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# Industry 3 Year Evaluation of low global warming potential refrigerant

HFO - 1234yf

MACS January 21, 2010 William Hill2



# SAE CRP History
 

# CRP ARCRP [Alternative Refrigerant CRP]  

## Started in April 2001 and phase II completed in Nov., 2004  

## Covered improved R134a, R744 [several iterations], R290 [secondary loop], and R152a  

# IMAC [Improved Mobile Air Conditioning] CRP  

## Started in April, 2004 and completed in June, 2006  

## Covered all sorts of improvements for R134a systems  

# CRP150  

## Started in Oct., 2006 and completed in Aug., 2007  

## Covered various blend refrigerants from various suppliers  

# CRP1234 Proposed in October, 2007 for HFO - 1234yf  

## Phase 1 completed in Feb, 2008  

### Material evaluations completed in Sept., 2008  

## Phase 2 completed in Apr, 2009  

## Phase 3 completed in Nov, 20093

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# HFO - 1234yf Cooperative

Research Program  

# Research was conducted over the last two years at international laboratories to get the best available expertise and to guarantee common worldwide acceptance  

# Issues Investigated include:  

### Safety and risk assessment  

### Air - conditioning system efficiency and performance  

### Material compatibility  

### Flammability  

### Toxicity 

###  

# Extensive testing at third - party facilities did not identify significant risks for the use of HFO - 1234yf in mobile air conditioning systems
.4

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# HFO - 1234yf Cooperative

Research Programs  

# Cooperative Research Programs (CRP) have been sponsored by automobile manufacturers and Tier One/Two Suppliers  

# Global Vehicle OEMs  

# Audi, BMW, Chrysler, Daimler, Fiat, Ford/Volvo, General Motors/Opel , Hyundai, Porsche, PSA, Renault, Shanghai Automotive, Tata , Jaguar Land Rover, Toyota, VW  

# Tier One/Two Suppliers  

# DuPont , Honeywell, Conti Tech, Dayco , Delphi, Denso, Doowan , Dow, Freudenberg , Goodyear, Hutchinson, Maflow , Egelhof , Parker Hannifin, Sanden, Trelleborg , Valeo , Visteon5



# Safety and Risk Assessment

 

# Detailed Fault Tree Analysis [FTA] has been completed with input from major OEMs from around the world  

# The following scenarios have been considered:  

# Potential risks due to refrigerant flammability  

## Accidental releases during vehicle operation and service  

# Potential risk due to refrigerant toxicity  

## Accidental releases during vehicle operation and service  

# Potential risk due to decomposition products  

## Accidental releases during vehicle operation and service

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# Safety and Risk Assessment
 

# Extensive Fault tree scenarios  

# Vehicle use in Field Scenarios  

# Component Failures  

# Vandalism  

# Vehicle Collision Scenarios  

# Occupant  

# Good Samaritan  

# Service Scenarios7



# CRP Methodology  

# Uses Fault Tree Analysis methods for key exposure scenarios  

## Vehicle exposures  

## Repair exposures  

# Qualitative evaluation of other scenarios with limited impact  

## Assembly plant workers  

## Parking garages, tunnels  

## Ecological impacts  

# Fault Tree Inputs are based on measured data, public databases, and consensus by the Vehicle Makers HVAC and Safety engineers  

# Results are compared to other non - AC related automotive risks8 

# Risk Assessment Input Data: Concentration Measurement Data  

# Refrigerant Concentration after Accidental Release  

## Vehicle Makers concentration measurements in vehicles (4 Vehicle Makers, different vehicle types)  

## Health - based limit never exceeded  

## LFL exceeded in a few instances with severe collision scenarios (typically in recirculation mode, low blower, near floor, generally away from possible ignition sources)
 Refrigerant concentration alone is not enough to produce a risk of refrigerant ignition or HF exposure  Sufficient refrigerant and sufficient ignition source must be present at the same time and location , occupant must also be present in limited area where ignition occurs  

## All measured concentrations and the scenarios leading to these were considered in the Fault Tree Analysis

Ignition and thermal decomposition risks addressed in FTA9



# Typical Concentration in Vehicle Interior

with Corrosion leak

 

## Interior cabin corrosion leaks do not develop refrigerant concentrations of concern  

## Corrosion cases excluded from FTA based on actual vehicle measurements (collected with vehicle switched on and off) 0.0% 1.0% 2.0% 3.0% 4.0% 5.0% 6.0% 7.0%

0 50 100 150 200 250 300 350 400 450 Time, minutesConcentration,Vol%
Driver's Foot Passenger's Foot Driver's Lap HFO - 1234yf Corrosion Leak (0.1 mm) 40  ̊ C Ambient Typical MidSize Sedan (2.5 m 3 ) 575 g charge Vehicle Off LFL

Measurements of cabin HFO - 1234yf concentration for corrosion leaks did not exceed 2% Full system discharge10



# Toxicity Input Data Toxicity Toxicity testing by TNO, WIL and Hamner Institutes  

# Based on studies and results of Phase I and II risk assessments, exposures are not of concern from the standpoint of refrigerant toxicity, therefore refrigerant toxicity was not addressed via FTA in Phase III

HFO - 1234yf does not pose an exposure risk due to chemical toxicity11



# Toxicology Comparison HFO - 1234yf and R 134a

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# HFO - 1234yf Combustion Energy Flammability is evaluated by ‘ Chance of Flame occurring ’ and ‘ Effect of Flame occurring ’

• 

### Effect of Flame occurring - > Burning Velocity, Heat of Combustion

* Burning Velocity of 1234yf has been measured at AIST. (Advance d Industrial Science and Technology / Japan)

Even if ignited, HFO - 1234yf burns only weakly, would have limited effect 0 10 20 30 40 50 60

0 5 10 15 20 25 30 35 40 45 50 Burning Velocity, cm/sHeatofCombustion,MJ/kg

I n c r e a s i n g I m p a c t

152a Ammonia

R32 1234yf
R134a methane
propane butane

ASHRAE Class 3 ASHRAE Class 2 Class 2L (proposed)13



# HFO - 1234yf Flammability Properties Flammability is evaluated by ‘ Chance of Flame occurring ’ and ‘ Effect of Flame occurring ’ • Chance of Flame occurring - > Lower Flame Limit, Minimum Ignition Energy

Difficult to ignite HFO - 1234yf due to high Minimum Ignition Energy 0.01 0.1 1 10 100 1000 10000

0 2 4 6 8

Lower Flame Limit, vol.%MinimumIgnitionEnergy,mJ

Methane

152a
Acetylene

Propane Iso - Butane Gasoline I n c r e a s i n g
F l a m m a b i l i t y HFO - 1234yf > 5000 times more energy to ignite!14



# Pressure Rise on Ignition

t = 63 ms 125 msec 250 msec 500 msec 750 msec 

## Isobutane Elect. Arc 4 vol % 

## R - 152a Elect. Arc 8 vol % 

## HFO - 1234yf Elect. Arc
– no ign Lighter
– above 4 vol %, no ign Elect. Arc + butane → ign 8 vol %, orange flame is butane 

# Watch the ping pong balls for pressure rise.

HFO - 1234yf Flames can best be characterized as ‘ Lazy and Unstable ’ with low energy release15



# Sources for Ignition  

# Potential ignition sources were evaluated by INERIS, DuPont , and Honeywell  

# Ineris results reported in Phoenix in 2008  

# Fiat analysis reported in SAE paper # 2009 - 0 - 0541  

# Very few capable of igniting HFO - 1234yf  

# Only credible sources were considered in the FTAs , such as:  

# Match (butane lighters are not operable above 4 vol %)  

# PTC heater failure, un - fused electrical short failure  

# Hot surfaces in the engine compartment under extreme vehicle use Details of testing in the Project Summary Referenced in the Pres s Release Possible ignition sources for HFO - 1234yf are limited16



# Ineris Potential Ignition Sources for HFO - 1234yf

Ineris testing found very few potential ignition sources within vehicle.

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### Butane Lighter17

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# Cigarette Smoking Test There were no significant differences in the amount of HF formed during inhalation of either R - 134a or HFO 1234yf through a cigarette. The HF values found during this investigation were very low (less than 10 ppm ). [With refrigerant concentrations up to 2%] R - 134a has been used for over 16 years within the automotive industry as a mobile air - conditioning refrigerant. Massachusetts smoking simulator18

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# Spark Testing with HFO1234yf
 

# Well - blended R1234yf/air mixture  

# Known concentration in a sealed 12 - l spherical flask  

# Moisture equivalent to 50% RH at 23C  

# 9.5 mm diameter copper electrodes located in the flask  

# Short - circuit of 12 - Volt automotive battery (1020 cranking amps) in the mixture HFO - 1234yf Ignitability to Spark from 12 - Volt Battery Short Circuit19

1/27/2010 

# Battery Short Testing with

HFO1234yf  

# Sparks Generated  

# No evidence of HFO 1234yf ignition
 

# Tests for 8.13, 8.5, and 9.0 vol % in air, HFO - 1234yf  

# Concentrations at 20 and 60C HFO - 1234yf Ignitability to Spark from 12 - Volt Battery Short Circuit NO IGNITION OBSERVED20



# Ignition testing in a vehicle mock - up with HFO - 1234yf

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### Simulated battery short NO IGNITION of refrigerant Cigarette lighting at breath Minor flame extension NO IGNITION Lighter at Vent Outlet Lighter fails to operate above 4 vol %21

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# Toxicology of HF  

# HF can be generated when Fluoro - carbon refrigerants decompose  

# Exposure limits for emergency exposures [ AEGLs ] developed under the National Research Council, supported by the USEPA  

## Agreed upon for use in this setting by an international group of OEM toxicologists  

# Initial warning sign due to strong irritancy  

## Irritancy perception starts at 2 - 3 PPM  

# HF AEGL - 2*:  

### 95ppm / 10 minutes

 95ppm also adopted by OEMs for 1 minute exposures [conservative approach]  

### 34ppm / 30 minutes *Acute Exposure Guideline Level - 2 AEGL - 2 is the airborne concentration (expressed as ppm or mg/m3) of a substance above which it is predicted that the general population, including susceptible individuals, could experience irreversible or other serious, long - lasting adverse health effects or an impaired ability to escape.22



# Thermal Decomposition/HF Generation below LFL  

## All fluorinated refrigerants, when exposed to sufficient energy sources, can decompose to produce primarily HF  

### The amount of HF generated depends on the amount of refrigerant in contact with energy source and time of contact  

### Testing of HF generation conducted with an actual vehicle (Hughe s Associates) and with “ bench - top ” studies (INERIS, Honeywell, DuPont )  

## Measured HF concentrations were evaluated using NRC AEGL - 2 values  

### AEGL - 2 limit for HF [95 PPM, 10 minute exposure] applies explicitly to acute, accidental exposure situations  

### AEGL - 2 protects against escape impairing or irreversible effects  

### Value adopted by the CRP1234 toxicologists for short time exposures, highly conservative approach  

### Irritancy perception (3 - 5 ppm ) is well below the AEGL - 2 Extensive testing and evaluation of HF generation potential23



# HF Concentrations Produced by Thermal Decomposition  

# Passenger cabin - HF concentration due to HFO - 1234yf thermal decomposition below the LFL after refrigerant release and exposure to flame source  

## Highest HF breath level concentration achieved was well below AEGL - 2  

## Lighter had to be augmented with strong spark to get a butane flame [no ignition of refrigerant]  

# Engine compartment - HF concentration measurements after HFO - 1234yf released onto hot surface  

## Highest HF breath level concentration was well below AEGL - 2 in passenger cabin, based on ... .  

### Extreme engine operation (700 o C)  

### Hood seal removed allowing direct path to cabin air intake  Secondary failure  

### Blower on outside air, high speed (full suction from engine) Estimated occupant HF exposures would not exceed AEGL - 2 value24



# Input Service Scenarios

 

# New CFD modeling was applied to service - related refrigerant releases  

# Service pits are assumed to be covered by existing confined space regulations and were not considered in the FTA  

# DIYers – Assumed that EPA will require that only certified professional technicians conduct AC service  

## SAE standards will require that AC service be conducted only by certified professional technicians

CFD modeling of repair scenarios suggests minimal refrigerant ig nition hazard25



# Basis of confidence in proposed Vehicle Maker use conditions

 

## Risk Analyses  

### Conservative assumptions  

### Scientifically valid  

### Reviewed by industry experts  

### Product is acceptable for market without concentration limits  

## SAE Standards  

### Standards and practices to assure proper system design, engineering, manufacturing and servicing for HFO - 1234yf refrigerant use in passenger motor vehicles  

## Experimental Test Program for Ignition and HF production  

### International, independent test laboratories in US, Europe and Japan  

## Addressed EPA concerns in the notice of proposed rule 

# Vehicle safety will not be compromised by use of this refrigerant26 

# Risk Comparison to Other Vehicle events

1/27/2010 *Data sources are shown on page 36 Risks from Various Events Compared to Risks Associated with Leaks of R - 1234yf Risk Risk per vehicle per operating hour* Citation Risk of being in a police reported vehicle collision 1 5 x 10- 5 NHTSA, 2007 Risk of vehicle collision due to vehicle brake failure 2 3 x 10 - 7 New York State DMV Risk of highway vehicle fire (any cause) 3 1 x 10- 7 Ahrens, 2008; BTS, 2004 Risk of an airbag - related fatality associated with a vehicle collision4 2 x 10- 10 NHTSA, 2001 Risk of vehicle occupant /former occupant experiencing HF exposure above health based limits associated with an R - 1234yf ignition event 5 3 x 10 - 12 Current analysis Risk of vehicle occ upant being exposed to an open flame due to R 1234yf ignition 5 9 x 10 - 14 Current analysis Risk Risk per working hour* Citation Non - fatal recordable Injury at work (all occupations) 6 2 x 10- 5 NSC, 2004 Risk among automotive repair technicians of being struck by object resulting in lost work days 7 2 x 10

- 6 BLS, 2007 Risk of recordable incident involving repair technicians being struck with high pressure R - 1234yf equipment hose (risk per hour of vehicle service)

5 3 x 10 - 8 Current analysis R isk of service technician exposure to an open flame due to R - 1234yf ignition 5 1 x 10 - 20 Current analysis27

1/27/2010 

# CRP1234 - 2 Material Compatibility Summary
In all cases some combination of materials is found acceptable

27 *Green color indicates no issues were noted, Yellow color indicates some improvements are suggested, no color indicates materials were not

tested. Table 1 a – Overall Project Summary

– Material Compatibility and Permeation * Material Compatibility Permeation Permeation Oil A HFO1234yf Oil - B

HFO1234yf Oil - C

R134a HFO 1234yf R134a Seals EPDM - 1 EPDM - 2 EPDM - 3 EPDM - 4 HNBR - 1 HNBR - 2 HNBR - 3 CR - 1 ormal T emp. Hoses CR - 1 CIIR - 1 CR - 2 CIIR - 2 PA - 1 PA - 2 igh Temp. Hoses CR - 3 CR - 4 IIR - 1 PA - 3 PA - 4 PA - 5 Thermo - plastics PPS - 1 PPS - 2 PEI - 1 Table 1 b

– Overall Project Summary

– Oils * Oil Thermal Stability Miscibility Daniel Plots

R134a HFO 1234yf R134a HFO 1234yf R134a HFO 1234yf Oil - A Oil - B Oil - C Oil - D

* Green color indicates no issues were noted, Yellow color indicates improvements are suggested, no color indicates materials were not tested28



# Life Cycle Impact of HFO - 1234yf Air conditioning systems derive their power to run from the vehicle ’ s engine, so their efficiency impacts the greenhouse tail pipe exhaust gas emission of the

vehicle.
Direct emissions: The greenhouse gas emissions resulting from the direct emission of the refrigerant 

### . Indirect emissions: The greenhouse gas emissions (CO2) resulting from the power needed to run the air conditioning system. The majority of total GHG emissions come from this, especially for low GWP fluids. In developing a low

- GWP solution, one must look at the GHG impact of the refrigerant and its efficiency with an eye on total greenhouse gas emissions 1/27/2010 28 Results are dependent on base system and level of system optimiz ation29



# Atmospheric effects The following impacts have been considered:  

# Climate change  

# Stratospheric ozone  

# Local air quality  

# Ecosystems (formation of noxious/toxic degradation products)

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### No significant impacts or concerns exist.30



# Conclusion The sponsors of the SAE CRP1234 have concluded that HFO - 1234yf can be used as global replacement refrigerant in future mobile air conditioning systems and it can be safely accommodated through established industry standards and practices for vehicle design, engineering, manufacturing, and service.

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