p.1 

OAR Box 1168 

Prepped by Ollie Stewart 

Document Number: 

124) II-C-39 

Docket Number: 

A-89-10 

Printed 4/29/2008 11:23:21 AM Sheet 124 of 131 
^ - UNITED STATES ENVIRONMENTAL PROTECTIC . . 

I ^3ft S Office of Air Quality Planning and Stand H-t-39 

\

,

y^-^ > #* Research Triangle Park, North Carolina 2771 1 

* i< opo^ 

F© I I ISSI 

Dear Reg Neg Committee Member: 

Please find attached for your review and comment a complete draft of the 

preamble to the proposed rule presenting the basis and purpose for the 

provisions. The draft discussion "Data and Information Considered," which you 

previously reviewed, has been revised based on comments received and has been 

incorporated into this draft as sections C and D. In this draft, I have 

attempted to document the principle basis for the provisions., 

Even though the preamble still has some rough edges, we believe that the 

most efficient way to proceed is to circulate it now for review and comment. 

Please limit your comments to those that change the content or where 

improvement is obviously necessary. Minor comments and wording edits consume 

time better spent on substantive improvements. I will then compare and 

incorporate comments. If there appear to be outstanding issues or 

disagreements, we will then schedule a meeting or conference call among the 

interested Committee members to resolve the issues. After resolution of the 

substantive issues, we will review the preamble for necessary editorial 

changes. 

Since the Committee's charter will expire soon, we would appreciate 

receiving your comments no later than February 27, 1991. © 

Thanks, 

Jafo/pleyer ' 

,--_.. _»• i M-a---------IMI_______M______l^^ _____________ .i.m- J -I-P_-.,._.UP. I 
FEB I ! 1991 

VI. Rationale for Negotiated Rule for Equipment Leaks 

A. Background 

Equipment leak emissions refer to the loss of volatile organic compounds (VOC) 

and volatile hazardous air pollutants (VHAP) through the sealing mechanism 

separating process fluid contained in equipment from the atmosphere. Because of the 

large number of valves, pumps, and other components within a process unit, total 

emissions from such equipment can be large. Equipment leaks have been estimated to 

contribute about one-third of all routine (nonaccidental) VOC emissions from the 

chemical industry. 

Existing regulations adopted under Sections 111 and 112 of the CAA and in 

State Implementation Plans (SIP's) have been effective in heightening awareness of 

the significance of equipment leaks and in stimulating control efforts. These rules 

basically require that pumps and valves be inspected periodically for leaks with a 

portable hydrocarbon detector. If a VOC concentration greater than 10,000 parts per 

million (ppm), as methane or hexane, is found, the component is identified as a 

"leaker" and maintenance is required. This approach is known as "leak detection and 

repair" (LDAR). When these rules were established, EPA estimated that emissions 

would be reduced by about 60 to 70 percent and that after control, leak frequencies 

would be approximately 5 percent 

Data gathered over the past several years on equipment leaks at some chemical 

plants indicate that much lower leak frequencies can be achieved. These data, 

however, did not identify specific factors that led to lower leak frequencies, nor 
indicate how low leak frequencies could be obtained at all chemical plants. 

Consequently, EPA saw a need for a new regulatory approach that would achieve low 

leak frequencies at all chemical plants. It was recognized that establishing such a 

regulation for as broad and varied a source category as chemical production units 

would be difficult. The challenges included determining how to achieve low leak 

frequency at all plants with a simple set of rules, how to provide more flexibility in 

achieving low leak rates than that provided by LDAR alone, how to apply standards 

across the industry using data from only a part of the industry, and EPA's need to 

establish standards consistent with the maximum achievable control technology 

(MACT) requirements of the CAA. 

On April 25, 1989, EPA announced its intention to establish a committee to 

negotiate a new approach for control of volatile organic chemical equipment leaks (54 

FR 17944), and conducted an initial informational meeting on May 15, 1989, to 

determine among interested parties whether negotiation would be desirable. The 

participants at the initial meeting responded favorably to the concept of negotiation, 

and on September 12, 1989, EPA established a negotiating committee (54 FR 37725). 

The Committee met over a period of one year, holding nine 2-day meetings and one 1-

day meeting, to resolve the various issues related to developing a MACT standard for 

equipment leaks. The Committee members are listed in Appendix 1. 

The Committee considered the many factors and uncertainties associated with 

regulating equipment leaks at a wide variety of chemical plants and developed an 

acceptably balanced approach, weighing the need to be flexible, the technical 
P.5 

uncertainties, the requirement for MACT standards, and the data limitations. At the 

final negotiating session, the Committee members conceptually resolved all 

outstanding major issues and decided to reach final agreement through a two-step 

process. The Committee members would first agree in principle to the regulatory 

language to be proposed and then to sign the final agreement after a draft preamble to 

the regulation describing in detail the scope, application, effect, and rationale has been 

prepared and concurred in by the Committee. The Committee reached final agreement 

on the draft preamble and regulation on . All Committee members have 

agreed to support the standard as long as EPA proposes and promulgates the standards 

and its preamble substantively unchanged from those that are the substance of the final 

agreement 

It is important to note that the parties to the negotiation concurred with the 

regulation when considered as a whole. Inevitably in any negotiation, this means that 

some parties may have made concessions in one area in exchange for concessions 

from other parties in other areas. As a result, it is difficult to assess how changes in 

particular parts of the negotiated rule would affect the consensus. 

B. Scope and Applicability 

1. Source Categories 

The negotiators originally were to develop standards for equipment leaks for 

13 source categories that would be affected by EPA's then expected hazardous organic 

national emission standard for hazardous air pollutants (NESHAP), or HON. These 

source categories included both synthetic organic chemical manufacturing industry 
_-__£-

i 

i 

(SOCMI) and non-SOCMI source categories, and the standards under development 

would only have applied to 8 hazardous organic chemicals. Over the course of the 

negotiations, and in anticipation of the CAA of 1990, EPA saw the need to expand 

this scope to include not only the original HON source categories, but also all SOCMI 

processes that used as a reactant or produce one of the organic chemicals listed in the 

CAA list of 189 hazardous air pollutants. The EPA identified 453 such processes. 

In addition, EPA determined that petroleum refinery processes would not be 

covered by these standards and that MACT standards for petroleum processes would 

be established in a separate rulemaking. These standards also would not be applicable 

to other petroleum -related facilities, including those engaged in petroleum exploration, 

production, marketing, or transportation. Refinery processes not covered by this 

regulation include cracking, reforming, coking, and other processes that produce blends 

of petrochemicals. Table VI-1 presents a more detailed list of refinery processes not 

included in the scope of this rule. 

_ B I 
P.7 

TABLE VI-1. REFINERY PROCESSES EXCLUDED FROM THE NEGOTIATED 

REGULATION 

Thermal Processes 

Gas-oil cracking 

Thermal cracking 

Visbreaking 

Coking (fluid) 

Coking (delayed) 

Other 

Catalytic Cracking 

Fluid 

Other 

Catalytic Reforming 

Semiregenerative 

conventional catalyst 

bimetallic catalyst 

Cyclic 

conventional catalyst 

bimetallic catalyst 

Other 

conventional catalyst 

bimetallic catalyst 

Catalytic Hydrocracking 

Distillate upgrading 

Residual upgrading 

Lube-oil manufacturing 

Other 

t____k-_ 
P.8 

Catalytic Hydrorefining 

Residual desulfurizing 

Heavy gas-oil desulfurizing 

Cat-cracker and cycle-stock feed pretreatment 

Middle distillate 

Other 
P.9 

TABLE VI-1. (Continued) 

Catalytic Hydrotreating 

Pretreating cat-reformer feeds 

Naphtha desulfurizing 

Naphtha olefin or aromatics saturation 

Straight-run distillate 

Other distillate 

Lube-oil "polishing" 

Other 

Alkylation 

Sulfuric acid 

Hydrofluoric acid 

— • — 
P.10 

2. Relationship Between this Regulation and Future Regulations for 

Refinery Equipment Leaks 

The Committee agreed on the following language to describe the relationship 

between this regulation and future regulations for refinery equipment leaks: 

The standards incorporated in this agreement were established by the Committee 

based primarily on data from well-controlled ethylene oxide plants and data from a 

number of SOCMI plants. The Committee did not review data from petroleum 

refining processes because they were outside the scope of the negotiations, and the 

Committee did not consider whether the numerical standards in this agreement are 

achievable by refinery processes. The Committee recognizes that there are technical 

differences between SOCMI categories and petroleum processes that may affect the 

achievability of the numerical standards (including percent leakers). Potential 

differences include the availability and effectiveness of emission control technologies, 

plant shutdown practices, line sizes, process temperatures and process pressures, and 

cost. These differences could work in the direction of making the numerical standards 

adopted by the Committee more easily achievable, or less easily achievable, for 

refinery processes. 

The Committee agrees that the framework used for the regulation developed 

during the current negotiation should be adopted in the MACT regulation for 

petroleum refinery equipment leaks unless there are sound technical reasons why a 

different framework would be more effective. 

API understands that the numerical standards included in this negotiated rule are 

more stringent than those that would have been selected if the rule had provided that 

exceedences of numerical standards, by themselves, constituted violations of the CAA. 

API recognizes that this will also be true of the numerical standards that will be 

included in a MACT regulation for refinery equipment leaks utilizing the framework 

of the currently-negotiated regulation. 

If EPA develops MACT refinery equipment leak regulations, it will conduct a 

separate rulemaking. Technical differences between SOCMI and refinery processes 

that may affect the achievability of the standards will be considered by EPA in the 

refinery equipment leak rulemaking. 

3. Equipment 
P.11 

The negotiated rule would apply to those pieces of equipment which are 

regulated in the existing section 111 and 112 equipment leaks rules, including all 

valves, pumps, compressors, pressure relief devices, open-ended valves or lines, 

connectors, closed vent systems and control devices, sampling connection systems, and 

product accumulator vessels. In the existing rules, connectors are referred to as 

"flanges and other connectors" or simply as flanges. To avoid potential 

misinterpretations of the negotiated rule and to eliminate redundancy within the 

phrase, the term connector is used in the negotiated standard to designate the same 

types of fittings which were previously termed flanges and other connectors; i.e., all 

flanged, screwed, or other joined fittings used to connect two pipe lines or a pipe line 

and a piece of equipment. The negotiated rule would not apply to flanges between 

sections of a vessel (e.g., body flanges on a distillation column, on a reactor, etc.), 

head gaskets on vessels, or access hatches (e.g., manholes). These types of seals are 

not included in the definition of connector. 

The negotiated rule also contains provisions for agitators and instrumentation 

systems. The rationale for the inclusion of agitators and the separate treatment of 

components in instrumentation systems in the negotiated rule is discussed below under 

the basis for the negotiated rule. 

The negotiated rule would apply to both existing and new process units. The 

negotiated rule categorizes the regulated processes into 5 groups and uses a staggered 

implementation scheme, requiring some process units to comply in 1/2 year, while 

others would comply as late as 1 and 1/2 years after final promulgation of the rule. 

___B 
P.12 

This staggered implementation was provided to alleviate the impact of applying the 

rules simultaneously to all sources. 

An affected "process unit" means equipment that uses or produces a VHAP or 

its derivatives as intermediate or final product(s), including all equipment associated 

with the unit process operation, storage and transfer of feed material to the unit 

process operation and final or intermediate product from the unit process operation and 

operations treating wastewater from the unit process operation. A plant site may 

consist of one or more process units. Process units covered by the negotiated rule are 

listed specifically in Section(s) XX.XO(b) and (c) of the negotiated rule. 

C. Background Information on Equipment Leaks 

This section presents an overview of findings from previous equipment leak 

studies and a summary of information that led to EPA's decision to develop a new 

regulatory approach for equipment leaks through negotiation. This synopsis is not 

intended to reflect the Committee discussions. Rather, it is intended to provide basic 

information for readers unfamiliar with the existing standards, the underlying studies, 

and recent trends. More detailed information on the basis for the existing 

requirements and underlying studies is available in the documents listed in section 

of this notice. 

1. Overview of Background Information 

One of the first published studies of equipment leak emissions was conducted in 

the 1950's in several petroleum refineries in the Los Angeles County Air Pollution 

Control District. The results of this study showed that a large quantity of 

10 
P.13 

l 

hydrocarbons could be lost to the atmosphere from various sources such as valves, 

pump and compressor seals, flanges, and pressure relief devices. In the late 1970's 

and early 1980's, EPA conducted several studies to evaluate and quantify emissions 

from equipment leaks in petroleum refinery operations and in chemical process units. 

In these studies, EPA collected data and evaluated leak frequency, mass emissions, and 

methods and effectiveness of leak prevention. These studies showed that equipment 

leaks were a significant source of emissions and that the majority of emissions at that 

time were associated with equipment leaks measured at concentrations greater than 

10,000 ppm. 

In the EPA Refinery Assessment Study data were gathered on equipment 

screening values (using a portable VOC instrument) and mass emissions. These data 

permitted the development of average emission factors and screening value/emission 

rate correlations. The study also provided other important results. Analyses to 

identify equipment or process variables (e.g., equipment manufacturer, age, or line 

size, process pressure, stream volatility) that effect leak frequency led to the separation 

of equipment component emissions by stream phase: gas/vapor, light liquid, and 

heavy liquid. These classifications have been used to design regulations based on leak 

potential. 

In 1980, EPA conducted a study of equipment leak emissions from 24 

individual SOCMI process units. In this study, the 24-Unit Study, EPA investigated 

leak frequency (at a concentration of 10,000 ppm) in equipment at 24 individual 

chemical process units. A study of the effects of maintenance on emissions was 

11 

i 
P.14 

performed concurrently at 6 of the units screened in the 24-Unit Study. The data from 

these studies were used to develop average emission factors and screening value/leak 

rate correlations; to evaluate leak frequency as a function of process parameters and 

equipment design; to evaluate the effect of instrument response factors on leak 

frequency; and to estimate the effect of leak occurrence and recurrence rates on mass 

emissions. These studies also demonstrated that a program consisting of inspection of 

equipment and maintenance of the leaking equipment was an effective means of 

reducing emissions. The control measures identified at that time were estimated to 

achieve overall a 60 to 70 percent reduction in emissions from equipment leaks. The 

data and conclusions from the studies on petroleum refinery units and chemical 

process units served as a basis for EPA's equipment leak regulations and guidehnes 

that were issued in the early 1980's. 

Information obtained in these studies also showed that leak frequencies varied 

widely among process units and source types and that factors that affect leak 

frequencies were not well understood. Specifically, studies such as EPA's 24-Unit 

Study showed that the frequency of leaks greater than 10,000 ppm ranged from 0 to 

approximately 30 percent among 15 different chemical processes. Similar chemical 

processes also showed large differences in leak frequencies; for example, the leak 

frequencies for gas valves varied from 0 to 18 percent for 3 ethylene dichloride units. 

In subsequent studies, EPA evaluated leak frequency as a function of process 

parameters and equipment design and identified no single factor that determined leak 

frequency. Leak frequencies are believed to be a function of component design, 

12 
P.15 

specifications, construction, material, and age; quality and frequency of maintenance; 

operating and training practices used by the company, diligence; process fluids and 

operating conditions; and other unidentified factors. Current regulations adopted under 

Sections 111 and 112 of the CAA require (1) a leak detection and repair program for 

valves in gas/vapor and light liquid service and pumps in light liquid service; 

(2) equipment for compressors, sampling systems, and open-ended lines; and (3) no 

detectable emissions (500 ppm as determined by Reference Method 21) for pressure 

relief devices in gas/vapor service during normal operation. These rules do not require 

sources to achieve particular performance levels or to install low emission equipment 

designs. As such, residual emissions will vary among process units and the best 

controlled units will emit less than typically or poorer controlled units. 

2. Recent Studies 

In the last 3 years, EPA has received information that shows significantly lower 

leak frequencies at 10,000 ppm for some chemical processes than was representative 

for the industry as a whole in the early 1980's. This information was one 

consideration in EPA's decision to develop a new regulatory approach for equipment 

leaks through the regulatory negotiation process. The information is briefly 

surnmarized in the paragraphs below. In addition, where sufficient information is 

available, these data are included in Table VI-2 which compares leak frequency by 

component type with the previously calculated SOCMI average leak frequency. In 

general, these data were collected following the procedures specified in Reference 

13 
P.16 

Method 21, and the results represent a single monitoring survey conducted over a 

limited time period. 

Units subject to the Benzene Equipment Leak NESHAP. During EPA's 

reconsideration of the benzene equipment leak NESHAP (September 14, 1989, 54 FR 

38044), EPA examined compliance reports from 1987 and 1988 for a randomly 

selected sample of 25 faciUties subject to the standard, which requires a 10,000 ppm 

leak detection and repair program. This review showed that many faciUties had no 

valves or pumps exceeding 10,000 ppm and no facilities had more than 1.5 percent 

valves or more than 12.5 percent pumps exceeding 10,000 ppm. The average 

frequencies of sources exceeding 10,000 ppm were 0.27 percent for valves and 2.3 

percent for pumps. These frequencies, in general, are lower than the average 

frequencies of 3 to 5 percent for valves and approximately 10 percent for pumps 

exceeding 10,000 ppm which had been expected after application of the standard. 

Acrolein process units. In 1989, EPA received screening data and process 

information on two acrolein process units. These data were collected voluntarily by 

the company to provide better emission estimates than could be obtained using the 

SOCMI average factors. The monitoring data represented eight types of equipment 

(gas valves, light liquid valves, light liquid pumps, flanges and other connectors, 

pressure relief valves, sample points, open-ended lines and compressors). These 

monitoring data were collected following the procedures specified in "Protocols for 

Generating Unit-Specific Emission Estimates for Equipment Leaks of VOC and 

VHAP", (Protocols) EPA-450/3-88-010. In general, particular care was taken in 

14 

! u B 
P.17 

measurements of equipment with near zero or less than 200 ppm emissions. In 

addition, one of the units had approximately 60 percent sealed bellows valves and the 

other unit had no sealed bellows valves. 

The screening data indicated average leak frequencies of 0.26 to 0.09 percent for 

valves and of 0.13 to 0 percent for flanges and other connectors at leak definitions of 

100, 1,000, and 10,000 ppm. These data also demonstrated that both conventional and 

sealed bellow valve designs can achieve very good performance. Pump leak 

frequencies were less than 4 percent at 100, 1000, and 10,000 ppm. Of all the 

components screened, more than 98 percent had screening values below 10 ppm. 

These leak frequencies are substantially below the levels found by EPA in studies 

conducted in the early 1980's. 

Amine Unit W.VA. In 1987, EPA received monitoring data for two process 

units handling amines. These units were selected for testing because of the relatively 

severe service conditions (i.e., temperature and pressure) and high vapor pressures of 

the process materials. One unit (unit 1) was characterized as handling relatively 

nontoxic and innocuous substances and the other unit (unit 2) was characterized as 

handling a more toxic compound, one with a threshold limit value (TLV) of 10 ppm, 

which was capable of causing a public nuisance. These data were collected 

voluntarily by the company to calculate a unit specific emission estimate using EPA's 

leak/no leak emission factors. Monitoring data were provided for pumps, valves, and 

flanges and other connectors. 

15 

^"*«*'i 
P.18 

i 

I 

The monitoring data for unit 1 showed 33 percent of the pumps, 16 percent of 

the light Uquid valves, 27 percent of the gas valves, and 0.4 percent of the flanges and 

other connectors exceeding 10,000 ppm. Unit 2 had 5.6 percent of the pumps, 0.8 

percent of the light liquid valves, 1 percent of the gas valves, and 0.1 percent of the 

flanges and other connectors exceeding 10,000 ppm. The data for unit 2 indicate that 

technology is available to reduce leaks and suggest that health and safety 

considerations are important factors affecting use of better technologies and 

maintenance practices. 

Ethylbenzene/Styrene (EB/S) Unit Tx. Limited information was received on 

screening values measured at this facility's ethylbenzene/styrene process unit, which is 

subject to the benzene equipment leak NESHAP. Screening data were provided for a 

total of approximately 2500 valves and pumps. The data were provided as time 

aggregated summaries of screening valves for a one year period from 1987 to 1988. 

These data indicated that 99 percent of the time the valves and 90 percent of the time 

the pumps had screening values less than 500 ppm. Information submitted for 

compliance with the benzene equipment leak NESHAP showed on an annual average 

basis 0.04 percent of the valves and 3.6 percent of the pumps exceeded 10,000 ppm. 

No description was provided of the procedures used in the data collection, other than 

that Reference Method 21 was used. 

Chemical Manufacturers Association Studies of Butadiene (BD), Ethvlene Oxide 

(EO). and Phosgene Process Units. In addition to the preceding information, 

comprehensive screening data were also provided to EPA on 33 butadiene (BD), 

16 

Ei_H 
P.19 

ethylene oxide (EO), and phosgene production process units. The monitoring data 

represented eight types of equipment (gas valves, light liquid valves, light liquid 

pumps, flanges and other connectors, pressure relief valves, sample points, open-ended 

lines and compressors) at essentially all BD, EO, and phosgene producers operating in 

the United States. These data were collected voluntarily by the CMA committees to 

provide EPA with better industry-wide estimates of emissions from equipment leaks at 

these process units than could be obtained using EPA average factors for SOCMI. 

These monitoring data were coUected following the procedures specified in the 

Protocols. These studies provide the most comprehensive equipment screening data 

available that document the full range of leak frequencies for large numbers of process 

units used for the production of specific chemicals. The EPA also obtained 

information on the plant work practices, operations and the equipment design 

specifications. Conditions in the equipment surveyed spanned a wide range of 

o 

temperatures and pressures (50°F to 550 F and 5 to 500 psig). 

The screening data indicated that most process units at these facilities are 

characterized by equipment leak frequencies far below levels found by EPA in studies 

conducted in the 1970's and 1980's. In addition, the data base indicated much lower 

leak frequencies at the phosgene process units than at the EO and BD units, and the 

EO units in general had lower leak frequencies than the BD units. Table VI-2 

presents the plant-specific leak frequency data by component type, at various leak 

definitions for the three processes. The data shown in Table VI-2 are the screening 

data that were judged to be consistent with proper calibration and use of the test 

17 

___H____M___^____^___^__-^---MII^H^^H H^^^^H H^H^^^^^^^HM___--------------------K---H---Si--|l 
P.20 

equipment. The screening values for the ten BD and nine EO process units were also 

adjusted for the instrument response factor to represent more accurately the screening 

concentration of equipment in BD or EO service. The data presented in Table VI-2 

represent process units in various stages of control and operations. Some plants 

operated using formal LDAR programs and others did not; some units were screened 

just before a shutdown for maintenance and others were screened just after startup 

following a scheduled maintenance shutdown. 

The above information, when compared with the earlier studies and analyses 

indicated to EPA that the performance capability of available technology is better than 

had been expected from a 10,000 ppm LDAR program alone. Furthermore, analyses 

of these data showed, like earlier studies, that no single factor or technology was 

responsible for the better performance. Rather, the recent data confirmed that effective 

leak control involves a combination of factors. For example, statistical analysis of the 

recent EO and BD data failed to identify specific process parameters or equipment 

designs that alone would significantly affect leak frequencies. 

D. Development of Framework and Selection of MACT 

Unlike many other source types, selection of MACT for equipment leaks 

requires a balancing of a number of interrelated factors and is not based on 

identification of a specific best control technique or approach. The following 

discussion explains the Committee's assessment and consideration of the available data 

in the development of the framework as well as the selection of MACT. 

1. Information considered 

18 

• E i sat 
P.21 

Vl-z. 

Table A,'- Sun-nary of Equipment Screening Data 

Unit ID 

EO 1 

EO 2 

EO 3 

EO 4 

EO 5 

EO 6 

EO 7 

EO 8 

EO 9 

BD 1 

BD 3 

BD 4 

BD 5 

BD 6 

BD 7 

BD 8 

BD 10 

BD 11 

BD 12 

Acrolein 

TACB 

A 

B 

C 

Average 

SOCMI 

at 10,000 

Valves % 

250 

0.6 

2.8 

1.4 

2 

0.4 

1.6 

1.2 

2.9 

5.3 

10.7 

5.6 

7.3 

11 

7.5 

2.2 

21.9 

25 

11.3 

5.9 

0.1 

. 

ppm 

500 

0.4 

2.2 

1.1 

1.3 

0.2 

1.4 

1.2 

2.5 

4.5 

8.8 

4.8 

6.3 

7.7 

5.4 

2.2 

18.4 

19.8 

10.1 

4.5 

0.1 

3.6 

0 

0.7 

11.5 

Leakers 

1000 

0.3 

1.1 

1.1 

0.9 

0.2 

1.3 

1.2 

1.5 

4 

7.5 

4.2 

5.4 

5-/ 

3.3 

2.2 

15.1 

17.1 

8 

3.7 

0.1 

Pumps % 

500 

0 

23 

36 

0 

0 

6 

25 

24 

2.9 

50 

33 

n/a 

58 

0 

16.7 

10 

4 

4 

4 

5 

1000 

0 

18 

27 

0 

0 

0 

25 

21 

0 

n/a 

50 

0 

16.7 

10 

4 

Leakers 

2000 5000 

0 0 

14 9 

9 9 

0 0 

0 0 

0 0 

25 25 

15 13 

0 0 

n/a n/a 

41.7 41.7 

0 0 

16.7 16.7 

10 10 

4 4 

9 

Connectors % 

250 

0 

0.9 

3.2 

2.8 

-0-

4.1 

0 

2.5 

7.6 

0 

0.7 

10 

3.4 

n/a 

0 

7.4 

5.1 

1.4 

0.6 

0.1 

500 

0 

0.9 

3.2 

1.5 

•fr 

4.1 

0 

2.5 

5.9 

0 

0.7 

8.6 

1.5 

n/a 

0 

6.7 

2.5 

1.4 

0.6 

0.1 

0 

n/a 

2 

2.1 

Leakers 

1000 

0 

0.9 

3.2 

°-7 „._«**. -9-

 A* 

4.1 

0 

2.5 

4.9 

0 

0.7 

7.1 

1.1 

n/a 

0 

5.9 

1.9 

0.7 

0.6 

0.1 

R 

gjQU 
In deliberations over the framework, the Committee considered screening data 

from the CMA surveys of EO, BD, and phosgene production units as well as data and 

information from other process units. The additional information considered included 

data provided on an EB/S process unit and on three facUities in Texas subject to a 500 

ppm leak permit condition. The information available for the EO, BD, and phosgene 

units and for the EB/S unit were described in the preceding section. The information 

provided on the three facilities in Texas is described below. 

Texas Air Control Board Data. Additional data from three plant sites were 

provided by the Committee member representing the Texas Air Control Board. These 

plants are subject to a Texas regulation that requires LDAR with directed maintenance 

at a 500 ppmv leak definition. This requirement has been applied as part of the 

permit program for new and modified sources. Data were provided for cumene, 

phenol/acetone, and butyraldehyde/butanol process units which had been operating a 

500 ppm LDAR program for one to six quarters. These units had average leak 

frequencies at 500 ppm for valves ranging from 0 to 3.6 percent. The average leak 

frequency at 500 ppm reported for pumps varied from 0 to 20 percent in the first 

period and from 3.6 to 5 percent in the second period. Average leak frequencies for 

flanges varied from 0 to 2 percent. These data show for several chemicals that a 500 

ppm LDAR program is effective and wiU significantly decrease leak frequency. 

In addition to considering the available screening data, the Committee visited 3 

integrated chemical plants, one of which had 20 operating units including a phosgene 

unit, a toluene diisocyanate unit, and a hydrogen fluoride unit. One conclusion drawn 

19 

H B 
from these visits was that the acute toxicity of phosgene and toluene diisocyanate has 

resulted in the routine use of a number of effective leak control practices in these 

process units. Measures taken to prevent and minimize leaks in phosgene and 

isocyanate units include design to minimize the number of components, stringent 

quality assurance/control programs, bench testing of equipment for leaks, and careful 

management and extensive continuous monitoring of the unit to detect leaks and 

problems. In addition, phosgene and isocyanate units are shut down for immediate 

repair whenever any leak is detected. Immediate shutdown is possible because 

phosgene and isocyanate process units are small and are not operated as part of an 

integrated process. In units where less acutely toxic compounds are used or produced, 

such measures were not observed and the units are not immediately shut down for 

repair whenever a leak is detected. Rather, these units are typically operated for a 

fixed time period before they are shut down for maintenance and repair. 

Representative operating times between scheduled shutdowns range from 6 months to 

several years, with typical time of approximately 3 years. 

The Committee also concluded that equipment design and an on-going quaUty 

control/assurance program has a significant role in achieving low leak frequencies. 

This conclusion was supported by remarks made to the Committee by a chemical 

industry representative who described his company's recent experience with two 

ethylene oxide production units. Following completion of a screening study, the 

company undertook a program to reduce the leak frequency and emissions from the 

units. Steps taken consisted of component inspection, complete or partial replacement 

20 
of over 700 valves and 2000 gaskets, modification of design to reduce leaks, and 

regular monitoring and inspection for leaks. The company reported that there was an 

overall reduction of about 80 percent in the number of leaking components following 

completion of this project. 

2. Committee Analysis and Consideration of the Data 

The Committee considered the data and information described in the preceding 

section and concluded that the EO, BD, and phosgene data should serve as the 

principle basis for establishing the performance of MACT for SOCMI processes. The 

EO, BD, and phosgene data, however, were considered in light of the broader data; 

especially, the Texas 500 ppm LDAR program and the site visits. On this basis, the 

Committee agreed that phosgene units are not similar in design, operation, and 

maintenance to most SOCMI processes. Some of the maintenance and operating 

practices for phosgene units control programs went beyond MACT for other SOCMI 

processes. One example of this is the practice of immediate shutdown. Immediate 

shut down is economically and technically infeasible for other processes because shut 

down of the one unit would require shut down of all the integrated operations at the 

site and it would be impractical to clear large volumes of chemicals in short time 

frames. In some cases, emissions from clearing process material from part or all of 

the units could greatly exceed the emissions that would result from the leaking 

equipment. Therefore, while the phosgene units' performance did provide an 

indication of the potential for leak reduction, the Committee concluded that the EO 

and BD units are more representative of the range of processes in SOCMI than are 

21 
P.25 

phosgene or toluene diisocyanate units. The Committee did recognize, as indicated by 

the framework and the base performance levels, that very low leak frequencies are 

generally achievable and that the rule should encourage attaining low emissions. 

From the data and observations, the Committee also concluded that low 

emission performance results from combinations of monitoring (or surveillance), repair 

of leaking equipment, use of quality assured and quality controlled equipment suitable 

for the process operating conditions, and a quality controlled maintenance and repair 

program. The Committee concluded that such combinations are MACT for SOCMI 

processes. The information available did not identify any single factor, such as 

particular equipment design or specific work practices or maintenance programs that 

by itself would guarantee low emission performance in all cases. Furthermore, the 

Committee did not identify the results at any one specific process unit or performance 

level as representing MACT performance because there is no apparent break point that 

represents a limit of what is achievable with a combination of technologies that are 

available. Thus, the Committee identified the best performing EO process units, the 

EB/S unit, the Texas 500 ppm units, and possibly the best performing BD process 

units as reflecting the performance of MACT for toxic chemical processes. 

3. Regulatory Approach 

Because available information indicated that best performance for equipment 

leaks could not be defined or reflected in a single numerical standard, type of 

technology, or group of work practices, the Committee focused on developing a 

regulatory framework that, when combined with performance levels, would reflect 

22 

jlif"" 
I 

I 

MACT. Key principles that evolved during the negotiations and that led to the 

regulatory framework are: 

(1) Motivation is a major factor determining performance. Incentives should be 

included in the standard to reward good performance and prescribed corrective actions 

should be included to ensure poor performance is corrected in a timely manner. 

(2) Flexibility in achieving specified results is important. This is necessary to 

allow consideration of process to process variations in operating conditions and 

equipment specifications and to provide incentives for identifying the most effective 

combination of equipment and practices. 

(3) Identifying, designing, and implementing systems to meet the specified 

results requires varying amounts of lead time. Effective control requires continual 

analysis and adjustment and may involve several technologies which cannot be 

identified or applied at one time or in one step. 

(4) More frequent monitoring and maintenance or a prescribed program should 

be employed, at a minimum, for those process units that do not achieve the specified 

results through a program of their own design or through quarterly inspection and 

maintenance alone. 

(5) There is insufficient information available to set a not-to-be-exceeded 

standard. The existing information is too limited in scope to predict with certainty 

what level of performance could be achieved by processes for which no data were 

available. 

23 

UI 
P.27 

The majority of the Committee deliberations concerned development of a 

regulatory framework and performance levels that would incorporate the above key 

principles, while reflecting the performance of MACT. These deliberations primarily 

focused on developing provisions for valves, pumps, and flanges because these 

emission sources offered the greatest potential for emission reductions. The 

Committee used the existing LDAR program as a starting point for development of the 

framework for these sources. Early-on, the Committee recognized the need for a 

phased-in approach for valves and pumps that would provide time for plants to 

develop and implement effective programs and to focus on larger emission sources 

first. The phased-in approach is necessary because effective control requires continual 

analysis and adjustment of programs as experience is gained. The Committee defined 

requirements for pumps and valves in terms of three phases of increasing stringency. 

Each phase as it occurs reflects the performance of MACT for units in that phase. 

The Committee also deliberated on several methods of linking monitoring 

frequency with performance and of providing incentives to use low emission 

equipment or to reduce the amount of equipment in VHAP service. The final decision 

was to link reduced monitoring frequency with lower leak frequencies, and to give 

credit for removal of equipment or use of low leak design equipment. The 

performance format of the standards would also encourage the use of low-leak 

technologies. This approach is consistent with the data which indicate that there are 

combinations of technology, maintenance practices, and quality assurance programs 

24 
P.28 

that can achieve very low leak frequencies while using less frequent monitoring 

intervals. 

The Committee also debated whether to require shut down of process units for 

repair of leaking equipment whenever performance deteriorates below some specified 

performance level. The Committee ultimately concluded that process units should not 

be shut down to meet a performance level. It was generally agreed that clearing of 

process materials could cause greater emissions than delaying repairs until the next 

scheduled shutdown. 

The Committee also agreed to retain the existing equipment standards for 

pressure relief devices, sample points, open-ended lines, product accumulator vessels, 

and compressors. The existing standards for these items of equipment require 

installation of equipment or control devices and essentially eliminate emissions from 

equipment leaks. The Committee considered these requirements to be MACT. 

For the valve, pump, and connector standards, the Committee primarily used 

the data from the better-performing EO units, the best- performing BD units, the Texas 

500 ppm units, and the EB/S unit to establish the performance levels for the 

monitoring frequency. A major consideration in the selection of performance levels 

was the understanding that the levels are interrelated with the framework and phasing 

and are not necessarily the levels that would have been chosen for a not-to-beexceeded standard. In the case of the valve standard, the selection of the base 

performance levels was also influenced by the inclusion of provisions that provide an 

alternative to monthly monitoring. Referred to as the Quality Improvement Program 

25 

iaa 
P.29 

(QIP), this program ensures that plants subject to these provisions install low emission 

performing replacement equipment (during normal replacement) and implement a 

quality assurance/control program to ensure that aU elements of MACT are utilized. 

Also, the QIP was included in the framework to allow those process units that do use 

all elements of MACT but do not achieve the specified numerical performance levels 

to remain on a quarterly monitoring schedule instead of increasing monitoring 

frequency. 

The basis for the selection of the base performance levels and other elements of 

MACT for valves, pumps, and connectors is discussed below. The basis for the other 

provisions of the valve, pump, and connector standards as well as the other specific 

requirements of the regulation is given in section F. 

Valves. For valves the Committee initially considered both equipment standards 

and LDAR programs and ultimately agreed upon a three phase LDAR program. 

Initially, the Committee considered requiring the use of equipment such as sealed 

bellows valves because the equipment is often believed to have zero emissions. This 

option was not selected for several reasons. First, these valves are not suitable for use 

in all operating conditions and services encountered in SOCMI processes. 

Specifically, these valves can not be used in corrosive streams, with gritty materials, 

or in extremely high pressure or temperature conditions. Second, sealed bellows 

valves can leak internally, and will eventually fail. When failure occurs, there is 

potential for massive leaks. Due to this possiblity for leaks, monitoring of these 

valves is necessary. Considering this, the Committee thought that the leak detection, 

26 

S H ^a^lH^^^^^^^MB|^^^^^^^^MHB«|«^^_^_^_B_M_B__«__^___MB_____^_____I 
repair, and base performance level standards framework described above would best 

reflect MACT. This approach allows and would give credit for any low emission 

performing valve regardless of its design. 

The Committee considered several LDAR programs which tied monitoring 

frequency to the performance level achieved and created a framework that consists of 

several combinations of work practices and performance levels. In determining the 

maximum monitoring frequencies for Phase III, the Committee considered requiring 

weekly monitoring and monthly monitoring. The weekly monitoring program was 

rejected as being impractical and unreasonable. The Committee agreed that a monthly 

program was the maximum frequency that would be generally feasible, and would 

reduce emissions, while being sufficiently costly to provide an incentive for owners of 

such sources to identify more cost-effective approaches. For plants that do not achieve 

the performance level required for quarterly monitoring of valves, the standard 

requires monthly monitoring or participation in the QIP program. In addition, the 

Committee also decided to allow less frequent monitoring to provide an incentive to 

achieve better performance than that required for the base quarterly monitoring 

program. Annual and semi-annual frequencies were selected for the incentive 

programs. 

In selecting the base performance level and leak definition, the Committee 

considered the performance of the better performing EO units (and possibly the best 

BD units) and the performance of the units subject to the Texas 500 ppm standard. 

Using these data, the Committee considered leak definitions in the range of 50 to 1000 

27 

ma 
P.31 

ppm and performance levels from 1 to 5 percent leaking valves. These data and the 

fact that, in practice, low leak frequencies were achieved by a 500 ppm LDAR 

program alone supported the practicality and achievability of a performance limit for a 

quarterly LDAR program of 2 percent leaking valves at a 500 ppm leak definition. 

Leak definitions lower than 500 ppm were not selected due to uncertainties about the 

practical ability to measure and repair smaller leaks. A leak definition greater than 

500 ppm was not selected in light of data demonstrating the practicality and current 

implementation of a 500 ppm LDAR program. The Committee also agreed that units 

with less than 1 percent leaking valves could monitor the valves semiannually and 

those with less than 0.5 percent leaking valves could monitor annually. These 

performance levels were selected considering the Committee had previously agreed to 

exclude nonrepairable valves (up to a maximum of 1 percent of the total valve pool) 

from the calculation of percent leaking valves (see section E.3 of this notice for 

discussion of the basis for the nonrepairable provision). These performance levels 

have been demonstrated by the better performing EO process units, the EB/S unit, and 

by the plants subject to the Texas 500 ppm regulation. The Committee considered 

these levels to represent the performance of MACT. 

Pumps. In deliberations on the standard, the Committee considered the data 

summarized in Table VI-2, additional analyses of the EO/BD data, and the comments 

of pump seal manufacturers. The EO/BD data showed pump leak frequencies and 

overall performance to be highly variable with leak frequencies ranging from 0 to 50 

percent at a 1000 ppm leak definition. Additional analyses were done to compare the 

28 
P.32 

performance of dual mechanical seal (DMS) and single mechanical seal (SMS) pumps. 

These comparisons showed that, in general, DMS pumps screened at 0 ppm and that 

SMS pumps performance varied widely among the process units. In some cases, the 

SMS pumps screened at less than 100 ppm and could be viewed as having comparable 

performance to that of DMS pumps. For the majority of SMS pumps screening at less 

than 10,000 ppm, the screening values were fairly uniformly distributed from 100 to 

9100 ppm. Thus, the data did not provide a clear indication of the performance level 

that can be achieved by SMS without incurring high maintenance costs. 

From its consideration of the available data, the Committee generally concluded 

that pumps equipped with DMS, as a group, have lower leak frequencies than those 

equipped with SMS. Consequently, the Committee deliberated at great length on 

whether MACT is reflected by an equipment standard for DMS on all pumps or by a 

performance standard. The Committee decided not to establish an equipment standard 

because DMS are not suitable for use in all cases and because a DMS equipment 

standard would be very costly and would preclude effective lower cost options. Dual 

mechanical seals cannot be used with materials where leakage of the barrier fluid 

would affect product purity, with polymerizing monomers, or on reciprocating pumps. 

Also, the pump casing of some existing packed seal and SMS pumps does not allow 

installation of a DMS assembly. In such cases, a DMS equipment standard would 

require replacement of the entire pump. The cost of a DMS equipment standard was 

considered only in a general sense; estimates of the cost of pump replacements and the 

cost of installation of DMS systems were not the subject of Committee discussions. 

29 
P.33 

I 

The opinion that a DMS equipment standard would be very costly was based on 

general knowledge and the experience of some Committee members. However, to 

give all Committee members some perspective on the potential costs, EPA provided an 

estimate of the annualized cost for retrofitting an existing pump with a DMS system. 

This estimate showed the cost would be approximately $2,200/year (1990 dollars) for 

each pump. In previous rulemakings, EPA has estimated that a requirement of DMS 

on pumps has an incremental cost effectiveness over a 10,000 ppm LDAR program of 

$5,600/megagram of total VOC (1978 dollars), which is comparable to approximately 

$15,000/megagram in current dollars. Some Committee members expressed an 

additional concern that a DMS equipment standard would have significant adverse 

economic effect on small producers. 

To establish a performance standard that would reflect MACT for pumps, the 

Committee considered the performance capabilities of SMS (and packed seals) 

compared to the performance, applicability, and cost of DMS. Discussions among the 

Committee members, chemical industry representatives, and pump seal manufacturers 

lead to the conclusion that it is not possible to identify precisely best performance 

levels achievable by SMS and that, although advances in technology could reasonably 

be expected over the next 5 years, the limits on these advances could not be 

established. Because of technical limitations on the use of DMS on pumps in 

food/medical service and the use of mechanical seals on pumps handling polymerizing 

monomers, the Committee agreed to establish separate performance standards for 

pumps in those two services. 

30 
P.34 

For pumps in general service, the Committee agreed that 1000 ppm represented 

a performance target reflecting MACT and that repair of pumps with, a leak rate less 

than 2000 ppm could result in significant and costly maintenance, without any 

attendant emission reduction. Therefore, 2000 ppm was established as the 

concentration at which repair is required. The Committee also concluded that a 10 

percent leak frequency (or 3 leaking pumps) is the appropriate point to impose a 

quality improvement program that includes a mandatory replacement provision. On 

balance, it was believed that this combination of requirements would provide the time 

and incentive needed to achieve best performance from SMS, would allow use of SMS 

where they can achieve low emissions, and would allow use of both SMS and DMS 

pumps, as appropriate, to achieve the standard. 

For pumps in food/medical service, the Committee selected 2000 ppm and 10 

percent leak frequency as the performance level. The leak definition was set at 2000 

ppm to account for the limited applicability of DMS pumps and the uncertainty that 

SMS seals could achieve lower performance levels without excessive replacements in 

this service. The Committee also agreed that processes with pumps in food/medical 

service that exceed 10 percent leaking pumps would not be subject to the mandatory 

replacement provisions in the quality improvement program. 

For pumps handling polymerizing monomers, the Committee selected 5000 ppm 

and 10 percent leak frequency for the performance level. This decision was based on 

the lack of data and uncertainties on the limits of performance of SMS or packed seals 

in this service. It was also agreed that facilities that exceed 10 percent leak frequency 

31 
P.35 

would not be subject to the mandatory replacement provision of the quality 

improvement program. 

Connectors. Provisions for a LDAR program for connectors were developed 

after the Committee generally agreed that connectors could be a significant source of 

emissions at a well-controUed plant and that emissions could be reduced. In the 

development of these provisions, the Committee considered the data summarized in 

Table VI-2 and the contribution of connector emissions to total emissions for several 

EO/BD process units. These data showed connector leak frequencies as high as 3 

percent, at a leak definition of 10,000 ppm, and showed that connectors contributed 

the majority of the total emissions. Because some EO/BD units had 0 percent leaking 

connectors at various leak definitions, including 250 and 10,000 ppm, the Committee 

concluded that connector leaks can be controlled to low levels. The general view was 

that the relatively high leak rates observed at some process units was a result of 

infrequent or no inspections and maintenance. A LDAR program was established to 

ensure that low leak frequencies are attained. 

In development of these provisions, the Committee agreed that LDAR can 

reduce connector leak frequencies and that assuring MACT performance requires less 

frequent monitoring than is necessary for pumps or valves. Less frequent monitoring is 

needed because connectors have no moving parts and once repaired they should 

remain leak free for extended periods. Information provided by industry members on 

the Committee indicated that a number of actions can be taken to reduce or eUminate 

leaks. In most cases, it was expected that tightening the flange bolts on flanged 

32 
connectors would eUminate the leak. It was also expected that in other cases it may 

be necessary to replace the gasket or to correct faulty aUgnment of surfaces. These 

latter cases are expected to be relatively infrequent. The Committee, therefore, 

decided that an annual monitoring was the maximum frequency that was reasonable. 

The Committee also concluded that process units that demonstrate sustained 

performance at the level of the standard should be allowed to monitor less frequently 

than annually. This concept is similar to the skip-period provisions for valves in the 

existing equipment leak regulations. This approach is consistent with quality control 

principles and the Committee concluded that this approach will ensure MACT 

performance. 

The Committee selected the performance level and leak definition considering 

the data from the EO/BD units, the Texas 500 ppm units, and the general conclusions 

drawn fron the Committee's discussions. These data and the fact that, in practice, low 

leak frequencies were achievable persuaded the Committee that a leak definition of 

500 ppm and a base performance level of 0.5 percent leaking connectors would reflect 

MACT. Process units that have 0.5 percent, or greater, leaking connectors are 

required to implement an annual LDAR program for connectors. Process units that 

have less than 0.5 percent leaking connectors are allowed to monitor all connectors in 

a biennial or quadrennial program. 

E. Selection of Format of Standards 

Under Section 112 of the CAA national emission standards must, whenever 

possible, take the format of a numerical emission standard. Typically, an emission 

33 
P.37 

standard is written in terms of an allowable emission rate (mass per unit of time), 

performance level (e.g., 90 percent control), or an allowable concentration. These 

types of standards require the direct measurement of emissions to determine 

compliance. For some source types, emission standards cannot be prescribed because 

it is not feasible to measure emissions. Section 112 (h)(2) recognizes this situation by 

defining two conditions under which it is not feasible to establish an emission 

standard. These conditions are: (1) if the poUutants cannot be emitted through a 

conveyance designed and constructed to emit or capture the pollutant; or (2) if the 

application of measurement methodology is not practicable due to technological and 

economic limitations. If an emission standard cannot be established, EPA may instead 

establish a design, equipment, work practice, or operational standard or combination 

thereof. 

For equipment leak sources, such as pumps and valves, EPA has previously 

determined that it is not feasible to prescribe or enforce emission standards. Except 

for those items of equipment for which standards can be set at a specific 

concentration, the only method of measuring emissions is total enclosure of individual 

items of equipment, collection of emissions for a specified time period, and 

measurement of the emissions. This procedure, known as bagging, is a timeconsuming and prohibitively expensive technique considering the great number of 

individual items of equipment in a typical process unit. Moreover, this procedure 

would not be useful for routine monitoring and identification of leaking equipment for 

repair. 

34 
P.38 

The proposed standards incorporate several formats: equipment, design, base 

performance levels, work practices, and operational practices. Different formats are 

required for different types of equipment because of the nature of the equipment, 

available control techniques, and applicability of the measurement method. In the next 

section, the rationale for selecting a particular format is explained for each type of 

equipment. For each source type, the feasibility of prescribing or enforcing an 

emission standard is discussed. 

F. Selection of Emission Limits and Work Practice Requirements 

1. Applicability 

The Committee considered and ultimately established several additional 

applicabiUty criteria that further defined the scope of the negotiated standard. This 

section presents the Committee's consideration of minimum VHAP concentration, time 

in VHAP service, and pilot plants and research facilities. 

Stream VHAP concentration. The Committee discussed at some length what 

concentration cutoff should be used for determining applicability of the negotiated 

standard for specific streams within an affected process. This cutoff was of particular 

concern to industry members of the Committee because there are trace quantities of 

VHAP in many process streams. The number of equipment components potentially 

subject to the standard and the associated costs increase substantially as the 

concentration is decreased; and the emission reduction becomes small. Other 

Committee members were concerned that emissions from equipment handling streams 

containing low VHAP concentrations (e.g., less than 10 percent) become increasingly 

35 

HB 
P.39 

significant as higher concentration streams are controlled. Based on these 

considerations, the Committee agreed the standard would apply to equipment 

containing or contacting process materials that are 5 percent VHAP or greater. In 

SOCMI processes, this concentration was viewed as being a point of relatively low 

emissions and diminishing returns. 

Time-in-VHAP service. In certain chemical plants, particularly batch processes 

which produce a number of different products, there is equipment that is used in 

VHAP service only occasionally. In such cases implementation of the standard could 

be difficult and would achieve very little emission reduction. Pumps and compressors 

used only during startup or shutdown of a process unit are one example of such 

equipment. Other examples include equipment used in batch pharmaceutical processes 

or batch steps in continuous processes. For these situations, the Committee concluded 

that equipment that is operated 300 hours per year, or less, in VHAP service should be 

exempt 

Pilot plants. Exemption of pilot plants and research and development facilities 

from the negotiated standard was discussed on several occasions by the Committee. 

Some members thought that frequent changes in operations at these plants would make 

compliance with the standard difficult or would incur unnecessary costs. Other 

Committee members were of the opinion that the negotiated standard applies equaUy 

weU to pilot plants and research facilities as production units, and that chemical 

industry pilot plants can be quite large and have substantial emissions. An additional 

concern expressed by some members was that any exemption should be based on 

36 

^ m asm 
P.40 

objective criteria, not the intended use of the material or the purpose of the facility. 

The Committee ultimately agreed, unless directed otherwise by the CAA, to include 

pilot plants in the negotiated standard. 

The CAAA does not exempt pilot plants or research facUities but rather directs 

EPA to establish a separate category for these facilities as necessary to assure 

equitable treatment. Since the negotiated standard includes special provisions for 

small plant sites and low hours of operation, it is not considered necessary to exempt 

pilot plants. 

2. Compliance Dates 

In developing the compliance schedule and framework of the standards, the 

Committee anticipated the CAAA requirement that compliance dates for each category 

apply as expeditiously as practicable, but not later than 3 years after the effective date 

of the standards. The Committee recognized in the selection of compliance dates that 

the equipment leak regulation is primarily a work practice standard. Unlike standards 

that require installation of control equipment, the equipment leak regulation does not 

require major installation of equipment or large capital expenditures. Also the time 

needed to identify all components in VHAP service, establish a recordkeeping system, 

obtain monitoring equipment, and initiate an inspection and maintenance program is 

relatively short. Based on these considerations, and recognizing that advance notice 

would be provided when the rule is proposed in 1991, the Committee concluded that 6 

months after promulgation was a reasonable lead time for compliance with Phase I. 

37 
P.41 

An additional concern to the Committee in establishing the compliance schedule 

was the potential for the negotiated rule to overwhelm the resources of both industry 

and regulatory agencies because of the large number of affected facilities (about xxxx 

process units) expected. The Committee considered several methods of distributing 

the peak demand for equipment and staff, and ultimately agreed to a staggered 

implementation schedule that spreads the compliance over a 1- year period. The 

affected source categories were divided into five groups roughly based on the 

carcinogenicity and weight of evidence for the chemicals associated with the category. 

Sources handling chemicals with the highest health hazard were assigned to group I 

and those with the lowest were assigned to group V. In addition, the 7 non-SOCMI 

source categories as well as benzene, toluene, and xylene production were included in 

the first group of source categories. The Committee agreed that this would allow 

industry, contractors, vendors and regulatory agencies the time necessary to manage 

successfully the increased demand on resources and personnel that is anticipated to 

result from the negotiated rule. 

The provisions of the negotiated rule would become applicable to those 

processes Usted in first Group 6 months after promulgation of the HON, and to one 

additional group of production processes each successive quarter. The negotiated rule 

would, therefore, become applicable to the last group 18 months after promulgation of 

the negotiated rule. Apart from staggered applicability dates, all other provisions of 

applicabiUty, including the provisions for a source to request an extension, remain as 

provided for in the General Provisions for NESHAP. 

38 

sat 
The negotiated rule also allows an owner or operator to elect to comply with the 

applicabiUty date of an earlier group. The Committee agreed that some owners or 

operators at plants having process units from two or more groups might prefer to 

comply with the provisions of the negotiated rule aU at once, or in fewer phases, in 

order to avoid confusion or misunderstandings about what rules or procedures were 

applicable to which individual items of equipment. 

3. Phases of Valve and Pump Standards 

Both the valve and pump standards were structured in three phases to allow time 

to improve performance and to achieve progress toward lower emission levels. The 

Committee designed Phase I to allow existing facilities unfamiliar with the existing 

rules the time necessary to develop and implement a 10,000 ppm LDAR program as 

weU as to assess the necessary changes in operations, maintenance, and training of 

employees. Phase I is considered necessary because the majority of existing facilities 

do not presently implement LDAR programs and it was recognized that establishing 

programs can be a lengthy process. The Committee agreed Phase I should begin on 

the applicability date for an existing unit and last for 1 year. A 1-year interval will 

allow 4 quarters of monitoring which should provide sufficient time to establish a 

program and to identify and repair valves and pumps with the highest emissions. 

Phase II was established to achieve further emission reductions by reducing the 

leak definition to 500 ppm for valves and 5000 ppm for pumps. This phase is 

intended to expand the focus from the higher screening value leaks to lower values 

and to continue the identification of problem equipment. The Committee agreed that 

39 
P.43 

Phase II would begin 1 year after the applicablity date for an existing process unit and 

would allow 1.5 year duration before implementing Phase III. 

In Phase III for valves, the Committee added a base performance level 

requirement to the work practice requirements of Phase II. The base performance 

level was added to ensure a more certain emission performance than achieved through 

the work practice requirement alone and to create an economic incentive to improve 

performance. For Phase III of the pump standard, the Committee added a base 

performance level requirement to the work practice requirements and reduced the 

concentration defined as a leak. The Committee established separate leak definitions 

for three categories of pumps to ensure that each category achieves MACT. 

For new process units, the Committee agreed that for both pumps and valves 

Phase II should be implemented at startup and Phase HI should be implemented 

beginning 1 year after startup. It was expected that new units will be designed using 

better equipment and considering the requirements of the standard. The Committee 

provided a 1 year period in Phase II to allow time needed for adjustments to 

operations and to correct any problems encountered during startup of the process unit. 

4. Valve Standard 

As discussed earlier, the Committee developed the valve standard using the 

LDAR program of the existing rule as a starting point. The standard recommended by 

the Committee consists of three phases of requirements of increasing stringency and 

these requirements are a combination of LDAR programs and performance levels. 

Fiqure VI-1 presents the conceptual approach for the valve standard. The rationale for 

40 
P.44 

PhSMl 10,000 ppm "SS 

Phase II 

Phat* III 

Monthly 

LDAR 

Quality 

Improvement 

<2%, 500 ppmv 

>2%, 500 ppmv 

>1% 

500 pp 

>0.5« 

500 pp 

mv 

It 

mv 

Quarterly 

LDAR 

. 

Semi-Annual 

LDAR 

i 

Annual 

LDAR 

50! 

< 

50 

< 1% 

9 ppmv 

:0.5% 

D ppmv 

VIFigure 1. Standard for Valves 

J\0 Oy-
the framework of the standard and the selection of the base performance levels was 

explained in Section D above. This section explains the rationale for other provisions 

in the proposed valve standard. 

The Committee used LDAR programs as the starting point because LDAR is an 

effective means of detecting and eliminating emissions from seal, failure. For emission 

sources such as valves, emission standards do not provide appropriate control 

procedures. As previously discussed, an equipment standard was not selected because 

equipment, such as sealed bellows valves, cannot be uniformly applied to all SOCMI 

processes. Moreover, proper use of equipment such as sealed bellows valves, also 

requires a LDAR program because these valves can fail and can have high emission 

rates upon failure. 

Valve repair intervals. Repair of leaks soon after detection is a key feature in 

the proposed rule and is a factor in the effectiveness of LDAR programs. The 

Committee agreed to retain, in the negotiated standard, the repair intervals (i.e., first 

attempt at repair in 5 days and repair within 15 days) specified in the existing rules 

(e.g., 40 CFR Part 61, Subpart V). The repair intervals in the existing standards are 

intended to provide effective emission reduction while allowing the time necessary for 

scheduling of more complex repairs. 

As in the existing equipment leak standards, the first attempt at repair is 

required as soon as practicable after detection of the leak and no later than 5 days 

after discovery. Most valve repairs, such as tightening the bonnet bolts, can be 

performed quickly, and 5 days should provide sufficient time to schedule simple field 

41 
P.46 

I 

repairs that do not require isolation of the valve from the process. Attempting to 

repair a leak within 5 days will help identify those valves that cannot be repaired with 

simple field repair or without shutdown of the process unit. Valves that are not 

repairable by simple field procedures may require removal from the process for repair. 

The 15-day repair interval provides sufficient time to identify methods for isolating 

leaking valves for repair when isolation is necessary and extensive repairs are required. 

Shorter repair intervals were not selected because they could cause problems in 

performing effective repairs on valves that must be isolated from the process. 

The Committee also recognized that some valves cannot be repaired without 

shutting down the process and that process shutdown is costly and may result in 

greater emissions than delaying repair until the next scheduled shutdown. For these 

reasons, the existing equipment leak regulations allow, under certain conditions, delay 

of repair of these "nonrepairables" until the next facility shutdown. These rules, in 

general, require that these valves be repaired during that shutdown. The Committee 

reviewed the delay of repair provisions in the existing rules and concluded that these 

provisions are appropriate and should be included in the negotiated standard. 

Nonrepairables. There was considerable discussion by the Committee of 

whether those valves that cannot be repaired without a process unit shutdown should 

be considered in determining the required monitoring frequency. One view was, if 

unrepairable components were included, the potential for increased monitoring 

frequency would provide a strong incentive for companies to take every possible step 

to prevent leaks or to repair leaking valves. However, it was also recognized that 

42 

_________! 
P.47 

nonrepairable valves may not be completely preventable and counting these could 

result in higher leak percentages in process units or facilities that have infrequent 

shutdowns. Moreover, increased monitoring frequency, if triggered by nonrepairable 

components, is of little direct benefit since the nonrepairable valves will remain 

unrepaired in spite of more frequent inspection. In light of these considerations, the 

Committee sought to provide a means to provide motivation for plants to limit the 

number of nonrepairable valves, while at the same time avoiding imposition of 

unproductive costs or inadvertently increasing emissions. The agreed upon approach 

achieves such a balance by excluding nonrepairable valves up to a total of one percent 

of the valves in VHAP service from the calculation of percent leaking valves for 

sampling periods after the leaking valve was first identified. 

Averaging periods for calculation of percent leaking. In establishing the base 

performance levels in Phase IH, the Committee considered the variability inherent in 

measurements of equipment leaks and the variability in leak rates over time. There 

was considerable debate as to whether measurements of equipment leaks are 

sufficiently precise to warrant performance criteria or how to consider this variability 

in the framework of the rule. The concept of a 2-period rolling average was 

introduced as a means of ensuring that random fluctuations, of themselves, do not 

force a faciUty into more frequent monitoring. In addition to the benefits of 

averaging, the rolling average of two consecutive monitoring periods provides the 

opportunity for the plant to take action, such as increased surveillance on a subset of 

valves, based on higher than normal leak rates in a single period. It also allows the 

43 

ESMM 
owner or operator the necessary flexibility to implement supplemental quaUty 

assurance programs to ensure that performance remains below base levels. The 2-

period rolling average is designed to encourage such plant designed quality assurance 

programs and it does not penalize more frequent inspection and maintenance. The 

Committee selected this approach for semiannual and more frequent monitoring 

schedules. 

The Committee did not choose to apply the 2-period average approach to annual 

monitoring programs because of the low performance level required for annual 

monitoring and concerns that effective control programs could be unintentionally 

penalized due to a single high monitoring result. Specifically, a Committee member 

described the effect of extreme weather that caused an unplanned shutdown and 

resulted in an abnormally high number of leaking valves after startup. In this case, the 

plant would have to revert to more frequent monitoring if only two monitoring periods 

were considered even though the leak frequency was normally near zero. Such a 

penalty would be inconsistent with the intent to encourage effective, plant designed 

quality assurance programs that achieve continuing low leak performance. In light of 

this, the Committee agreed to base the annual monitoring criterion on the average of 3 

out of 4 years of data. This averaging procedure is intended to provide relief for 

facilities with histories of good performance from the effects of unusual and infrequent 

perturbations. 

Credits for removing valves. In developing the negotiated standard, the 

Committee recognized that minimizing the number of components in a process is one 

44 
P.49 

of the most effective means for reducing leaks. Therefore, the Committee gave careful 

consideration to formats for, or means of, providing an incentive to minimize the 

number of components and the amount of credit provided. 

For new process units, no mechanisms could be identified that would provide 

such an incentive for all SOCMI processes. New unit designs differ widely from 

process to process and it was not possible to define a norm or baseline from which 

component reductions could be determined for new units. In contrast, equipment 

count baselines can be established for existing process units at the time these units 

become subject to the standards (for new units at startup) and can be used as the basis 

for calculating credits for future reductions in the number of valves. The Committee 

elected to provide these credits in the calculation of percent leaking valves and the 

associated determination of monitoring frequency. The Committee also decided that 

use of the valve credit provisions should be at the option of the owner or operator of 

the process unit because of the burden associated with the recordkeeping needed to 

document the reduction. 

The Committee considered credits for components removed ranging from full 

credit to one-half credit for each component removed. The full credit option was not 

selected because it could be used to achieve a good performance level without actually 

reducing the number of leaking valves. Based on a desire to provide credit for 

reducing the number of components, while at the same time ensuring that removal 

credits do not reduce the incentive for low-leak performance in the remaining 

components, the Committee selected a 67 percent credit for net reductions in the 

45 
P.50 

number of valves; i.e., 2 out of every 3 valves removed from a process unit may 

continue to be counted in the total number of valves when calculating leak frequency. 

Unsafe-to-monitor and difficult-to-monitor valves. The Committee agreed that 

the "unsafe-to-monitor" and the "difficult-to-monitor" provisions in the existing 

equipment leak standards are appropriate and should be included in the negotiated 

standard. Valves that are "unsafe-to-monitor" are defined as valves that could expose 

personnel to imminent hazards from temperature, pressure, or explosive process 

conditions. Examples of such locations include valves at the top of or located nearby 

high pressure reactors. Valves that are unsafe-to-monitor cannot be eliminated from 

new or existing units. The rule, therefore, would exempt valves in unsafe locations 

from routine monitoring requirements, but would require monitoring as frequently as 

practicable during safe-to-monitor periods. 

At existing process units, valves may be located where they can be reached only 

through extraordinary means. The Committee concluded that the criteria for difficultto-monitor valves are appropriate and that routine monitoring should not be required 

for valves that require elevating personnel more than 2 meters above any permanent 

support surface. This means that valves that cannot be safely monitored from a step 

ladder or portable scaffolding could be classified as inaccessible and exempt from 

routine monitoring. As in the existing rules, the difficult-to-monitor exemption would 

be available only for existing units. The Committee agreed that routine monitoring of 

valves that have the potential to leak should be considered in the design of new units. 

46 

fi---H^--^--l---^---H---^---^---M----^---^---^--^^^^^^^^^^^^^^BBBHBH^--i--l 
P.51 

250 valve exemption from Phase III monthly monitoring. The Committee 

agreed to require a quarterly LDAR program in Phases I and II and in Phase III to 

base the monitoring frequency on the performance level achieved. In Phase HI, 

sources that exceed the base performance level have the option of monthly monitoring 

or participation in a QIP. For small plants, however, there was concern that either 

monthly monitoring or QIP would present an unreasonable burden. Because of the 

limited technical and financial resources and the relatively low emissions from small 

plants with a quarterly LDAR program, the Committee established 250 valves per 

plant site as the level below which quarterly monitoring would be the most frequent 

monitoring interval required. The Committee defined a small plant as a site with 250 

valves, or fewer, based on an industry estimate of representative number of valves at 

small facilities and the estimated emissions from such facilities. 

5. Pump Standard 

As discussed earlier in "Development of Framework and Selection of MACT", 

the Committee developed the pump standard using the provisions of the existing 

standards as a starting point. The recommended standard consists of three phases of 

requirements of increasing stringency and these are a combination of LDAR programs 

and performance levels. The Committee also retained the existing provisions for DMS 

systems and for sealless pumps (e.g., canned pumps). Figure VI-2 presents the 

conceptual approach for the pump standard. The rationale for the framework and the 

selection of the base performance levels was explained earlier in this notice. This 

section explains the rationale for other provisions in the proposed pump standard. 

47 
P.52 

PfJOCOll 

PtiQCOll 

I. toco I 

General Pumpo 

Monthly, LDAR 

>10%or3 

(S month rolling 

avg. at 1,000 ppm) 

(ropair at 2,000 ppm) 

Full QIP 

20% RoplGcomcn. 

poryoor 

10,000 ppm 

5,000 n m 

Food/Mcdlcol 

Monthfy, LDAR 

>10%or3 

(6 month rolling 

avg. at 2,000 ppm) 

3__ 

Polymerizing Monomoro 

Monthly, LDAR 

QIP 

No Replacement 

>10%or3 

(6 month rolling 

avg. at 5,000 ppm) 

\jh 

Figure 2. Standard for Pumps 

it 
P.53 

As with valves, the Committee used LDAR programs as the starting point 

because it is an effective means of detecting and controlling emissions and because 

these sources are not amenable to application of an emission standard. As discussed 

previously, the Committee did not establish a standard requiring the use of DMS 

systems or seaUess pump designs because this equipment cannot be used in all SOCMI 

processes. Moreover, this equipment can fail and leaks can occur. Thus, proper 

operation and maintenance of DMS systems and sealless pumps requires periodic 

monitoring. For these reasons the Committee developed a standard that requires use 

of LDAR programs or use of DMS systems and sealless pump designs with periodic 

monitoring. 

Pump repair intervals. For the reasons discussed in the valve standard, the 

Committee retained the 5-day first attempt and the 15-day repair intervals of the 

existing rules in the pump standard. The Committee agreed that, with a minor 

clarification, these repair intervals were appropriate. The Committee added language 

to clarify the types of simple field repair that are intended to represent first attempt at 

repair. This provision was added to reduce uncertainty regarding compliance and to 

consider the increased maintenance that will be required with leak definitions lower 

than 10,000 ppm. 

The Committee also recognized that some pumps are not spared in chemical 

process units and cannot be repaired without shutting down the process. The delay of 

repair provisions for pumps in the existing standards were reviewed and the 

48 

m 
P.54 

Committee concluded that it was appropriate to include these in the proposed standard. 

Averaging period for calculation of percent leaking. During development of the 

Phase HI base performance level, concerns were expressed by Committee members 

regarding the inherent variablity of percent leaking calculations given the small 

number of pumps typically present in process units and the inherent variability of the 

leak measurements. WhUe there were no data available to quantify the month-tomonth variability of pump leak frequencies, it was expected from general experience 

that leak frequencies would be highly variable. It was also judged that leak 

frequencies based on short time periods of data would be poor predictors of the type 

of performance that the QEP was intended to remedy. The Committee, therefore, 

concluded that pump leak frequencies should be averaged over a period of several 

months to provide an indication of trends in performance. A rolling 6-month average 

was selected by the Committee as an appropriate measure for indicating upward trends 

and the need to take additional measures to reduce pump seal failures. 

Calculation of percent leaking pumps. The calculation procedure specified in 

the pump standard is designed to address additional concerns about the variabiUty of 

pump leak frequencies and to encourage the use of low leak design pumps and pump 

seals. Because of the smaU number of pumps in typical process units, the Committee 

provided the owner or operator the option of calculating percent leaking on a process 

unit or plant site basis. This option was provided to allow the necessary flexibility to 

consider further problems associated with small population statistics and site specific 

49 

-f-H 
P.55 

concerns. The Committee also decided to require the owner or operator to designate 

the basis for calculating percent leaking pumps in the first monitoring period and to 

use that basis for all subsequent calculations. This was required (1) to preclude 

sources from using the most favorable basis for the period and circumventing the 

intent of the pump standard and (2) to simplify enforcement. 

The Committee also agreed that pumps equipped with DMS systems and sealless 

pumps (e.g., canned or magnetic pumps) could be included in the calculation of 

percent leaking pumps. For the purpose of this calculation, these pumps are assumed 

not to leak. The calculation procedure, thus, gives credit for use of inherently low 

leak designs and is intended to provide an incentive to install these designs. 

The negotiated standard would exclude pumps that leak shortly after startup of a 

process unit from the calculation of percent leaking for that monitoring period. This 

exclusion was added because industry members of the Committee reported that 

preinstaUation testing does not necessarily ensure that a pump will not leak when put 

into service. The industry members also thought that these leaks are not indicative of 

a long term problem. The Committee concluded that such pumps should be subject to 

the repair requirement, but that this problem is not indicative of the type of poor 

performance that QIP is intended to remedy. 

Requirements for low leak design pumps. The Committee retained, with slight 

modifications, the provisions in the existing standards for pumps with DMS systems 

and for sealless pumps (e.g., 40 CFR §61.242-2 (d) and (e)). For pumps with DMS 

systems, the Committee agreed that it was only necessary to prohibit use of light50 
P.56 

liquid VHAP as barrier fluids. The Committee aUowed the use of heavy-liquid VHAP 

barrier fluids because the operation and monitoring requirements for DMS systems 

were considered sufficient to minimize any emissions from leaks from the DMS 

system. The Committee also reevaluated the requirement for annual demonstration of 

no detectable leaks from sealless pumps in the existing standards (e.g., §61.242-2 (e)). 

The Committee considered the causes of failures of these designs and concluded that 

weekly visual inspection would achieve equivalent performance and assure that these 

pumps have no emissions. Consequently, under the negotiated pump standard these 

sealless design pumps would be subject to a weekly visual inspection work practice 

standard and would not be subject to an annual performance test requirement to 

demonstrate no emissions. 

6. QIP for Valves and Pumps 

As discussed earlier in "Development of Framework and Selection of MACT" 

section of this notice, the Committee recognized that there is uncertainty in the 

achievability of the performance levels by all SOCMI processes, given that these 

levels are based on information from a small number of chemicals. Consequently, the 

Committee developed provisions that would require process units not achieving the 

base performance levels for valves to implement more frequent monitoring or a quality 

improvement program (QIP) designed to ultimately achieve the performance levels and 

units not achieving the base performance levels for pumps to implement a QIP. A 

process unit not able to achieve the performance levels is not out of compliance if it 

undertakes these additional measures. The provisions for quality improvement were 

51 

lJll 
P.57 

included in the framework to allow those owners or operators of process units that do 

use all elements of MACT but do not achieve the base performance levels the 

flexibility to develop process unit-specific, cost-effective methods for improving 

emission performance. The QIP also provides an innovative mechanism for focusing 

efforts on reducing emissions while avoiding lengthy enforcement actions. 

Only a few process units are expected to use the valve QIP. It is expected that 

in the majority of cases, a systematic program of monitoring individual components 

and repair of those that leak will achieve the performance levels of the standards. It is 

recognized, however, that there may be situations where the performance levels cannot 

be achieved due to specific process and operating conditions. The valve and pump 

QIP's were designed to provide a mechanism for improving performance in such 

situations. These QIP prescribe programs that will require a commitment to quality 

improvement and wiU involve many aspects of plant operations (e.g., engineering and 

maintenance). This section presents the basis for the specific provisions in the valve 

and pump QIP. 

Valves. 

The CdtTimittee developed two alternative QIP for valves and agreed to restrict 

the availability of both of these alternatives. The QIP may be a program that either 

demonstrates progress in reducing the percent leaking valves or implements a 

technology review and improvement program. The decision to use either of these 

alternative QIP must be made during the first year of Phase III for both new and 

existing units. Under either alternative QIP, after the process unit has achieved less 

52 

a 
P.58 

than two percent leaking valves, the owner or operator may elect to continue the QIP. 

If the owner or operator discontinues the QIP, however.the QIP may not be used in 

the future if the unit again exceeds two percent leaking valves. In such cases, the 

owner or operator must implement monthly monitoring until the unit has less than two 

percent leaking valves, 

a. Demonstration of Progress QIP. 

This alternative QIP would allow an owner or operator of a source to design and 

implement a site specific program to achieve steady progress in lowering the percent 

leaking valves. Any combination of measures such as increased maintenance 

frequency or replacement of components may be used, provided it achieves the 

required reductions in percent leaking valves. 

Under this QIP. the owner or operator would be required to continue quarterly 

monitoring and to demonstrate an average 10 percent reduction in the percent leaking 

valves each quarter, based on a rolling average of 2 quarters of monitoring data. If an 

owner or operator fails for 2 consecutive averaging periods to demonstrate at least an 

overall average reduction of 10 percent per quarter, the owner or operator must either 

implement a technology review and improvement QIP or monthly monitoring. If this 

QIP is continued after a process unit has less than two percent leaking valves, the 

owner or operator must continue quarterly monitoring, but does not have to continue 

to demonstrate the 10 percent reduction per quarter. 

The Committee developed this QIP to provide an ad hoc performance limit for 

those owners or operators interested in a less formal improvement program than that 

53 

• 
P.59 

specified in the technology review and improvement QIP. It was envisioned that this 

alternative QIP would be useful primarily for those process units with leak frequencies 

only slightly greater than 2 percent. The Committee judged that an average reduction 

in percent leaking valves of 10 percent per quarter, calculated as a rolling average of 2 

quarters of monitoring data, would provide a reasonable basis for determining whether 

progress was being made in approaching the 2 percent performance level. Moreover, 

it was expected that this rate of reduction would achieve the performance levels of the 

base monitoring program at a time comparable to that expected under the technology 

review and improvement QIP. To ensure that continual progress is achieved, the 

Committee required that units failing to show progress, as measured by the reduction 

in percent leaking valves, either implement monthly monitoring or a technology review 

and improvement QIP. With either of these more structured alternatives, it was 

expected that adherence to the program would reduce emissions, 

b. Technology Review and Improvement QIP. 

This QIP was designed to provide a generic process for identifying appropriate 

solutions to systematic problems. The Committee developed these provisions 

considering the fundamentals of problem solving and quality improvement principles. 

The QIP is structured as three classes of requirements: data collection and analysis, 

performance trials, and quality assurance and improvement. 

The principal basis for the provisions in the QIP was general knowledge of 

factors affecting equipment leaks and recent experience in leak control at some 

chemical production units. Key principles used in developing this QIP are (1) the 

54 
P.60 

detatis of programs (e.g., specific designs or equipment) are best determined by the 

source for the conditions in the process unit and (2) good performance is the 

cumulative result of analysis and attention to quality improvement over a period of 

several years. Specific information that the Committee considered included the 

reported recent experience of one EO producer in reducing and eliminating leaks from 

two process units. The experience of CMA's phosgene panel and the process that was 

used over the past 10 or more years to achieve their present performance were also 

considered. How the Committee weighed the various factors in arriving at the details 

of this QIP is described in the paragraphs below. 

The Committee included a requirement for extensive data collection because 

these data are essential to understanding the causes of problems and to development of 

a corrective program. The QIP would require that specific information be recorded on 

each valve's design, materials of construction, packing, type, service conditions, and 

screening values. Engineering evaluations would also be required to determine the 

causes of failure of all valves removed from the process unit due to leaks. These 

records are required to ensure that the data necessary for evaluation of causes of leaks 

is available. 

The QIP would require analysis of the data to determine if there are specific 

problem services, operating conditions, valve types, designs, and materials of 

construction. A second, and equally important, objective of the analysis would be to 

identify valve designs and operating practices that will operate with less than 2 percent 

leaking valves under conditions comparable to those in the process problem areas. 

55 
P.61 

Such valve designs or technologies are referred to in the QIP as superior performing 

valve technologies. Because process conditions and causes of valve leakage do vary 

among process units and the combinations of equipment and procedures that are 

"superior" may differ, superior performing valve technology is not specified 

exclusively in terms of specific valve types or designs. Rather, superior performance 

is defined as including any combination of valve type and process, operating practices, 

and maintenance practices that achieves the base performance level of the standard. 

This flexibUity was provided because it was recognized that best performing 

equipment has to be determined in context of the application. In some cases, superior 

performance may be achievable by use of a different packing material in the valve; in 

other cases, use of a different valve design or design changes to the process 

configuration may be required. Such specific decisions are best determined by the 

source owner or operator. 

These superior performing valve technologies may be identified through analysis 

of the process unit (or plant) data, or through review of available literature and the 

experience of other facilities. Both the process unit (or plant) data and outside 

experience must be considered in identification of candidate superior valves for 

performance trials. This was specified to ensure that a comprehensive assessment was 

conducted. For similar reasons, the Committee agreed that the analysis and 

identification of better performing equipment may be conducted through an inter or 

intra-company program and may be for a single process unit, a company, or group of 

process units. 

56 
The Committee decided that the first data analysis must be completed no later 

than 18 months after the start of Phase HI. This schedule was established considering 

both the time necessary for understanding the problem(s) and the need to achieve a 

reasonable rate of progress. The data analysis must be reevaluated each year the 

process unit is in the QIP and has two or more percent leaking valves. This was 

included to ensure continued improvement. 

Performance trials would be required where the data analysis for the process unit 

does not identify any superior performing valve designs or technologies that can be 

applied to the process unit. Performance trials of candidate equipment will ensure that 

possible solutions are evaluated and that application of new equipment or operating 

procedures makes good engineering sense. These trials must be conducted as part of 

an experimental program that identifies all the designs and technologies to be 

evaluated, the stages of the evaluation, the range of planned test conditions, estimated 

duration of each stage, and documentation of the conclusions for each test. The 

purpose of the performance trials provision is to detennine if candidate equipment or 

operation and maintenance procedures can be used in the conditions in the process 

unit. Because these performance trials are primarily intended to be tests of feasibiUty 

of application to the process conditions, the number of valves in the trial program was 

set at a realistic number for experimental evaluation. The performance trials are not 

intended to provide an estimate of the leak frequency. The QIP would require 

performance trials for one percent of the valves up to a maximum of 20 valves in a 

single process unit or 50 valves in a plant site study. The first performance trials shall 

57 

t_t__i 
be completed by 24 months after the start of Phase HI, or 6 months after conclusion of 

the first data analysis. At that time, the owner or operator shall have identified valve 

designs or technologies that combined with appropriate process, operation, and 

maintenance practices operate with low emissions. The owner or operator shall 

continue performance trials until a superior performing technology is identified, the 

process unit has less than 2 percent leaking valves, or there are no additional 

technically feasible candidate technolotgies remaining. As additional information and 

experience are gained in the QIP, the list of identified low emission performing 

equipment shall be updated. 

The owner or operator would be required to prepare a quality assurance plan 

that is based on the results of the data analysis, engineering evaluations of valves, and 

the performance trials. The plan must include procedures that will ensure that each 

valve that is replaced is replaced with a quality assured valve that will achieve low 

emissions in the process unit. These valves must be valve technologies that have been 

identified as superior emission performance technology for that category of valves, 

unless no superior performers could be identified. Where this occurs, the valves must 

be one of the lowest technologies identified for the specific application. The quality 

assurance plan must specify minimum design standards for each category of valves 

established by the owner or operator, a written procedure for bench testing of valves 

for leaks, provide an audit procedure for quality control of purchased equipment, and 

procedures to ensure quality of any rebuilt equipment. The quality assurance program 

for replacement valves must be implemented as long as the process unit remains in the 

58 

mm 
P.64 

QIP. These provisions were included to guarantee there would be continued 

improvement in the emission performance of the process unit. 

This quality assurance plan is to be established by the start of the third year of 

Phase III for most plant sites and by the start of the fourth year of Phase in for plant 

sites that meet the exemption for small facilities. 

The Committee exempted plant sites that have fewer than 400 valves and that is 

owned by a company with fewer than 100 employees from the requirement to conduct 

performance trials. This exemption from performance trials was provided to consider 

the limited technical resources available for conducting research at smaller companies 

and to minimize any adverse impacts of the standard on small companies. The 

Committee selected the exemption criteria based on typical valve counts in a small 

process unit and an industry estimate of the typical number of employees for a smaU 

company. These facilities were also allowed an additional year to develop a quality 

assurance plan and to begin using quality assured valves that will operate with low 

emissions in the process unit. The Committee provided this additional time to allow 

these smaller facilities the time needed to obtain the necessary information from peers, 

vendors, literature, and other sources. 

The Committee considered, but rejected, provisions that would have required 

mandatory replacement of some proportion of the valves in the process unit each year. 

Such a provision was not established for valves for several reasons. Leaking valves 

can only be repaired on-line a limited number of times before they can no longer be 

adjusted to achieve lower emissions and must be replaced. Typically, on an 

59 

_________ 
P.65 

industrywide basis, 7 to 10 percent of the valves are reportedly replaced each year for 

reasons other than emission performance (i.e.,they are leaking). If valves that are 

replaced (for any reason) are replaced with quality assured valves appropriate to the 

service conditions, an improvement in emission performance can be achieved at 

nominal additional cost. The Committee judged that the normal replacement of 7 to 

10 percent of the valves each year was a reasonable rate of improvement considering 

that a mandatory replacement program would cause very high expenditures for 

negligible benefit. 

Pumps. 

The Committee developed a technology review and improvement QIP as a 

means for process units (or plants) to ultimately achieve the performance level of the 

standard. Only this QIP was employed because the Committee believed that for 

pumps the only practical solution was an engineering analysis to determine the causes 

of systematic problems (e.g., design, application, etc.). Like the valve QIP, this QIP 

was designed to provide a generic approach to evaluate the problem, identify solutions, 

and improve equipment and operations. The Committee also recognized that sufficient 

time must be provided to identify both the causes of leaks and cost-effective solutions. 

Thus, the pump QIP specifies similar requirements on the same schedule as the valve 

QIP. The pump QIP differs from the valve QIP in several respects due to differences 

between the two standards and between the equipment. This section presents the 

rationale for the differences between the provisions for the two QIP and the additional 

factors that were considered in developing the pump QIP. 

60 

L-i _i-ll-l 
Unlike the valve provisions, the pump QIP would not be an option for selection 

by the owner or operator and there would be no restrictions on when a process unit (or 

plant) enters a QIP. An owner or operator must comply with the requirements of the 

QIP whenever the greater of either 10 percent of the pumps or 3 pumps in a process 

unit (or at a plant) leak. A process unit must remain in the QIP as long as the percent 

leaking pumps is greater than the base performance level. Theoretically, a process unit 

(or plant) could be subject to the QIP provisions more than one time. In cases where 

a process unit (or plant) again becomes subject to the QIP, the QIP must be resumed 

starting at the performance trials stage. Resumption at the performance trials was 

specified because there should be no need for data collection and analysis since that 

should be available from the earlier QIP. 

As with the valve technology and review QIP, the Committee required that a 

comprehensive database be developed on pump type, design, materials of construction, 

service characteristics, and screening values. The engineering evaluation requirement 

differs in that inspections are required for pumps removed from the process due to 

leaks and for pump seal designs associated with high failure rates. It is specified in 

this manner to ensure that evaluations are of equipment with apparently fundamental 

design or application problems and are not of equipment at the end of the design life. 

Both pumps and pump seals were included to ensure that aU possible sources of 

leakage (e.g., split casings on large pumps) are included. 

. As in the valve QIP, the data are analysed to identify problem areas and services 

as well as to identify superior pump performing technologies. Again, these 

61 

l.Ai.i--.-i 

_•',_]__.,_,___-.-- • MM - =-__-_=_--—__«==-.-----.--»--- n ^ .___,,.._- . — . ,.„... . , „..,..„ _ 
technologies are not considered to solely include particular pump or seal designs. 

Superior emission performance technology may include material or design changes to 

existing pumps, pump seals, seal support systems, use of multiple mechanical seals, or 

replacement by a canned pump or a magnetically driven pump. Any combination of 

equipment and operating practices that achieves the standard is considered to be 

superior emission performance technology. 

The pump performance trial provision sets a lower limit than the valve QIP does 

on the number of performance trials; for pumps the number of tests is one percent of 

the pumps up to a maximum of two for a single process unit and five for a plant. The 

smaller number of trials is specified because pump populations are much smaller than 

valve populations. Furthermore, with pumps there will be far fewer changes in 

operation, maintenance, and design parameters that can be evaluated. Again, because 

the purpose of the trials is to test the feasibility of using the technology and not to 

predict the leak frequency, a large number of trials is not necessary. 

The quality assurance program for pumps would have the same basic objectives 

and requirements as does the valve program. The minor differences between the pump 

and valve requirements arise because bench testing of pumps is not a useful predictor 

of on-line performance and was not required. 

For pumps in general chemical service, the Committee decided to require 

replacement of 20 percent per year of the pumps or pump seals with equipment, 

operations, and maintenance practices identified as superior emission performance 

technology. As discussed earlier, this superior emission performance technology is not 

62 
considered to be exclusively represented by specific designs such as canned pumps or 

specific types of pump seals such as dual mechanical seals. Rather, it is envisioned as 

consisting of the combination of pump and seal design combined with appropriate 

process, operation and maintenace practices that will achieve the performance level of 

the standard. The mandatory replacement provision was included for general chemical 

service pumps to ensure that process units (or plants) achieve demonstrated 

performance levels. The Committee intended for this provision to serve as an 

incentive to improve performance. 

Mandatory replacement provisions were not applied to pumps in food/medical 

service or to pumps handling polymerizing monomers since in both cases no 

demonstrated performance level or technology could be identified. No data were 

available to the Committee that showed the performance level that could be achieved 

by these services. As explained earlier in discussion of the proposed pump standard, 

the Committee also concluded that dual mechanical seals could not be used on pumps 

in these services. Consequently, the Committee agreed that replacement equipment 

must be quality assured and be one of the lowest emission performance technologies 

identified. 

7. Standard for Connectors in Gas/Vapor and Light Liquid Service 

As discussed earlier, the Committee developed a standard for connectors that 

consists of a LDAR program in which the monitoring frequency is based on the 

percent leaking connectors and a leak is defined as an instrument reading of 500 ppm 

or higher. This standard would not be phased in and would apply as soon as the rule 

63 
P.69 

is effective for a process unit. The Committee judged that phase in of the standard 

was unnecessary since once connectors are leak tight they should remain leak tight. 

i 

Figure VI-3 presents the conceptual approach to the connector standard. In addition to 

the basic LDAR program, the Committee also established several provisions to address 

situations unique to connectors. This section explains the rationale for these additional 

provisions. 

As with other equipment, the Committee judged that it is not technically or 

economically feasible to establish an emission standard for connectors. A work 

practice standard, consisting of a LDAR program and a base performance level, was 

developed because it provided a practical means of detecting and controlling emissions. 

Connector repair intervals. For the reasons discussed in the valve standard, the 

Committee applied the 5-day first attempt at repair and the 15-day repair interval of 

the existing rules to connectors. These repair intervals were considered appropriate for 

instances where leaks can be reduced by tightening bolts or where the connector can 

be isolated from the process. The Committee also recognized that most connectors 

cannot be isolated from the process and cannot be repaired without shutting down the 

process. In such cases, the Committee agreed that delay of repair until the next 

process unit shutdown is appropriate and the delay of repair provisions in the existing 

rules should be allowed for connectors. 

In some situations, repair of a leaking connector would expose personnel to 

imminent danger. Therefore, a special provision was added to the connector standard 

that allows the owner or operator to designate unsafe-to-repair connectors and to delay 

64 
Annual 

<0.5%, 500 ppmv 

- >0.5% -

500 ppmv 

Every 2 years 

<0.5%, 500 ppmv 

Ev ory 4 years 

>1% 

500 ppmv 

- >0.5% -

500 ppmv 

• / - ^-»nr.*cf"ar^ 

Figure 3. Standard for fteR§ess 

s 

OH 

nt 

• -__DH 
P.71 

repair of these connectors until the next process unit shutdown. Connectors which are 

unsafe-to-repair are those that would expose repair personnel to imminent hazards 

from temperature, pressure, or explosive process conditions. An example such a 

hazard would be connectors on high pressure lines where tightening a bolt could cause 

failure and result in a major or catastrophic release. 

Nonrepairable connectors. The Committee recognized that nonrepairable 

connectors may not be completely preventable and that increased monitoring 

frequency, if triggered by nonrepairable components, would be of little benefit. As 

with valves, the Committee sought to strike a balance between providing an incentive 

to limit the number of nonrepairable connectors and avoiding imposition of 

unproductive costs. The agreed approach allows excluding up to two percent of the 

connectors from the calculation of percent leaking if disturbed connectors are 

monitored for leaks within three months. The Committee allowed more connectors 

than valves to be excluded from the calculation (i.e., 2 vs. 1 percent) because it is 

more likely that connectors cannot be removed from the process and repair would 

have to be delayed until the next process unit shutdown. 

The Committee also allowed owners or operators the option of foregoing 

followup monitoring of disturbed connectors in exchange for not excluding 

nonrepairable connectors in the calculation of percent leaking connectors. This option 

provides flexibility and encourages owners or operators to develop their own program 

to ensure low leak frequencies for connectors. Exercising this option would mean that 

a process unit would have to have less than 0.5 percent leaking connectors to monitor 

65 

HB 
P.72 

less frequently than annually. The Committee also agreed to allow an owner or 

operator to switch from one option to the other provided the new option begins with 

annual monitoring. This optional provision was developed because of some 

Committee member's concerns that the administrative burdens would exceed any . 

benefits provided. 

Calculation of percent leaking. For connectors, the Committee decided that the 

percent leaking should be calculated for each monitoring period and should not be 

based on rolling averages of several monitoring periods. This decision was based on 

the judgement that properly designed, constructed, and installed connectors should 

operate for an extended time before failure and exhibit a low frequency of random 

failures. The results of a single monitoring period were, therefore, expected to provide 

a reliable estimate of the actual leak frequency. 

Credits for removing connectors. For the reasons discussed previously for 

valves, the Committee elected to provide a partial credit in the calculation of percent 

leaking connectors for connectors permanently removed from the process unit. If a 

connector is removed from a process unit by welding the connector or by welding the 

pipe together, the integrity of the weld must be verified to be eligible for removed 

connector credits. This was required to ensure that credits are only provided for actual 

reductions in emissions. Like the valve credit, this credit is included to provide an 

incentive for owners of facilities to minimize the number of connectors. 

Unsafe-to-monitor and inaccessible connectors. The Committee added 

provisions to the connector standard to consider situations where connectors may be 

66 

 

___3_n 
P.73 

unsafe to monitor or inaccessible. Like valves, unsafe-to-monitor connectors are 

connectors that could expose personnel to imminent hazards from temperature, 

pressure, or explosive conditions. These connectors must be monitored as frequently 

as practicable during safe-to-monitor periods. 

The Committee also exempted inaccessible connectors and glass or glass-lined 

connectors from the requirement for routine monitoring. Inaccessible connectors are 

defined as buried; insulated in a manner that prevents access by the monitor probe; 

obstructed by equipment or piping; or not accessible from a 25-foot portable scaffold 

on the ground and greater than 6 feet above a support surface. These different 

categories of inaccessible connectors were identified as presenting situations where 

monitoring would be extremely difficult, dangerous, or physically impossible. 

Specifically, buried and obstructed connectors were exempted because it is not 

possible to monitor these connectors. Insulated connectors were exempted because 

removal of the insulation from cold systems could cause leaks due to thermal stress 

and would be very costly. Removal of insulation from hot systems would create a 

safety hazard in addition to being costly. Connectors that cannot be reached from a 25 

foot portable scaffold or from a step ladder would also present a safety hazard to 

monitoring personnel. Glass and glass-lined connectors were exempted because the 

potential for on-line repair by tightening bolts is limited due to the possibility of 

breakage and attendant accidental releases. For both inaccessible and glass or glasslined connectors, however, if leaks are detected by visual, audible, or other means, the 

leaking connector shall be repaired no later than 15 days after the leak is detected. 

67 

l4____tl 
Provisions for screwed connectors. The connector standard would include a 

provision that allows an owner or operator the option of exempting existing screwed 

connectors of 2 inches or smaller diameter from routine monitoring provided these 

connectors are monitored once after the standard takes effect and after the seal is 

broken or disturbed. Any leaking connectors shall be repaired. This provision was 

designed to aUeviate costly monitoring of the large number of small connectors in 

some process units. 

The Committee agreed to include this provision for several reasons. The general 

opinion of engineers on the Committee was that screwed connectors once properly 

threaded and leak tight should stay leak tight since there are no moving parts and the 

seal does not rely on gaskets or other materials that can deteriorate. Thus, an initial 

check and one-time followup monitoring after opening the connector were judged to 

provide sufficient assurance that the connectors are leak tight. However, because the 

available data were insufficient to demonstrate this, new screwed connectors of any 

size and existing screwed connectors greater than 2 inches were not allowed this 

option and are treated the same as any other connector. The standard would also 

require that data on the leak frequency of screwed connectors be reported. The EPA 

intends to review this information and, based on the findings will consider whether to 

amend the standard to require routine monitoring for existing screwed connectors 2 

inches, or smaller, diameter or to apply the initial check and one-time follow-up to aU 

connectors. 

8. Provisions for Other Equipment 

68 

iBB 
P.75 

Compressors. As with other equipment, an emission standard was not developed 

for compressors because application of available measurement methods is not 

technically or economically feasible. The requirements in the existing standards were 

judged to be MACT and were used as the basis for the negotiated standard for 

compressors. The standard requires the use of mechanical seals equipped with a 

barrier fluid system and controlled degassing vents or enclosure of the compressor seal 

area and venting of emissions through a closed vent system to a control device. These 

systems can provide control efficiencies approaching 100 percent. 

Pressure relief devices in gas/vapor service. The negotiated standard, like the 

existing standards, is based on the use of rupture disk systems or control devices, 

which are considered to effectively eliminate emissions, when properly instaUed, 

maintained and operated. The existing equipment leak standards establish a "no 

detectable emission limit" of 500 ppmv for control techniques that eliminate emissions. 

The Committee considered redefining the emission limit for pressure relief devices, 

but agreed that there were insufficient data to redefine the limit below 500 ppmv. The 

general opinion was that a 500 ppm standard would ensure essentially zero emissions 

and would ensure that an effective control system would not be found to be in 

violation due to residual VHAP in the vent exit. Therefore, the negotiated rule would 

require that pressure retief devices be operated with an instrument reading of less than 

500 ppmv above background, except during pressure relief. 

The 500 ppmv above background limit would not apply to discharges through 

the relief device during pressure relief, because the function of relief devices is to 

69 
P.76 

discharge process fluid, thereby reducing dangerously high pressures witiiin the 

equipment. Relief devices must operate with an instrument reading of less than 

500 ppmv above background within 5 days after such a discharge. A definition of 

"set pressure" was added to the standard to clarify that set pressure is where a properly 

operating pressure relief device opens to reUef atypical process system operating 

pressure. 

As an alternative to rupture disks and other techniques that wUl achieve less 

than 500 ppm above background, owners or operators may vent pressure relief devices 

to closed vent systems connected to a control device. 

Sampling connection systems. The Committee agreed the closed-purge 

sampling, closed-loop sampling, and closed vent vacuum systems in the existing rules 

represent MACT for sampling connection systems. Closed-purge sampling systems 

eliminate emissions due to purging by either returning the purge material directiy to 

the process or by collecting the purge in a collection system which is not open to the 

atmosphere for recycle or disposal. Closed-loop sampling systems also eliminate 

emission due to purging by returning process fluid to the process through an enclosed 

system that is not directly vented to the atmosphere. Closed vent vacuum systems 

capture and transport the purged process fluid to a control device. An emission limit 

was not specified because measuring mass emissions from sampling systems would 

require enclosing each system (i.e., bagging), a measurement method which is timeconsuming, costly, and impractical. A concentration limit is also not feasible because 

although the VOC and VHAP control efficiency on a closed-purge or closed-loop 

70 

.. -JJ.— •BiTiiiran~—~~^^TM—|^ ^ M*—^^——*—= i mmiiininii mum 
P.77 

sampling system is approximately 100 percent, some VOC and VHAP could be 

emitted during its transfer to a closed collection device or during its ultimate disposal. 

Because emission standards cannot feasibly be prescribed for sampling 

connection systems, several alternative formats were considered and equipment 

standards found to be most appropriate. The proposed standards for sampUng 

connection systems in the negotiated rule would require the use of closed-purge or 

closed-loop sampling equipment or a closed vent system. In situ sampling systems 

would be exempted from these regulations. 

Open-ended valves or lines. Emissions from open-ended valves or lines can be 

eliminated, except when the line is used for draining, venting, or sampling operations, 

by enclosing the open end by a cap, plug, or a second valve. The control efficiency 

associated with these techniques is approximately 100 percent and is considered to be 

MACT. As with other items of equipment, establishing an emission limit is neither 

effective nor technologically feasible. Therefore, the Committee based the standard on 

the combination of equipment and operational requirements in the existing rules. 

The negotiated rule would require the use of a cap, plug, blind flange, or a 

second valve or other equipment to close the open-ended valve or line. To insure the 

proper operation of the equipment, open-ended lines are also covered by operational 

standards. If a second valve is used to close the open end, the proposed standards 

would require the upstream valve to be closed first. After the upstream valve is 

completely closed, the downstream valve would be closed. This operational 

requirement is necessary in order to prevent trapping process fluid between the two 

71 
valves, which could result in a situation equivalent to the uncontrolled open-ended 

line. 

Product accumulator vessels. The technique for controUing product accumulator 

vessels is to connect the vessel to a closed vent system and control device. Anything 

in compliance with the requirements for closed vent systems and control devices is 

acceptable. 

Control Devices. Control devices would be used to dispose of VHAP captured 

in closed vent systems from barrier fluid degassing systems and enclosed pump and 

compressor seal areas. In all cases, these control devices would receive streams with 

low and intermittent flow rates. These control devices would in some cases be 

designed to dispose of organic streams from other sources in the plant, so that the 

VHAP streams may contribute a very small percentage of the total loading on the 

control device. Because it would be technologically and economically impractical to 

measure very low-flow streams and differentiate these streams from others, an 

emission standard was not proposed for these control devices. 

Design requirements for control devices were considered to ensure that 

appropriate emission reductions would be achieved from control devices used in 

conjunction with closed vent systems. Enclosed combustion sources, flares, and vapor 

recovery systems were considered as control devices for the closed vent system. The 

design requirements specified in the negotiated rule for enclosed combustion are the 

attainment of a minimum temperature of 760°C for 0.5 seconds. Under these 

conditions, at least 95 percent VOC destruction is achieved. Flares used as control 

72 

as^maam^^m^^^t^^mm^^^mtmmammmm^^^^^^K^^^^^^^^^^^^^^^^^^Bmmmmmms^ 
devices to comply with the negotiated standard shall comply with the requirements of 

40 CFR 60.18. Vapor recovery systems would also be allowed as control devices for 

VHAP from closed vent systems. A control efficiency of at least 95 percent was 

chosen as the design requirement because it is the highest control efficiency that has 

been demonstrated consistently for vapor recovery systems such as carbon adsorption 

or condensation units. 

Agitators. Agitators were not evaluated during regulatory development of the 

existing regulations and are not presently regulated by any standard. Therefore, very 

limited information is available on this equipment. The Committee determined that 

agitators should be included in the negotiated standard for several reasons. First, a 

limited amount of screening data indicate that agitators may be a significant source of 

emissions. Second, agitators are technologically similar to pumps, and, like pumps, 

emissions can be controlled using seal technology. However, agitators have longer 

and larger diameter shafts than pumps and produce greater tangential shaft loadings. 

The performance of pump seal systems, therefore, cannot be used to estimate agitator 

seal performance. Considering this and the potential for large leaks, the Committee 

agreed to require a monthly LDAR program only and to define a leak as a 

concentration of 10,000 ppmv or higher. This program will require replacement of 

agitator seals with significant leaks and will encourage development of effective 

bearing and seal systems. 

Instrumentation systems. The Committee created this equipment category to 

address industry members concerns with application of LDAR programs to equipment 

73 
P.80 

used in monitoring process operations. Small diameter tubing and other components 

are used to convey process samples to analyzers to determine chemical composition 

and to instruments such as pressure and flow transducers. Instrumentation systems 

typically contain valves 0.5 inch in diameter or less and connectors 0.75 inch or less 

and are located in a confined area such that monitoring of individual components is 

generally infeasible. Because these systems provide critical process operating 

information, they are subject to frequent surveillance and maintenance to assure the 

reliability of measurements. Leaking equipment in these systems would be readily 

detected by changes in temperature, pressure, flow rates, or by observation. 

Additionally, it is common practice in the industry after maintenance or repair to 

verify the integrity of these systems by soap bubble testing or pressure checks. 

Therefore, a routine LDAR program would be redundant and would provide no 

benefit. The Committee concluded for these reasons that it was appropriate to develop 

alternative provisions for these systems. 

The Committee judged that it was appropriate to require repair of leaking 

instrumentation systems in a timely manner and agreed to treat these systems in a 

manner similar to equipment in heavy liquid service. In addition, the Committee 

agreed that monitoring of individual components in instrumentation systems by 

Method 21 is not necessary if the leak is repaired and the repair is verified. The 

verification may be by soap testing, a pressure check, or any other visible, audible, 

olefactory, or other means. 

74 
P.81 

Miscellaneous. As in the existing equipment leak standards, pumps, valves, 

connectors, and agitators in heavy liquid service (HAP fluids with vapor pressures less 

than 0.3 kPa at 20°C), and pressure relief devices in light Uquid or heavy Uquid 

service would be excluded from the routine monitoring and inspection requirements. 

However, if leaks are detected from these sources, the same allowable repair interval 

that applies to pumps, valves, connectors, and compressors would apply. These 

sources were excluded from routine monitoring on the basis that they contribute only a 

very small portion of overaU emissions from a process unit and including them in the 

monitoring and equipment requirements was not considered reasonable. 

9. Alternative Standards 

Under the provisions of Section 112(h) of the CAA, if the Administrator 

establishes work practice, equipment, design, or operational standards, then the 

Administrator must allow use of alternative means of emission reductions if an owner 

or operator can demonstrate emission reductions equivalent to that achieved by the 

standards. Generally, alternative means of emission reduction are based on specific 

circumstances at individual plant sites and must be handled individually. During the 

course of the Committee's deliberations, however, two situations were identified where 

development of generic alternative standards was appropriate. These situations were 

batch processes and enclosed process units. Consequently, the negotiated rule includes 

alternative standards for batch operations and for process units located in enclosed 

buildings as well as general provisions for demonstration of equivalency. 

75 
P.82 

Batch processes. At one of the early meetings of the Committee, the problems 

associated with application of LDAR programs to batch processes were raised. At 

continuous processes, equipment can be monitored rapidly, one after another on an 

established route, without consideration of the process schedule because there is 

always process fluid in the lines. For several reasons, rapid monitoring of one 

component after another is not possible at some batch processes. This is particularly 

true for processes such as those in the pharmaceutical industry where equipment may 

not be dedicated to a particular process and where different components are used in 

different batch operations to produce different products. In any particular 

configuration, process fluid may flow through a series of valves, connectors, and a 

pump into a reactor. Several hours later, the process fluid would exit the reactor 

through other equipment for subsequent processing steps and storage. Also, the 

equipment used wtil contain process fluids for only a brief period during the batch 

(e.g., a few minutes per batch). In this case, the monitoring team would have to wait 

for an extended time between screening equipment on the upstream and downstream 

side of the reactor. Equipment not used in a particular confiquration could not be 

monitored until the equipment is in actual use. Thus, it would be difficult to schedule 

monitoring of equipment and the cost, both in total and on a component basis, could 

be much higher than for a continuous process. Moreover, this intermittent operation 

and low time-in-use of individual components also results in lower annual emissions. 

For these reasons, the Committee formed a batch process subcommittee to 

develop alternative approaches that could be used for batch processes. This 

76 
P.83 

subcommittee explored various alternatives which would ensure effective control while 

considering the nature of batch operations. The subcommittee developed alternative 

procedures that allow owners or operators of batch processes the option of meeting 

standards similar to those for continuous processes or of periodically pressure testing 

the batch equipment. If the owner or operator elects to monitor equipment for leaks, 

the monitoring frequency is prorated to the time in use and the equipment may be 

monitored when it is in VHAP service or in use with a surrogate VOC or other 

detectable compound. These modifications to the continuous standards were designed 

to provide roughly comparable provisions for batch processes. In fact, as time in use 

increases to 75 percent and higher, the monitoring frequency becomes the same for 

both continuous and batch processes. The alternative provisions allow pressure testing 

of batch equipment using either a gas or a liquid. The Committee allowed use of 

either procedure because hydrostatic testing can be safer than high pressure tests using 

gases and either technique can be used to demonstrate the equipment is not leaking. 

The criteria specified as defining a leak were based on a limited amount of field 

testing by the pharmaceutical industry, general industry practice for pressure tests, and 

EPA's experience with vapor-tightness testing of tank trucks and railcars. Although 

little information is available for direct comparison, the Committee concluded, based 

on general knowledge and engineering considerations, that the relative cost and 

effectiveness of the alternative procedures for batch processes should be roughly 

comparable to those for continuous processes. 

77 
Enclosed processes. Processes operated in butidings or enclosures maintained 

under negative pressure and vented to the atmosphere through a 95 percent efficient 

control device would be exempted from the monitoring requirements. This alternative 

standard was developed because members of the Committee were aware of cases 

where processes have been isolated from personnel because of safety hazards. In such 

instances, no benefit will be achieved by monitoring the equipment, and it may present 

a safety hazard to monitoring personnel. 

10. Delay of Repair 

As previously noted, the Committee recognized that there are circumstances 

when repair of equipment is not feasible without a process unit shutdown and this may 

result in greater emissions than delaying repair until the next scheduled shutdown. 

The Committee, therefore, included the delay of repair provisions in the existing rules 

in the negotiated standard. A primary consideration of the Committee in this was 

whether the provisions reflected the actual feasibility of repairing equipment and 

avoided extended delays in returning a unit to production after it is shutdown briefly 

due to unforeseen circumstances. Based on this evaluation, the Committee agreed to 

modify the definition of "process unit shutdown" to reflect more accurately those 

situations where it was judged reasonable to require clearance of process materials and 

repair of equipment. The revised definition specifies that it must be technically 

feasible to clear process material from the unit consistent within safety constraints and 

that under certain circumstances unscheduled shutdowns of more than 24 hours 

duration are not classified as a shutdown. These conditions are: (1) the shutdown 

78 

n 
must be for a period shorter than the time required to clear process materials and start 

up the unit and (2) it must result in greater emissions than delaying the repair until the 

next scheduled shutdown. 

The delay of repair provisions in the negotiated standard also include the other 

types of delay of repair provisions in the existing standards. The negotiated standard 

would allow delay of repair for spared equipment that does not remain in VHAP 

service. Delay of repair would also be allowed for valves, connectors, and agitators if 

the owner or operator shows that emissions of purged materials from repair would be 

greater than the emissions likely to result from delay of repair. When the equipment 

is repaired, the purged material must be destroyed or recovered in a control device that 

complies with the requirement for closed-vent systems and control devices. Delay of 

repair beyond a process unit shutdown for valves would also be allowed when 

unforeseen circumstances deplete valve assembly supplies. The owner or operator 

would have to document that valve assembly supplies had been sufficiently stocked. 

This delay of repair may not be extended beyond the next process unit shutdown 

unless the next shutdown occurs sooner than 6 months after the first shutdown. It is 

expected that this delay of repair provision will seldom be used. 

As with the other types of equipment, delay of repair would be allowed for 

pumps that cannot be repaired without a process unit shutdown. Delay of repair, up to 

6 months after detecting a leak, would also be allowed when the owner or operator 

determines that repair of the pump requires requires replacement of a SMS system 

with a DMS system, a pump with no externally actuated shaft, or a closed-vent control 

79 
system. This provision differs slightly from the present standards in that it allows 

delay of repair for replacement of single seal pumps with other types of low leak 

technology. Delay of repair is not expected for most situations, however, because 

pumps are commonly spared. 

G. Test Methods and Procedures 

The negotiated standard basically retains the use of Method 21 to detect leaks of 

organic compounds from equipment; however, several modifications were made to the 

existing procedures. These modifications consist of changes to the calibration gases 

required, addition of procedures for response factor correction, and addition of 

procedures for pressure testing of batch processes. The bases for the changes to the 

provisions are described in this section. 

Method 21 specifies procedures for measuring the concentration of leaks of 

VOC near individual pieces of process equipment. This method requires the use of a 

portable organic vapor analyzer that meets the method's performance specifications for 

response, linearity, flow rate, and safety. The instrument detector may be any that 

meets the methods specifications and performance criteria. Detector types that are 

believed to meet Method 21 specifications for most VHAP include catalytic oxidation, 

flame ionization, infrared absorption, and photoionization. Although these detectors 

have been shown to be broadly applicable to measurements of organic compounds, no 

one detector can be universally applied to all organic compounds: some VHAP may 

require evaluation of other types of detectors. 

80 

mu 
The negotiated standard would require calibration of the portable organic vapor 

analyzer before each monitoring survey with calibration gas mixtures consisting of 

methane and air and with zero gas. For this standard, zero gas has been specified as 

containing less than 0.2 ppmv VOC in air. Zero gas was specified at a concentration 

below the less than 10 ppmv criterion used in the existing standards in 40 CFR Parts 

60 and 61 to improve the quality of measurements near 0 ppm. The negotiated 

standard would also require calibration with mixtures of methane in air at 

concentrations near each of the various leak definitions. Therefore, in Phase III, 

calibration gases with VOC concentrations near 10,000 ppm, 5,000 ppm, 2,000 ppm, 

1,000 ppm, and 500 ppm may be required at some plant sites, depending upon the 

equipment that is in use. To reduce the number of calibration gases required, the 

Committee agreed to allow the option of using an analyzer calibrated at a higher 

concentration, up to 2000 ppm, for monitoring equipment subject to a lower leak 

definition. This provision was included since that procedure will introduce only a 

small positive bias (i.e., observed values wUl be slightly higher than actual) in the 

instrument readings and the results would be acceptable for demonstrating compliance. 

The negotiated standard would also limit the acceptable range of response 

factors. The response factor is a factor which adjusts for differences in instrument 

sensitivity or response to the compounds being measured and to the reference 

compound. For the negotiated standard, the reference compound is methane. These 

provisions were added to ensure that the effect of the standard is not significantly 

81 

m 
altered by the instrument used in conducting the monitoring surveys or the stream 

composition. Correction of instrument readings for response factors is required where 

the individual response factors, at 500 ppm, for the VHAP that account for 90 percent, 

or more, by weight of organic materials in the process stream are 3 or greater. The 

requirement was structured in this manner to avoid imposition of unproductive costs. 

Specifically, the 90 percent by weight criterion was included in order to avoid the 

need to adjust response factors due to trace contaminants in process streams. For 

many compounds, response factors may not be available and cannot be obtained 

without considerable difficulty (e.g., solids, explosive substances.etc). Where these 

compounds represent only a small fraction of the process stream composition, it was 

judged inappropriate to require development of response factors. The provision is 

included as a series of checks on compounds in the process streams and on the process 

streams. The steps are intended to eliminate quickly those streams for which response 

factor correction is obviously unnecessary. The first step looks at the individual 

compounds used in the process. If no compound in the process has a response factor 

of 3 or greater, then no further evaluation is needed. The second step looks at the 

individual streams to identify any that contain an individual compound or have a 

weighted average factor that is 3 or greater. The third step looks at streams with 

weighted average factors of 3 or more and considers whether to adjust the instrument 

readings or use another instrument or calibration gas. 

The Committee also added procedures for pressure testing of batch process 

equipment to the negotiated standard. These procedures were derived from general 

82 

EI 
P.89 

industry practice and experience with gas and liquid pressure tests on equipment and 

EPA experience with testing tank trucks and railcars for vapor-tightness demonstration. 

The negotiated standard also would specify that Method 18 is to be used to 

determine the VHAP content of process fluids whenever that is in question. Method 

18 is a general procedure for gas chromatographic analysis of organic compounds. 

The method can be used to analyze roughly 90 percent of gaseous organic compounds 

emitted by sources. In most cases, engineering calculations, knowledge of the process, 

or analyses of the process should provide sufficient demonstration of VHAP content 

and Method 18 analysis will not be required. 

H. Recordkeeping and Reporting 

Owners or operators of a process unit that would be covered by the negotiated 

standard are subject to the recordkeeping and reporting requirements of the standard as 

weU as those prescribed in the proposed General Provisions (Subpart A) of 40 CFR 

part 63. Compliance with the standards will be assessed through inspections at the 

plant site and review of records and reports that document implementation of the 

requirements. 

1.Recordkeeping 

Records of leak detection, repair attempts, and maintenance for leaking 

equipment would be required by the negotiated standard. These records consist of the 

information needed to document compliance with: (1) work practice standards, (2) 

equipment standards, (3) operational standards, (4) emission standards, and (5) 

83 
P.90 

information required for equipment subject to a QIP. These records are also necessary 

for evaluating the effectiveness of repair efforts. For equipment subject to equipment 

standards, records would be required of the dates of installation, equipment repair, and 

equipment modifications. For closed vent systems and control devices, records would 

be required of the location and type of equipment, the design specifications, and the 

monitoring parameters. 

In many respects, the recordkeeping requirements would be similar to those in 

the existing standards for equipment leaks. Some differences between the standards 

result from the additional provisions of the negotiated standard while others result 

from changes made to clarify the requirements. In addition, changes were made to 

simplify the recordkeeping requirements and to reduce the associated burden. 

These records must be maintained for a period of 2 years in a readily accessible 

recordkeeping system and made available to the EPA upon request. This system may 

be maintained by physically locating the records at the plant site or by accessing the 

records from a central location by computer. 

2. Reporting 

The negotiated standard would require an initial report and semiannual reports of 

leak detection and repair efforts as weU as notifications of initiating monthly 

monitoring or a QIP for valves or pumps. The initial report is to be submitted for 

existing process units, or new process units with startup dates preceding the effective 

date of the negotiated rule, within 90 days after the (earliest) applicability date 

covering that process unit. The initial report for all other new process units would be 

84 

_BI 
P.91 

submitted with the application for approval of construction, reconstruction, or 

modification as required by the General Provisions. This initial report would notify 

the Administrator that the process unit is (or will be) subject to this subpart and 

identify the process unit, number and type of equipment components, and the method 

of compliance for each piece of equipment. The planned monitoring schedule for each 

type of equipment in each phase would also be required. 

The semiannual report is to include information on the numbers of leaking and 

non-leaking components; leak frequencies of pumps, valves, and connectors; attempts 

to repair, reasons for delay of repair; process unit shutdowns; and changes in the 

information submitted in the initial report. The reports shall also include the results of 

performance tests conducted within the reporting period for equipment subject to a 500 

ppm performance standard and notifications of initiation of monthly monitoring or QIP 

for valves or pumps. 

End of Equipment Leaks Fart of the Notice 

85