






Memorandum
To:		Docket EPA-HQ-OAR-2014-0198
From:		Margaret Sheppard
      EPA/Stratospheric Protection Division
Subject:	Information on workplace exposure limits for foam blowing agents
Date:		July 7, 2014

	This document summarizes information on workplace exposure limits for foam blowing agents mentioned in the preamble to the proposed rule, "Protection of Stratospheric Ozone: Change of Listing Status for Certain Substitutes under the Significant New Alternatives Policy Program."
	Table 1 provides the meaning of a number of abbreviations and terms that will be used later in this document. Table 2 identifies the workplace exposure limits for the foam blowing agents mentioned in the preamble, as well as setting out the foam blowing agents that are acceptable by end-use. HCFC foam blowing agents are not included here; these foam blowing agents are restricted under EPA's phaseout regulations implementing Section 605(a).  

          Table 1. Explanation of Exposure Limit-Related Terminology
                Organizations Issuing Workplace Exposure Limits
Abbreviation
Full Name of Organization
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
                           Workplace Exposure Limits
Abbreviation
Name of Exposure Limit
Explanation
Short-Term Exposure
STEL
Short-Term Exposure Limit
A 15-minute time-weighted average (TWA) exposure that should not be exceeded at any time during a workday, even if the 8-hour TWA exposure is within the 8-hour Threshold Limit Value (TLV) - TWA set by ACGIH. (OSHA may also set a STEL).
Excursion Limit
Excursion Limit 
Where a compound does not have a TLV-short-term exposure limit, an excursion limit may be applied. Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a workday, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded according to ACGIH. 
Long-Term Exposure
AEL
Acceptable Exposure Limit
This is a recommended workplace exposure limit, typically an 8-hour TWA exposure limit. Manufacturers may recommend an AEL for their products, particularly where there is not an industry recommendation such as a TLV or Workplace Environmental Exposure Limit (WEEL) or where there is no permissible exposure limit (PEL) from OSHA.
PEL
Permissible Exposure Limit
This is a mandatory 8-hour time-weighted average exposure limit set by OSHA. 
REL
Recommended Exposure Limit
This is a recommended 10-hour TWA exposure limit set by NIOSH.
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. 
WEEL
Workplace Environmental Exposure Limit
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 AIHA.

Table 2. 8-Hour Workplace Exposure Limits and End-Uses for Substitute Flow Blowing Agents

Substitute
                          Exposure Limit Information
                      Listing for Substitute, by End-Use

         8-hr TWA Workplace Exposure Limit in parts per million (ppm)
                        Abbreviation for Type of Limit

     Rigid Polyurethane (PU) & Polyiso-cyanurate Laminated Boardstock

                            Rigid PU, Appliance[1]
                              Rigid PU, Spray[1]

              Rigid PU, Commercial Ref &  Sandwich Panels[1]

                            Rigid PU, Slabstock[1]

              Polystyrene, Extruded Boardstock & Billet (XPS)

                   Phenolic Insulation Board & Bunstock

                            Integral Skin PU[1, 2]

                          Polystyrene Extruded Sheet

                                  Flexible PU

                                 Polyolefin[3]

Water
N/A
N/A
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

CO2
5000
PEL
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

HFC-134a
1000
WEEL
                                       
                                       X
                                       
                                       X
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X

HFC-152a
1000
WEEL
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

HFC-245fa
200
WEEL
                                       
                                       X
                                       
                                       X
                                       
                                       
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X
                                       
                                       X
HFC-365mfc
1000
Manufacturer (Mfr) AEL
                                       X
                                       
                                       X
                                       
                                       
                                       X
                                       X
                                       
                                       X
                                       X
                                       X
                                       X
                                       X
                                       X
Commercial blends of 7-13% HFC-227ea and remainder HFC-365mfc
1000
Mfr AEL
                                       
                                       
                                       
                                       
                                       
                                       X
                                       
                                       
                                       
                                       
                                       
HFO-1234ze
800
WEEL
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

Exxsol Blowing Agents
600
TLV
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

Saturated Light Hydrocarbons C3-C6
(e.g., n-pentane)
600 to 1000
TLV
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

Formic Acid
5
PEL
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

Acetone
250/500
REL/TLV
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

Methyl Formate
100 
PEL
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

2-Chloropropane
350
EPA AEL
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

Vacuum Panels
N/A
N/A
                                       
                                             
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
Blends of HFC-365mfc and at least 5% HFC-245fa
200 to 1000
Mfr AEL
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

Ecomate
100
PEL
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
Formacel B
1000
Mfr AEL
                                       
                                       
                                       
                                       
                                       
                                       X
                                       
                                       
                                       
                                       
                                       
Formacel TI
1000
Mfr AEL
                                       
                                       X
                                       X
                                       X
                                       X
                                       
                                       
                                       X
                                       X
                                       
                                       X
Formacel Z-6
1000
Mfr AEL
                                       
                                       X
                                       
                                       
                                       X
                                       X
                                       X
                                       
                                       X
                                       X
                                       
                                       X
HFC-152a/Saturated Light Hydrocarbon Blends
600 to 1000
WEEL/TLV
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
Trans-1-chloro-3,3,3-trifluoro-prop-1-ene (Solstice[TM] LBA)
800
WEEL
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       

1. - Acceptability listings include blends of acceptable substitutes in these end-uses.
2. - Under the Section 610 Non-Essential Use Ban, the sale and distribution or offer for sale and distribution of polyolefin foam manufactured with HCFCs is banned except for closed cell rigid polyethylene foam when such foam is suitable in shape, thickness and design to be used as a product that provides insulation around pipes used in heating, plumbing, refrigeration, or industrial process systems 
                                       
                                       
KEY:  Currently Acceptable	                                       X
                                       X
      Proposed unacceptable	

  	Currently no listing

References
ACGIH 2004. The Documentation of the Threshold Limit Values and Biological Exposure Indices. American Conference of Governmental Industrial Hygienists. Available online at: www.acgih.org. 
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.  Stratospheric Protection Division.  March, 1994.

