Document ID: EPA-HQ-OAR-2003-0118-0311
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2012-08-10T04:00Z

Significant New Alternatives Policy Program
Refrigeration and Air Conditioning Sector
Risk Screen on Substitutes for CFC-113 in Non-Mechanical Heat Transfer 

               Substitute: C7 Fluoroketone (C7 FK or FK-6-1-14)
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 decade, 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 largely 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 C7 Fluoroketone (also referred to as FK-6-1-14 or C7 FK) as a substitute for CFC-113 to be used as a non-mechanical heat transfer fluid. As indicated by the submitter, C7 FK is intended for use in organic Rankine cycles (ORC) and in direct immersion cooling. Table 1 presents information on the proposed substitute.
                         Table 1. Composition of C7 FK
                                  Constituent
                               Chemical Formula
                                  CAS Number
                               Percent of Total
                                (by weight)[a]
        3-Pentanone,1,1,1,2,4,5,5,5-octafluoro-2,4-bis(trifluoromethyl)
                                    C7F14O
                                   813-44-5
                                    55-65%
       3-Hexanone,1,1,1,2,4,4,5,5,6,6,6-undecafluoro-2-(trifluoromethyl)
                                    C7F14O
                                   813-45-6
                                    35-45%
  .	

The potential risks associated with use of substitutes in non-mechanical 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 occupational exposure modeling was performed to ensure that use of the proposed substitute did not pose unacceptable risk to workers during equipment manufacture. Modeling was performed at the end-use to ensure that potential releases of the substitute did not pose unacceptable risk to those responsible for filling and maintenance of the heat transfer units where the substitute is intended for use. General population exposure is not expected to occur.   

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: Flammability Assessment
         * Section 5: Potential Health Effects
         * Section 6: Occupational Exposure Assessment
         * Section 7: End-Use Exposure Assessment
         * Section 8: General Population Exposure Assessment
         * Section 9: Volatile Organic Compound Assessment
         * Section 10: References
2. 	SUMMARY OF RESULTS
Use of C7 FK as a non-mechanical heat transfer fluid is not expected to pose a significant risk to atmospheric integrity or to the health of the general population, and is therefore recommended for SNAP approval for the proposed end-use. Given that proper training will be given to personnel and that appropriate personal protective equipment (PPE) (Occupational Safety & Health Administration [OSHA] Category D or higher) and proper procedures according to the MSDS (including provisions of adequate ventilation) will be used during manufacturing, end-use, and disposal, no risk to workers, end-users, or the general population is anticipated. In addition, this risk screen indicates that the use of the proposed substitute will be less harmful to the atmosphere than the continued use of CFC-113, perfluorohexanes, and HFC-245fa. 

3. 	ATMOSPHERIC ASSESSMENT
This section presents an assessment of the potential risks to atmospheric integrity posed by the use of C7 FK as a non-mechanical heat transfer fluid.  The ODP, GWP, and ALT of the proposed substitute are presented in Table 2.  The substitute is substantially less harmful to the ozone layer and has less climate impact than CFC-113. In addition, its low GWP relative to other non-ODS heat transfer fluids will provide environmental benefit compared to other available options.  

Table 2.  Atmospheric Impacts of C7 FK Compared to CFC-113 and Other Intended Non-ODS Replacements
                              Heat Transfer Fluid
                                      ODP
                                      GWP
                                  ALT (years)
                                     C7 FK
                                     0[a]
                                     1[a]
                                   7 days[a]
                                    CFC-113
                                    0.8[b]
                                   6,130[c]
                                     85[c]
                                   C6F14[e]
                                       0
                                   9,140[d]
                                   3,200[d]
                                   HFC-245fa
                                       0
                                   1,020[d]
                                    7.6[d]
                                    Pentane
                                       0
                                     11[a]
                                   8 days[f]
   a  3M Submission 2011  
   [b] Available at: http://www.epa.gov/ozone/ods.html.
   [c] IPCC 4th Assessment Report (Forster et al. 2007).
   [d] Available at: http://www.epa.gov/ozone/geninfo/gwps.html 
   [e] Perfluorohexanes are acceptable in heat transfer applications where no other substitutes are feasible
   [f] Available at: http://www1.chem.leeds.ac.uk//Atmospheric/Field/campaigns/ARCICE/arcicepaper.pdf 
   
4. 	FLAMMABILITY ASSESSMENT
C7 FK is not flammable, and therefore, a flammability assessment was not performed (3M C7 FK SNAP Submission, 2001). 
5. 	POTENTIAL HEALTH EFFECTS
According to the MSDS, exposure to C7 FK above the exposure guideline may result in potentially harmful health effects. Inhalation of C7 FK could cause respiratory tract irritation and symptoms may include cough, sneezing, nasal discharge, headache, hoarseness, and nose and throat pain. If thermal decomposition of the compound occurs, inhalation of the decomposition products may also be harmful. If overexposure due to inhalation of C7 FK above the exposure guideline occurs, person(s) should be immediately removed and exposed to fresh air and medical attention should be sought if the abovementioned symptoms develop. Contact with the eyes and skin during product use is not expected to result in significant irritation. Ingestion of C7 FK is not expected to cause health effects, and there is no anticipated need for first aid if ingestion of C7 FK occurs (3M 2011b). EPA's review of the environmental and human health impacts of this proposed substitute is contained in the public docket for this decision. 

When good industrial hygiene practices and the PPE and engineering control (e.g., ventilation) recommendations outlined in the MSDS for C7 FK, as summarized in Sections 6 and 7 of this risk screen, are followed, these potential health effects are unlikely to occur. 
6. 	OCCUPATIONAL EXPOSURE ASSESSMENT
C7 FK is manufactured in a closed system. According to the submitter, workers may be exposed to C7 FK during the manufacture of the product during direct line filling of drums and containers for offsite delivery, as well as during filling of heat transfer units. The potential for personnel exposure during manufacture and installation and maintenance are examined in this section. ICF's estimated acceptable exposure limit (AEL) for C7 FK is 225 ppm (3368 mg/m[3]) averaged over an 8-hour time period (8-hour TWA).  The AEL was derived using an interspecies uncertainty factor of 3 and an uncertainty factor of 3 to compensate for uncertainty in the database -- i.e., use of a 28-day, rather than a 90-day subchronic or 2-year chronic study to develop the 8-hour AEL. The reader is referred to Appendix A for a detailed explanation of the development of the AEL.  The substitute's manufacturer also recommends an AEL of 225 ppm (8-hr TWA) for C7 FK.
6.1	Occupational Exposure during Manufacture
For small to moderate spills of C7 FK (< 100 kg), it is recommended that the area in which the spill occurs be cleared of personnel until ambient concentrations return to acceptable levels. The submitter modeled two scenarios to determine the appropriate reentry time in case of a spill. In both scenarios, the ventilation rate was fixed at 6 air changes per hour (ACH) and 4.5 kg of C7 FK was released to simulate a small leak (see Table 3) (3M 2011a).  

                        Table 3. C7 FK Spill Monitoring
                             Scenario Room Volume
                              Peak Concentration
                                 Reentry Time
                                   100 m[3]
                                   2,200 ppm
                                    28 min
                                   1000 m[3]
                                    225 ppm
                                   Immediate

It is recommended that each manufacturing facility has the appropriate staff and resources to design the appropriate working environment and adhere to reentry time guidance following a leak of the substance. The submitter concludes that factory production of the C7 FK using the same procedures for C6 FK would result in short term worker exposure of less than 1 ppm for C7 FK. In addition, personal protective equipment (PPE), as suggested in the MSDS, is recommended for workers dealing with C7 FK in industrial settings.
6.2	Occupational Exposure during Installation and Maintenance
To address the potential employee exposure to C7 FK of larger spills associated with installation and maintenance, the submitter provided surrogate air monitoring studies for a C6 fluorinated ketone (C6 FK or Novec(TM) 1230) analog. Air concentrations found during the air monitoring studies with a C6 FK (described below) would be a conservative estimate of air concentrations of C7 FK, due to the higher boiling point and vapor pressure of C7 FK (see Table 4) (3M Novec(TM) 1230 SNAP Submission, 2001). 

     Table 4. Boiling Point and Vapor Pressure for C7 FK and C6 FK Analog
Parameter
                           C7 FK Proposed Substitute
                                 C6 FK Analog
Boiling Point
                                     74 C
                                     49 C
Vapor Pressure
                              125 mmHg (at 20 C)
                              244 mmHg (at 20 C)

According to the submitter, monitoring was conducted in two scenarios to determine the concentration of C6 FK during installation and maintenance operations, which are reflective of the conditions for either draining the reactor or draining to drums post purification to prepare for offsite delivery of the proposed substitute. The first scenario modeled was tote filling, and monitoring was conducted without local exhaust which resulted in an area TWA concentration of 60 ppm. The peak instantaneous concentration for this scenario was 300 ppm, which is above the recommended AEL of 225 ppm over an 8 hour period; however, this scenario was modeled without the use of local exhaust. The second scenario, drum filling, was performed with local exhaust and resulted in personal TWA exposure of 1.3 ppm. Table 5 shows the additional results of the air monitoring.

                     Table 5. C6 FK Air Monitoring Results
Scenario
                              Peak Concentration
                            Area TWA Concentration
Tote Filling -- no local exhaust
                                    300 ppm
                                    60 ppm
Drum Filling-with local exhaust
                                   11.7 ppm
                                    1.3 ppm

The submitter concludes that factory production of the C7 FK using the same C6 FK procedures would result in short term worker exposure of less than 1 ppm for C7 FK, which is much lower than the AEL of 225 ppm for C7 FK. Therefore, toxicity risks due to use of C7 FK are expected to be minimal.  The submitter has recommended use of OSHA Category D or higher PPE such as safety glasses with side shields and neoprene, nitrile rubber, or polymer laminate gloves for workers dealing with C7 FK in industrial settings and that good ventilation, such as that provided by local exhaust fans, is in place. All spills should be cleaned up immediately in accordance with good industrial hygiene practices and the MSDS for C7 FK. In addition, all technicians should be properly trained in working with the transformers and related recovery equipment and possess EPA section 608 technician certification.
7.	END-USE EXPOSURE ASSESSMENT
The submitter also performed a study to simulate drum to drum transfer of C6 FK that would be reflective of conditions that may occur under customer use for filling or top-off of heat transfer equipment. In the most conservative scenario, in which no vapor return line was used and no room ventilation was running, the maximum concentration was 60 ppm, with an average concentration of 54 ppm. If the same study was performed with C7 FK, the leak concentrations would be even lower due to the nature of C7 FK's physical properties (see Table 4).  The substitute is proposed for use in hermetically sealed systems that are operated near atmospheric pressure. Any exposure scenario would occur infrequently and would result in very low emissions. 
8. 	GENERAL POPULATION EXPOSURE ASSESSMENT
C7 FK is not expected to cause a significant risk to human health in the general population when used as a non-mechanical heat transfer fluid. The substitute is proposed for use in closed systems that are operated near atmospheric pressure. General population exposures to ambient air and surface water releases are not expected from this end use. 
9. 	VOLATILE ORGANIC COMPOUND ASSESSMENT
C7 FK has not been exempted as a volatile organic compound (VOC) under the CAA (40 CFR 51.000). However, through standard industry practices, VOC emissions should be controlled.  The submitter intends to manufacture C7 FK for two heat transfer applications: organic rankine cycle (ORC) and direct immersion cooling systems. Using leak estimates from the Vintaging Model for ORC, which is expected to be used for geothermal heat recovery and plant-based heat recovery, the annual release rate -- including operating, servicing, and disposal leak rates -- for ORC applications was found to be approximately 1%. Direct immersion cooling is only used in highly specialized electronic applications with clean, controlled environments. This application is expected to have very low VOC emissions, and a 1% release rate is assumed. Assuming a 1% release rate for both applications, an assessment was performed to compare the annual VOC emissions from use of C7 FK in heat transfer applications in one year to other anthropogenic sources of VOC emissions. Assuming the portion for heat transfer applications of the submitter's maximum allowable annual production, only approximately 3.3x10[-3] percent of the VOC emissions caused by the generation of electricity in the United States, or only approximately 1.2x10[-5] percent of all anthropogenic VOC emissions in the U.S. would be released from the charged equipment. Moreover, even if the entire portion for heat transfer applications of the allowable quantity of C7 FK produced by the submitter in one year was all released to the atmosphere (extremely unlikely), the resulting annual VOC emissions would be approximately equal to 0.24 percent of annual VOC emissions caused by the generation of electricity in 2010, or approximately 8.2x10[-][4] percent of all annual anthropogenic VOC emissions.  As these emissions are several orders of magnitude less than other anthropogenic emissions, and because heat transfer equipment is hermetically sealed, the environmental impacts of these VOCs are not considered a significant risk. 

.  

10.	REFERENCES
3M 2001.  SNAP Submission to EPA for Novec 1230.  January 3, 2001.

3M 2010a. SNAP Addendum to EPA for C7 FK. February 22, 2010.

3M 2010b. P-10-135  -  C7 FK (Fluoroketone) teleconference EPA/3M Summary. November 22, 2010.

3M 2011a. Response to Incomplete SNAP submission for Fluoroketone. February 17, 2011.

3M 2011b. Material Safety Data Sheet  -  L-20154 Development Material. Issued August 11, 2011.

EIA 2010. Summary Statistics for the U.S. (Electric Power Industry), 1998 through 2009. Last updated, April 2011. Accessed October 3, 2011.

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.

EPA 2009.  Volatile Organic Compounds  -  National Summary of VOC Emissions.  Last updated 04 November 2009.  Accessed 16 May 2011. Available at <http://www.epa.gov/air/emissions/voc.htm>.

ICF 2011.  Determination of an Acceptable Exposure Limit for C7 Fluoroketone.  May 2011.  

                                  Appendix A
              Determination of an AEL for C7 Fluoroketone (C7 FK)
                                       
Recommended AEL: 		225 ppm (8-hour)				
	
Basis and Endpoints: 		NOAEL 3000 ppm for male rats 

Study: 	Sub acute (29-day) Inhalation Toxicity Study with MTDID 10800 in Rats

Protocol:	6 hours/day, 5 days/week for 4 weeks (whole body exposure)

Concentrations:			0; 3,000; 7,500; 15,000 ppm 

NOAEL:	3,000 ppm (males) (excluding peroxisomal proliferation) 

Uncertainty Factor:	10 (3 - interspecies extrapolation; 3  -  use of a sub-acute study)

AEL 	225 ppm (= 3,000 * 6 hours (exposure of rats)/8 hours (workday))* (1/10)

Derivation of a preliminary AEL for C7 FK relies on the reported NOAEL of 3,000 ppm for male Wistar rats from the 29-day inhalation study at exposure doses of 0, 3,000, 7,500, and 15,000 ppm (Muijser and Staal, 2008).  The only exposure-related effects of note in male rats were peroxisomal proliferation in liver cells at all exposure concentrations, and a significant increase in hepatocellular hypertrophy, as well as significant increases in the number of total white blood cells, lymphocytes, and neutrophils at 7,500 and 15,000 ppm.  No other effects in males were found by histological examination.  All the reported effects were found to be reversed in a separate group of recovery males who were held for 13-days post exposure.  No exposure-related effects were noted in female rats at any concentration; thus the NOAEL for females was identified as 15,000 ppm.  Peroxisomal proliferation is common in male rats which have been exposed to certain toxicants, and the effect has been debated within the risk assessment community with regard to predicting liver toxicity in humans (Keshava and Caldwell 2006; Melnick 2001).  The study authors discounted the peroxisomal proliferation, and identified a NOAEL of 3,000 ppm based on other mild responses at the mid- and high concentrations.  ICF agrees with this decision, particularly given the reversibility of the effects and given the similarity in the toxicity of C7 FK with the structurally similar C6 FK.

 Compensation for 6 hour/day exposure for 5 days/week is accomplished by multiplying the AEL of 3,000 ppm by a factor of 0.75 (6 hour study exposure/ 8 hour typical worker exposure) to obtain a Human Equivalent Concentration (HEC) of 2,250 ppm. An interspecies uncertainty factor of 3 is used to account for the pharmacodynamic differences between rats and humans. An additional uncertainty factor of 3 is recommended to compensate for use of a 29-day, rather than 90-day subchronic or 2-year chronic, study to develop the 8-hour AEL. The supporting toxicological data for C6 fluorinated ketone (C6 FK), which is structurally similar to C7 FK, precludes the need for an additional UF for the quality of the database.  Division of the HEC by 10 (multiplicative value of uncertainty factors) produces a derived AEL for C7 fluorinated ketone of 225 ppm.  
References

Keshava N and JC Caldwell (2006) Key issues in the role of peroxisome proliferator-activated receptor agonism and cell signaling in trichloroethylene toxicity.  Environ Health Perspect 114(9):1464-1470.
Melnick RL (2001) Is peroxisome proliferation an obligatory precursor step in the carcinogenicity of di(2-ethylhexyl)phthalate (DEHP)? Environ Health Perspect 109(5):437-442.

Muijser H. and Staal YCM. (2008) Sub-acute (29-day) inhalation toxicity study with MTDID 10800 in rats. TNO Quality of Life, The Netherlands, for 3M Company, St Paul, MN 17 December