HFO-1234yf – Safety when exposedto ignition sourcesHoltappels, K. ; Schröder, V.BAM Federal Institute for Materials Research and TestingHoffmann, G.; Plehn, W.UBA Federal Environment Agency2Contents10AARS-00151. Motivation2. Safety Characteristics3. Case study – Explosion regions4. Case study – HF formation5. Case study – Leakage6. Conclusions3Motivation10AARS-0015•Hazard assessment cannot take place based onlyon a single individual test series or safetycharacteristic.•Various systematic scenarios ("incidents") mustbe analyzed.•Finally only a holistic hazard analysis can lead toan accurate evaluation.4Contents10AARS-00151. Motivation2. Safety Characteristics3. Case study – Explosion regions4. Case study – HF formation5. Case study – Leakage6. Conclusions5Safety Characteristics10AARS-0015Already known and published safety characteristics(MSDS Honeywell, Version 1 from 11/10/2008):•Flammability limits:LEL = 6.2 vol%UEL = 12.3 vol%•Minimum ignition temperature:MIT = 405 °C6Safety Characteristics10AARS-0015•Determined according to existing standard methods(EN, ASTM ...)•Strongly influenced by experimental parameters:initial temperature and pressurevessel size and dimensionignition source (type and strength)direction of flame propagationturbulenceeffect of inert admixturesoxygen concentrationflammable mixture compositionand many more ...7Contents10AARS-00151. Motivation2. Safety Characteristics3. Case study – Explosion regions4. Case study – HF formation5. Case study – Leakage6. Conclusions8Explosion regions10AARS-0015Effect of hydrocarbons (e.g. crack products of oil):0 5 10 15 20 25 30 35 40 45 50amount of inert gas respectively refrigerent [vol%]0246810121416

amount of ethane [vol%]explosion region of ethane-R134a-airexplosion region of ethane-HFO1234yf-airexplosion region of ethane-CO2-airexplosion regionETHAN_IG_ALLE_LUFT_XY_DIN51649 | 23.5.20109Contents10AARS-00151. Motivation2. Safety Characteristics3. Case study – Explosion regions4. Case study – HF formation5. Case study – Leakage6. Conclusions10HF formation10AARS-0015Determination of the amount of HF when refrigerent-airmixturesare exposed to hot surfaces:•3-dm3stainless steel vessel (German steel code 1.4122)•pre-mixed homogeneous mixtures•10 min exposure time•recording of p-t- and T-t-histories (ignition phenomena)•500 ml gas sample for IC analysis11HF formation10AARS-00157.27yes50080.020.0 + oilUBA 321.81yes50090.010.0 + oilUBA 310.62no50095.05.0 + oilUBA 300.11no35080.020.0 + oilUBA 281.07no35090.010.0 + oilUBA 271.74no35095.05.0 + oilUBA 266.90yes50080.020.0UBA 185.58yes50090.010.0UBA 170.71no50095.05.0UBA 1645.9yes35080.020.0UBA 0915.9yes35090.010.0UBA 082.04yes35095.05.0UBA 070.01no20080.020.0UBA 060.01no20090.010.0UBA 050.01no20095.05.0UBA 04airHFO1234yfHFconcentration[mol-%] **Explosionyes / noTemperature[°C]Mixture composition [mol-%]Test no.HFO1234yf-air mixtures12Contents10AARS-00151. Motivation2. Safety Characteristics3. Case study – Explosion regions4. Case study – HF formation5. Case study – Leakage6. Conclusions1310AARS-0015Release to a hot metal surface and HF determination:•200-dm3plastic box•pre-heated metal block (tmax= 1200 °C)•release of 50 g of pure refrigerents and mixtures ofrefrigerents with oil•500 ml gas sample for IC analysisLeakage14Leakage10AARS-0015Release to a hot metal surface and HF determination15Leakage10AARS-0015Release to a hot metal surface and HF determination16Leakage10AARS-0015Release to a hot metal surfaceand HF determinationno analysisno ****900R134a;50 g *Box 17no analysisno ****800R134a;51 g *Box 16no analysisno700R134a;51 g *Box 15no analysisno600R134a;52 g *Box 14> 90 ***no500HFO1234yf; 50 g *Box 13> 90 ***no500R134a; 51 g *Box 125.0 ***no500HFO1234yf; 50 gBox 110.5 ***no500R134a;52 gBox 10no analysisyes600HFO1234yf; 51 g *Box 09500 (0.05 mol-%)no500HFO1234yf; 52 g *Box 08700 (0.07 mol-%)no500HFO1234yf; 54 gBox 07no analysisno700HFO1234yf; 55 gBox 06no analysisno800HFO1234yf; 52 gBox 05no analysisyes900HFO1234yf; 54 gBox 04no analysisno900R134a;52 gBox 03no analysisno800R134a; 53 gBox 02no analysisno700R134a; 56 gBox 01HF concentration[ppm]Explosionyes / noTemperatureof metal [°C]Refrigerant andreleased massTest no.1710AARS-0015Release to a model volume:•200-dm3plastic box•burning candle•release of 50 g of pure refrigerents or•smaller leakage rates (layer of refrigerent on the bottom)•detection tube for HF analysisLeakage1810AARS-0015Release to a model volumeLeakageno analysisFlame extinguished after360 s.CO2(mass not determined)V 06> 90Flame larger after 120 s,extinguished after 350 s.R134a(mass not determined)V 05> 90Blue flame after 500 s, max.height 10 cm. Flameextinguished after 18 min.HFO1234yf(mass not determined)V 04> 90Blue flame after 30 s,increasing with amount ofrefrigerant. Flame extinctionafter 70 s.HFO1234yf, 46 gV 03> 90Flame larger after 30 s,extinguished after 70 s.R134a; 52 gV 02no analysisFlame extinguished after50 s.CO2(mass not determined)V 01HFconcentration[ppm]ObservationRefrigerant andreleased massTest no.19Release to a model volumeLeakageV 03: Release of 46 g HFO1234yf within 70 sHF > 90 ppm!20Release to a model volumeLeakageV 04: Release of HFO1234yf (picture after 300 s release)HF > 90 ppm!21Leakage10AARS-0015Release to passenger compartment:Ignition of HFO1234yf low stream and HF determination•real car prepared for refrigerent release through air conditionat front passenger side•First ignition source: high voltage spark•Second ignition source: match igniter•Third ignition source: open flame (propane burner)•HF analysis after activation of each ignition source at threeplaces (seat behind front passenger, seat behind driver anddriver)22Leakage10AARS-0015Release to passenger compartment:Ignition of HFO1234yf low stream and HF determinationSpark igniter and match igniter:no ignition and no HF detected!23Leakage10AARS-0015Release to passenger compartment:Ignition of HFO1234yf low stream and HF determinationOpen flame: no ignition or flame phenomena,but HF concentration > 90 ppm!24Leakage10AARS-0015Release of total amount HFO1234yf of MAC to passengercompartment:•Release of 900 g HFO1234yf through air condition at frontpassenger side•Three match igniter•Three thermocouples and one pressure transducer•Online O2-analysis close to first ignition source•Six fans for homgenisation of gas mixture•Webcam for inside video record•Two camcorder25Leakage10AARS-0015Release of total amount HFO1234yf of MAC to passengercompartment:two of six fanspressure transducerwebcamthermocouplepipe for O2-analysis26Leakage10AARS-0015Release to motor compartment, directed to part of exhaustsystem:One of three match igniters andpipe for O2-analysisInlet pipe for HFO1234yf release27Leakage10AARS-0015Release to motor compartment, directed to part of exhaustsystem – video sequence28Leakage10AARS-0015Release to motor compartment, directed to part of exhaustsystem – Corrosion of windows due to HF29Leakage10AARS-0015Release to motor compartment, directed to part of exhaustsystem:30Contents10AARS-00151. Motivation2. Safety Characteristics3. Case study – Explosion regions4. Case study – HF formation5. Case study – Leakage6. Conclusions31Conclusions10AARS-0015•Presented case studies are only examples. Holistichazardanalysis is much more extensive.•Flammability of HFO1234yf is strongly dependent onreleased mass and rate•Flammability of HFO1234yf is not a barrier for use.•Preventive measures are necessary (filling stations, servicestations, transport as well as storage of substanceetc.).•Leaking MACTransport of cars as dangerous good?•Possible HF formation after contact to hot surfacesandflames.•HF concentration are often higher than 90 ppm.32Thank you very much for your attention. If thereare any questions left don`t hesitate to ask me.33HF formationHFO1234yf-air mixtures0123456789100 50 100 150 200 250 300 350time in s

pressure in bar050100150200250300350400450500 temperature in °Cpressure in bar abstemperature in °CUBA_09: 20 % HFO1234yf34HF formation10AARS-00150.61no50080.020.0 + oilUBA 250.28no50090.010.0 + oilUBA 240.15no50095.05.0 + oilUBA 235.35yes35080.020.0 + oilUBA 220.04no35090.010.0 + oilUBA 210.03no35095.05.0 + oilUBA 200.33no50080.020.0UBA 150.21no50090.010.0UBA 140.36no50095.05.0UBA 1312.07yes35080.020.0UBA 120.60no35090.010.0UBA 110.24no35095.05.0UBA 100.01no20080.020.0UBA 030.01no20090.010.0UBA 020.03no20095.05.0UBA 01airR134aHF concentration[mol-%] **Explosionyes / noTemperature[°C]Mixture composition [mol-%]Test no.R134a-air mixtures35Leakage10AARS-0015Enclosed Space Ignition Testaccording to model regulations for transport of dangereous goods(5th revisded edition of Manual for Tests and Criteria, 2010)36Ignition after 15 sHFO1234yf, liquid phase, no flow limitationESI 11Ignition after 50 sHFO1234yf, gas phase, no flow limitation(repetition of ESI 09)ESI 10Ignition after 50 sHFO1234yf, gas phase, no flow limitationESI 09Flame stretch, blue colouredHFO1234yf; liquid phase; 54 gESI 08Flame stretch, blue colouredHFO1234yf; gas phase; 52 gESI 07Flame stretch, blue colouredHFO1234yf + 3% oil; liquid phase; 52 gESI 06Flame stretch, blue colouredHFO1234yf + 3% oil; gas phase; 55 gESI 05No visible reactionR134a + 3% oil, liquid phase, 51 gESI 04No visible reactionR134a + 3% oil, gas phase, 47 gESI 03No visible reactionR134a, liquid phase, 50 gESI 02No visible reactionR134a, gas phase, 56 gESI 01ObservationRefrigerant, aggregate state andreleased massTest no.LeakageEnclosed space ignition test