Final

— July 2, 2015 1 

## Significant New Alternatives Policy Program

Refrigeration and Air Conditioning Sector

Risk Screen on Substitute s in Household Refrigerators and Freezers and Water Coolers

Substitute: R

- 513A (Opteon® XP10)

This risk screen does not contain Clean Air Act (CAA) Confidential Business Information (CBI) and, therefore, may be disclosed to the public.



### 1. INTRODUCTION
Ozone

- depleting substances (ODS) are being phased out of production in response to a series of diplomatic and legislative efforts that have taken place over the past two decades, including the Montreal Protocol 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 Significan t New Alternatives Policy (SNAP) Program, which identifies acceptable and unacceptable substitutes for ODS in specific end

- uses based on assessment of their health and environmental impacts. 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 posed by the substitute in specific applications. EPA has already screened a large number of substitutes in many end

- use applications within all of the major ODS

usi ng sectors including: refrigeration and air conditioning, solvent cleaning, foam blowing, aerosols, fire suppression, adhesives, coatings and inks, and sterilization. The results of these risk screens are presented in a series of Background Documents that are available in EPA's docket. The purpose of this risk screen is to supplement EPA’s Background Document on the refrigeration and air conditioning sector (EPA 1994) (hereinafter referred to as the Background Document). This risk screen evaluates the poten tial use of R

- 513A (also known as Opteon® XP10) as a substitute in the household refrigerator and freezer end

- use and the drinking water cooler end

- use. Table 1 presents the composition of the proposed substitute.

Table 1

. Composition of R

- 513A and Potential Impurities

Constituent Chemical Formula CAS Number Concentration (Weight Percent) 2,3,3,3

- Tetrafluoropropene (HFO

- 1234yf) CH 2 CFCF 3 754

- 12

- 1 ≤ 56 % 1,1,1,2

- Tetrafluoroethane (HFC

- 134a) CF 3 CH 2 F 811

- 97

- 2 ≤ 44 % Potential Impurities

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

- U se 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 AssessmentFinal

— July 2, 2015 2 • Section 11 : General Population Exposure Assessment

• Section 12 : References



### 2. SUMMARY OF RESULTS

R

- 513A is recommended for SNAP approval for household refrigerators and freezers and water coolers

. 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 to the ozone layer, has lower climate impact, and a shorter atmospheric lifetime. The components of R

- 513A 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 substances is not a concern. In addition, because R

- 513A is considered to be nonflammable , the proposed substitute is not expected to present a flammability concern. It is expected that the manufacturer’s safety data sheet (SDS) for R

- 513A and good manufacturin g practices will be adhered to during handling or use of R

- 513 A. Additionally, it is expected that the appropriate safety and personal protective equipment (PPE) (e.g., protective gloves, tightly sealed goggles, protective work clothing, and suitable respiratory protection in case of leakage or insufficient ventilation) consistent with Oc cupational Safety and Health Administration (OSHA) guidelines will be used during manufacture, installation and servicing, and disposal of household refrigerators and freezers and water coolers using R

- 513A

. Because h ousehold refrigerators and freezers and water coolers are to be installed in locations with adequate space and/or ventilation in accordance with EPA recommendations and the equipment maintenance manuals for R

- 513A in each end

- use, significant toxicity risk to consumers is also unlikely.
Additi onal safeguards, including specified refrigerant concentration limits (RCL) of R

- 513A components, are also provided by adherence to industry standards including American Society of Heating, Refrigerating and Air

- Conditioning Engineers (ASHRAE) Standards 15
, 1 34, 2 and 62. 3



### 3. ATMOSPHERIC ASSESSMENT This section presents an assessment of the potential risks to atmospheric integrity posed by the use of R

513A in household refrigerators and freezers and water coolers . The ozone depletion potential (ODP), glo bal warming potential (GWP), and atmospheric lifetime (ALT) of the proposed substitute are presented in Table 2

. The proposed substitute is substantia lly less harmful to the ozone layer, has lower climate impact, and a shorter ALT when compared to refrigerants such as CFC

- 12, R

- 502, and HCFC

- 22. In addition, R

- 513A has lower climate impact and a shorter ALT than those predicted for other substitutes examined in the Background Document as well a s commonly utilized refrigerant HFC

- 134a . Thus, EPA believes that the use of R

- 513A would result in substantially less harm to the climate and ozone layer than the con tinued use of ODS and other commonly used refrigerant s

.

1 Safety Standard for Refrigeration Systems ASHRAE Standard 15 establishes safeguards for life, limb, health, and property and prescribes safety requirements.
2 Designation and Safety Classification of Refrigerants ASHRAE Standard 34 establishes a uniform system for assigning reference numbers, safety classifications, and refrigerant concentration limits to refrigerants. Safety classifications based on toxic ity a nd flammability data are included.
3 Ventilation for Acceptable Indoor Air Quality ASHRAE Standard 62 establishes minimum ventilation rates and other measures intended to provide indoor air quality that is acceptable to human occupants and that minimizes a dverse health effects.Final

— July 2, 2015 3 Table 2 . Atmospheric Impacts of R

- 513A Components Compared to Other Refrigerants Used in Household Refrigerators and Water Coolers
Refrigerant Ozone Depleting Potential (OD P) a Global Warming Potential (GWP) b Atmospheric Lifetime in Years (ALT) b R

- 513A 0 631 NA c Individual Components HFC

- 134a 0 1,430 14 HFO

- 1234yf 0 4 d 11 days d CFC

- 12 0.82 10,900 100 R

- 502 e 0.2 4,650 NA f HCFC

- 22 0.13 1,810 12 a HFC

- 134a 0 1,430 14

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, because the components separate in the atmosphere. The ALT for the individual components are listed in the table.
d Papadimitriou et al. ( 2007 )

e R

- 502 is a blend consisting of HCFC

- 22 (49%) and CFC

- 115 (51%).
f Atmospheric lifetimes are not given for blends, because the components separate in the atmosphere. The AL T 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]).



### 4. VOLATILE ORGANIC COMPOUND ASSESSMENT The components of R

- 513A
, HFC

- 134a and HFO

- 1234yf, are exempt from the definition of VOCs under CAA regulations (40 CFR 51.100(s)). Therefore, VOC impacts from the release of R

- 513A are not a

concern

. 

### 5. DISCUSSION OF END

- USE SCENARIOS MODELED
The submitter states that R

- 513A household refrigerators and freeze rs will have a typical charge size of 100 grams and a maximum charge size of 1,000 grams. Water coolers are expected to have a typical charge size of 100 grams and a maximum charge size of 500 grams . The intended maximum and typical charge sizes for all of the proposed appli cations are listed in Table 3.
Table 3 . Typical and Maximum Charge Sizes for Various R

- 513A End

- Uses and Applications

End

- Use Typical Charge Size ( g rams ) Maximum Charge Size (grams ) Household Refrigerators and Freezers 100 1,000 Water Coolers 100 500
Household refrigerators and freezers and water coolers can be installed in a wide range of locations with varying room volumes (e.g., residential homes, commercial office buildings). Because the typical and maximum charge sizes for household refrigerators and freezers (i.e.
, 100 to 1,000 grams) encompasses the typical and maximum charge sizes for water coolers (i.e., 100 to 500 grams), the reasonable worst

- case scenario for this analys is assumes that a catastrophic leak of refrigerant occurs while a household refrigerator is installed at the end

- use (i.e., a small kitchen) for both the typical and maximum charge size provided by the submitter ( e.g. , 100 grams and 1,000 grams, respective ly). T he analysis in this risk screen conservatively assumes that the household refrigerator is located in a small residential kitchen with an effective volume of 18 m 3 (640 ft 3 ) (i.e., excluding the space filled by cabinets, other kitchen equipment, etc.) and a height of 2.4 4 meters

. This location also represents a likely installation location for water coolers.
Under the reasonable worst

- case scenario, the full charge of the unit is assumed to be emitted into the kitchen with 2.3 air changes per hour (ACH ) over the course of two time durations: 1) one minute, whichFinal

— July 2, 2015 4 represents a catastrophic release of refrigerant due to a puncture or other major damage to the refrigeration system, and 2) fifteen minutes, which represents the accidental release of refrigera nt due to a non

catastrophic leak in the system (e.g., valve failure , pinhole leaks ). The one

- minute time duration is most appropriate for flammable refrigerants and presents a less relevant scenario for R

- 513A, which is nonflammable. Therefore, while we e valuate both of these scenarios in this risk screen for consistency purposes, the scenario which analyzes a release of refrigerant over a 15

- minute time duration more accurately represents a reasonable worst

- case scenario for R

- 513A in household refrigerat ors and freezers and water coolers. A vertical concentration gradient is also assumed since R

- 513A is denser than air (i.e., the specific gravities of both HFC

- 134a and HFO

- 1234 yf are greater than 1) and will settle in higher concentrations closer to the ground. In order to simulate the vertical concentration gradient of refrigerant following release , it is assumed that 95 percent of the leaked refrigerant mixes evenly into the bottom 0.4 meter s (1.3 feet) of the room, and the rest of the refrigerant mixes evenly in the remaining volume (Kataoka 2000). Additionally, because the average breat hing zone is above 0.4 meters and mixing is likely to occur upon release of R

- 513A from the unit because the system pressure is higher than the surrounding atmospheric p ressure, the absence of the vertical concentration gradient was also evaluated i n the end

- use exposure assessment (Section 9 ). Table 4 details the end

- use modeling assumptions used throughout the risk screen (i.e., in Sections 8 and 9 ).
Table 4. End

- Use Sc enario Model Assumptions Parameter Assumption Room Type Household Kitchen

S ize (m 3 ) 18 a (640 ft 3 ) V

entilation Rate (air changes per hour) 2.3 a Refrigeration Unit Household Refrigerator

Charge S ize (g) 1 00 b ; 1,000 c Duration of R elease (minutes) 1 d ; 15 e Vertical Concentration Gradient Yes; No

a Background Document (EPA 1994)
b Typical charge size for household refrigerators and freezers and water coolers ( DuPont Fluoroproducts 2014b)

c The m aximum charge size for household refrigerators and freezers is 1,000 grams , which is greater than the maximum charge size for water coolers of 500 grams , and is more conservative for this end

- use scenario ( DuPont Fluoroproducts 2014b )

. d Represents catastrophic release due to puncture and/or destruction of system

e Represents non

- catastrophic release due to leak in the system (e.g., valve failure, pinhole leak) EPA recognizes that household refrigerators and freezers and water coolers m ay be placed in a variety of locations with differing room sizes and ventilation rates. When units are installed in smaller, enclosed spaces, there is a higher risk for asphyxiation or exposure concerns. To address this variability in room volumes and char ge sizes for installed household refrigerators and freezers and water coolers , this risk screen incorporates threshold analyses in addition to the worst

- case scenario modeling. The threshold analyses are performed in order to determine the room size and ch arge size requirements that ensure that the use of R

- 513A in these end

- uses does not present risk to end

- users or servicing technicians.



### 6. POTENTIAL HEALTH EFFECTS To assess potential health risks from exposure to the proposed substitute in household refrigerators and freezers and water coolers , EPA identified the relevant toxicity threshold values for comparison to modeled exposure concentrations for different scenarios

. According to ASHRAE Standard 34

- 2013, R

513A is listed under safety group A1 with a RCL of 72,000 ppm (ASHRAE 2015) . ASHRAE 34 RCLs are intended to reduce the risks of acute toxicity, asphyxiation, and flammability hazards in normally occupied, enclosed spaces during refrigerant use and 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 concentration of refrigerant in an enclosed space following aFinal

— July 2, 2015 5 complete discharge of a high

- probability system shall not exceed the RCL” (ASHRAE 2010a). As such, this risk screen references the proposed RCL for R

- 513A in addition to the hypoxia no observed adverse effect level (NOAEL) and exposure limits, as an additional, conservative limit to ensure that significant

as phyxiation and end

- use exposure risks, respectively, do not occur. For the occupational exposure analysis, potential risks from chronic and acute worker exposure were evaluated by comparing exposure concentrations to available occupational exposure limit s. Potential risks of chronic worker exposure were evaluated using workplace guidance levels (WGLs) , such as Workplace Environmental Exposure Levels (WEELs)

. Risks from potential short

- term consumer exposures were evaluated by comparing exposure concentra tions to emergency guidance levels (EGLs). In the absence of an established short

- term exposure limit (STEL), acute exposure guideline level (AEGL), or emergency response planning guideline (ERPG) for R

- 513A , potential short

- term, end

- use exposures were ev aluated on a component basis (i.e., HFC

- 134a and HFO

- 1234yf). Table 5 lists the relevant toxicity limits for R

513A and its components and is followed by Table 6, which provides an explanation of each toxicity limit. EPA’s approach for identifying or devel oping these values is discussed in Chapter 3 of the Background Document.
Table 5. Exposure Limits of R

- 513A Components

R

- 513A Component WGL (Long

- term Exposure)

P pm EGL (Short

- term Exposure) ppm Refrigerant Concentration Limit (RCL) ppm
R

- 513A 653 (8

- hour AEL) 1,960 (15

- min STEL) a 72,000
Individual Components

HFC

- 134a 1,000 (8

- hour WEEL) 8,000 (10

- min AEGL

- 1) 8,000 (30

- min AEGL

- 1) 50,000
HFO

- 1234yf 5 00 (8

- hour WEEL) 1,500 (15

- min STEL) b 100,000 c

a Neither the American Conference of Governmental Industrial Hygienists ( ACGIH ) nor the American Industrial Hygiene Association ( AIHA ) recommend ceiling or short term exposure limits for the blend R

- 513A . A STEL for R

- 513A of 1,960 ppm was developed by EPA based on the 653 ppm acceptable expo sure 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 . [STEL] = [AEL] x 3 = 653 ppm x 3 ≈ 1,960 ppm b Neither ACGIH nor AIHA recommend ceiling or short term exposure limits for HFO

- 1234 yf

. A STEL for HFO

- 1234 yf of 1,5 00 ppm was developed by EPA based on the 5 00 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 li mit by ACGIH . [STEL] = [AEL] x 3 = 5 00 ppm x 3 ≈ 1,500 ppm

c Although a RCL has not been proposed for HFO

- 1234yf, t he recommended acute toxicity exposure limit ( ATEL ) for HFO

- 1234yf is 101,000 ppm ( DuPont Fluoroproducts 2014a ). Table 6. Explanation of Exposure Limit

- Related Terminology a Organization Definition OSHA Occupational Safety and Health Administration NIOSH National Institute for Occupational Safety and Health ACGIH American Conference of Governmental Industrial Hygienists 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 (ODL), and Flammable Concentration Limit (FCL). Determination ass umes full vaporization with no removal by ventilation, dissolution, reaction, or decomposition and complete mixing of refrigerant in the space to which it is released.Final

— July 2, 2015 6 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 occupied, enclosed spaces according to ASHRAE Standard 34. The ATEL includes consideration of mortality, cardiac sensitization, anesthetic or central nerv ous system effects and other escape i mpairing effects and permanent injury. The ATEL is similar to the Immediately Dangerous to Life or Health (IDLH) concentrations set by NIOSH

. STEL Short

- Term Exposure Limit A 15

- minute time

- weighted average (TWA) expos ure that should not be exceeded during a workday, even if the 8

- hour TWA is within the threshold limit value

- time

- weighted value ( TLV

– TWA ) , set by ACGIH.

AEGL b,c Acute Exposure Guideline Level 1 AEGL

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

- 2 is the airborne concentration (expressed as ppm or mg/m 3 ) 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. Acute Exposure Guideline Level 3 AEGL

- 3 is the airborne concentration (expressed as ppm or mg/m 3 ) of a substance above which it is predicted that the general 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 against acute and chronic health effects, th is limit is based on repeated 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 lifetime without adverse effect according to ACGIH.

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

c A pplicable to emergency exposure periods ranging from 10 minutes to 8 hours. According to the SDS, exposure to R

- 513A may be hazardous if inhalation, skin contact, or eye contact with the proposed substitute occurs. The most likely pathway of exposure is through inhalation. R

- 513A can cause symptoms of asphyxiation when present in concentrations high enough to significan tly lower oxygen concentrations below 19.5 percent by volume, such as headaches, ringing in ears, dizziness, drowsiness, nausea, vomiting, depression of all senses, and also unconsciousness. Under some circumstances of over

- exposure (i.e., oxygen levels fa ll below 6 percent by volume), death may occur. If inhaled, R

- 513A can cause symptoms such as light

- headedness, dizziness, confusion, incoordination, drowsiness, unconsciousness, and anesthetic effects. Excessive inhalation of R

- 513A may also result in an irregular heartbeat or death, due to cardiac effects. Furthermore, R

- 513A vapors are denser than air and can cause asphyxiation if the oxygen concentration in a room is significantly reduced.
If R

- 513 A is inhaled, person(s) should be immediately removed from the contaminated space and exposed to fresh air. In accordance with the SDS, EPA further recommends that if breathing is difficult or irregular
, person(s) should be given oxygen, provided a qualified operator is present, a nd medical attention beFinal

— July 2, 2015 7 soug ht. Exposures of R

- 513 A to the skin may cause frostbite. In the case of dermal exposure, the SDS for R

- 513 A recommends that person(s) immediately wash the affected area with water and remove all contaminated clothing; if frostbite occurs, bathe (not rub) t he affected area with lukewarm, not hot, water. If water is not available, cover the affecte d area with a clean, soft cloth , and seek medical attentio n immediately. Exposures of R

- 513 A to the eyes could cause eye irritation. In case of ocular exposure, the SDS for R

- 513A recommends that person(s) immediately flush the eyes, including under the eyelids, with copious amounts of water for 15 minutes. EPA’s review of the human health impacts of this proposed substitute is contained in the public docket for thi s decision. These risks and procedures after exposure are similar for other common refrigerants. The potential health effects of R

- 513A can be minimized by following the exposure guidelines and ventilation and PPE recommendations outlined in the SDS for R

- 513A and this risk screen

.


### 7. FLAMMABILITY ASSESSMENT

R

- 513A is classified as an A1 refrigerant by ASHRAE, and is considered to be nonflammable (DuPont Fluoroproducts 2014 a ; ASHRAE 2015). Based on this classification, manufacture, servicing, and use of R

513A is not expected to pre sent a flammability risk in household refrigerators and freezers and water coolers

. 

### 8. ASPHYXIATION ASSESSMENT The risk of asphyxiation for the reasonable worst

- case scenario described in Section 5 was investigated for R

- 513A . In this section, risk of asphyxiation is assessed in three ways: 1) modeling the oxygen concentration under the charge size and room size specified in the worst

- case scenario, 2) performing a threshold analysis of minimum charge size at which an asphyxi ation 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 analysis of the maximum room size at which an asphyxiation risk co uld occur with the charge size specified in the worst

- case scenario (i.e., room sizes smaller than this are expected to cause an asphyxiation risk). This analysis does not consider ventilation or conditions that are likely to occur that would increase oxyg en levels to which individuals would be exposed, such as open doors or windows, fans operating, 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

reasona ble worst

- case scenario assumes a vertical concentration gradient. If the proposed substitute passes the screening analysis with these restrictive assumptions in place, it can be reasonably assumed that no risks of asphyxiation will be present under real

- w orld conditions. The results of the asphyxiation assessment are summarized in Table 7 below. Table 7. Asphyxiation Assessment a,b

Scenario Charge Size (g

) Effective Room Size (m

3 ) Percent Oxygen Concentration in Lower 0.4 Meters Reasonable Worst

- Case 1 100 18 (640 ft 3 ) 2 1 % Reasonable Worst

- Case 2 1,000 18 (640 ft 3 ) 21% Threshold Analysis 1a: Charge Size 5,630 18 (640 ft 3 ) 12% Threshold Analysis 2a: Room Size 100 0.32 ( 11.3 ft 3 ) 12% Threshold Analysis 2b: Room Size 1,000 3.2 ( 113 ft 3 ) 12% Bold font indicates modeling results.

a Cells highlighted in green are the scenarios in which the charge and room sizes evaluated in this risk screen are acceptable according to the threshold analysis or the scenarios with acceptable oxygen concentrations, given various modeling assumption opt ions.
b The typical concentration of oxygen in air is considered to be 21 percent (Mackenzie & Mackenzie 1995).Final

— July 2, 2015 8 In order for a risk of asphyxiation to occur, the normal concentration of oxygen in air (21 percent) must be reduced to 12 percent. 4 Based on t he reasonable worst

- case scenario modeling, a release of R

- 513A from household refrigerators has an insignificant impact on the concentration of oxygen in the air and therefore does not present a significant risk of asphyxiation. This modeling does not tak e into account any ventilation which is likely to occur, such as conditioned airflow, open doors, or even openings at the bottom of doors that allow air to flow in and out, as mentioned above; therefore, the actual asphyxiation risk to person(s) is likely to be even smaller than modeled. For the asphyxiation thr eshold analyses shown in Table 7 , the conditions at which an asphyxiation concern would exist were determined. Within the reasonable worst

- case room size of 18 m 3 (640 ft 3 ), as shown under Threshold Analysis 1 a , the charge size of the R

- 513A refrigerator would have to be at least 5,63 0 grams for asphyxiation to be a concern, which is more than 5 times the maximum charge size anticipated by the submitter for household refrigerators and freezers ( or mor e than 11 times the maximum charge size anticipated for water coolers) . In Threshold Analyses 2a and 2b, the volume of the room would have to be 0 .32 m 3 (11.3 ft 3 ) and 3.2 m 3 (113 ft 3 ) or smaller f or asphyxiation to be of concern for units with 1 00

- gram and 1,000

- gram charge sizes, respectively.
Based on the worst

- case modeling results and threshold analysis, EPA does not believe that the use of R

513A in household refrigerators and freezers or water coolers poses a significant risk of asphyxiation or imp aired coordination to end

- users or servicing technicians , provided systems are installed in appropriate spaces according to guidelines from the manufacturer and the SDS for R

- 513A

. 

### 9. END

- USE EXPOSURE ASSESSMENT This section presents estimates of potentia l end

- user exposures to R

- 513A and each of its components in the event of a catastrophic release from the proposed substitute’s use in household refrigerators and freezers and water coolers . An end

- use exposure analysis was performed to examine potential c atastrophic releases of R

- 513A under the reasonable worst

- case scenarios outlined in Section 5.
For the end

- use exposure assessment scenario, 15

- minute TWA exposures for the proposed substitute were calculated using the box model described in the Background Document, which was adapted to estimate concentrations on a minute

- by

- minute basis. Estimates for acute/short

- term end

- use exposures resulting from catastrophic leakage of refrigerant from a household refrigerator were examined. As discussed in Section 5, the full charge of the unit is assumed to be emitted over the course of 1 minute and 15 minute s, where the latter scenario more accurately represents a reasonable worst

- case scenario for R

- 513A in household refrigerators and freezers
, because R

- 513A is nonflammable. The analysis was undertaken to determine the 15

- minute exposures for R

- 513A , which were then compared to the standard toxicity limits presented in Table 5 to assess the risk to end

- users. The estimated TWA values are fairly conservative as the analysis does not consider opened windows, fans operating, conditioned airflow (either heated o r cooled) and other variables that would reduce the levels to which individuals would be exposed. Because HFO

- 1234yf is present in larger concentrations and because it has a lower exposure limit than HFC

- 134a, Table 8 only display s exposures for HFO

- 1234yf, the component with greater potential concerns

.

4 Twelve percent oxygen in air is the NOAEL for hypoxia (ICF 1997).Final

— July 2, 2015 9 Table 8. End

- Use Exposure Assessment for HFO

- 1234yf Component a

Scenario Charge Size (g) Room Size (m 3 ) Vertical Concentration Gradient Duration of Release

(min) 15

- min TWA End

- Use Exposure

(ppm) b 15

- min Short Term Exposure

Limits (ppm) Acute Toxicity Exposure

Limit (ATEL) ( ppm ) Reasonable Worst

- Case Scenario 1a 100 18 (640 ft 3 ) Yes 1 2,880

1,500 101,000 b Reasonable Worst

- Case Scenario 1b No 1 480 Reasonable Worst

- Case Scenario 1c Yes 15 1,680 Reasonable Worst

- Case Scenario 2a 1,000 18 (640 ft 3 ) Yes 1 28,800 Reasonable Worst

- Case Scenario 2b No 1 4,800 Reasonable Worst

- Case Scenario 2c Yes 15 16,800 Threshold Analysis 1: Charge Size 52 18 (640 ft 3 ) Yes 1 1,500 Threshold Analysis 2a: Room Size 100 35 (1,130 ft 3 ) Threshold Analysis 2b: Room Size 1,000 350 (11,300 ft 3 ) Bold font indicates modeling results.

a Cells highlighted in green are the scenarios with acceptable exposure levels given various modeling assumption options.
b ATEL for HFO

- 1234yf is 101,000 ppm; s ee Table 5 for more information.

Under the reasonable worst

- case scenario described in Section 5 for household refrigerators and freezers and water coolers
, catastrophic releases of the typical and maximum charge size of R

- 513A in a household refrigerator were modeled. The modeling scenarios evaluate the presence and absence of a vertical concentration gradient as well as two refrigerant release time durations (i.e., 1 minute and 15 minutes). The anticipated 15

- minute TWA exposures of the HFO

- 1234yf component of R

- 513A do exceed its STEL (i.e., 1,500 ppm) for all scenarios except Reasonable Worst

- Case Scenario 1b, which does not assume the presence of a vertical concentr ation gradient. Although most of the exposure estimates for the reasonable worst

- case scenarios exceed the STEL of HFO

- 1234yf (i.e., 1,500 ppm) (see Table 8), the STEL is a conservatively

- derived exposure limit that is intended to protect workers in an oc cupational setting in which they are exposed to these chemicals on a daily basis (see Table 5)

. The STEL values do not represent limits for a single exposure in a lifetime

. T hese modeled exposures are one

- time exposures
, so exceedances of the STEL values d o not necessarily indicate a significant risk of harm to consumers. The effect of a one

- time exposure can be more accurately evaluated by comparing the modeled exposure concentration s to the ATEL for HFO

- 1234yf
, which is a limit intended to reduce the risk s of acute toxicity hazards in normally occupied, enclosed spaces according to ASHRAE Standard 34 (see Table 5 )

. All of these exposure estimates are significantly lower than the ATEL of 101,000 ppm for HFO

- 1234yf

. Furthermore, the estimated exposures for R

- 513A in each of these scenarios are also significantly lower than the RCL for R

- 513A (i.e., 72,000 ppm). In addition, t hese exposure estimates were derived using fairly conservative assumptions (e.g., minimum room volume
, low ventilation rate) that do not necessarily reflect the actual room attributes where R

- 513A household refrigerators and freezers and water coolers will be installed

. Specifically, Reasonable Worst

Case Scenarios 1a through 1c model a 100

- gram refrigerato r, which represents an average refrigerator size (i.e., 20

– 25 ft 3 capacity), in a fairly small kitchen size that would likely contain a smaller refrigerator (e.g., 10 ft 3 capacity). In addition, a 1,000

- gram refrigerator represents a high

- end, commercial

- sized refrigerator, that is generally installed in large homes (i.e., greater than 5,000 ft 2 or 465 m 2 ) and are therefore unlikely to be installed in a kitchen with an effective volume of 18 m 3 (640 ft 3 ). Furthermore, kitchen spaces are often connected to other rooms through open pathways without doors (e.g., an eat

- in space or a dining area in an open floor plan home), which would increase the effective volume of the space into which a refrigerant would be released, thereby reducing the likelihood that en d

- users would be exposed to modeled concentrations.Final

— July 2, 2015 10 Finally, the exposures assuming a vertical concentration gradient represent concentrations of leaked refrigerant in the bottom 0.4 meter s (1.3 feet) of the room , accounting for 95 percent of the refriger ant charge in this lower portion of the room. The probability that an individual would be present in this lower portion (e.g., prone or supine on the floor or crawling infant) in the event of the catastrophic release of refrigerant is low. Furthermore, a lt hough 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 the room, the probability that they are present in the location in which a catastrophic release of the entire charge of the household refrigeration system is low

. To prevent exposure and potential serious side effects during larger releases, EPA recommends that the proposed RCL for R

- 513A (i.e., 72,000 ppm or 320 g/m 3 ) is not ex ceeded in any location where an R

513A system is installed, unless proper leak protection devices are in place in order to prevent exposures of R

- 513A beyond the recommended limits. Proper leak protection devices , engineering control requirements, and adhe rence 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 work ers during manufacture, installation and servicing, and dispo sal of R

- 513A household refrigerators and freezers and water coolers. To ensure that use of the proposed substitute in household refrigeration units does not pose an unacceptable risk to workers during servicing and disposal, occupational exposure modeling was perfor med using a box

- model approach. For a detailed description of t he methodology used for this screening assessment, the reader is referred to the occupational exposure and hazard analysis described in Chapter 5 of the Background Document.
Estimat es of refrigerant release per event for various release scenarios were obtained from EPA’s Vintaging Model. 5 To determine the estimated level of occupational exposure for a constituent in a blend, the total anticipated release rate of the refrigerant is multiplied by the weight percent compositio n of each compound in the blend

. For charging, servicing, and disposal activities, t he release rate per event was multiplied by the number of events estimated to occur over a workday. During charging and servicing , the release per event was conservatively assumed be 0.4 percent of the equipment charge

. For equipment charging and servicing, the number of events per workday was conservatively assumed that eight events of servicing a unit by one servicing technician o ccur in an 8

- hour work day (see Section 10.2 ). For disposal , the release per event was conservatively assumed to be 100 percent of the equipment charge (representing a catastrophic release). It was assumed that 10 units are disposed of during an 8

- hour wo rk day; however, it was assumed that of the 10 units, only the last unit per workday would experience the catastrophic release (i.e., 100 percent). The remaining 9 units were assumed 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 worker was exposed to the entire charge of a system during disposal activities, they would immediately stop working, clear the area until all refrigerant has been removed from the s pace (e.g., through ventilation), and adhere to the exposure procedures recommended in the SDS for the proposed substitute (see Section 10.3). The modeled exposure concentrations were compared to short

- term oc cupational exposure limits at charging and servicing and long

- term exposure limits at disposal.

5 ICF International maintains the Vintaging Model for EPA in order to simulate the aggregate impacts of the ODS phaseout on the use and emissions of various ODS and their substitutes over a period of several years across 60 different end

- uses. The model tracks the use and emissions of various compounds for the annual vintages of new equipment that enter service in each end

- use. The vintage of each type of equipment determines such factors as leak rate, charge size, number of units in operation, and the initial ODS substance that the equipment contained.Final

— July 2, 2015 11 10.1 Occupational Exposure at Manufacture
During manufacture of the components and blending of R

- 513A , the SDS for both HFC

- 134a and HFO

1234yf should be referenced and proper engineering controls and PPE used. Refrigerant quality control testing may also result in release of de minimus quantities of refrigerant, which would typically be to exhaust ducts or fume hoods. To prevent significant ex posure if such leaks occur, e ngineering controls should be used, includ ing normal and local ventilation (e.g., chemical hoods) and vapor

- in

- air detection systems for standard manufacturing procedures so workers can avoid physical contact with the refrigera nt and to achieve emission control. In general, use of PPE consistent with OSHA guidelines is recommended, such as respiratory protection (including a self

- contained breathing apparatus [SCBA] in case of insufficient ventilation), tightly sealed goggles, a nd 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

- 134a or HFO

- 1234 yf are exposed to high temperatures or fire. Other reaction products such as carbon dioxide might also be present. Containers should be stored in cool, dry conditions (maximum storage temperature should be 40 ° C) in well

- sealed receptacles and should not be allowed to contact open flames, glowi ng metal surfaces, or electrical heating elements. EPA believes that when proper handling and disposal guidelines are followed
, in accordance with both good industrial hygiene and manufacturing practices and the SDS for R

- 513A and its components, there is no significant risk to workers during the manufacture of R

- 513A

. 10.2 Occupational Exposure at Charging and Servicing Household refrigerators and freezers and water coolers would typically be charged by the Original Equipment Manufacturer (OEM). During OEM system manufacture ( i.e., charging at OEM location), points of release for charging and servicing these l eak

- tight systems would be from connection/disconnection of temporary lines for charging and recovery equipment. Charging occurs within an enclos ed area equipped with automatic ventilation, refrigerant detectors, and alarm systems. Release points during charging would be connection/disconnection of temporary lines from charging equipment. Charging and servicing activities for household refrigerato rs and freezers and water coolers are not expected to result in significant worker exposure when certified technicians follow the procedures outlined in the R

- 513A SDS and maintenance manual, undergo proper training, and wear appropriate PPE (e.g., gloves and safety glasses). Nevertheless, the potential occupational exposure during servicing was analyzed. The maximum 15

- minute TWA exposures for each R

- 513A constituent were estimated for the charging and servicing exposure scenario s and compared to their res pective STELs (see Table 9). T he modeling results indicate that the maximum anticipated occupational exposure concentrations at no point exceed the short

- term exposure limit for either component

. Table 9. Occupational Risk Assessment at Servicing a Component 15

- minute TWA Occupational Exposure (ppm) Short Term Exposure Limits (ppm) Charge Size: 100 grams Charge Size: 1,000 grams HFC

- 134a 0.20 2.0 8,000 b HFO

- 1234yf 0.23 2.3 1,500 c Bold font indicates modeling results.

a Cells highlighted in green are the scenarios that are deemed to be acceptable given various modeling assumption options.
b 10

- minute a nd 30

- minute AEGL

- 1; see Table 5 for more information.

c EPA

- derived 15

- minute STEL; see Table 5 for more information.
T he estimated exposures were derived using conservative assumptions, and represent a reasonable worst

case scenario with a low probability of occurrence. These types of systems are typically serviced byFinal

— July 2, 2015 12 trained personnel using proper industrial hygiene tech niques and proper engineering controls (e.g., local ventilation, refrigerant detectors, and alarm systems). Thus, EPA does not believe that installation or servicing of household refrigerators and freezers and water coolers containing R

- 513A presents a sig nificant concern to workers.

10.3 Occupational Exposure at Disposal Disposal of R

- 513A household refrigerators and freezers and water coolers is expected to occur with limited frequency (up to approximately ten disposal events per day) at disposal facilities and with limited duration of exposure to the installed refrigerant. Typically, potential exposures to the refrigerant during recovery and disposal are expected to occur during activities related to decommissioning refrigeration systems (e.g., attaching of hoses associated with draining or otherwise discharging of refrigerant from the refrigeration units into cylinders) and would be similar t o those during servicing, because 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).
Table 10 displays the maximum estim ated 8

- hour TWA occupational exposure levels for each component of R

- 513A during disposal. To model a worst

- case scenario, 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 catastrophic release of refrigerant (i.e., 100 pe rcent of the equipment charge). Because modeled exposure levels for both the typical and maximum charge sizes are significantly lower than the 8

- hour exposure limits for each component, occupational exposure to the proposed substitute during disposal is no t considered a toxicity risk. Further, estimated exposures were derived using conservative assumptions (e.g., no ventilation or use of PPE assumed) and represent a worst

case scenario with a low probability of occurrence. These types of systems are typical ly disposed of by trained personnel using proper industrial hygiene techniques.
Table 10 . Occupational Risk Assessment at Disposal a Component 8

- hour TWA Occupational Exposure (ppm) 8

- Hour Long Term Exposure Limits (ppm) Charge Size: 100 grams Charge Size: 1,000 grams HFC

- 134a 7.3 73 1,000 b HFO

- 1234yf 8.3 83 800 b Bold font indicates modeling results.

a Cells highlighted in green are the scenarios with exposure levels deemed to be acceptable given various modeling assumption o ptions.
b 8

- hour WEEL Although anticipated occupational exposures are well below the exposure limits for both R

- 513A components for both typical and maximum charge sizes , the recommendations for proper engineering controls and PPE in the SDS for R

- 513A should be followed. Adequ ate ventilation should always be established during any use, handling, or storage of propane . Engineering controls should include vapor

- in air detection systems and local exhaust ventilation during use of R

- 513A to prevent dispersion throughout the workpla ce. In addition, an eye wash and safety shower should be near the manufacturing facility and locations where R

- 513A is stored and ready for use. In general, use of PPE is recommended, such as splash goggles, mechanically

- resistance gloves when handling cyl inders
, and chemically

- resistant gloves when handling the gas mixture (e.g., butyl rubber, chlorinated polyethylene, or neoprene). EPA believes that if proper handling and disposal guidelines are followed in accordance with good industrial hygiene and manu facturing practices and the SDS for R

- 513A , there is no significant risk to workers during the manufacturing, installation, servicing, and disposal of R

- 513A in household refrigerators and freezers and water coolers

. 

### 11. GENERAL POPULATION EXPOSURE ASSESSM ENTFinal

— July 2, 2015 13 R

- 513A 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 household refrigerators and freezers and water coolers

. The proposed substitute will be manufactured in a closed process and is proposed for use in closed syst ems ; thus, significant releases are not anticipated. At room temperature, R

- 513A is a gas and, therefore, releases to ground or surface water are not anticipated, as R

- 513A is anticipated to dissipate into the atmosphere upon release to outside air (i.e., because natural ventilation rates would be higher and there is no enclosed space to maintain a high concentration of R

- 513A ). Should air releases during manufacturing operat ions occur, engineering controls should be used (e.g.
, carbon absorption scrubbers) to collect R

- 513A and prevent the release of R

- 513A to the atmosphere. EPA believes that by using proper engineering controls and by following disposal and containment reco mmendations outlined in the proposed substitute’s SDS and this risk screen , exposure to R

- 513A is not expected to pose a significant toxicity risk to the general population.Final

— July 2, 2015 14 

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