### FINAL July 2, 2015 1 

## Significant New Alternatives Policy Program Refrigeration and Air Conditioning Sector
Risk Screen on Substitutes in Retail Food Refrigera tion and Commercial Ice Machines

Substitute: R-448A

This risk screen does not contain Clean Air Act (CA A) Confidential Business Information

(CBI) and, therefore, may be disclosed to the publi c.



### 1. INTRODUCTION Ozone-depleting substances (ODS) are being phased o ut of production in response to a series of diploma tic and legislative efforts that have taken place over the past two decades, including the Montreal Protoc ol and the Clean Air Act Amendments of 1990 (CAAA). The U .S. Environmental Protection Agency (EPA), as authorized by Section 612 of the CAAA, administers the Significant New Alternatives Policy (SNAP) Program, which identifies acceptable and unacceptab le substitutes for ODS in specific end-uses based o n assessment of their health and environmental impact s. EPA’s decision on the acceptability of a substitute is based on the findings of a screening assessment of potential human health and environmental risks pose d by the substitute in specific applications. EPA has already screened a large number of substitutes in m any end-use applications within all of the major OD Susing sectors including: refrigeration and air cond itioning, solvent cleaning, foam blowing, aerosols, fire suppression, adhesives, coatings and inks, and ster ilization. The results of these risk screens are pr esented in a series of Background Documents that are availa ble in EPA's docket. The purpose of this risk screen is to supplement EP A’s Background Document on the refrigeration and ai r conditioning sector (EPA 1994) (hereinafter referre d to as the Background Document). This risk screen evaluates the potential use of R-448A as a substitu te in the retail food refrigeration (specifically, convenience stores, direct racks, indirect racks, r emote condensing units, and stand-alone display cas es) and commercial ice machines end-uses. Table 1 prese nts the composition of the proposed substitute.

Table 1. Composition of R-448A and Potential Impur ities

Constituent Chemical Formula CAS Number Concentration (Weight Percent) a Difluoromethane (HFC-32) CH 2 F 2 75-10-5 ≤26% Pentafluoromethane (HFC-125) C 2 HF 5 354-33-6 ≤26% 1,1,1,2

- Tetrafluoroethane (HFC

134a) CF 3 CH 2 F 811-97-2 ≤21%
2,3,3,3

- Tetrafluoro

- prop

- 1

- ene (HFO-1234yf) C 3 H 2 F 4 754-12-1 ≤20%

trans

- 1,3,3,3,

- Tetrafluoro

- 1

- propene (HFO-1234ze(E)) CHFCHCF 3 29118-24-9 ≤7%
Potential Impurities (Maximum Concentration)

### FINAL July 2, 2015 2 Constituent Chemical Formula CAS Number Concentration (Weight Percent) a



### Section 2 summarizes the results of the risk screen for the proposed substitute blend listed in Table 1. The remainder of the risk screen is organized into the following sections:

• Section 3: Atmospheric Assessment

• Section 4: Volatile Organic Compound Assessment

• Section 5: Discussion of End-Use Scenario Modeled

• Section 6: Potential Health Effects

• Section 7: Flammability Assessment

• Section 8: Asphyxiation Assessment

• Section 9: End-Use Exposure Assessment

• Section 10: Occupational Exposure Assessment

• Section 11: General Population Exposure Assessment

• Section 12: References



### 2. SUMMARY OF RESULTS
R-448A is recommended for SNAP approval for the ret ail food refrigeration and commercial ice machine end-uses. EPA's risk screen indicates that the use of the proposed substitute will be less harmful to the atmosphere than the continued use of ODS and other commonly used refrigerants, as it is less harmful t o the ozone layer, has lower climate impact, and a sh orter atmospheric lifetime. The components of R-448 A are not subject to volatile organic compound (VOC) regulations under the CAA (40 CFR 51.100(s)), so environmental impact from the release of these subs tances is not a concern. In addition, because R-448 A is considered to be nonflammable, the proposed substit ute is not expected to present a flammability conce rn. It is expected that the safety data sheet (SDS) for R-448A and good manufacturing practices will be adhered to. Additionally, it is expected that the appropriate s afety and personal protective equipment (PPE) (e.g.

, protective gloves, tightly sealed goggles, protecti ve work clothing, and suitable respiratory protecti on in case of leakage or insufficient ventilation) consis tent with Occupational Safety and Health Administra tion (OSHA) guidelines will be used during manufacture, installation and servicing, and disposal of retail food refrigeration systems and commercial ice machines u sing R-448A. Because retail food refrigeration systems and commercial ice machines are to be insta lled in locations with adequate space and/or ventilation in accordance with EPA recommendations and the equipment maintenance manuals for R448A in each end-use, significant toxicity risk to consumers is also unlikely.

### FINAL July 2, 2015 3 Additional safeguards, including specified refriger ant concentration limits (RCL) of R-448A components

, are also provided by adherence to industry standard s including American Society of Heating, Refrigerat ing and Air-Conditioning Engineers (ASHRAE) Standards 1 5, 1 

### 34, 2 

### and 62. 3



### 3. ATMOSPHERIC ASSESSMENT
This section presents an assessment of the potentia l risks to atmospheric integrity posed by the use o f R448A in retail food refrigeration and commercial ic e machines. The ozone depletion potential (ODP), global warming potential (GWP), and atmospheric lif etime (ALT) of the proposed substitute are presente d in

1 Safety Standard for Refrigeration Systems ASHRAE St andard 15 establishes safeguards for life, limb, he alth, and property and prescribes safety requirements.

2 Designation and Safety Classification of Refrigeran ts ASHRAE Standard 34 is establishes a uniform syst em for assigning reference numbers, safety classifications, and refr igerant concentration limits to refrigerants. Safe ty classifications based on toxicity and flammability data are included.
3 Ventilation for Acceptable Indoor Air Quality ASHRA E Standard 62 establishes minimum ventilation rates and other measures intended to provide indoor air quality that is acce ptable to human occupants and that minimizes advers e health effects.

### FINAL July 2, 2015 4 Table 2. The proposed substitute is substantially less harmf ul to the ozone layer, has lower climate impact, an d a shorter ALT when compared to refrigerants currently used in these end uses such as CFC-12, R-502, and HCFC-22. In addition, R-448A also has lower climate impact and a shorter ALT than those predicted for other substitutes examined in the Background Docume nt, as well as commonly utilized refrigerants in commercial refrigeration, such as HFC-134a, R-404A, R-507A, and R-407C. Thus, EPA believes that the use of R-448A would result in substantially less ha rm to the climate and ozone layer than the continue d use of ODS and other commonly used refrigerants.

### FINAL July 2, 2015 5 Table 2. Atmospheric Impacts of R-448A Components Compared to Other Refrigerants Used in

Retail Food Refrigeration and Commercial Ice Machin es Refrigerant Ozone Depleting Potential (ODP) a Global Warming Potential (GWP) b Atmospheric Lifetime in Years (ALT) b
R

- 448A 0 1,38 7 NA c Individual Components HFC

- 32 0 675 4.9 b HFC

- 125 0 3,500 29 b HFC

- 134a 0 1,430 14 b HFO

- 1234yf 0 4 d 11 days d HFO

- 1234ze(E) 0 1 e 16.4 days e CFC

- 12 0.82 10,900 100 R

- 502 f 0.2 4,650 NA g HCFC

- 22 0.13 1,810 12 a R

- 404A h 0 3,922 NA i R

- 507A

j 0 3,985 NA k R

- 407C l 0 1,774 NA m

a WMO 2010 Scientific Assessment Report (2011)

b IPCC 4 th Assessment Report (Forster et al. 2007)

c Atmospheric lifetimes are not given for blends, be cause the components separate in the atmosphere. Th e ALT for the individual components are listed in the table.

d Papadimitriou et al. (2007)

e Hodnebrog, O. et al. (2013)

f R-502 is a blend consisting of HCFC-22 (49%) and CF C-115 (51%).

g Atmospheric lifetimes are not given for blends, be cause the components separate in the atmosphere. Th e ALT for HCFC-22 is 12 years and the ALT for CFC-115 is 1,700 years (IPCC 4 th Assessment Report [Forster et al. 2007]).

h R-404A is a blend consisting of HFC-143a (52%), HF C-125 (44%) and HFC-134a (4%).

i Atmospheric lifetimes are not given for blends, be cause the components separate in the atmosphere. Th e ALT for HFC-143a is 52 years, the ALT for HFC-125 is 29 years, and the ALT for HFC-13 4a is 14 years (IPCC 4 th Assessment Report [Forster et al. 2007]). j R-507A is a blend consisting of HFC-125 (50%) and HFC-143a (50%).

k Atmospheric lifetimes are not given for blends, be cause the components separate in the atmosphere. Th e ALT for HFC-125 is 29 years and ALT for HFC-143a is 52 years (IPCC 4 th Assessment Report [Forster et al. 2007]).

l R-407C is a blend consisting of HFC-32 (29%), HFC- 125 (25%) and HFC-134a (52%).

m Atmospheric lifetimes are not given for blends, be cause the components separate in the atmosphere. Th e ALT for HFC-32 is 4.9 years, the ALT for HFC-125 is 29 years, and the ALT for HFC-13 4a is 14 years (IPCC 4 th Assessment Report [Forster et al. 2007]).



### 4. VOLATILE ORGANIC COMPOUND ASSESSMENT The components of R-448A (i.e., HFC-32, HFC-125, HF C-134a, HFO-1234yf, and HFO-1234ze(E)) are exempt from the definition of VOCs under CAA regula tions (40 CFR 51.100(s)). Therefore, VOC impacts from the release of R-448A are not a concern.



### 5. DISCUSSION OF END-USE SCENARIOS MODELED

The submission states that R-448A retail food refri geration equipment will contain typical charge size s ranging from 0.9 kg for a typical stand-alone, self -contained display case to a maximum charge size of 300 kg for a direct rack system. Commercial ice machine s are anticipated to have a typical charge size of 8 kg and a maximum charge size of 20 kg. The intended ma ximum and typical charge sizes for all of the proposed applications are listed in Table 3.

### FINAL July 2, 2015 6 Table 3. Typical and Maximum Charge Sizes for Vario us R-448A End-Uses and Applications

End-Use Application Typical Charge Size (kg) Maximum Charge Size

(kg)

Retail food refrigeration Convenience Store 30 60 Direct rack / 4 compressor 300 400 Indirect rack / 4 compressor 150 250 Remote condensing unit / air-cooled 5 hp unit 10 12 Remote condensing unit / air-cooled 10 hp unit 36 4 7 Stand

- alone self

- contained display case (charge size is per door) 0.9 1.2

Commercial ice machines Packaged and split 8 20
Bolded applications and charge sizes represent those modeled in this risk screen. 

### To represent a reasonable worst-case scenario for t he retail food refrigeration end-use, it is assumed that a catastrophic leak of refrigerant occurs at the end- use for the following applications: direct rack sys tem (i.e., grocery supermarket), stand-alone beverage cooler ( i.e., convenience store), or commercial ice machine (i.e., seafood processing facility). The analysis c onsiders the maximum charge size provided by the submitter for each scenario. Because retail refrige ration equipment can be installed in a wide range o f locations with varying room volumes, the analysis i n this risk screen conservatively assumes that the direct rack system is located in a grocery supermarket, th e beverage cooler is located in a convenience store , and the commercial ice machine is located in a seafood processing facility. 4


### The grocery supermarket is assumed to have an effec tive volume of 24,200 m 3 

### (855,000 ft 3 

### ) with an effective floor area of 4,400 m 2 

### (i.e., excluding the space filled by the rack syst em, shelving, display cases, etc.) and a height of 5.5 meters (Armines 2008). Ba sed on a minimum convenience store sizes located in California (Armines 2008), the convenience store is assumed to have an effective volume of 244 m 3 

### (8,620 ft 3 

### ) with an effective floor area of 100 m 2 

### (i.e., excluding the space filled by the beverage cooler, shelving, display cases, etc.) and a height of 2.44 meters.
For the commercial ice machine end-use, it is assum ed that the ice machine is located in a seafood processing facility with an assumed effective volum e of 5,700 m 3 

### (201,300 ft 3 

### ), with an effective floor area of 1,040 m 2 

### (i.e., excluding the space filled by the ice machi ne, shelving, processing equipment, etc.) and a height of 5.5 meters. Under these worst-case scenarios, the full charge o f each unit is assumed to be emitted into the groce ry supermarket, convenience store, or seafood processi ng facility with 8, 1, and 15 air changes per hour (ACH), 5,6 

### respectively over the course of two time durations : 1) one minute, which represents a catastrophic release of refrigerant due to a punctu re or other major damage to the refrigeration syste m, and 2) fifteen minutes, which represents the accidental release of refrigerant due to a non-catastrophic l eak in the system (e.g., valve failure). The one-minute ti me duration is most appropriate for flammable refrigerants and presents a less relevant scenario for R-448A, which is nonflammable. Therefore, while both scenarios are evaluated in this risk screen fo r consistency purposes, the scenario which analyzes a release of refrigerant over a 15-minute time durati on more accurately represents a reasonable worst-ca se scenario for R-448A in retail food refrigeration an d commercial ice machines.

4 A seafood processing facility is assumed to appropr iately represent the use of commercial ice machines in any large industrial facility and recognizes that a commercial ice machi ne with a large production capacity can be installe d in a wide variety of industrial locations.
5 The air exchange rates for a grocery supermarket an d convenience store are derived from the requiremen ts in ANSI/ASHRAE Standard 62.1-2007, Table 6.1 (ANSI/ASHRAE 2007). V entilation requirements (presented as cubic feet pe r minute per square foot of ventilated space in the standard) were conv erted to air exchanges per hour using the assumed r oom size for the scenario.
6 The air exchange rates for a seafood processing fa cility are derived from the suggested sufficient ai r changes per hour in enclosed processing and food handling areas of between 5 and 25 air changes per hour (Lelieveld, H.L.M. 2014).

### FINAL July 2, 2015 7 A vertical concentration gradient is also assumed s ince R-448A is denser than air (the specific gravit ies of both HFC-134a and HFO-1234ze(E) are greater than 1) and will settle in higher concentrations closer to the ground. In order to simulate the vertical conc entration gradient, it is assumed that 95 percent o f the leaked refrigerant mixes evenly into the bottom 0.4 meters of the room, and the rest of the refrigeran t mixes evenly in the remaining volume (Kataoka 2000) . Table 4 details the end-use modeling assumptions used throughout the risk screen (i.e., in Sections 8 and 9). Table 4. End-Use Scenario Model Assumptions

Parameter Assumptions Large Retail Food Small Retail Food Ice Machine
Refrigeration Unit Direct Rack System Stand

- Alone Beverage Cooler Commercial Ice Machine

Room Grocery Supermarket Convenience Store Seafood Processing Facility Charge Size (kg) 400 1.2 20 Length of Release (minutes) 1; 15 1; 15 1; 15 Room Size (volume

- m 3 ) 24,200 a 244 b 5,700 c Room Ventilation (air changes per hour) 8 1 15 Vertical Concentration Gradient Yes Yes Yes

a The average grocery supermarket sales area size fou nd during a California survey (Armines 2008) – 4,40 0 m 2 – was used for this scenario and a 5.5 m (18-foot) ceiling was assumed.

b Specific information was not available regarding wh ich types of stores would utilize beverage cases or commercial ice machines, so a small store (i.e., a convenience store) was used in the m odel. The minimum convenience store size found dur ing a California survey (Armines 2008) – 100 m 2 (1,076 ft 2 ) – was used for this scenario and a 2.44-meter (8 ft) ceiling was assumed.

c The average size of the seafood processing facilit y is assumed to be consistent with typical factory size used in occupational exposure modeling.



### EPA recognizes that direct rack systems, beverage c oolers, other retail food refrigeration units and commercial ice machines may be placed in a variety of locations, including retail stores, manufacturin g establishments, and other spaces with differing siz es and ventilation rates. When units are installed in smaller, enclosed spaces, there is a higher risk fo r asphyxiation or exposure concerns. To address thi s variability in room volumes and charge sizes for in stalled retail food equipment and commercial ice machines, this risk screen incorporates threshold a nalyses in addition to the worst-case scenario mode ling. The threshold analyses are performed in order to de termine the room size and charge size requirements that ensure that the use of R-448A in retail food r efrigeration and commercial ice machines does not present risk to end-users or servicing technicians.



### 6. POTENTIAL HEALTH EFFECTS
To assess potential health risks from exposure to t he proposed substitute in retail food refrigeration and commercial ice machines, EPA identified the relevan t toxicity threshold values for comparison to model ed exposure concentrations for different scenarios. Ac cording to ASHRAE Standard 34-2013, R-448A is listed under safety group A1 with a RCL of 110,000 ppm (ASHRAE 2015). ASHRAE 34 RCLs are intended to reduce the risks of acute toxicity, asp hyxiation, and flammability hazards in normally occupied, enclosed spaces during refrigerant use an d protect end-users from the potential dangers of a catastrophic leak from a refrigeration unit (ASHRAE 2010b). ASHRAE Standard 15 implements the aforementioned standard, requiring that “the concen tration of refrigerant in an enclosed space followi ng a complete discharge of a high-probability system sha ll not exceed the RCL” (ASHRAE 2010a). As such, this risk screen references the proposed RCL for R- 448A in addition to the lower flammability limit, hypoxia no observed adverse effect level (NOAEL), a nd exposure limits, as an additional, conservative limit to ensure that significant asphyxiation, toxi city risks, and end-use exposure risks, respectivel y, do not

occur.

### FINAL July 2, 2015 8 For the occupational exposure analysis, potential r isks from chronic and acute worker exposure were evaluated by comparing exposure concentrations to a vailable occupational exposure limits. Potential r isks of chronic worker exposure were evaluated using wor kplace guidance levels (WGLs), such as Workplace Environmental Exposure Levels (WEELs). Risks from potential short-term consumer exposures were evaluated by comparing exposure concentrations to e mergency guidance levels (EGLs). In the absence of an established short-term exposure limit (STEL), ac ute exposure guideline level (AEGL), or emergency response planning guideline (ERPG) for R-448A, pote ntial short-term, end-use exposures were evaluated on a component basis (i.e., HFC-32, HFC-125, HFC-13 4a, HFO-1234yf, and HFO-1234ze(E)). Table 5 lists the relevant toxicity limits for R-448A and i ts components and is followed by Table 6, which pro vides an explanation of each toxicity limit. EPA’s approa ch for identifying or developing these values is discussed in Chapter 3 of the Background Document.

Table 5. Exposure Limits of R-448A Components

R-448A Component WGL

(Long-term Exposure) ppm EGL

(Short-term Exposure) ppm Refrigerant Concentration Limit (RCL) ppm R-448A 890 (8-hour AEL) 2,670 (15-min STEL) a 110,000

Individual Components HFC-32 1,000 (8-hour WEEL) 3,000 (15-min STEL) b 36,000 HFC-125 1,000 (8-hour WEEL) 3,000 (15-min STEL) c 75,000
HFC-134a 1,000 (8-hour WEEL) 8,000 (10

- min AEGL

- 1) 8,000 (30-min AEGL-1) 50,000
HFO-1234yf 500 (8-hour WEEL) 1,500 (15-min STEL) d NA e HFO-1234ze(E) 800 (8-hour WEEL) 2,400 (15-min STEL) f NA g NA = Not available

a Neither the American Conference of Governmental Ind ustrial Hygienists (ACGIH) nor the American Industr ial Hygiene Association (AIHA) recommend ceiling or short term exposure limits for the blend R-448A. A STEL for R-448A of 2,670 ppm w as developed by EPA based on the 890 ppm acceptable exposure limit (AEL) value. The STEL was estimated as three to five times the AEL, which is an established method of estimating a short-term exposure limit by ACGIH. [S TEL] = [AEL] x 3 = 890 ppm x 3 ≈ 2,670 ppm

b Neither ACGIH nor AIHA recommend ceiling or short t erm exposure limits for HFC-32. A STEL for HFC-32 o f 3,000 ppm was developed by EPA based on the 1,000 ppm WEEL value. The STEL was estimated as three to five times the AEL, which is an established method of estimating a short-term exposure limit by ACGIH. [S TEL] = [AEL] x 3 = 1,000 ppm x 3 ≈ 3,000 ppm.

c Neither ACGIH nor AIHA recommend ceiling or short t erm exposure limits for HFC-125. A STEL for HFC-125 of 3,000 ppm was developed by EPA based on the 1,000 ppm WEEL value. The STEL was estimated as three to five times the AEL, which is an established method of estimating a short-term exposure limit by ACGIH. [S TEL] = [AEL] x 3 = 1,000 ppm x 3 ≈ 3,000 ppm.

d Neither ACGIH nor AIHA recommend ceiling or short t erm exposure limits for HFO-1234yf. A STEL for HFO- 1234yf of 1,500 ppm was developed by EPA based on the 500 ppm WEEL value. T he STEL was estimated as three to five times the AE L, which is an established method of estimating a short-term exposure limit by ACGIH. [STEL] = [AEL] x 3 = 500 ppm x 3 ≈ 1,500 ppm

e Although a RCL has not been proposed for HFO-1234yf , the recommended ATEL for HFO-1234yf is 101,000 pp m (Honeywell 2014a).

f Neither ACGIH nor AIHA recommend ceiling or short t erm exposure limits for HFO-1234ze(E). A STEL for H FO-1234ze(E) of 2,400 ppm was developed by EPA based on the 800 ppm WEEL value. T he STEL was estimated as three to five times the AE L, which is an established method of estimating a short-term exposure limit by ACGIH. [STEL] = [AEL] x 3 = 800 ppm x 3 ≈ 2,400 ppm

g Although a RCL has not been proposed for HFO-1234ze (E), the recommended ATEL for HFO-1234ze(E) is 59,0 00 ppm (Honeywell 2014a).

### FINAL July 2, 2015 9 Table 6. Explanation of Exposure Limit-Related Term inology a Organization Definition OSHA Occupational Safety and Health Administration NIOSH National Institute for Occupational Safety and Health ACGIH American Conference of Governmental Industrial Hygi enists AIHA American Industrial Hygiene Association OARS Occupational Alliance for Risk Science Exposure Limit Definition Explanation Short

- Term Exposure RCL Refrigerant Concentration

Limit The RCL for a refrigerant is intended to reduce the risks of acute toxicity, asphyxiation, and flammability hazards in normally occupied, enclosed spaces. The RCL for each refrigerant is the lowest of the Acute-Toxicity Exposure Limit (ATEL), Oxygen Deprivation Limit (OD L), and Flammable Concentration Limit (FCL). Determination assumes fu ll vaporization with no removal by ventilation, dissolution, reaction, o r decomposition and complete mixing of refrigerant in the space to whic h it is released. ATEL Acute Toxicity Exposure Limit The ATEL is t he refrigerant concentration limit intended to r educe the risks of acute toxicity hazards in normally occupie d, enclosed spaces according to ASHRAE Standard 34. The ATEL includes consideration of mortality, cardiac sensitization, anesthetic or cen tral nervous system effects and other escape impairing effects and perm anent injury. The ATEL is similar to the Immediately Dangerous to Lif e or Health (IDLH) concentrations set by NIOSH. STEL Short

- Term Exposure Limit A 15

- minute time

- weighted average (TWA) exposure that should not be exceeded during a workday, even if the 8-hour TWA i s within the threshold limit value-time weighted average (TLV–TW A), set by ACGIH.

AEGL b,c Acute Exposure Guideline

Level 1 AEGL

- 1 is the airborne concentration (expressed as ppm or mg/m 3 ) of a substance above which it is predicted that the gene ral population, including susceptible individuals, could experience notable discomfort, irritation, or certain asymptomatic nonsensory effe cts. However, the effects are not disabling and are transient and rev ersible upon cessation of exposure. Acute Exposure Guideline Level 2 AEGL

- 2 is the airborne concentration (expressed as ppm o r mg/m 3 ) of a substance above which it is predicted that the gene ral population, including susceptible individuals, could experience irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape. Acute Exposure Guideline Level 3 AEGL

- 3 is the airborne concentration (expressed as ppm o r mg/m 3 ) of a substance above which it is predicted that the gene ral population, including susceptible individuals, could experience life-threatening health effects or death. Long

- Term Exposure PEL Permissible Exposure Limit This is an 8

- hour TWA exposure limit set by OSHA. AEL Acceptable Exposure Limit The maximum 8

- hour TWA at which a worker can be exposed regularly without adverse effects. WEEL Workplace Environmental

Exposure Level Developed by OARS for to protect healthy workers ag ainst acute and chronic health effects, this limit is based on repe ated daily exposures over a working lifetime and averaged over an 8-hour workday. TLV

- TWA Threshold Limit Value

– Time

Weighted Average The TWA concentration for a conventional 8

- hour workday and a 40

- hour workweek, to which it is believed that nearly all workers may be repeatedly exposed, day after day, for a working li fetime without adverse effect according to ACGIH.

a All information in this table taken from EPA (1994) except where otherwise noted.
b EPA (2012)

c Applicable to emergency exposure periods ranging fr om 10 minutes to 8 hours.

### FINAL July 2, 2015 10 According to the SDS, exposure to R-448A may be haz ardous if inhalation, skin contact, or eye contact with occurs. The most likely pathway of exposure is through inhalation. R-448A can cause symptoms of asphyxiation when present in concentrations high en ough to significantly lower oxygen concentrations below 19.5 percent by volume, such as headaches, ri nging in ears, dizziness, drowsiness, nausea, vomit ing, depression of all senses, and also unconsciousness. Under some circumstances of over-exposure (i.e., oxygen levels fall below 6 percent by volume), deat h may occur. If R-448A is inhaled, person(s) should be immediate ly removed from the contaminated space and exposed to fresh air. In accordance with the SDS, EPA furth er recommends that if breathing is difficult or irr egular, person(s) should be given oxygen, provided a qualif ied operator is present, and medical attention be sought. Rescuers should not attempt to retrieve vic tims of exposure to R-448A without adequate PPE. At a minimum, a self-contained breathing apparatus (SCBA ) should be worn. Exposures of R-448A to the skin may cause frostbite. In the case of dermal exposure , the SDS for R-448A recommends that person(s) immediately wash the affected area with water and r emove all contaminated clothing; if frostbite occur s, bathe (not rub) the affected area with lukewarm, no t hot, water. If water is not available, cover the affected area with a clean, soft cloth, and seek medical att ention immediately. Exposures of R-448A to the eyes could cause eye irritation. In case of ocular expos ure, the SDS for R-448A recommends that person(s) immediately flush the eyes, including under the eye lids, with copious amounts of water for 15 minutes. EPA’s review of the human health impacts of this pr oposed substitute is contained in the public docket for this decision. These risks and procedures after exposure are simil ar for other common refrigerants. The potential health effects of R-448A can be minimized by following the exposure guidelines and ventilati on and PPE recommendations outlined in the SDS for R-4 48A and this risk screen.



### 7. FLAMMABILITY ASSESSMENT

R-448A is classified as an A1 refrigerant by ASHRAE 34, an d is considered to be nonflammable (Honeywell 2014a, ASHRAE 2015). Based on this class ification, manufacture, servicing, and use of R448A is not expected to present a flammability risk in industrial process air conditioning.



### 8. ASPHYXIATION ASSESSMENT
The risk of asphyxiation for the reasonable worst-c ase scenario described in Section 5 was investigate d for R-448A. In this section, risk of asphyxiation is as sessed in three ways: 1) modeling the oxygen concentration under the charge size and room size s pecified in the worst-case scenario, 2) performing a threshold analysis of minimum charge size at which an asphyxiation risk could occur in the room size specified in the worst-case scenario (i.e., charge sizes greater than this are expected to cause an asphyxiation risk), and 3) performing a threshold a nalysis of the maximum room size at which an asphyxiation risk could occur with the charge size specified in the worst-case scenario (i.e., room si zes smaller than this are expected to cause an asphyxia tion risk). This analysis does not consider ventila tion or conditions that are likely to occur that would incr ease oxygen levels to which individuals would be exposed, such as open doors or windows, fans operat ing, conditioned airflow (either heated or cooled), or even openings at the bottom of doors that allow air to flow in and out. As specified in Section 5, the reasonable worst-case scenario assumes a vertical c oncentration gradient. If the proposed substitute p asses the screening analysis with these restrictive assum ptions in place, it can be reasonably assumed that no risks of asphyxiation will be present under real-wo rld conditions. The results of the asphyxiation assessment are summarized in Table 7.

### FINAL July 2, 2015 11 Table 7. Asphyxiation Assessment a,b

Equipment Scenario Charge Size (kg) Effective Room

Size (m 3 ) Percent Oxygen

Concentration in Lower 0.4 Meters Direct Rack System Reasonable Worst-Case 1 400 24,2 00 (855,000 ft 3 ) 20% Beverage Cooler Reasonable Worst-Case 2 1.2 244 (8,620 ft 3 ) 21% Ice Machine Reasonable Worst-Case 4 20 5,700 (201,3 00 ft 3 ) 21%

Direct Rack System Threshold Analysis 1a: Charge Size 3,000 24,200 (855,000 ft 3 ) 12%

Threshold Analysis 1b: Room Size 400 3,230 (114,000 ft 3 ) 12%
Beverage Cooler Threshold Analysis 2a: Charge Size 70 244 (8,620 ft 3 ) 12%

Threshold Analysis 2b: Room Size 1.2 4 (141 ft 3 ) 12%

Ice Machine Threshold Analysis 3a: Charge Size 710 5,700 (201,300 ft 3 ) 12%

Threshold Analysis 3b: Room Size 20 160 (5,690 ft 3 ) 12%
Bold font indicates modeling results.

a Cells highlighted in green are the scenarios in wh ich the charge and room sizes evaluated in this ris k screen are acceptable according to the threshold analysis or the scenarios with acceptable oxygen concentrations, given various modeling ass umption options.

b The typical concentration of oxygen in air is cons idered to be 21 percent (Mackenzie & Mackenzie 1995 ).


### Based on the worst-case scenario modeling assumptio ns, R-448A in retail food refrigeration and commercial ice machines does not present a signific ant risk of asphyxiation. In order for a risk of asphyxiation to occur, the normal concentration of oxygen in air (21 percent) in the lower 0.4 meters of the room must be reduced to 12 percent. 7 

### Based on the reasonable worst-case scenario modeli ng assumptions, use of R-448A in retail food refrigeration equipmen t and commercial ice machines does not present a significant risk of asphyxiation:

• As shown in Threshold Analysis 1a for direct rack s ystems, the minimum charge size of R-448A necessary to reduce the oxygen levels to 12 percent in air in the lower 0.4 meters of a room of volume 24,200 m 3 

### (855,000 ft 3 

### ) was calculated to be 3,000 kg assuming that 1) ni trogen and oxygen retain the same relative volumes in the room s with the balance composed entirely of R448A, and 2) the pressure of the room does not incr ease significantly with the addition of the refrigerant. This amount represents ten times the t ypical charge of approximately 300 kg (or more than seven times the maximum charge size of 400 kg) for a direct rack R-448A system.

• Under Threshold Analysis 2a for beverage coolers, t he minimum charge of R-448A necessary to reduce the oxygen levels to 12 percent in air in th e lower 0.4 meters of a room of volume 244 m 3 

### (8,620 ft 3 

### ) was calculated to be approximately 70 kg, which r epresents approximately 78 times the typical charge of 0.9 kg for a single R-448A bevera ge cooler (or more than 58 times the maximum intended charge size of 1.2 kg).

• For commercial ice machines, Threshold Analysis 3a shows that the minimum charge of R-448A necessary to reduce oxygen levels to 12 percent in air in the lower 0.4 meters of a room of volume 5,700 m 3 

### (201,300 ft 3 

### ) was calculated to be approximately 710 kg, more t han 88 times the typical charge of approximately 8 kg for a commercial ice m achine (or more than 35 times the maximum charge size of 20 kg). Because this threshold modeling does not take into account any ventilation which is likely to occur, s uch as conditioned airflow, open doors, or even opening s at the bottom of doors that allow air to flow in and out, as mentioned above, the actual asphyxiation ri sk to consumers is likely to be lower than modeled.

5 Twelve percent oxygen in air is the No Observed Ad verse Effect Level (NOAEL) for hypoxia (ICF 1997).

### FINAL July 2, 2015 12 For the room size threshold scenarios, the room siz e at which an asphyxiation concern would exist (i.e

., when the oxygen concentration in the lower 0.4 mete rs of the room is 12 percent) using the typical equipment charge sizes provided by the submitter we re also determined:

• For direct rack systems, in order for asphyxiation to be of concern with the maximum charge size of 400 kg, the system would have to be installed in a store with an effective volume of 3,230 m 3 

### (114,000 ft 3 

### ) (see Threshold Analysis 1b in Table 7).

• For beverage coolers, in order for asphyxiation to be of concern with the maximum charge size of 1.2 kg, the volume of the food preparation area wou ld have to be about 4 m 3 

### (141 ft 3 

### ) (see Threshold Analysis 2b in Table 7).

• For commercial ice machines, Threshold Analysis 3b indicates that the volume of the commercial ice machine area would have to be about 160 m 3 

### (5,690 ft 3 

### ) with the maximum charge size of 20 kg in order for asphyxiation to be of concern. Based on the worst-case modeling results and thresh old analysis, EPA does not believe that the use of R448A in retail food refrigeration and commercial ic e machines poses a significant risk of asphyxiation or impaired coordination to personnel, provided system s are installed in appropriate spaces according to guidelines from the manufacturer and the SDS for R- 448A.



### 9. END-USE EXPOSURE ASSESSMENT
This section presents estimates of potential end-us er exposures to R-448A and each of its chemical constituents in the event of a catastrophic release from the proposed substitute’s use in retail food refrigeration and commercial ice machines. An end-u se exposure analysis was performed to examine potential catastrophic releases of R-448A under the reasonable worst-case scenarios outlined in Sectio n 5. For the end-use exposure assessment scenario, 15-mi nute TWA exposures for the proposed substitute were calculated using the box model described in the Bac kground Document, which was adapted to estimate concentrations on a minute-by-minute basis. Estimat es for acute/short-term end-use exposures resulting from catastrophic leakage of refrigerant from retai l food refrigeration and commercial ice machines we re examined. As discussed in Section 5, the full charg e of the unit is assumed to be emitted over the cou rse of 1 minute and 15 minutes, where the latter scenario more accurately represents a reasonable worst-case scenario for R-448A in retail food refrigeration an d commercial ice machines because R-448A is nonflammable. The analysis was undertaken to determ ine the 15-minute exposures for R-448A, which were then compared to the standard toxicity limits presented in Table 5 to assess the risk to end-user s. The estimated TWA values are fairly conservative as the analysis does not consider opened windows, fans operating, conditioned airflow (either heated or co oled) and other variables that would reduce the lev els to which individuals would be exposed.

### FINAL July 2, 2015 13 Table 8. End-Use Exposure Assessment for R-448A Co mponents a

Equipment R-448A

Component Charge

Size (kg) Room

Size (m 3 ) 15

- minute TWA Occupational

Exposure (ppm) 15-min Short Term Exposure Limits (ppm) Refrigerant

Concentration Limit (RCL) ppm 1

- minute release 15

- minute

release

Direct Rack System HFC

- 32

400 24,400 13,900 9,110 3,000 36,000

HFC

- 125 6,020 3,950 3,000 75,000 HFC

- 134a 5,720 3,800 8,000 50,000 HFO

- 1234yf 4,900 3,200 1,500 101,000 b HFO

- 1234ze(E) 1,710 1,120 2,400 59,000 c

Beverage Cooler HFC

- 32

1.2 244 3,140 1,700 3,000 36,000

HFC

- 125 1,360 750 3,000 75,000 HFC

- 134a 1,293 710 8,000 50,000 HFO

- 1234yf 1,100 610 1,500 101,000 b HFO

- 1234ze(E) 390 210 2,400 59,000 c

Ice Machine HFC

- 32

20 5,700 1,910 1,430 3,000 36,000

HFC

- 125 826 622 3,000 75,000 HFC

- 134a 785 591 8,000 50,000 HFO

- 1234yf 669 503 1,500 101,000 b HFO

- 1234ze(E) 234 176 2,400 59,000 c Bold font indicates modeling results.

a Cells highlighted in green are the scenarios with acceptable exposure levels given various modeling a ssumption options.

b ATEL for HFO-1234yf is 101,000 ppm; see Table 5 fo r more information.

c ATEL for HFO-1234ze(E) is 59,000 ppm; see Table 5 for more information.



### Under the reasonable worst-case scenarios described in Section 5 for direct rack systems, beverage coo lers and ice machines, catastrophic releases of the maxi mum charge sizes of R-448A were modeled. The modeling scenarios evaluate two refrigerant release time durations (i.e., 1 minute and 15 minutes). Th e anticipated 15-minute TWA exposures are likely to e xceed the respective STELs for the HFC-32, HFC125, and HFO-1234yf components of R-448A in direct rack systems assuming both 1-minute and 15- minute release scenarios, as well as for the HFC-32 component of R-448A in beverage coolers assuming a 1-minute refrigerant release (see Table 8). Although the exposure estimates for the reasonable worst-case scenario for a direct rack system exceed the respective STELs for the HFC-32, HFC-125, and HFO-1 234yf components of R-448A and the HFC-32 component of R-448A for beverage coolers (see Table 8), the STEL is a conservatively-derived exposure limit that is intended to protect workers in an occ upational setting in which they are exposed to thes e chemicals on a daily basis. The STEL values do not represent limits for a single exposure in a lifetim e. These modeled exposures are one-time exposures so e xceedances of the STEL values do not necessarily indicate a significant risk of harm to consumers. T he effect of a one-time exposure can be more accura tely evaluated by comparing the modeled exposure concent rations to the refrigerant concentration limit (RCL ) or acute toxicity exposure limit (ATEL) for each re spective component, which are limits intended to reduce the risks of acute toxicity hazards in norma lly occupied, enclosed spaces according to ASHRAE Standard 34 (see Table 6). All of these exposure e stimates are significantly lower than the RCL or AT EL for each component. Furthermore, the estimated expo sures for R-448A in each of these scenarios are als o significantly lower than the RCL for R-448A (i.e., 110,000 ppm). In addition, these exposure estimates were derived using fairly conservative assumptions (e.g., minimu m room volume for the modeled maximum charge size, lo w ventilation rate) that do not necessarily reflect the actual room attributes where R-448A retail food refrigeration equipment and commercial ice machine s will be installed. Finally, these exposures represe nt concentrations of leaked refrigerant in the bott om 0.4 meter (1.3 feet) of the room, accounting for 95 per cent of the refrigerant charge in this lower compar tment of the room. The probability that an individual wou ld be present in this lower compartment (e.g., pron e or

### FINAL July 2, 2015 14 supine on the floor) in the event of the catastroph ic release of refrigerant is low. Furthermore, alth ough children may be at increased risk because of their short stature when the proposed substitute is found at higher concentrations in the lower compartment of t he room, the probability that they are present in t he location in which a catastrophic release of the ent ire charge of the commercial refrigeration system i s low. To prevent exposure and potential serious side effe cts during larger releases, EPA recommends that the proposed RCL for R-448A (i.e., 110,000 ppm or 390 g /m 3 

### ) is not exceeded in any location where an R448A system is installed, unless proper leak protec tion devices are in place in order to prevent expos ures of R-448A beyond the recommended limits. Proper lea k protection devices, engineering control requirements, and adherence to the SDS will further ensure that exposure limits are maintained below those described in Table 8.



### 10. OCCUPATIONAL EXPOSURE ASSESSMENT
This section assesses potential exposures to worker s during manufacture, charging and servicing, and disposal of R-448A retail food refrigeration equipm ent and commercial ice machines. To ensure that use of the proposed substitute in retail food refrigeratio n and commercial ice machines does not pose an unacceptable risk to workers during servicing and d isposal, occupational exposure modeling was performed using a box-model approach. For a detail ed description of the methodology used for this screening assessment, the reader is referred to the occupational exposure and hazard analysis describe d in Chapter 5 of the Background Document. Estimates of refrigerant release per event for vari ous release scenarios were obtained from the Vintag ing Model. 8 

### To determine the estimated level of occupational exposure for a constituent in a blend, the total anticipated release rate of the refrigerant is mult iplied by the weight percent composition of each compound in the blend. For charging, servicing, and disposal activities, the release per event was multiplied by the number of events estimated to occ ur over a workday. During charging and servicing of the retail food refrigeration end-uses, the release per event was conservatively assumed to range betw een 0.25 percent and 5 percent of the equipment charge, respectively. For equipment charging and servicing

, the number of events per workday was assumed to equ al the maximum number of units anticipated to be serviced in one day (i.e., 8 units divided by 8 hou rs per workday for beverage coolers and commercial ice machines and one unit divided by 8 hours per workda y for direct rack systems) (see Section 10.2). For disposal of direct rack systems, it was conserv atively assumed that one unit is disposed of during an 8- hour work day. For beverage coolers and commercial ice machines, the release per event was conservatively assumed to be 100 percent of the equ ipment charge (representing a catastrophic release) . It was assumed that 10 units are disposed of during an 8-hour work day; however it was assumed that of th e 10 units, only the last unit per work day would exp erience the catastrophic release (i.e., 100 percent of the equipment charge). The remaining 9 units were assum ed to release an incidental amount of refrigerant (i.e., 1 percent per unit) from the connecting and disconnecting of lines, as it is likely that if a w orker was exposed to the entire charge of a system during dis posal activities, they would immediately stop worki ng, clear the area until all refrigerant has been remov ed from the space (e.g., through ventilation), and adhere to the exposure procedures recommended in the SDS f or the proposed substitute (see Section 10.3). The modeled exposure concentrations were compared t o STELs at installation and servicing and long-term exposure limits at disposal.

8 ICF International maintains the Vintaging Model fo r EPA in order to simulate the aggregate impacts of the ODS phaseout on the use and emissions of various ODS and their substitu tes over a period of several years across 60 differ ent end-uses. The model tracks the use and emissions of various compounds f or the annual vintages of new equipment that enter service in each end-use. The vintage of each type of equipment determines su ch factors as leak rate, charge size, number of uni ts in operation, and the initial ODS substance that the equipment contained.

### FINAL July 2, 2015 15 10.1 Occupational Exposure at Manufacture

HFC-134a is obtained from other manufacturers and H FO-1234ze(E) is manufactured by the submitter in the United States. During manufacture of the compon ents and blending of R-448A, the SDS for each component (i.e., HFC-32, HFC-125, HFC-134a, HFO-123 4yf, and HFO-1234ze(E)) should be referenced and proper engineering controls and PPE used. R-448A and its components are not expected to pose a risk to workers during manufacture or blending when the engineering controls and PPE recommendatio ns referenced in the SDS for R-448A and all of its components are followed. Release points and exposur e during refrigerant blending operations would typically be where temporary lines are connected or disconnected (i.e., filling of portable cylinders and portable bulk containers). Refrigerant quality cont rol testing may result in release of de minimus quantities of refrigerant, which would typically be to exhaust ducts or fume hoods. Engineering controls should include normal and local ventilation (e.g., chemica l hoods) and vapor-in-air detection and alarm syste ms for standard manufacturing procedures so workers ca n avoid physical contact with the refrigerant and t o achieve emission control. In general, use of PPE co nsistent with OSHA guidelines is recommended, such as respiratory protection (including a SCBA in case of insufficient ventilation), tightly sealed goggl es, and protective gloves (OSHA 1994). In addition, as for other halogenated refrigerants, there is a risk of generation of toxic degradation products such as hydrogen fluoride and hydrogen chloride if HFC-32, HFC-125, HFC-134a, HFO-1234f, or HFO1234ze(E) are exposed to high temperatures or fire. Other reaction products such as carbon dioxide mig ht also be present. Containers should be stored in coo l, dry conditions (maximum storage temperature shou ld be 40 ° C) in well-sealed receptacles and should not be all owed to contact open flames, glowing metal surfaces, or electrical heating elements. EPA belie ves that when proper handling and disposal guidelin es are followed in accordance with both good industria l hygiene and manufacturing practices and the SDS f or R-448A and its components, there is no significant risk to workers during the manufacture of R-448A.

10.2 Occupational Exposure at Charging and Servicin g As indicated by the submitter, large commercial ref rigeration equipment (e.g., direct rack systems) is typically field-erected and therefore, equipment is charged in the field. Charging for smaller retail refrigeration equipment (e.g., beverage coolers and commercial ice machines) would be conducted by the Original Equipment Manufacturer (OEM). For both OEM system manufacture (i.e., charging at OEM location) and field charging (i.e., charging at the end-use location), points of release for charging and servicing these leak-tight systems would be from co nnection/disconnection of temporary lines for charg ing and recovery equipment. Charging occurs within an enclosed area equipped wi th automatic ventilation, refrigerant detectors, an d alarm systems. The submitter indicated that chargin g equipment is operated only by trained technicians

. Release points during charging would be connection/ disconnection of temporary lines from charging equipment. Refrigerant contained in temporary lines during charging would be recovered, and breaking o f fittings should result in de minimus releases (Honeywell 2014a). During servicing, used refrigerant from R-448A reta il food refrigeration equipment and commercial ice machines is pumped into a canister, where it is sto red until it is recycled (i.e., filtered and reused ). During the transfer to the initial canister, incidental re frigerant releases may occur during connection and disconnection of the recharging hose fittings (Hone ywell 2014a). Isolation and evacuation of lines or equipment prior to servicing or repair and the use of compatible seals, gaskets, O-rings, thread seala nts, and minimization of threaded joints all contribute to limiting releases. Room ventilation, leak monito rs, and alarms also help minimize exposure. Charging and servicing activities for retail refrig eration equipment and commercial ice machines are n ot expected to result in significant worker exposure w hen certified technicians follow the procedures out lined in the R-448A SDS and maintenance manual, undergo p roper training, and wear appropriate PPE (e.g.,

### FINAL July 2, 2015 16 gloves and safety glasses). Nevertheless, the poten tial occupational exposure during servicing was analyzed. The maximum 15-minute TWA exposures for e ach R-448A constituent were estimated for the charging and servicing exposure scenarios and compa red to their respective STELs (see Table 9). Table 9. Occupational Risk Assessment at Charging and Servicing for R-448A Components a

Equipment R-448A

Component Charging Servicing 15-min Short Term Exposure Limits (ppm) c Release Rate b 15

- minute

TWA (ppm) Release

Rate b 15

- minute TWA (ppm)

Direct Rack System d HFC

- 32

2% 1,140

5% 2,860 3,000 HFC

- 125 495 1,240 3,000 HFC

- 134a 470 1,180 8,000 HFO

- 1234yf 4 01 1,000 1,500 HFO

- 1234ze(E) 140 91 2,400

Beverage Cooler HFC

- 32

1% 13.0

0.25% 13.7 3,000 HFC

- 125 5.63 5.92 3,000 HFC

- 134a 5.35 5.56 8,000 HFO

- 1234yf 4.56 4.79 1,500 HFO

- 1234ze(E) 1.60 0.44 2,400

Ice Machine HFC

- 32

1% 217

3% 2,730 3,000

HFC

- 125 93.9 1,180 3,000 HFC

- 134a 89.2 1,120 8,000 HFO

- 1234yf 76.0 958 1,500 HFO

- 1234ze(E) 26.6 87.2 2,400 Bold font indicates modeling results.

a Cells highlighted in green are the scenarios that a re deemed to be acceptable given various modeling a ssumption options.

b Release rates are consistent with IPCC (2006), CAR B (2013), and EPA’s Vintaging Model.

c See Table 4 for more information

d One installation or servicing event per day was mo deled for direct rack systems 

### The 15-minute STEL for all components of R-448A is not exceeded in the charging or servicing exposure scenarios for all three equipment types. These esti mated exposures were derived using conservative assumptions and do not take into account the use of ventilation or PPE, and all of these exposure esti mates are significantly lower than the RCL or ATEL for ea ch component, which are limits intended to reduce t he risks of acute toxicity hazards in normally occupie d, enclosed spaces according to ASHRAE Standard 34. Furthermore, these types of systems are typically s erviced by Section 608-certified personnel using pr oper industrial hygiene techniques and using proper engi neering controls (e.g., local ventilation, refriger ant detectors, and alarm systems). Thus, EPA does not b elieve that charging, installation, or servicing of retail food refrigeration units and commercial ice machine s containing R-448A presents a significant concern to workers. 10.3 Occupational Exposure at Disposal Disposal of R-448A retail food refrigeration equipm ent is expected to occur with limited frequency (up to approximately ten disposal events per day for small er equipment such as beverage coolers and commercia l ice machines and one disposal event per day for dir ect rack systems) at disposal facilities or, for la rger equipment (e.g., direct rack systems) at the end-us e and with limited duration of exposure to the inst alled refrigerant. Typically, potential exposures to the refrigerant during recovery and disposal are expect ed to occur during activities related to decommissioning refrigeration systems (e.g., attaching of hoses associated with draining or otherwise discharging o f refrigerant from the refrigeration units into cyl inders) and would be similar to those during servicing, bec ause similar refrigerant charging and/or recovery equipment would be used (see Section 10.2 and Table 9 for information and modeling results related to exposure during servicing activities). As shown in Table 9 in Section 10.2, exposures duri ng servicing (and therefore during typical disposal activities) are not anticipated to present a signif icant concern for workers. To model a worst-case sc enario

### FINAL July 2, 2015 17 during disposal for direct rack systems, it was con servatively assumed that 14 percent of the equipmen t charge would be released per disposal event. For be verage coolers and commercial ice machines, it was assumed that of the 10 disposal events, 9 units are properly disposed of with only incidental releases of refrigerant (i.e., 1 percent per unit) followed by the disposal of one unit that results in a catastro phic release of refrigerant (i.e., 100 percent of the eq uipment charge). Table 10 displays the maximum estimated 8-hour TWA occupational exposure levels for the R-448A components at disposal. Based on the assumptions de scribed in the beginning of Section 10, under the disposal release scenarios, the modeling indicates that occupational exposure could exceed the 8-hour long term exposure limit for HFC-32 in direct rack syste ms and for HFC-32, HFC-125, HFC-134a, and HFO1234yf for commercial ice machines.

Table 10. Occupational Risk Assessment at Disposal for R-448A Components a

Equipment R-448A Component 8

- Hour TWA Occupational Exposure (ppm) 8-Hour Long Term

Exposure Limits b (ppm)

Direct Rack System HFC

- 32 1,160 1,000 HFC

- 125 502 1,000 HFC

- 134a 477 1,000 HFO

- 1234yf 407 5 00 HFO

- 1234ze(E) 142 800

Beverage Cooler HFC

- 32 102 1,000 HFC

- 125 44 1,000 HFC

- 134a 42 1,000 HFO

- 1234yf 36 5 00 HFO

- 1234ze(E) 12 800

Ice Machine HFC

- 32 1,700 1,000 HFC

- 125 735 1,000 HFC

- 134a 700 1,000 HFO

- 1234yf 595 5 00 HFO

- 1234ze(E) 2 10 800 Bold font indicates modeling results.

a Cells highlighted in green are the scenarios with e xposure levels deemed to be acceptable given variou s modeling assumption options.

b WEEL OEL


### Although the modeling indicates that the worst-case disposal scenario for the HFC-32 component of R448A in direct rack systems and commercial ice mach ines and the HFO-1234yf component in commercial ice machines exceed the 8-hour exposure limits for these components, the estimated exposures were derived using conservative assumptions (e.g., no me chanical or local exhaust ventilation), and represe nt a worst-case scenario with a low probability of occur rence. These types of systems are also typically disposed of by Section 608-certified personnel usin g proper industrial hygiene techniques to maximize recovery efficiency and limit releases. The average recovery efficiencies and maximum disposal release rates (see Table 10) are also representative of rel ease rates for currently used refrigerants in comme rcial refrigeration equipment (e.g., R-404A, R-507A, R-40 7C), and there are already established standards of practice and training requirements that apply to fl uorinated refrigerants to reduce exposures (and wou ld therefore extend to R-448A systems). It is also unlikely that workers would be exposed t o the unrecoverable portion of refrigerant during t he recovery process, and therefore anticipated exposur es would be much lower. For example, some of the refrigerant would likely be dissolved in the refrig erant oil (which would be drawn out and separated f rom the recovered refrigerant) or trapped within deeper parts of the refrigeration circuit (e.g., the accu mulator or receiver) and wouldn’t be released until the sys tem is actually dismantled later on in the disposal process (Oko-Recherche 2003).

### FINAL July 2, 2015 18 Because anticipated occupational exposures could be above the exposure limits for HFC-32 in direct rac k systems and for HFC-32, HFC-125, HFC-134a, and HFO- 1234yf for commercial ice machine disposal release scenarios, the recommendations for proper e ngineering controls and PPE in the SDS for R-448A should be followed. Adequate ventilation should alw ays be established during any use, handling, or storage of R-448A. If recovery and disposal is taki ng place in an enclosed space without any mechanica l ventilation, facilities should be cleared of non-es sential personnel and technicians should wear a SCB A and other appropriate protective equipment. Engineering controls should include vapor-in air de tection systems and local exhaust ventilation durin g use of R-448A to prevent dispersion throughout the work place. In addition, an eye wash and safety shower should be near the manufacturing facility and locat ions where R-448A is stored and ready for use. In general, use of PPE is recommended, such as splash goggles, mechanical-resistance gloves (e.g., oilrepellent or thermal resistant gloves) when handlin g cylinders and chemically-resistant gloves when handling the gas mixture (e.g., butyl rubber, chlor inated polyethylene, or neoprene). For larger retai l food refrigeration (e.g., rack systems) and commercial i ce machine (e.g., remote systems) systems, toxicity risks could be further minimized through the installation of signage which warns room occupants to remain standing (as higher concentrations are likely to ac cumulate near the floor) and not to enter recessed parts of the facility (e.g., maintenance crawl spaces and be low grade service areas) and exit the facility immediately should they hear the refrigerant detect or alarm and/or smell the leaked refrigerant. EPA believes that if proper handling and disposal guide lines are followed in accordance with good industri al hygiene and manufacturing practices and the SDS for R-448A, there is no significant risk to workers during the manufacturing, installation, servicing, and disposal of R-448A in retail food refrigeration units and commercial ice machines.



### 11. GENERAL POPULATION EXPOSURE ASSESSMENT
R-448A is not expected to cause a significant risk to human health in the general population when manufactured for use and used as a refrigerant in r etail food refrigeration and commercial ice machine s. The proposed substitute will be manufactured in a c losed process and is proposed for use in closed systems; thus, significant releases are not anticip ated. At room temperature, R-448A is a gas and, therefore, releases to ground or surface water are not anticipated, as R-448A is anticipated to dissip ate into the atmosphere upon release to outside air (i.e., b ecause natural ventilation rates would be higher an d there is no enclosed space to maintain a high concentrati on of R-448A). Should air releases during manufacturing operations occur, engineering control s should be used (e.g., carbon absorption scrubbers ) to collect R-448A and prevent the release of R-448A to the atmosphere. EPA believes that by using proper engineering controls and by following disposal and containment recommendations outlined in the proposed substitute’s SDS and this risk screen, exp osure to R-448A is not expected to pose a significa nt toxicity risk to the general population.

### FINAL July 2, 2015 19 

### 12. REFERENCES

Armines. 2008. Inventory of Direct and Indirect GHG Emissions from Stationary Air Conditioning and Refrigeration Sources, with Special Emphasis on Ret ail Food Refrigeration and Unitary Air Conditioning

. CARB Agreement No. 06-325. Available at: http://www.arb.ca.gov/cc/commref/armines_report_03_ 625.pdf.

ACGIH. 2012. Guide to Occupational Exposure Values. American Conference of Governmental Industrial Hygienists.

ANSI/ASHRAE. 2015. 2015 Supplement to Standard 34: Designation and Safety Classification of Refrigerants. American Society of Heating, Refriger ating and Air-Conditioning Engineers, Inc.

ANSI/ASHRAE. 2013. Standard 62: Ventilation for Acc eptable Indoor Air Quality. American Society of Heating, Refrigerating and Air-Conditioning Enginee rs, Inc.

ANSI/ASHRAE. 2010a. Standard 15: Safety Standard fo r Refrigeration Systems. American Society of Heating, Refrigerating and Air-Conditioning Enginee rs, Inc.

ANSI/ASHRAE. 2010b. Standard 34: Designation and Sa fety Classification of Refrigerants. American Society of Heating, Refrigerating and Air-Condition ing Engineers, Inc.

CARB. Gallagher, Glenn, Tao Zhan, Ying-Kuang Hsu, e t. al. 2013. “High-global Warming Potential Fgas Emissions in California: Comparison of Ambient- based versus Inventory-based Emission Estimates, and Implications of Refined Estimates.” Environ. Sci. Technol., 2014, 48 (2), pp 1084–1093. DOI: 10.1021/es403447v. Publication Date (Web): December 13, 2013. Copyright © 2013 American Chemical Society. Available at http://pubs.acs.org/doi/abs/1 0.1021/es403447v

Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D.W. Fahey, J. Haywood, J. Lean, D.C. Lowe, G. Myhre, J. Nganga, R. Prinn, G. Raga, M. Sc hulz and R. Van Dorland. 2007. Changes in Atmospheric Constituents and in Radiative Forcing. In: Climate Change 2007:The Physical Science Basis. Contribution of Working Group I to the Fourt h Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marqu is, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Ca mbridge, United Kingdom and New York, NY, USA.

Hodnebrog, Ø., Etminan, M., Fuglestvedt, J. S., Mar ston, G., Myhre, G., Nielsen, C. J., Shine, K. P., Wallington, T. J. 2013. Global Warming Potentials a nd Radiative Efficiencies of Halocarbons and Related Compounds: A Comprehensive Review, Reviews of Geophysics, 51 , 300-378, doi:10.1002/rog.20013.

Honeywell, Inc. 2014a. Solstice® N-40 (R-448A). Sig nificant New Alternatives Policy Program Submission to the United States Environmental Prote ction Agency. May 2014.

Honeywell, Inc. 2014b. Response to Incompleteness L etter for Solstice® N-40 (R-448A) Significant New Alternatives Policy Program Submission to the Unite d States Environmental Protection Agency. August 11, 2014.

ICF. 1997. Physiological Effects of Alternative Fir e Protection Agents - Hypoxic Atmospheres Conference. Stephanie Skaggs prepared the proceedin gs of the conference held May 22, 1997 in New London, CT.

### FINAL July 2, 2015 20 IPCC. 2013. Climate Change 2013: The Physical Scien ce Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Pa nel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Na uels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingd om and New York, NY, USA, 1535 pp.

IPCC. 2006. IPCC Guidelines for National Greenhouse Gas Inventories. Volume 3: Industrial Processes and Product Use, Chapter 7: Emissions of Fluorinate d Substitutes for Ozone Depleting Substances.”November 2008. Available at: http://www.ipccnggip.iges.or.jp/public/2006gl/pdf/3_Volume3/V3_7_C h7_ODS_Substitutes.pdf.

Kataoka, O., M. Yoshizawa, & T. Hirakawa. 2000. “A llowable Charge Limit of Flammable Refrigerants and Ventilation Requirements.” Daikin Industries. International Refrigeration and Air Conditioning Conference. Paper 506. Available online at: http:// docs.lib.purdue.edu/iracc/506.

Lelieveld, H.L.M., J. Holah, D. Napper. 2014. Hygie ne in food processing: Principles and practice. Second Edition. Woodhead Publishing Series in Food Science, Technology and Nutrition.

Mackenzie, F.T. and J.A. Mackenzie. 1995. Our chang ing planet. Prentice-Hall.

Oko-Recherche GmbH. 2003. Final Report on Establish ing the Leakage Rates of Mobile Air Conditioners. Prepared for the European Commission. Available at: http://ec.europa.eu/clima/policies/eccp/docs/leakag e_rates_final_report_en.pdf.

OSHA. 2004. “Safety and Health Topics: Isobutane.” February 2004. Available online at: <http://www.osha.gov/dts/chemicalsampling/data/CH_2 47840.html>.

UL. 2010. UL 471: Commercial Refrigerators and Free zers. Underwriters Laboratory.

Papadimitriou, V., R.K. Talukdar, R.W. Portmann, A. R. Ravishankara, and J.B. Burkholder. 2007. CF3CF=CH2 and (Z)-CF3CF=CHF: Temperature dependent OH rate coefficients and global warming potentials. Physical Chemistry Chemical Physics. 9: 1-13.

UK Department of Energy & Climate Change (DECC). 20 11. “Development of the GHG Refrigeration and Air Conditioning Model.” Prepared by ICF Intern ational. November 2011. Available at https://www.gov.uk/government/uploads/system/upload s/attachment_data/file/48250/3844-greenhousegas-inventory-improvement-project-deve.PDF.

U.S. EPA. 2012. Acute Exposure Guidelines (AEGLs) D efinitions. Available online at: http://www.epa.gov/oppt/aegl/pubs/define.htm.

U.S. EPA. 1994. Significant New Alternatives Polic y Technical Background Document: Risk Screen on the Use of Substitutes for Class I Ozone-depleting Substances: Refrigeration and Air Conditioning. Stratospheric Protection Division. March, 1994.

WMO (World Meteorological Organization). 2011. Scie ntific Assessment of Ozone Depletion: 2010, Global Ozone Research and Monitoring Project-Report No. 52, 516 pp., Geneva, Switzerland.