SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

Final Staff Report with Appendices 

for Revised Proposed Amendments to Rule 4682

APPENDIX B 

Emissions Reduction Analysis for 

Revised Proposed Amendments to Rule 4682 (Polystyrene Foam, 

Polyethylene, and Polypropylene Manufacturing) 

September 20, 2007 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

 Final Staff Report with Appendices 

 for Revised Proposed Amendments to Rule 4682 

B-2

EMISSIONS REDUCTION ANALYSIS 

Rule 4682 (Polystyrene Foam, Polyethylene, and Polypropylene Manufacturing) 

I. SUMMARY 

District staff has estimated the VOC emissions reduction from foam manufacturing that 

would comply with the proposed VOC emission or control system limits of proposed 

amendments to Rule 4682. All of the Valley foam manufacturing would be subject to the 

proposed rule amendments, but due to differences in existing control equipment not all 

would be impacted to the same degree. Some of the facilities may actually already be in 

compliance with the proposed VOC emission or control system requirements or would only 

have to make minor modifications to comply. This appendix identifies the estimated VOC 

emissions reduction and estimated reductions for the proposed amendments to Rule 4682. 

The 2007 Ozone Plan indicated that for Polystyrene Foam, Polyethylene, and 

Polypropylene (S-Ind-6) control measure, the 2012 baseline of VOC emissions is 0.39 

tons per day and that a reduction of about 0.10 tons of VOC per day (26%) is anticipated 

upon final implementation. The analysis indicates that the VOC emissions from foam 

manufacturing is closer to 1.4 tons VOC /day (2,770 lb VOC/day). Reductions due to the 

proposed amendments are calculated at 0.4 tons VOC/day (750 lb VOC/day) which is a 

28% percent reduction from the adjusted baseline. Therefore, although the adjusted 

baseline is higher than the Plan inventory, the percent reduction still matches the 

District's reduction commitment 

II. BACKGROUND 

This category was listed in the Ozone Rate of Progress Plan as an all feasible measure 

suggested by the EPA. Amending Rule 4682 is intended to reduce VOC emissions from 

manufacturing polymeric foam and foam products by specifying total VOC emission limits 

or emission control device requirements. The two major categories of processes in this 

category are extruded foam operations and molded foam operations. Although there are 

key differences between the two processes, each process basically employs a blowing 

agent to create spaces in the plastic structure and produce a strong, but lightweight 

material with good thermal insolating properties that is inert to water and grease. 

 

Currently operators have to either use an non-VOC blowing agent; capture and control 

VOC emissions from certain manufacturing processes; or demonstrate an equivalence. 

The proposed amendments increase the stringency of those requirements add a fourth 

compliance option of meeting a specific VOC emissions limit. Specifically, operators 

would have to comply with one of four rule requirements: 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

 Final Staff Report with Appendices 

 for Revised Proposed Amendments to Rule 4682 

B-3

1. Limit total uncontrolled VOC emissions and residual VOC amounts to more 

than 2.4 lb of VOC for each 100 pounds of total material processed, or 

2. Use a non-VOC blowing agent, or 

3. Control all manufacturing emissions with an approved system and store the 

finished product in a controlled warehouse for 24 or 48 hours, or 

4. Control the manufacturing emissions to obtain an equivalent reduction to that 

achieved if complying with option 3. 

Based on a review of existing permit conditions, emission limits, and material data, 

District staff feels that the proposed limits can be met through the use of VOC capture 

and control system; modifications to materials or manufacturing processes; or a 

combination of the two. 

III. FACILITIES AFFECTED BY PROPOSED RULE AMENDMENTS 

In order to determine the VOC emissions reduction from the proposed amendments of 

this project, District staff identified the number of foam manufacturing facilities that would 

be affected and pertinent operating characteristics of such units. The District’s Permits 

database was used to identify the units currently under permit. Based on the information 

in the database, District staff identified 12 facilities that could be subject to the proposed 

rule amendments. One of the facilities does not use a VOC blowing agent and would be 

exempt under Section 4.1. The remaining eleven facilities had some or all of their 

manufacturing processes and storage area controlled or limited by permit conditions. 

Based on the current operating permits for these facilities, VOC emissions were 

calculated and are summarized in Table B-1. Because of differences in the way the 

permits were written, it is not possible to illustrate a specific calculation methodology. In 

some cases, the permit contain a single, facility-wide limit, while in others, the emissions 

from several permits must be added together. To allow for occasional surges in 

operations some facilities have a higher permitted daily emissions than shown. To make 

comparisons between facilities possible, however, the annual or quarterly limits were 

used when available, to reflect long-term operations and not overestimate emissions. 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

 Final Staff Report with Appendices 

 for Revised Proposed Amendments to Rule 4682 

B-4

Table B-1 Facility VOC Emissions and Residual Summary 

Process/Product 

Potential VOC 

Emissions after 

Controls(1) 

Residual 

VOC(2) 

Potential 

Reductions(3) 

1 Molded - Cups 250 lb/day 830 lb/day 40 lb/day 

2 Exempt - Low VOC N/A N/A 

3 Extruded - Sheet Material 50 lb/day 1,300 lb/day 60 lb/day 

4 Molded - Containers 50 lb/day 400 lb/day 20 lb/day 

5 Extruded - Food-grade 

Products 540 lb/day 1,960 lb/day 100 lb/day 

6 Extruded - Sheet Materials 820 lb/day 6,000 lb/day 300 lb/day 

7 Molded - Containers 150 lb/day 860 lb/day 40 lb/day 

8 Extruded- Food-grade 

Products 1,450 lb/day 5,200 lb/day 260 lb/day 

9 Molded - Containers 40 lb/day 210 lb/day 10 lb/day 

10 Molded - Containers 2 lb/day 2,200 lb/day 110 lb/day 

11 Molded - Packaging 270 lb/day 1,200 lb/day 60 lb/day 

12 Extruded - Packaging 70 lb/day Not available 

Total 3,692 lb/day 1,000 lb/day 

Adjusted (1) 2,770 lb/day 750 lb/day 

(1) "Potential VOC Emissions After Controls" represents the permitted VOC emissions 

from manufacturing processes after all required control requirements and limitations were 

taken into account. The "Adjusted" controlled emissions is 75% of that total or 2,770 lb 

VOC/day. This is to account for variations in the actual operations which typically put 

emissions below the permitted limits. Individual facilities may be higher or lower than that 

number, but the 75% should represent the industry as a whole. 

(2) "Residual VOC" represents the assumed retained amount of blowing agent in the 

product immediately after manufacturing. Both the South Coast and Bay Area air districts 

include the residual values when calculating their emission limits. Some of these 

emissions will off-gas in the first 24 to 48 hours after manufacturing which is the rationale 

behind the South Coast requiring a mandatory period of controlled storage for finished 

goods. The remainder of the residual VOC is expected to off-gas during the life of the 

product. 

• Some facilities had a permit condition requiring a specific residual amount in the 

finished product. The residual amount will vary depending on the raw material 

used, the facilities operating temperature and humidity, and the type of product 

produced. Unless specified in the operating permit, a 50% retention rate was 

applied to the permitted blowing agent total. Residual emissions are uncontrolled 

and therefore much higher than the manufacturing emissions which are typically 

captured and vented to a control device. Manufacturing operations release 

roughly half of the initial blowing agent, but are typically less than 15% of the total 

VOC emissions due to the controls. 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

 Final Staff Report with Appendices 

 for Revised Proposed Amendments to Rule 4682 

B-5

• Some facilities had a permit condition limiting the specific amount of VOC in the 

raw material. Actual material content, for molded products, will vary from 6% to 

2.5% VOC depending on the supplier and product. Unless specified in the 

operating permit, a 5% blowing agent factor was applied to the permitted raw 

material limit to determine the total permitted blowing agent. Extruders add the 

blowing agent to the raw material during the extrusion phase so typically their raw 

material has no VOC, but the 5% mix would also, typically apply. 

(3) "Potential Reductions" reflects the approximate reductions necessary to comply with 

the proposed rule limit. The specific compliance option will be determined by the 

operator, so a case-by-case analysis is not possible. Also, some operators may already 

be in compliance due to their current emission controls. 

• One of the most cost-effective methods, and therefore the most likely compliance 

option, to reduce VOC emissions is to reduce the amount of blowing agent in the 

raw material. In that scenario, no additional emission controls would need to be 

added or maintained and material cost should be roughly equivalent to the higherVOC material. 

• Reducing the VOC in the raw material would reduce both the manufacturing 

emissions and the residual amount. Because the residual VOC content is 

approximately half of the total VOC content, and is uncontrolled, the impact of 

reducing the raw material content would have the biggest impact on these 

emissions. 

• Table B-1 reflects the result of a 5% reduction in the residual VOC content of the 

final products. This is not to imply that such a reduction in material VOC content 

will automatically result in compliance for all sources. Some operations will 

require a greater material VOC content reduction and others may require 

emission controls or manufacturing operations to comply with the proposed 

requirements. The 5% assumption is merely a method of estimating potential 

reductions when the exact operator response is not certain. 

• Reducing the raw material VOC content would have a relatively less significant 

impact on the emissions which are captured and controlled. As previously stated, 

those emissions are only about 15% of the residual amounts so a 5% reduction 

would only result in a 0.75 % reduction (21 lb VOC/day) in those emissions. 

• It may be possible for some operators to add additional controls on currently 

uncontrolled manufacturing points. The effects of such controls would be a 

between 80 to 95% reduction in those emissions, but at a higher cost for 

equipment and operating than achieved by changing the raw materials. 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

 Final Staff Report with Appendices 

 for Revised Proposed Amendments to Rule 4682 

B-6

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