## MEMORANDUM

To: Julius Banks and Karen Thundiyil, U.S. EPA From: Sarah Menassian, Lauren Smith, Emily Herzog, and Mark Wagner, ICF International Date: August 21, 2008 Re: Air Conditioning Refrigerant Charge Size to Pas senger Compartment Volume Ratio Analysis

(EPA Contract Number EP-W-06-008 Task Order 018, Ta sk 06)

In this memorandum ICF presents the highest refrige rant charge to compartment volume ratios for each class of 2007-2008 model year (MY) 1 

### vehicles. Also included is as a comparison of the ratios for the 2000 Ford Crown Victoria (the reasonable worst-case scenario vehicle used in the 2005 Risk Analysis for Alternative Refrigerant in Motor Vehicle Air Condit ioning) and the 2008 Crown Victoria. To determine refrigerant charge size to passenger c ompartment volume ratios, ICF obtained 2007-2008 model year (MY) refrigerant charge size data 2 

### from a database maintained by Motor Information Sy stems and passenger compartment volume data for 2008 MY v ehicles from the Department of Energy’s FuelEconomy.gov website and Black Book USA’s databa se, New Car Cost Guide . The charge to compartment volume ratio was calculated for all veh icles for which charge and volume data could be obtained. 3 

### Table 1 presents the highest ratios for each vehi cle class size and indicates which car has each ratio. Table 1: Highest Refrigerant Charge to Passenger Co mpartment Volume Ratios per Vehicle Class (MY 2008, unless otherwise indicated)

CLASS Passenger

Compartment Size (m 3 

### ) a 

### MAC Charge

Size (grams) HFC-134a b 

### Ratio of HFC134a Charge to Compartment Volume (g/m 3 

### ) Manufacturer Model

TWO SEATERS 1.42 907.2 640.75 MERCEDESBENZ SL65 AMG (MY

2007)

SMALL PICKUP TRUCKS 1.48 940 633.27 FORD RANGER

S.U.V. 3.01 1250 414.96 MERCURY MOUNTAINEER (w/ Aux Heat)

STANDARD PICKUP TRUCKS 1.59 632 397.84 TOYOTA TOYOTA TACOMA PRERUNNER REG CAB

1 Data source did not have data for all makes and mo dels in 2008. In particular, data for multiple Eur opean cars were unavailable due to the fact that European automakers do not rel ease this information until later in the year. For these vehicles, 2007 data were used.

2 Please note that these data are confidential.

3 Both FuelEconomy.gov and the Black Book USA websit e did not have passenger compartment volume data fo r all vehicles. Generally, volumes for trucks, SUVs, two-seaters, a nd some vans were not available. These values were estimated using the methods outlined in 40 CFR 600, Subpart D (Fuel Eco nomy Regulations for 1977 and Later Model Year Auto mobiles— Labeling): sum of ((Head Room * Shoulder Room * Le g Room)/1728) for both front and rear seats (as app licable).

### CLASS Passenger Compartment Size (m 3 

### ) a 

### MAC Charge

Size (grams) HFC-134a b 

### Ratio of HFC134a Charge to Compartment Volume (g/m 3 

### ) Manufacturer Model

COMPACT CARS 2.63 935.55 355.25 MERCEDESBENZ CLS Class (MY

2007)

SUBCOMPACT CARS 2.29 793.8 346.08 BMW 650i and M6 (MY 2007)

MINICOMPACT CARS 2.10 725 345.99 JAGUAR JAGUAR XKR

MIDSIZE CARS 2.72 935.55 343.44 MERCEDESBENZ E Class (MY 2007)

LARGE CARS 2.94 793.8 269.55 BMW 750i (MY 2007)

SMALL STATION WAGONS 2.66 670 251.71 PONTIAC VIBE

MINIVAN 4.42 1100 248.85 DODGE GRAND CARAVAN SXT WAGON

VANS 8.20 1600 195.08 CHEVROLET EXPRESS VAN (Passenger/Cargo)

MIDSIZE STATION WAGONS c 3.06 475 155.32 KIA RONDO

a Source: FuelEconomy.gov, and if not available there , BlackBookUSA.com. 2008 New Car Cost Guide. When volume unavailable, value was estimated using BlackBook da ta and methods at 40 CFR 600, Subpart D.
b Source: Motor Information Systems database. These data are confidential.

c Data were available for only 1 vehicle in this clas s. By default it has the ‘highest’ ratio. 

### Higher ratios signify that in the event of a large leak, drivers and passengers in the indicated vehic le would potentially be exposed to higher concentratio ns of refrigerant than in a vehicle with a lower ra tio. Calculations show that in a worst case exposure sce nario, two-seaters may have the highest concentrati on of refrigerant in the passenger compartment. Of al l vehicles analyzed, the 2007 Mercedes SL65 AMG two-seater has the greatest refrigerant charge per passenger compartment volume ratio (640.75 g/m 3 

### ), while the 2008 Nissan Rogue SUV has the smallest ra tio (139.69 g/m 3 

### ). In general, the higher ratios were seen in the German cars (Mercedes-Benz and BMW ) and following those, high ratios were also seen in some American S.U.V.s. The accompanying “2008 A nalysis_8.19.08.xls” spreadsheet presents all ratios calculated, sorted from largest to smallest ratio, overall, and by class.

In the 2005 Risk Analysis for Alternative Refrigerant in Motor Vehicle Air Conditioning , the Ford Crown Victoria was assumed to represent a ‘reasonable wor st case scenario.’ Based on the average HFC-134a charge sizes (derived from CFC-12 charge sizes) and passenger compartment volumes for each vehicle class used in the analysis, large cars have the hig hest ratio of refrigerant to compartment volume, th ereby representing a possible worst case scenario. While the 2000 Crown Victoria was a good representation of the possible worst case scenario used in the report (being a large car with a ratio close to that of t he average large car), results of the analysis using 2 008 charge size data show that the Mustang currentl y has a higher ratio than the Crown Victoria. In light o f this finding, ICF analyzed the 2000 Ford Mustang ratio

### as well when revisiting the assumption that the Cro wn Victoria represents a worst case scenario. Table 2

presents the results of this analysis. 4


### Table 2: Crown Victoria and Mustang Refrigerant Cha rge to Passenger Compartment Volume Ratios (MY 2000 vs. MY 2008)

2000 2008

Model Vehicle

Class HFC-134a

Charge a (g) Passenger

Compartment Volume b (m 3 ) Ratio -

Charge to Volume (g/m 3 ) HFC-134a Charge a (g) Passenger

Compartment Volume b (m 3 ) Ratio -

Charge to Volume (g/m 3 )

Crown Victoria Large 1,077.28 3.14 342.7 765.44 3.03 252.6
Mustang Subcompact 963.88 2.32 415.1 737.08 2.41 306.23

a Source: Ford Motorcraft’s Refrigerant Charge Capaci ties Reference Sheet.

b Source: FuelEconomy.gov 

### As seen in Table 2, even in 2000, the Mustang had a higher ratio than the Crown Victoria. Consistent with the findings of the most recent analysis (cond ucted using 2007/2008 MY vehicles), the higher char ge to compartment volume ratios are seen in small vehi cles. While the most extreme values were seen in two-seaters (a finding anticipated by the authors o f the 2005 report), relatively high ratios were als o seen in other small vehicles (particularly minicompacts, subcompacts and compacts). Therefore, the 2005 report’s decision to not include small cars in the list of possible worst case scenarios may need to b e revisited.

Please contact Sarah Menassian at 202-862-1172 or M ark Wagner at 202-862-1155 with any questions or
comments.

4 Charge size data for this analysis came from the F ord Motorcraft reference sheet on charge sizes, ava ilable at http://www.fcsdchemicalsandlubricants.com/supplier/ quickref/refrigerant%20charge%20cap.pdf. Compartme nt volumes were taken from FuelEconomy.gov.