MEMORANDUM

Date: July 31, 2014

Subject: Revised Cost Impacts of Pressure Relief Device Monitoring for the

Amino/Phenolic Resins Production Source Category

From: Lesley Stobert, EC/R Incorporated

To: Nick Parsons, EPA/OAR/OAQPS/SPPD

______________________________________________________________________________

The purpose of this memorandum is to present revised estimated cost impacts of the final 

requirements for pressure relief device (PRD) monitoring for the Amino/Phenolic Resins (APR) 

Production source category. The addition of PRD monitoring to the NESHAP for this source 

category is being finalized along with other changes evaluated under EPA’s Risk and 

Technology Review (RTR) program, which is addressing statutory requirements under section 

112(d)(6) and 112(f)(2) of the Clean Air Act (CAA). The revised cost impacts for PRD 

monitoring include an additional facility that the EPA learned is subject to the APR MACT 

standards during the comment period for the proposed amendments to the rule. Section 1 

provides background information, followed by the revised estimated costs impacts of the PRD 

monitoring program for the source category in section 2. 

1.0 BACKGROUND

The EPA is finalizing requirements for monitoring PRDs in organic HAP service that 

release to the atmosphere. This PRD monitoring system must be able to identify pressure 

releases, record the time and duration of each pressure release and immediately notify operators 

that a pressure release is occurring. Owners or operators would be required to keep records and 

report any pressure release with an estimate of the amount of organic HAP released to the 

atmosphere with the next periodic report. These provisions are being finalized to address 

concerns that PRD releases may emit large quantities of HAP, may not be identified and 

controlled in a timely manner and may be due to repeat problems that have not been corrected.

The EPA proposed these monitoring requirement and estimated the cost impacts associated with 

these requirements on January 9, 2014 (79 FR 1676) for the APR Production source category, as 

well as for the Polycarbonate (PC) Production and the Acrylic and Modacrylic Fibers (AMF) 

Production source categories. During the public comment period for the proposed rule

amendments, the EPA received a comment from the Occidental Chemical Corporation, which 

noted that it operates a facility in Petrolia, Pennsylvania that is subject the APR MACT 

standards, but which was not considered in the analyses conducted prior to the proposal of the 

rule amendments. We are revising the PRD cost impact estimates for the APR Production source 

category to include this additional facility. No other comments affecting the cost impacts

analyses were received for the APR source category or for the AMF or PC Production source 

categories, and no other revisions to these analyses are being made.
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2.0 COST IMPACTS 

Owners or operators could use a range of methods to identify pressure releases, record 

the time and duration of each pressure release and immediately notify operators that a pressure 

release is occurring, including parameter monitoring systems that facilities may already have in 

place. However, in order to estimate the costs associated with requiring monitoring of PRDs for 

APR production facilities, it was conservatively assumed that operators would install wireless 

electronic indicators on each PRD in organic HAP service that vents to the atmosphere to 

identify and record the time and duration of each pressure release and notify operators of the 

release. To estimate the cost of these electronic indicators, we used information from analyses 

performed by the South Coast Air Quality Management District (SCAQMD) of California, 

which were conducted in support of a rule that requires continuous monitoring of a percentage of 

PRDs at refineries by installing a monitoring device capable of recording the duration of each 

release and quantifying emissions. Wireless technology allows continuous monitoring of PRDs 

and makes it easier for operators to identify releases and leaks.1 There are several monitoring 

devices available, including acoustic sensors and pressure/differential pressure sensors. These 

sensor units communicate with a base radio that interfaces with the existing control system. The 

costs for PRD wireless monitoring, based on information from the SCAQMD analyses, are 

summarized in Table 1. 

The monitoring device cost provided by the SCAQMD was based on vendor costs and 

ranged from $5,000 to $10,000, with an average of $7,500, and includes device parts, 

installation, and maintenance, as well as a data retrieval system. According to SCAQMD, annual 

operating costs are minimal because they typically only include periodic replacement of 

inexpensive batteries. It was assumed that, for this analysis, these costs were presented in 2007 

dollars and were escalated to 2012 dollars. As a result, the total capital investment was 

determined to be $8,345 per PRD. According to the SCAQMD analyses, the cost of electronic 

monitoring systems is not linear, and facilities requiring a larger number of monitors are 

expected to benefit from economies of scale. Therefore, the sixth-tenths rule was applied to 

calculate initial costs.2

To estimate PRD monitoring requirement costs, we made assumptions regarding PRD 

equipment component counts based on available information. For the APR Production source 

category, PRD equipment component counts for individual facilities that were reported in a 

memorandum developed for the original APR Production MACT standards were used. It was 

assumed that the average of the reported number of PRDs, which is 5 PRDs, would be most 

representative of a typical APR production facility. As such, using this average number of PRDs 

and scaled costs per PRD, the total capital investment is estimated to be $21,919 and annual 

costs are estimated to be $3,121 per APR production facility. There are 19 facilities in the APR 

source category each estimated to have five PRDs. Therefore, the total capital cost associated 

 

1 Ellis, Kennard, SCAQMD. Final Staff Report for Proposed Amended Rule 1173 - Control of Volatile Organic 

Compound Leaks and Releases from Components at Petroleum Facilities and Chemical Plants. May 15, 2007. 

Docket No. EPA-HQ-OAR-2010-0869-0024.

2 Sixth-tenths rule is used to adjust for economies of scale. Cost to facility = cost of one PRD * (number of PRDs at 

facility)^0.6.
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with the requirement to monitor PRDs is $416,000 with an annualized cost of $59,000 for the 

APR source category.

Table 1. Revised Estimate of Total Capital Investment and Annualized Cost of PRD 

Monitoring for the APR Source Category

Cost Parameter APR Source Category

Number of PRDs at Model Planta5

Unit Device Installation Cost $7,500 (2007 Dollars)

$8,345 (2012 Dollars)b

Plant Site Total Capital Investmentc$21,919

Capital Recovery Factord0.142

Plant Site Total Annualized Cost $3,121

Number of Plants in Source Category 19

Source Category Total Capital Cost $416,000

Source Category Total Annualized 

Cost

$59,000

aBased on average number of PRDs at APR facilities reported in a memorandum developed for the 

original MACT standards: Memorandum from Meardon, K., Pacific Environmental Services, Inc., to 

Schaefer, J., EPA/OCG. Equipment Leak Analysis for Amino and Phenolic Resins NESHAP. May 4, 

1998.

b Chemical Engineering Index for 2007 is 525.4 and 584.6 for 2012.

c Calculated using sixth-tenths rule. Plant site Cost ($) = PRD Unit Cost ($) * (No. of PRDs)^0.6

d Capital recovery factor calculated based on 7 percent interest and 10 year equipment life.