottom of right column)
LikelihoodAnalysis
Milestone
Mini-sprit risk assessment
VRF risk assessment
Chiller risk assessment
Progress Report
Progress Report
New legislation
Kobe Symposium
88. Conclusion. Conclusion• ISO and IEC standards are being revised to cope
with climate change. Precise flammability evaluation and quantitative requirements are necessary.
• Burning velocity is employed to assess flammability precisely in ISO817 draft.
• Precise pooling calculation is employed in
25
• Precise pooling calculation is employed in IEC60335-2-40 then copied ISO5149 draft.
• A2L flammability appears acceptable for general use, since single failure unlikely results in significant accident.
• IEC61D WG9 is developing requirements for A2L.• Japanese A2L project supporting standardizations.
26
ENDEND
Thank you for your attention!
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