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Significant New Alternatives Policy Program 

Refrigeration and Air Conditioning Sector 

Risk Screen on Substitutes in Heat Transfer 

Substitute: trans-1-Chloro-3,3,3-trifluoroprop-1-ene 

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 Significant 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-uses within all of the major ODS-using 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 potential use of trans-1-chloro-3,3,3-trifluoropro-1-ene (hereinafter referred to as SolsticeTM 

1233zd(E)) as a substitute in the heat transfer end-use. As indicated by the submitter, SolsticeTM 1233zd(E) 

is intended for use in organic rankine cycle (ORC) and sensible (i.e., non-mechanical) heat transfer end-uses. 

SolsticeTM 1233zd(E) has previously been listed by EPA’s SNAP as acceptable for use in centrifugal chillers. 

Table 1 presents information on the proposed substitute. 

Table 1. Composition of SolsticeTM 1233zd(E) 

Constituent Chemical Formula CAS Number Percent of Total 

(by weight) 

trans-1-Chloro-3,3,3-trifluoroprop-1-ene C3H2ClF3 102687-65-0 >99% 

Potential Impurities (maximum concentration) 
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The potential risks associated with use of substitutes in heat transfer have been examined at length in the 

Background Document. The reader is referred to this reference for a detailed discussion of the methodologies 

used to conduct this risk screen. This risk screen addresses flammability risk and assesses the impact of 

potential releases of SolsticeTM 1233zd(E) on the atmosphere and climate. Additionally, occupational 

exposure modeling was performed to ensure that manufacture and application of the proposed substitute in 

the proposed heat transfer end-uses do not pose unacceptable risk to workers. Lastly, general population 

exposure was assessed to ensure that the proposed substitute would not pose an unacceptable risk to the 

population at large. 

Section 2 of this report summarizes the results of the risk screen for the proposed substitute. The remainder 

of the report is organized into the following sections: 

 Section 3: Atmospheric Assessment 

 Section 4: Volatile Organic Compound Assessment 

 Section 5: Discussion of End-Use Scenarios 

 Section 6: Potential Health Effects 

 Section 7: Flammability Assessment 

 Section 8: Occupational Exposure Assessment 

 Section 9: General Population Assessment 

 Section 10: References 

2. SUMMARY OF RESULTS 

SolsticeTM 1233zd(E) is recommended for SNAP approval as a heat transfer fluid for ORC and nonmechanical heat transfer 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 CFC-113, HCFC-123, and other commonly used 

refrigerant, as it is less harmful to the ozone layer, has lower climate impact, and a shorter atmospheric 

lifetime. In addition, SolsticeTM 1233zd(E) contributions to volatile organic compound (VOC) emissions are 

not a concern as SolsticeTM 1233zd(E) is exempt under CAA regulations (40 CFR § 51.100(s)). Given that 

appropriate personal protective equipment (PPE) and engineering controls (e.g., exhaust ventilation, vaporin-air detection systems) will be used during installation, maintenance, and disposal activities, no significant 

toxicity risks to workers or the general population are expected. In addition, based on the characteristics of 
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the proposed substitute and the proper precautions listed in the MSDS for SolsticeTM 1233zd(E), the 

proposed substitute is not expected to present a significant flammability concern during manufacture or enduse (see Section 7). 

3. ATMOSPHERIC ASSESSMENT 

This section presents an assessment of the potential risks to atmospheric integrity posed by the use of 

SolsticeTM 1233zd(E) as a heat transfer fluid. The ozone depletion potential (ODP), global warming potential 

(GWP), and atmospheric lifetime (ALT) of the proposed substitute are presented in Table 2. 

The proposed substitute is substantially less harmful to the ozone layer, has lower climate impact, and a 

shorter atmospheric lifetime when compared to refrigerants currently used in heat transfer, such as CFC-113, 

HCFC-22, HCFC 141b, and HCFC-123. In addition, SolsticeTM 1233zd(E) also has lower climate impact and 

a shorter atmospheric lifetime than those predicted for other substitutes examined in the Background 

Document, as well as commonly utilized substitutes HFC-245fa, HFC-236fa, and HFC-134a. SolsticeTM 

1233zd(E) has a non-zero ODP, but at 0.00024, this value is very small when considering continued use of 

CFC-113, HCFC-22, HCFC-141b, and HCFC-123. A recent report by Wang et al. (2011) modeled the 

potential of SolsticeTM 1233zd(E) to affect the amount of ozone in the global atmosphere (tropospheric and 

stratospheric). This report found that the release of all SolsticeTM 1233zd(E), assuming it were substituted for 

all compounds it might replace and that the entire amount used would be released, there would be a 

statistical impact of zero on global atmospheric ozone (less than 0.01% change in total column ozone). Thus, 

EPA believes that use of SolsticeTM 1233zd(E) would result in substantially less harm to the climate and 

ozone layer than the continued use of ODS and other commonly used refrigerants. 

Table 2. Atmospheric Impacts of SolsticeTM 1233zd(E) Compared to Other Heat Transfer Refrigerants 

Chemical ODPc GWP (100-year)d ALTd

SolsticeTM 1233zd(E) 0.00024a 4.6b 30.5 daysb

CFC-113 0.85c 6,130 85 years 

HCFC-123 0.01c 77 1.3 years 

HCFC-22 0.05c 1,810 12 years 

HCFC-141b 0.12c 725 9.3 years 

HFC-245fa 0 1,030 7.6 years 

HFC-236fa 0 9,810 240 years 

HFC-134a 0 1,430 14 years a Assuming SolsticeTM 1233zd(E) emissions occur with the same geographic distribution as the blowing agents it might replace (Wang et al. 2011). b Wuebbles et al. (2013) 

c

 WMO (2011) 

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

4. VOLATILE ORGANIC COMPOUND ASSESSMENT 

SolsticeTM 1233zd(E) is exempt from the definition of volatile organic compound (VOC) under CAA 

regulations (40 CFR 51.100(s)). Therefore, environmental impacts from the release of SolsticeTM 1233zd(E) 

as a VOC are not a concern. 

5. DISCUSSION OF END-USE SCENARIOS 

SolsticeTM 1233zd(E) has been proposed for the non-mechanical heat transfer end-use, including ORC and 

sensible (non-mechanical) heat transfer applications. As indicated by the submitter, the applications for ORC 

include geothermal and waste heat recovery systems generating from less than 1 megawatt (MW) to 

approximately 5 MW of power. Such systems can be installed in both small power plants and supplemental 
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systems in larger steel, cement, or refining industrial plants. In addition, end-users may also develop custom 

systems in which several smaller systems are coupled together to generate a higher output (i.e., serially 

connect eight-125 kW systems to generate a 1 MW output system). Although geothermal applications utilize 

the largest charge size of this proposed substitute (i.e., up to 75 metric tons [MT]), these applications are 

typically located outdoors in a remote area. (Anonymous Submitter 2013b) 

Non-mechanical heat transfer applications include solar water heating, immersion cooling/heating, 

recirculating coolers, and thermosiphons. These applications, which are typically located indoors and used 

commercially, operate using a smaller charge size than ORC applications (i.e., less than 10 kg). Despite the 

differences in size and application between ORC and non-mechanical heat transfer systems, these 

applications are anticipated to have similar release patterns. Specifically, charging and recovery of the 

proposed substitute from both system types occur using a refrigerant recovery unit or vacuum pump 

following similar procedures. Furthermore, the submitter estimates that the annual leak rate from ORC 

systems using HFC-245fa can reach up to approximately 2 percent; however such leak rates are expected to 

be much smaller for systems using SolsticeTM 1233zd(E) because of its lower operating pressure and also for 

larger ORC systems, which are expected to have annual leak rates similar to chillers (i.e., 0.5 percent) 

(Anonymous Submitter 2011). Because non-mechanical heat transfer systems typically operate at relatively 

lower pressures (e.g., vacuum, atmospheric) than ORC, annual leak rates from these systems are expected to 

be even smaller. Therefore, any potential exposure to the proposed substitute is expected to occur in the 

same manner and at low amounts for both types of heat transfer applications. 

6. POTENTIAL HEALTH EFFECTS 

To assess potential health risks from exposure to this proposed substitute, the submitter provided a 

workplace environmental exposure limit (WEEL) of 800 ppm for SolsticeTM 1233zd(E) (OARS 2013). The 

WEEL represents the maximum 8-hour time weighted average (TWA) at which a worker can be exposed 

regularly without adverse effects. 

According to the MSDS, exposure to SolsticeTM 1233zd(E) through ocular or dermal absorption, inhalation, 

or ingestion may be harmful. Ocular exposures to SolsticeTM 1233zd(E) will cause serious eye irritation and 

may cause frostbite through dermal exposure. In case of ocular exposure, the MSDS for SolsticeTM 

1233zd(E) recommends that person(s) should immediately flush the eyes, including under the eyelids, with 

water for 15 minutes; should frostbite occur, affected areas should be rinsed with lukewarm water. Medical 

attention should be sought if irritation develops or persists. 

In the case of dermal exposure to SolsticeTM 1233zd(E), the MSDS for SolsticeTM 1233zd(E) recommends 

that person(s) should immediately wash the affected area with water and remove all contaminated clothing to 

avoid irritation; should frostbite occur, bathe (do not rub) the affected area with lukewarm, not hot, water. If 

water is not available, cover the affected area with a clean, soft cloth. Medical attention should be sought if 

irritation develops or persists. SolsticeTM 1233zd(E) vapors are heavier than air and cause suffocation by 

reducing oxygen available for breathing, causing asphyxiation in high concentrations. If person(s) are 

exposed to high concentrations, the person(s) will likely not realize that he/she is suffocating, but may 

experience central nervous system effects, such as drowsiness and dizziness. If SolsticeTM 1233zd(E) is 

inhaled, person(s) should be immediately removed and exposed to fresh air. The MSDS recommends that if 

breathing is difficult, person(s) should be given oxygen, provided a qualified operator is present, and medical 

attention be sought. 

SolsticeTM 1233zd(E) is not likely to be hazardous by ingestion; however, in case of ingestion, the MSDS 

recommends the person(s) drink a cup of water, if fully conscious, and consult a physician immediately. Do 
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not induce vomiting without medical advice. EPA’s review of the human health impacts of this proposed 

substitute is contained in the public docket for this decision. 

The potential health effects of SolsticeTM 1233zd(E) are unlikely to occur when following good industrial 

hygiene practices and the PPE and engineering control (e.g., ventilation) recommendations outlined in the 

MSDS for SolsticeTM 1233zd(E) and Sections 7 and 8 of this risk screen. 

7. FLAMMABILITY ASSESSMENT 

SolsticeTM 1233zd(E) is not considered to be flammable at ambient temperatures and atmospheric pressure, 

but can ignite when mixed with air under pressure and exposed to strong ignition sources; also, containers of 

SolsticeTM 1233zd(E) may rupture when exposed to heat or temperatures above the proposed substitute’s 

auto-ignition temperature of 380°C (Anonymous Submitter 2011). By keeping SolsticeTM 1233zd(E) away 

from all sources of ignition and high heat and adhering to the other precautions listed in the proposed 

substitute’s MSDS, SolsticeTM 1233zd(E) does not pose a significant flammability risk. 

8. OCCUPATIONAL EXPOSURE ASSESSMENT 

This section assesses potential exposures to workers during manufacture, installation, servicing and disposal 

of SolsticeTM 1233zd(E) in heat transfer systems, including ORC and non-mechanical heat transfer 

applications. As indicated by the submitter, the manufacture of the proposed substitute for use in heat 

transfer is similar to manufacture at refrigerant facilities and is conducted in a closed system (Anonymous 

Submitter 2012); as a result, exposure during manufacturing operations is not anticipated. However, 

exposure to the proposed substitute can occur during charging and de-commissioning activities during 

installation, servicing, and disposal. 

The potential occupational exposure to SolsticeTM 1233zd(E) during installation, servicing, and disposal of 

heat transfer systems was analyzed. Potential exposures to the proposed substitute are anticipated to occur 

during charging and de-commissioning activities of the heat transfer system. The submitter provided 

exposure monitoring data for the heat transfer end-use, specifically ORC. Monitoring was conducted in two 

scenarios, i.e., charging and de-commissioning of the heat transfer system, to determine the concentration of 

SolsticeTM 1233zd(E) during installation, service, and disposal operations. The total quantity of refrigerant 

used in this monitoring data was 9.1 – 11.3 kg (20 – 25 lbs.).1 The first scenario, which modeled the 

charging of the proposed substitute into a previously evacuated system, demonstrated a peak concentration 

of 86 ppm. The second scenario, which modeled the de-commissioning of the system, demonstrated a peak 

concentration of 114 ppm. (Anonymous Submitter 2013a) These maximum measured vapor-in-air values, as 

shown in Table 3, are well below the proposed substitute’s WEEL of 800 ppm. 

Table 3. Exposure Monitoring Data for the Heat Transfer Application of SolsticeTM 1233zd(E)a 

Scenario Peak Concentration (ppm) Average Concentration (ppm)b WEEL (ppm) 

Charging 86 1.4 800 De-commissioning 114 0.61 

a The concentrations were measured by a room sniffer that was located nearby where a technician would be servicing the equipment. b Concentrations were recorded in one second intervals for a 24-hour period. 

To further minimize potential exposures when systems are located indoors, engineering controls should be in 

place during installation and servicing of SolsticeTM 1233zd(E) heat transfer systems, such as vapor-in-air 

detection systems. Adequate ventilation should always be established during any use, handling, or storage of 

 

 Anonymous Submitter 
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SolsticeTM 1233zd(E). In addition, an eye wash and safety shower should be near the manufacturing facility 

and ready for use. In general, use of PPE is recommended, such as respiratory protection (a NIOSHapproved positive-pressure supplied-air respirator is recommended where there is insufficient ventilation; 

self-contained breathing apparatus should be used for rescue and maintenance work in storage tanks), 

chemical splash goggles or face shield, impervious gloves, and chemical-resistant boots and clothing 

(Anonymous Submitter 2011, OSHA 1994). Contaminated clothing is not to leave the workplace and must 

be cleaned before reuse (Anonymous Submitter 2011). 

During handling of liquid SolsticeTM 1233zd(E), there is also a risk of generation of toxic decomposition 

products such as hydrochloric acid, hydrofluoric acid, and carbonyl halides if liquid SolsticeTM 1233zd(E) is 

exposed to fires or temperatures greater than 250°C. Containers of SolsticeTM 1233zd(E) should not be 

allowed to contact open flames, glowing metal surfaces, or electrical heating elements. 

EPA believes that if proper handling guidelines are followed in accordance with good industrial hygiene and 

manufacturing practices and the MSDS for SolsticeTM 1233zd(E), as described above, manufacture, 

installation, and disposal of SolsticeTM 1233zd(E) when used as a heat transfer fluid does not present a 

significant risk to workers. In addition, all technicians should possess EPA section 608 technician 

certification and be properly trained in working with heat transfer systems and related refrigerant recovery 

equipment. 

9. GENERAL POPULATION EXPOSURE ASSESSMENT 

SolsticeTM 1233zd(E) is not expected to cause a significant impact on human health in the general population 

when manufactured or used as a heat transfer fluid. The proposed substitute will be manufactured in a closed 

process and any transfer of fluids during installation, servicing, or disposal is also conducted in a closed 

process. Should air releases during manufacturing operations occur, engineering controls should be used 

(e.g., carbon absorption scrubbers) to collect and prevent the release of the proposed substitute to the 

atmosphere. In addition, all service technicians should be properly trained in working with SolsticeTM 

1233zd(E) in heat transfer systems and related recovery equipment and possess EPA section 608 technician 

certification. In heat transfer applications, SolsticeTM 1233zd(E) is proposed for use in closed systems that 

are operated near atmospheric pressure (and would therefore release slowly into the outside air) and at room 

temperature, SolsticeTM 1233zd(E) is a gas. Therefore, releases to ground or surface water are not 

anticipated, as SolsticeTM 1233zd(E) 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 keep SolsticeTM 

1233zd(E) concentrated). 

Due to the low toxicity of SolsticeTM 1233zd(E) and minimal expected release, EPA believes that such 

exposures do not pose a significant toxicity risk, and thus, SolsticeTM 1233zd(E) is not expected to cause a 

significant impact on human health in the general population when used as a heat transfer fluid in ORC and 

non-mechanical heat transfer.
 

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10. REFERENCES 

Anonymous Submitter 2011. SNAP Submission to EPA for SolsticeTM 1233zd(E). May 13, 2011. 

Anonymous Submitter 2012. Conference Call with Submitter on June 6, 2012 on SolsticeTM 1233zd(E) in 

the Heat Transfer End-Use. June 6, 2012. 

Anonymous Submitter 2013a. Exposure Monitoring Data for the Heat Transfer (ORC) Application of 

SolsticeTM1233zd(E). June 27, 2013. 

Anonymous Submitter 2013b. Response to 1233zd – Refrigeration Sector Letter sent on July 31, 2013. 

September 17, 2013. 

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. Schulz 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 Fourth Assessment Report of the Intergovernmental Panel 

on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and 

H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. 

ICF International. 2012. Determination of an Acceptable Exposure Limit (AEL) for SolsticeTM 

1233zd(E). Prepared for U.S. Environmental Protection Agency. January 23, 2012. 

Occupational Alliance for Risk Science (OARS). 2013. Workplace Environmental Exposure Level 

(WEEL): trans-1-Chloro-3,3,3-Trifluoropropene (1233zd(E)). Conducted for Honeywell International, 

2013. 

OSHA. 1994. General description and discussion of the levels of protection and protective gear. 1910.120 

App B. Last updated August 22, 1994. Available at: 

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9767

U.S. EPA. 1994. Significant New Alternatives Policy Technical Background Document: Risk Screen on 

the Use of Substitutes for Class I Ozone-depleting Substances: Refrigeration and Air Conditioning. U.S. 

Environmental Protection Agency, March 1994. 

Wang D., Olsen S., Wuebbles D. 2011. “Preliminary Report: Analyses of tCFP’s Potential Impact on 

Atmospheric Ozone.” Department of Atmospheric Sciences. University of Illinois, Urbana, IL. September 

26, 2011. 

WMO (World Meteorological Organization). 2011. Scientific Assessment of Ozone Depletion: 2010, 

Global Ozone Research and Monitoring Project—Report No. 52, 516 pp., Geneva, Switzerland, 2011. 

Wuebbles, D.J., Wang, D., Patten, K.O., et al. 2013. Analyses of new short-lived replacements for HFCs 

with large GWPs. Geophysical Research Letters. Vol. 40, Issue 17. pp. 4767-4771. September 16, 2013.