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Suncor Energy (U.S.A.) Inc.

Commerce City, Colorado

NSPS Subpart Ja Flare Management Plan

Gasoline Benzene Reduction Unit (GBR) Flare

5801 Brighton Boulevard

Commerce City, Colorado

Adams County

April 2014
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TABLE OF CONTENTS

Section 1 Introduction ......................................................................................................... 1-1

1.1 Facility Description ............................................................................................ 1-1

1.2 NSPS Ja Applicability ........................................................................................ 1-1

1.3 Revisions to the Flare Management Plan ........................................................... 1-2

1.4 Flare Management Plan Contents....................................................................... 1-3

Section 2 Description of Flare Systems.............................................................................. 2-1

2.1 Flare Type........................................................................................................... 2-1

2.2 Flare Tip.............................................................................................................. 2-1

2.3 Flare Header System........................................................................................... 2-2

2.4 Knockout Drum .................................................................................................. 2-3

2.5 Flare Gas Recovery System................................................................................ 2-4

2.6 Water Seal........................................................................................................... 2-4

2.7 Assist System...................................................................................................... 2-4

2.8 Pilot Gas.............................................................................................................. 2-5

2.9 Ignition System................................................................................................... 2-5

2.10 Purge Gas............................................................................................................ 2-6

2.11 Sweep Gas .......................................................................................................... 2-6

2.12 Supplemental Gas............................................................................................... 2-7

2.13 Monitoring Instrumentation................................................................................ 2-7

2.13.1 Vent Gas Flow ........................................................................................ 2-8

2.13.2 Sulfur Content......................................................................................... 2-9

Section 3 Flare Minimization.............................................................................................. 3-1

3.1 Description of Contributions to Flare Header .................................................... 3-1

3.2 Minimization Assessment................................................................................... 3-1

3.3 Baseline Flow Evaluation ................................................................................... 3-3

3.4 Startup and Shutdown......................................................................................... 3-6

3.5 Fuel Gas Imbalance ............................................................................................ 3-7

3.6 Fuel Gas Recovery Outage ................................................................................. 3-7

Section 4 Root Cause Analysis and Corrective Action..................................................... 4-1

4.1 Root Cause Analysis........................................................................................... 4-1

4.1.1 RCA – Flow Exceedance........................................................................ 4-2

4.1.2 RCA – SO2 Exceedance.......................................................................... 4-2

4.2 Corrective Action Analyses................................................................................ 4-4
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LIST OF APPENDICES

Appendix A Plan revision log

Appendix B NSPS Ja Cross-Reference Table

Appendix C Process Flow Diagrams

Appendix D Flare Tip Drawing

Appendix E Alt. Test Method 099 - Approval of Optical Flow Meters for Flares
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April 2014 GBR - Flare Management Plan

SECTION 1

INTRODUCTION

1.1 Facility Description

Suncor Energy (U.S.A.) Inc. (Suncor) owns and operates a petroleum refinery in Commerce 

City, Colorado (Commerce City refinery). The Commerce City refinery is a 98,000-barrelper-day refinery that produces gasoline, distillate fuels, and paving-grade asphalt. 

In 2012, Suncor completed a project at the Commerce City refinery to construct a new 

process unit at Plant 1 of the refinery to saturate benzene in the reformate stream. The 

project, referred to as the Gasoline Benzene Reduction (GBR) Unit, was necessary in order 

for Suncor to comply with Mobile Source Air Toxic rule (MSAT2), which requires refiners 

to produce gasoline with low benzene content. The construction of the new GBR Unit 

included the construction of the GBR flare.

1.2 NSPS Ja Applicability

The most recent promulgation of the petroleum refinery New Source Performance Standard 

(NSPS) is contained within 40 CFR 60 Subpart Ja. NSPS Ja applies to fluid catalytic 

cracking units (FCCU), fluid coking units (FCU), delayed coking units, fuel gas combustion 

devices, flares, and sulfur recovery plants. 

According to NSPS Ja 60.101a, the definition of a Flare is as follows:

“Flare means a combustion device that uses an uncontrolled volume of air to burn gases. 

The flare includes the foundation, flare tip, structural support, burner, igniter, flare 

controls (including air injection or steam injection systems), flame arrestors, and the 

flare gas header system. In the case of an interconnected flare gas header system, the 

flare includes each individual flare serviced by the interconnected flare gas header 

system.”

An affected flare under NSPS Ja is one for which construction, modification or 

reconstruction commenced after June 24, 2008. A modification to a flare occurs when a 

project that includes any of the following activities commences:

 Any new piping from a refinery process unit, ancillary equipment, or a fuel gas 

system is physically connected to the flare; or

 A flare is physically altered to increase the flow capacity of the flare.

However, the following activities do not, by themselves, constitute a modification:

 Connections made to install monitoring systems to the flare;

 Connections to install or enhance a flare gas recovery system;

 Connections made to replace or upgrade existing pressure relief or safety valves;
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 Connections made for flare gas sulfur removal;

 Connections made to install redundant equipment associated with the flare, provided 

they do not increase the capacity of the flare;

 Replacement or relocation of pipe “in kind”; or

 Connections that interconnect two or more flares. 

The GBR Flare (FLR-6 as it is referenced in the facility Air Permit) construction was 

completed in May 2012. Under the rule, the GBR Flare is subject to the requirements and 

compliance timeframes of a “new flare” since it was initially constructed after the NSPS 

proposal date of June 24, 2008. 

NSPS Ja contains work practice provisions that are applicable to refinery flares1. These work 

practice standards, as well as the applicability triggers for flares, were proposed to be 

changed in the Federal Register dated December 22, 20082. On September 12, 2012, the 

revised NSPS Ja standards were finalized and published in the Federal Register. 

The work practice standards of 60.103a(a) require the preparation of this Flare Management 

Plan (FMP). As the GBR flare system is considered to be a single, new affected source that 

is subject to the rule, the Commerce City refinery must develop and implement a FMP for the 

GBR flare by no later than 60 days after the rule was published in the Federal Register, or 

November 13, 2012. The Commerce City refinery is required to submit a copy of this initial 

FMP to the EPA and maintain a copy of the initial FMP until it is revised. See Section 1.3 

for operational changes which trigger a revision to the FMP.

1.3 Revisions to the Flare Management Plan

The FMP and all documents referenced herein should be internally reviewed and updated 

periodically to account for changes in the operation of the GBR flare system. These changes 

include, but are not limited to, adding new connections to the flare header system or the 

installation of a flare gas recovery system. The Commerce City refinery is required to 

maintain a copy of the current FMP. It is recommended that one copy be placed in a central, 

easy-to-access location so that the FMP can be provided to agency inspectors in the event of 

an agency visit. 

It is important to note that not all events which trigger the need for an internal revision of the 

FMP require a re-submission of the revised FMP to the United States Environmental 

Protection Agency (USEPA) Administrator. The rule requires the FMP to be re-submitted to 

the Administrator for one of the following four reasons: 

 Addition of an alternative baseline flow rate, 

 Revision of an existing baseline,

 Installation of a flare gas recovery system, or 

 Change of flare designations and monitoring methods. 

 

1

40 CFR 60.103a

2

73 FR78522, dated December 22, 2008
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A Plan Revision History log is included in Appendix A. The log should be utilized to 

document all periodic changes to the FMP, both the internal revisions and the revisions that 

are submitted to the Administrator.

1.4 Flare Management Plan Contents

This FMP fulfills the requirements of NSPS Ja regarding the development of a written FMP

and has been prepared pursuant to the requirements and provisions of the rule. Appendix B

includes a table that cross-references the specific requirements of NSPS Ja and their location 

within this FMP. The following information is specifically required to be included in or 

referenced by this FMP: 

 Listing of all process units, ancillary equipment, and fuel gas systems that are 

connected to the flare header system;

 Flare minimization assessment;

 Descriptions of all flare components and design parameters;

 Specifications for all required monitoring instrumentation;

 Baseline flow evaluation; and

 Procedures to reduce flaring during planned startups and shutdowns, during

imbalances of the fuel gas system, and during outages of the fuel gas recovery 

system.

This Plan also includes or references information which is not explicitly required to be 

included in the FMP under NSPS Ja. The inclusion of this supplemental information enables 

the FMP to fully document the management practices and flaring minimization measures and 

strategies that are in place. The following supplemental information is provided in or 

referenced by this FMP: 

 Description of triggering events and compliance timeframes for Root Cause Analyses

(RCAs) and Corrective Action Analyses and Implementation; and,

 Details of the required records, reports, and notifications. 

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SECTION 2

DESCRIPTION OF FLARE SYSTEMS

This section outlines the details of the GBR flare system and its components. Appendix C

includes process flow diagrams depicting this flare system.

2.1 Flare Type

The GBR flare is an elevated flare. An elevated flare consists of a tip that is mounted on a 

flare stack, which is raised high above grade, and supports combustion at the upper end of a 

vertical riser. The combustion zone is elevated in order to separate the heat generated by 

combustion from people, equipment, or structures at grade level and to aid in air dispersion.

Per the definitions contained in the rule, this flare is a non-emergency flare that is not 

cascaded and does not operate as a backup flare.

The GBR flare is a self-supported elevated flare that stands 249 feet above the ground, with a 

156” diameter base. The diameter of the flare tip is 28”. The flare has a maximum design 

capacity of 491,018 pounds per hour (lb/hr) of hydrocarbon flow and has a smokeless 

capacity of 73,655 lb/hr of hydrocarbon flow.

The flare includes a fixed velocity seal within the flare stack to limit the possibility of air 

infiltration through the flare tip into the flare stack and header. The velocity seal is located at 

the base of the flare tip and out of the flame zone.

2.2 Flare Tip

The function of the flare tip is to mix the flare gas and assist gas at velocities, turbulence, and 

concentration required to establish and maintain proper ignition and stable combustion for 

the maximum specified relief gas flow rates at the system-allowable pressure drop. Although 

the GBR normally has a low base load of flare gas in the flare system during normal 

operations, the largest concern with respect to the flare system is its ability to handle the rare 

yet large emergency flaring events. The design of the flare tip is an integral part of the flare 

system because it enables the refinery to handle large variances in the volume, pressure drop, 

concentration, and temperature of the flare gas streams.

The GBR flare tip, which was installed in April 2012, is a 28” diameter tip designed by 

Zeeco Inc., model number QFSC-24/28. Based on a review of the flare tip drawings, the 

flare tip appears to be unobstructed by the steam ring and pilot assemblies; therefore the 

effective diameter of the tip is approximately 28”. It consists of a single burner equipped 

with steam assist gas. The upper steam is supplied through a single 4” steam supply pipe, 

radially, using a 40” diameter external steam ring with 18 star-shaped steam diffusers 

arranged outside of the flare stack circumference. The center steam injection includes a 

single internal steam injection nozzle using a 1.5” supply pipe centered inside the stack and 

just above the velocity seal, but below the plane of the flare tip, thus causing no decrease of 
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the effective tip area. There are no lower steam nozzles inside the effective area of the flare 

tip. Each of the two steam supply lines can be controlled independently. The minimum tip 

and center steam requirement for continuous cooling and protection of the tip is 630 lb/hr and 

350 lb/hr, respectively. A drawing of the tip is included in Appendix D. Further information 

on the steam assist system can be found in Section 2.7.

2.3 Flare Header System

According to the definitions promulgated in Subpart Ja, the flare gas header system is 

defined as:

“all piping and knockout pots, including those in a subheader system, used to collect 

and transport gas to a flare either from a process unit or a pressure relief valve from 

the fuel gas system, regardless of whether or not a flare gas recovery system draws 

gas from the flare gas header system. The flare gas header system includes piping 

inside the battery limits of a process unit if the purpose of the piping is to transport 

gas to a flare or knockout pot that is part of the flare.”

The primary function of the flare gas header is to safely accumulate and transfer gases to the 

flare for combustion. In addition to hard-piped connections for normal operating conditions, 

the flare gas header also has connections for equipment depressurization and purging for 

maintenance activities, such as startup, shutdown, and turnaround. 

The flare gas header provides the process units with a controlled low-pressure outlet for any 

excess vapor flow that originates with high-pressure operations within the refinery. Nearly 

all refinery vapors are flammable, making the flare gas header an essential safety feature of 

every refinery. The flare gas header relieves the pressure and lowers the temperature of the 

gas, rendering the gas safe to both equipment and surrounding personnel.

In the GBR flare gas header system there are currently 29 process connections to this 

dedicated flare header. These process connections are made utilizing continuous vents, 

manually operated valves, control valves, relief valves (RVs), and sample connections. The 

connections are detailed in Table 2-1 below.
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Table 2-1. PSV Connections to GBR Flare Header System

Type Description Quantity

Continuous Vented Pump Seal Pots 12

Sample Analyzer Building 1

Sample Sample Port Purges 3

RV Overhead OF 1

RV Fuel Gas to KO Drum* 1

RV Splitter Overhead Drum 2

RV Light Reformate Guard Beds 2

RV BERT Tower Overhead Drum 1

RV BERT Tower 1

RV H2 Guard Beds 1

Manual Light Reformate Guard Beds 1

Manual Fuel Gas to KO Drum Drain* 1

Control 

Valve From BERT Overhead 1

Control 

Valve From PC 1108 1

*These sources originate outside of the GBR unit battery limits.

2.4 Knockout Drum

The hydrocarbon liquid knockout (KO) drum removes any potential liquid hydrocarbons 

from the flare gas prior to combustion. Generally, liquid hydrocarbons cannot be safely or 

completely burned in most flare systems. KO drums contain a specified amount of liquid 

that is monitored and maintained to ensure proper operation. Most KO drums utilize a mist 

eliminator, located upstream of the gas outlet, to enhance the knockout drum’s performance 

by removing suspended water droplets that are entrained in the vapor streams. 

The GBR Knockout Drum, D-3924, is a horizontal vessel that is located on the main flare gas

header upstream of the flare stack. The inner diameter of the vessel is 126 inches and the 

length, from tangent to tangent, is 34 feet. The Maximum Allowable Working Pressure 

(MAWP) is 50 psig and the Maximum Allowable Working Temperature (MAWT) is 500° F. 

The flare gas continues to the flare stack, while the liquid that accumulates in the boot of the 

KO vessel is pumped to the Sour Water Collection Drum (D-260) by pumps P-3914 and P3915 (in-line spare). The level in the boot is controlled with a high level switch, LSH-2310, 

which provides a high level alarm to trigger pumps P-3914 and/or P-3915 to start to lower 

the water level in the KO Drum. Pump P-3924 is connected to the KO Drum to remove any 

accumulated hydrocarbons by pumping the material to crude tank T-58. Level transmitters

LT-2300A and LT-2300B monitor the hydrocarbon liquid level in the vessel and trigger 

pump P-3924 to start to remove the hydrocarbon layer in the KO Drum.
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2.5 Flare Gas Recovery System

According to the definitions promulgated in Subpart Ja, flare gas recovery system is 

“a system of one or more compressors, piping and the associated water seal, rupture 

disk or similar device used to divert gas from the flare and direct the gas to the fuel 

gas system or to a fuel gas combustion device.” 

The GBR flare at Suncor Commerce City does not utilize a flare gas recovery system. 

2.6 Water Seal

Water seals, if present, are generally located downstream of the knockout drum or at the base 

of each flare. Liquid (typically water) is maintained at a certain level in the seal drum to 

create a barrier which seals the flare gas header from the flare stack and burner tip. The 

maximum height of liquid in the seal must be determined by the maximum exit back pressure 

allowable in the flare gas header.

For this specific case, the GBR flare does not utilize a water seal. The addition of a water 

seal would require the facility to perform an engineering and safety study to re-evaluate the 

pressure settings for the in-process RVs to ensure proper function as safety release devices.

2.7 Assist System

Assist gas is added to the flare tip to encourage additional flame zone turbulence, improved 

air entrainment, and thus, improved combustion efficiency and the reduction of smoke 

formation. Care must be taken to ensure the combustible mixture of the combined gases is 

not diluted by excess use of assist gas.

The GBR flare is a steam assisted flare. The flare receives both tip steam and center steam, 

which are both provided at approximately 175 psig. Steam is delivered to the flare tip by 

means of two parallel control valves (FV-2401A and FV-2401B). The tip steam line is 

reduced from 6-inches to 4-inches to feed into the external steam ring. The tip steam flow is 

monitored by two flow transmitters (FT-2401A and FT-2401B) and viewed in the Light Oil

control room. Steam supply to the tip is adjusted by a flow control devices (FC-2401A/B). 

Once FC-2401A, which controls the low flow range steam, is opened to 100%, then FC2401B is automatically opened to control the high flow range steam to supply any additional 

steam needed. The flare tip is monitored by a video camera fixed onto the flare line of sight 

and is monitored on a color display located in the Light Oil control room. If smoke is 

observed, the steam is manually increased by remote operation from within the control room 

to stop the smoking. The maximum tip steam flow rate is 28,976 lb/hr. Center steam is 

delivered to the flare stack just above the velocity seal by means of 1.5 inch piping. The

center steam flow is monitored by a flow transmitter (FT-2402) and viewed in the Light Oil

control room. The center steam supply line has a manual 0.5 inch globe valve that is sized 

for continuous minimum flow of 350 lb/hr. The center steam valve cannot be remotely 

operated and can be manually adjusted only in the field. It is not adjusted to respond to 
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smoking events. The minimum steam additions for thermal conditioning of the flare tip is 

350 lb/hr of center steam and 630 lb/hr of ring steam.

2.8 Pilot Gas

Pilot gas is introduced through the pilot tips of a flare in order to provide a flame to reliably 

ignite the flare. If the pilot is unreliable, the potential for unburned hydrocarbons and/or 

toxic gases releasing to the atmosphere increases drastically and may result undesirable 

health effects, vapor-cloud explosion, and/or odor problems. Since the flare must be 

removed from service to maintain or replace a pilot, pilot systems are designed to operate for 

extended periods without requiring maintenance.

The GBR flare has three natural gas fueled pilot lights that are paired with redundant 

thermocouples (TE-2401 – 2406), which are operational at all times. If the temperature on 

those thermocouples drops below 350 °F, the automatic ignition system (see Section 2.9) 

immediately attempts to re-ignite the inactive pilot. The pilot lights are spaced at 120 degree 

intervals around the flare tip. The pilot gas flow rate is adjusted by a 1-inch Pilot Gas 

Regulator (PCV-2407) to a design flow rate of 186 scf/hr total (61.9 scf/hr per pilot). PCV2407 has a maximum design rating of 250 scf/hr. The design heat release for each pilot is 

58,678 Btu/hr. The pilot gas flow rate is maintained at all times and spread evenly to all 

three pilots. The flow is regulated by an orifice with a 3/64” bore size. The pilot orifice 

drilling is based on 947.34 Btu/scf gas with 0.62 specific gravity.

The pilot lights at all three flares are fueled by purchased, pipeline quality, natural gas. The 

NSPS Ja rule in 60.107a(b) explicitly allows all pilot gas lines associated with the GBR flare 

to be exempt from sulfur content monitoring as they are considered inherently low in sulfur 

content. Therefore, an analysis of the H2S concentration in the pilot gas is not required. 

2.9 Ignition System

Pilot ignition is a critical concern because without a flame, there will be no flare gas 

combustion, and a pilot light is required to ensure that a flame remains always present. 

The ignition equipment functions to reliably light the pilot. The two ignition types described 

below are used for the GBR flare:

1. Automatic - Spark ignition at the pilot tip is easy and simple to automate. Spark 

generation is located so that it is exposed to the combustible flare gas stream that 

exits the tip. This is the primary ignition system for each of the pilots. 

2. Flame-Front Generator (FFG) System - The compressed-air flame-front 

generator ignition system is the most widely-used flare ignition system and is 

utilized as backup for each of the existing pilots. Compressed air and fuel are 

introduced through a sparking device located downstream of the mixing chamber 

with the pilot tip. A flame front that ignites the pilot is sent through the piping 

when the flare gas stream is ignited by the sparking device. The primary 

advantage of the compressed-air flame-front generator is that both the sparking 

device and flow controls are located at ground level and can be maintained and 
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repaired without removing the flare from service. However, the primary 

disadvantage of this ignition system is with its propensity for moisture formation 

in the piping leading to the pilot, which, if corrosive, may potentially render the 

ignition system useless. Therefore, it is common to flush each ignition line after 

use to reduce the moisture problem.

The GBR flare ignition system consists of three pilot lights, all of which are continuous. All 

three pilots have an automated high energy ignition (HEI) system with a manual FFG system 

as backup. Ignition gas is supplied through the Pilot Gas Regulator, PCV-2407, when the 

HEI system is used. When the FFG system is used, ignition gas is supplied through a 1-inch 

control valve, PCV-2401. When the HEI system is activated, the ignition sequence takes 

place for 1 minute to light the pilot. If the pilot cannot be lit, an alarm alerts the operator to 

manually start the flame using the FFG System. When the FFG system is used, an operator 

standing at the ignition panel within proximity to the base of the flare manually closes the gas 

valve once the pilot flame has been visually detected through the control panel sight glass. 

Ignition at the pilot tip can take 1-2 minutes. 

2.10 Purge Gas

According to the definitions promulgated in Subpart Ja, purge gas is 

“Gas introduced between a flare’s water seal and a flare’s tip to prevent oxygen 

infiltration (backflow) into the flare tip. For flares with no water seals, the function of 

purge gas is performed by sweep gas (i.e., flares without water seals do not use purge 

gas)”. 

All flare systems have the propensity for flashback, in-line detonation, and potential 

explosion in the flare stack if oxygen enters through the flare burner and travels down the 

flare stack. A continuous purge is therefore necessary to prevent atmospheric oxygen from 

entering down through the flare burners. The purge is an injected gas designed to provide a 

minimum continuous momentum flux upward thru the flare tip ensuring no reversal of flow 

and so that no intrusion of air that could create an ignitable mixture.

For flares with no water seals, such as the GBR flare, the function of purge gas is performed 

by sweep gas. See Section 2.11 for information regarding sweep gas. The GBR Flare does 

not utilize any purge gas.

2.11 Sweep Gas

Sweep gas is defined as:

“Gas introduced in a flare gas header system to maintain a constant flow of gas to 

prevent oxygen buildup in the flare header. For flares with no water seals, sweep gas 

also performs the function of preventing oxygen infiltration (backflow) into the flare 

tip”. 
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The GBR flare was put in place using the philosophy to install natural gas sweeps for major 

collection headers in the flare system. The volume of each sweep shall be adequate for a 

velocity of 0.1 feet per second in the header. The total volume of sweep gas required will 

depend on flare tip requirements, type of flare seal, and control systems.

The GBR flare gas header utilizes a 3⁄4”-inch natural gas supply line at the beginning of the 

flare header to provide the initial introduction of sweep gas. The sweep gas flow rate 

required to meet the design specification is 300 scf/hr. The sweep gas flow is monitored 

using flow indicator FI-1707. The sweep gas flow rate is generally not adjusted and remains 

constant. 

Downstream of the process connections to the GBR flare header, the flare header diameter 

increases from 14 inches to 24 inches. At this point of diameter increase, a second sweep gas 

line is connected to the header. This second sweep gas addition point is required, in 

conjunction with the first, to maintain the appropriate continuous exit velocity of flare gases 

thru the velocity seal below the flare tip. This minimum flare exit velocity was determined 

by Zeeco to require an additional minimum injection of 630 scf/hr of sweep gas. 

Because natural gas, according to the rule, is inherently low in sulfur concentration, NSPS Ja

offers provisions that allow gas lines that are exclusively natural gas to be exempted from 

sulfur content monitoring. Therefore, an analysis of the H2S concentration in the sweep gas 

to demonstrate compliance with the rule is not required.

2.12 Supplemental Gas

Supplemental gas is gas that is introduced to the flare in order to comply with the net heating 

value (NHV) requirements of 40 CFR §60.18(b) and/or 40 CFR 63.11(b). Supplemental gas 

is used as a calorific boost to the vented gas to ensure optimal combustion. When 

combustible gases are used for sweep gas or purge gas, it simultaneously functions as 

supplemental gas. 

The GBR flare does not have a dedicated supplemental fuel gas line that is used to increase 

the heating value of the combusted flare gases. However, since natural gas is utilized for the 

sweep gas, it simultaneously functions as supplemental gas. 

2.13 Monitoring Instrumentation

Monitoring of key parameters, such as flare performance, gas stream flow rate and 

composition, heating value, assist gas flow rate, pilot flare presence, and process unit 

performance, enables a facility to identify, respond to, and correct most flaring activities.

Monitoring helps to ensure proper flare operation and provide reliable data for emissions 

calculation. Without proper monitoring, it is impossible to know whether a flare is

performing according to design specifications. Improving the reliability, completeness, and 

accuracy of flare data is expected to promote flare reduction activities and prioritize potential 

future investments. Reliable data is vital for effective and consistent enforcement of flaring 

regulations. It also informs operators of the potential economic losses resulting from flaring. 
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Therefore, a rigorous flare monitoring and reporting program is integral to a facility’s ability 

to reduce flaring to the maximum extent possible. 

Flare monitoring devices do have specific limitations of accuracy and these limitations 

should be well understood by the operators and regulators. For example, flares potentially 

operate over a very wide range of flow rates. Normal vent gas flow rates are typically a 

fraction of the overall maximum design capacity. In this example, flow meter technology 

should be assessed to provide the most accurate data within the range of most likely flow 

rates. It is also important that any recommendations regarding monitoring devices of a flare 

system will be based on prior analysis of reliable data derived from the actual monitoring of 

the system. This principle applies to all flare monitoring devices or equipment.

NSPS Ja identifies monitoring schemes to demonstrate compliance with the rule.

2.13.1 Vent Gas Flow

NSPS Ja requires the GBR flare to operate with a flare gas header flow meter that provides a 

representative measurement of the total flow rate discharged to each flare. The flow rate data 

that is collected will be used to determine if flaring events occur that exceed the Root Cause 

Analysis (RCA) threshold of 500,000 scf in a 24-hour period above the established baseline. 

The following standards for the flow meter are required pursuant to the rule in 60.107a(f)(1): 

 Must be located in a position that is representative of the total gas flow rate,

 Must have a flow sensitivity of no more than 5% of the flow rate or 10 scfm, 

whichever is greater,

 Must be maintainable online, and

 Must continually correct for pressure and temperature and record flow in standard 

conditions,

The GBR flare uses a GE Panametrics GF868 Flare Gas Flow Meter System with T5 

Ultrasonic Flow Transducers to measure the flow rate to each flare. The GF868 is

manufactured according to the specifications in the rule, and the Suncor Commerce City

refinery has ensured that the GBR flare flow meter is installed in a representative location, 

thereby complying with the selection and installation of the flow meter. The following table 

summarizes the specifications of the GF868 as provided by the manufacturer’s datasheet.

Table 2-2: Flow Meter Specifications

Required Information Monitor Information

Make General Electric

Model DigitalFlowTM GF868-1-11-20014-FM-0-0

Type Panametrics Ultrasonic Flare Gas Mass Flow Meter

Range 0.1 fps to 328 fps

Precision Repeatability = ±1% 

Accuracy ±2.4% to 5%
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Maintenance and calibrations on the GF868 are conducted per manufacturer’s 

recommendations and are in compliance with the April 5, 2013 US EPA published 

Alternative Test Method 099 – Approval of Optical Flow Meters for Flares. This alternative 

test method is included as Appendix E.

The flow meter (FE-2301A/B, DCS tag No. FI-2301A/B) is located downstream of flare KO 

Drum, D-3924. The meter configuration is a single-channel bias-90 setup with temperature 

and pressure corrected readings. The pressure and temperature sensors that are configured 

with FT-9006 are PT-2302 (DCS tag No. PI-2302) and TT-2302 (DCS tag No. TI-2302), 

respectively. The pressure and temperature readings are used to automatically correct the 

raw flow meter reading to standard condition flow rates and are reported to the DCS. 

Baseline flow evaluation is discussed in Section 3.3. 

2.13.2 Sulfur Content

NSPS Ja requires that a flare should operate a monitoring device to measure the sulfur 

content of the gases combusted in the flare to demonstrate compliance with the H2S 

concentration limit of 162 ppmvd and to determine if the SO2 emissions have exceeded the 

threshold for conducting an RCA (500 pounds in a 24 hour period). However, if the gases 

combusted in the flare are inherently low in sulfur, the rule allows the Commerce City 

Refinery to apply for an exemption from sulfur monitoring. 

The exemptions for sulfur monitoring are provided in §§60.107a(a)(3)(i) through (iv). The 

process gases that constitute the feed to the GBR Unit meet the requirements of 

60.107a(a)(3)(iii), which allows gas streams that are produced in process units that are 

intolerant to sulfur contamination to be considered inherently low in sulfur content. Specific 

examples that are provided in the rule of units that are intolerant to sulfur include hydrogen 

plants and catalytic reforming units, which are the very units at Suncor that generate the 

specific feed for the GBR unit. Additionally, the GBR unit utilizes guard beds that function 

to remove sulfur, chlorides, and free water from the feed streams to further reduce the 

amount of sulfur fed to the GBR unit. Therefore, because each of the gas streams that are 

routed to the GBR flare header meets the requirements to be considered inherently low in 

sulfur, the Commerce City Refinery is not be required to monitor the sulfur concentration of 

flare gas in the GBR flare header. 

Although sulfur concentration analysis of the GBR flare header may not be required, the 

Suncor Commerce City refinery voluntarily installed, maintained, and certified an H2S 

monitor on the GBR flare for operational purposes to ensure that there was negligible sulfur 

content generated from the GBR unit. On February 7, 2014 Suncor submitted an 

Administrative Amendment (Administrative Amendment No. 9 to Title V Permit No. 

96OPAD120) to the Colorado Department of Public Health and the Environment (CDPHE) 

that proposed the decommissioning of the H2S monitor at the GBR flare. This 

Administrative Amendment was approved on the grounds that the flare streams generated by 

the GBR unit are inherently low in sulfur. 

Based on an analysis of the GBR H2S data, Suncor and the CDPHE agreed to use a constant 

H2S value of 0.07 ppm to estimate emissions from flared gas. This information was 

incorporated into Appendix H of the above-referenced Title V Permit. The H2S monitor has 
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been decommissioned and is no longer being used to demonstrate compliance, nor is it being 

maintained per 40 CFR 60 Appendix F.
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SECTION 3

FLARE MINIMIZATION

3.1 Description of Contributions to Flare Header

As detailed in Section 2.3, the process connections to the GBR header consist of RVs, pump 

seal vents, sample points, and manual service valves. The process contributions from each 

type of connection are as follows:

 Relief valves are utilized in the process as emergency relief devices that will release 

gases into the flare header to prevent an unsafe pressure buildup in a process vessel;

 Pump seal vents are used to discharge any gases that accumulate in the pump seal 

pots of the liquid seal pumps;

 Sample points are connected to the flare header to allow the sample line to be purged 

to ensure that a representative sample to be obtained.

 Manual valves are generally used to remove process gases that have condensed out of 

process gas lines and have been collected in condensate collection pots, such as KO 

drums or demisters. While the material is a liquid at the time of accumulation, it 

immediately vaporizes when the valve is opened to route it to the flare. 

This contributions analysis was reviewed in detail during the design of the new process and 

each contribution/point of entry was deemed critical and necessary. In addition, each source 

was assessed for minimization alternatives during engineering design. In addition to the 

process contributions, the GBR flare header includes the contributions of two sweep gas 

injection points. See Section 2.11 for further information on the sweep gas contributions.

3.2 Minimization Assessment

According to the NSPS Ja, the Suncor refinery must conduct a further assessment of whether 

discharges to the new flare from the process units, from associated equipment, and from the 

fuel gas system can be minimized. The assessment must include the following items:

 Elimination of process gas discharge to the flare through process operating changes or 

gas recovery at the source;

 Reduction of the volume of process gas to the flare through process operating 

changes;

 Installation of a flare gas recovery system*; and,

 Minimization of sweep and purge gas flow rates, if applicable.

* If a facility is fuel rich, a flare gas recovery system and a co-generation unit or combined 

heat and power unit would also need to be considered.
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For each of the items above, the minimization assessment must provide rationale in terms of 

the following considerations:

 Costs, including capital and annual operating;

 Natural gas offset credits, if applicable;

 Technical feasibility;

 Secondary environmental impacts , and,

 Safety considerations.

If a reduction in flow cannot be achieved, a statement must be made justifying why the 

minimization could not occur.

Suncor reviewed the various connections to the GBR flare header during detailed design 

phase of the new unit, and it assessed each type of connection for the potential for 

minimization. The contributions and the rationale for minimization from each type of 

connection are as follows:

 Relief valves are utilized in the process as an emergency relief device. Emergency 

conditions within a process vessel are an undesired condition that process controls are 

constantly attempting to minimize. Therefore, releases through an RV to the GBR 

flare header are currently minimized through process controls. Additionally, the RVs 

are serviced every five years as part of Suncor’s preventative maintenance program

(removal and visual inspection plus pressure testing). This maintenance reduces the 

potential for routine minor leakage through the RVs. Acoustic leak surveys of RVs 

are also performed as indicated or on an as needed basis to identify sources of flow 

outside of the normal operating ranges. Currently, there are only 9 PRVs routed to 

this GBR flare. Their contribution towards routine flow is negligible.

 Pump seal vents discharge any gases that accumulate in the pump seal pots of the 

liquid seal pumps. These pump seal pots are equipped with pressure transmitters that 

provide an indication of the performance of the pump seal. When the pressure of the 

pump seal pot reaches an undesirable level, the pump is taken out of service for 

maintenance, thereby minimizing the flow to the GBR flare header. Currently, the 

DCS system will alarm when the pressure transmitters on each pump seal pot reaches

7 psig.

 Sample points are connected to the flare header to allow the sample lines to be purged 

prior to obtaining a sample. The sample lines associated with each sample point 

consist of 1⁄2 inch piping or tubing. Additionally, the sample points are located in 

close proximity to the process vessel to be sampled. Therefore, the volume of gas 

required to be purged prior to sampling has been minimized by design to the extent 

possible.

 Manual valves are generally used to remove process gases that have condensed and 

been accumulated in condensate collection pots. These liquids must be removed from 

the vessels to ensure proper operation. When the liquids are released to the flare 
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header, due to the change in conditions, the liquids vaporize and are combusted in the 

flare as gases. Based on operational knowledge, the frequency of contributions to the 

GBR flare header can range from approximately once per day to once per year 

depending on the type of vessel and service. The volumes released through these 

valves are minimal and are not likely to correlate to increased flaring events. See 

Section 3.3 for a discussion of the baseline flow evaluation. Currently, it is not 

possible to route these liquids to another location within the refinery for beneficial 

use. If these contributions are observed to increase in frequency and volume in the 

future, Suncor will utilize the RCA procedure to investigate whether redirecting these 

flows is warranted.

 Control valves are generally used during startup conditions. These valves are opened 

during the startup of a unit when out of specification materials are being 

processed/produced. By directing these initial startup materials towards the flare, 

operations can prevent potentially excessive disturbances to the fuel gas system, 

which has the potential to upset other units causing additional flaring. Control valves 

will be discussed further in Section 3.4.

 Sweep gas contributions occur at two distinct points at the GBR flare header. The 

first addition point is located upstream of all contributions to the flare header. During 

the design of the GBR flare system, it was determined that the GBR flare header 

requires a minimum flow of 0.1 feet per second (fps). Based on the size of the flare 

header, the flow required to meet the 0.1 fps flow is approximately 300 scf/hr. At a 

point after the process connections to the GBR flare header have been made, the flare 

header diameter increases from 14 inches to 24 inches. At this point of diameter 

increase, a second sweep gas addition point is made. This addition point is required 

to maintain the appropriate exit velocity of flare gases from the flare tip. This 

minimum flare velocity was determined to require the addition of a minimum of 630 

scf/hr of sweep gas. As these sweep gas flow additions were determined to be the 

lowest flow rates required for proper operation of the GBR flare system, these flows 

have been minimized.

Based on the flare minimization assessment performed, the Commerce City refinery has 

determined that the current contributions to the GBR flare header have been minimized by 

proper engineering design. This minimization is consistent with Suncor’s operational 

philosophy which attempts to minimize losses of material as they represent lost products and 

lost revenue.

3.3 Baseline Flow Evaluation

NSPS Ja specifies in 60.103a(4) that a baseline flow evaluation must be conducted after the 

minimization assessment has been completed. The determination of the baseline flow does 

not include pilot gas or purge gas, provided that these flow rates remain relatively constant. 

See Sections 2.8 and 2.10 for further information on pilot gas and purge gas, respectively. 

The numeric value of the baseline flow is the sum of all flows that the minimization 
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assessment determined could not be further minimized. See Section 3.2 for further 

information on the Minimization Assessment.

Alternative baseline flow rates can be established for different operating conditions provided 

that the following information is included with the development of separate baseline flow 

rates: 

 Identification of a primary baseline that will be used as the default baseline;

 Description of each operating condition for which a separate baseline is established; 

and

 Procedures to minimize discharges to the flare during each operating condition for 

which a separate baseline is established. 

As the GBR Flare has been operational since May of 2012, Suncor reviewed the approximate 

twelve months of available flare gas header flow rate data, which is presented as Figure 3-1 

below.

Figure 3-1. Available Flow Rate Data for Baseline Analysis

The available flow rate data illustrates that the majority of the flows to the GBR flare are of a 

relatively constant, low flow. The period of increased flaring at the beginning of the time 

period is associated with the startup of the GBR unit. The spike in the middle of the chart is 

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

GBR Flare Flow (Mscf/hr)
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associated to a planned shutdown resulting in excess hydrogen having to be sent to the GBR 

Flare. These non-routine episodes were not included within the normal baseline assessment.

The data was organized into a histogram and analyzed to determine the flow rates at which 

the majority of normal operations occur. The distribution of low flows is illustrated in Figure 

3-2 below.

Figure 3-2. Distribution of Flow Rates to the GBR Flare

The distribution of the average hourly flow rate data illustrates a decreasing trend in 

occurrences and sharp decrease in flow rates greater than 2,000 scf/hr and again after 3,000 

scf/hr. The flow rate data presented includes the sweep gas as the flow meter is located 

downstream of both of the sweep injection points. The number of average hourly data points 

for the 12 months evaluated that were less than 3,000 scf/hr represents approximately 76% of 

the operating hours analyzed. Because the number of data points available for analysis is 

limited to only twelve months of data, this baseline will likely need to be revised as 

additional data becomes available. Based on the distribution of flow rates and the limited 

time that the GBR unit has been operational, Suncor plans to utilize 3,000 scf/hr less the 

necessary 930 scf/hr of established sweep gas flow, as the normal baseline flow to the GBR 

flare, which corresponds to 2,070 scf/hr. This is for normal operating conditions. During 

startups, shutdowns, and periods of excess hydrogen a different baseline is required. See 

sections below for detailed description of the baseline limit during abnormal operation.

0

1000

2000

3000

4000

5000

6000

7000

>1 >2 >3 > 5 >10 >20 >30 >50 >75 >100 >125

Number

GBR Flare Flow Rates (Mscf/hr)

Distribution of Flow Rates to GBR Flare
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3.4 Startup and Shutdown

The Commerce City refinery reviewed the procedures that detail its planned shutdowns and 

startups. These procedures elaborate upon the specific steps taken by operators of the GBR 

unit to startup and shutdown the unit in a planned, step-wise manner, while maintaining safe 

conditions within the unit. The operational philosophy at Suncor works to minimize losses to 

flaring through the use of their procedures as flaring represents lost raw materials and 

products. Therefore, Suncor believes it has minimized the potential for excessive flaring 

during planned startups and shutdowns through the use of the standard operating procedures.

Two control valves were identified that were utilized primarily during startup conditions of 

the GBR:

 The BERT overhead system connection utilizes a startup line for the overhead gases 

to go to the GBR flare during startup instead of the plant’s fuel system. During 

startup, if the BERT overhead gases were allowed to be sent to the fuel gas system, 

the fuel gas system would experience excessive pressure fluctuations that have the 

potential to disrupt the operation of additional units. When the GBR is in steady 

operation, the control value is closed and the control directing the gases to the fuel 

gas system is opened.

 Control valve PC1108 is utilized during startups and emergency trips of the No. 3/No. 

4 HDS units to direct hydrogen to the GBR flare. During startup of the GBR unit, the 

hydrogen will be released to the GBR flare only until the H2 guard bed system is in 

steady operation. As the No. 3/No. 4HDS units start to accept the hydrogen, the 

control valve will slowly close to minimize disturbances to the system.

Additionally, if the No. 3/No. 4 HDS units have an emergency trip causing the 

pressure in the line to build, the control valve PC1108 will automatically open to 

redirect the hydrogen to the GBR flare until the operators can manage the hydrogen in 

the fuel system or reduce the hydrogen plant production until the hydrogen flows are 

returned to normal.

Because the number of data points available for analysis is limited to only twelve months of 

data, this startup/shutdown baseline will likely need to be revised as additional data becomes 

available after additional startups and shutdowns have occurred. Based on the distribution of 

flow rates and the limited time that the GBR unit has been operational, Suncor plans to 

utilize a 125,000 scf/hr less the necessary 930 scf/hr of established sweep gas flow, as the 

startup/shutdown baseline flow to the GBR flare, which corresponds to 124,070 scf/hr.
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3.5 Fuel Gas & Hydrogen Imbalance

After reviewing the various scenarios regarding the fuel gas and hydrogen system that could 

result in flaring at the GBR flare, Suncor identified two scenarios that are discussed in detail 

below:

 Over-pressuring of the fuel gas KO Drum; 

 Shutdown of any of the hydrodesulfurization (HDS) units; and

 Various operating scenarios that could require additional Hydrogen to be sent to the 

GBR flare for destruction.

Because the fuel gas KO drum is connected to the GBR flare header via an RV connection, 

this vessel only vents to the flare header during emergency situations (a manual valve is also 

present to bypass the PRV during infrequent maintenance events). As discussed earlier, 

releases from each RV are minimized by operations and maintenance personnel through 

continual process control. 

The refinery’s two reformers and the hydrogen plant feed the new GBR unit. Approximately 

14% of the material produced by the reformers and hydrogen plant pass through the guard 

beds at the GBR unit. The remaining 86% is sent to the fuel gas system. The material sent 

through the guard beds is then split between the GBR unit and the HDS units. When the 

HDS units trip or are shutdown, the pressure in the line to the HDS units experiences an 

increase in pressure. This increase in pressure triggers a control valve to open, sending 

hydrogen rich material to the GBR flare. If the amount of time required to bring the HDS 

units back into operation is minimal, the facility will continue to flare the excess material 

until the HDS units are brought back online. If the amount of time required to bring the HDS 

units back into operation is significant, the facility will reduce the production of the 

reformers and the hydrogen plant which has the ability to stop flaring at the GBR flare. As a 

refinery is a complex system of interconnected units, this decision to reduce production of 

the reformers and the hydrogen plant will be unique for each episode and will be dependent 

on the available resources at the facility. During periods of excess fuel gas and/or hydrogen 

as outlined above Suncor plans to utilize a 125,000 scf/hr less the necessary 930 scf/hr of 

established sweep gas flow, as the baseline flow during periods of excess fuel gas and/or 

Hydrogen to the GBR flare, which corresponds to 124,070 scf/hr.

3.6 Fuel Gas Recovery Outage

Suncor does not utilize fuel gas recovery within the GBR unit; therefore Section 3.6 does not 

apply to the GBR flare.
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SECTION 4

ROOT CAUSE ANALYSIS AND CORRECTIVE ACTION

This section provides a discussion on Root Cause Analysis (RCA) and Corrective Action 

Analysis that are required by NSPS Ja. These analyses are not specifically required to be a part 

of the FMP; however, the monitoring systems that provide the data for the RCA threshold 

determinations are detailed in the FMP and the conclusions obtained from the RCA and 

Corrective Action analyses will potentially require changes to be made to the FMP. Therefore, 

the RCA and Corrective Action Analysis requirements have been included in the FMP. Suncor

currently is required to perform RCAs for sulfur and flow exceedances as part of their Global 

Refinery Initiative Consent Decree (CD) dated 2005. Suncor will perform RCAs to comply with 

the requirements of both the Consent Decree and NSPS Ja.

4.1 Root Cause Analysis

As defined in NSPS Ja, an RCA is

“an assessment conducted through a process of investigation to determine the primary 

cause, and any other contributing cause(s), of a discharge of gases in excess of specified 

thresholds.” 

The Rule specifies two thresholds for flares that trigger an RCA in 60.103a(c)(i) and (ii). An 

RCA must be completed as soon as possible, but no later than 45 days after a discharge that 

exceeds one or both of the specified thresholds. The two thresholds which trigger an RCA are as 

follows:

 Anytime the SO2 emissions exceed 500 lb in any 24-hour period, or

 Any discharge to one or more flares in excess of 500,000 scf above an established 

baseline in a 24-hour period.

A detailed discussion regarding each threshold is provided below. 

The rule delineates three special circumstances that affect the number of RCAs that the 

Commerce City refinery must perform following an RCA threshold exceedance:

 If a single discharge event lasts for two or more consecutive 24-hour periods, only one 

RCA must be performed;

 If a single discharge event triggers an RCA based on both of the specified thresholds, 

only one RCA must be performed;

 If a discharge that triggers an RCA is the result of a planned startup or shutdown during 

which the Planned Startup & Shutdown procedures referenced in Section 3.4 were 

followed, an RCA is not required; and

 If multiple flares in a cascaded flare system each trigger an RCA in the same 24-hour 

period, only one RCA must be performed.

As the GBR unit is intolerant to sulfur, sulfur monitoring is not required. Additionally, due to 

the inherently low sulfur requirements of the unit, exceedances of the flow threshold will likely 
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occur prior to exceedances of the sulfur threshold. However, for completeness, this FMP details 

the RCA requirements for both flow exceedances and SO2 exceedances.

4.1.1 RCA – Flow Exceedance

The specified flow threshold which triggers an RCA is the discharge to a flare of greater than 

500,000 scf above the established baseline flows in a 24-hour period to the flare. 

When performing an RCA for a flow exceedance at the Commerce City refinery, there are 

several key parameters that should be documented as part of the investigation: 

 the connections that were contributing to the header, 

 the duration of the flaring event, 

 what was occurring in the process that led to the flaring event, and, if possible,

 the sequence of events that lead to the flaring event.

Once these items have been investigated and documented, a determination of potential actions 

that could have prevented the flaring event or reduced the volume or duration of the flaring event 

should be evaluated and documented.

Once the investigation has been completed, the key information and data gathered during the 

process should be assembled into an RCA Report to be retained in internal records. Because the 

rule specifies that certain items must be recorded for each RCA, each internal report should, at 

minimum, include the following:

 A description of the discharge.

 Date and time of when the discharge was first identified and the duration of the 

discharge.

 The measured quantity of gas discharged over the discharge duration. If the discharge 

duration exceeds 24 hours, record the quantity for each 24-hour period.

 The steps taken to limit the emissions during the discharge.

 Statement as to whether the discharge resulted from the same root cause(s) identified in 

previous RCAs.

 Description of the recommended corrective action(s) or an explanation of why corrective 

action is not necessary.

 If the discharge was a result of a planned startup or shutdown of a refinery process unit or 

ancillary equipment connected to the affected flare, a statement that an RCA is not 

necessary because the facility followed the FMP. For further information on the 

procedures to minimize flaring during planned startup and shutdown, see Section 3.4.

4.1.2 RCA – SO2 Exceedance

The specified sulfur content threshold which triggers an RCA is the emission from the flare of 

more than 500 lbs of SO2 in any 24-hour period. In contrast to the RCA flow threshold, there is

no reference baseline upon which to compare SO2 emissions. The SO2 emissions are determined 

by monitoring the H2S concentrations in the gases sent to the flare for combustion. Pilot gas is 

specifically exempt from sulfur monitoring. The GBR flare is currently equipped with an H2S 
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monitor that is utilized to determine total daily SO2 emissions; however, this monitor does not 

currently meet the upper span requirements of NSPS Ja and is not being used to show 

compliance with the Rule.

When performing an RCA for an SO2 exceedance at the Suncor refinery, there are several key 

parameters that should be documented as part of the investigation: 

 the connections that were contributing to the header, 

 the duration of the flaring event, 

 what was occurring in the process that lead to the flaring event, and, if possible,

 the sequence of events led to the flaring event. 

Once these items have been investigated and documented, a determination of potential actions 

that could have prevented the flaring event or reduced the volume or duration of the flaring event 

should be evaluated and documented.

Once the investigation has been completed, the key information and data gathered during the 

process should be assembled into an RCA Report to be retained in internal records. Because the 

rule specifies that certain items must be recorded for each RCA, each internal report should, at a 

minimum, include the following:

 A description of the discharge.

 Date and time of when the discharge was first identified and the duration of the 

discharge.

 The measured quantity of gas discharged over the discharge duration. If the discharge 

duration exceeds 24 hours, record the quantity for each 24-hour period.

 The measured total sulfur concentrations in the fuel gas at a representative location in the 

flare inlet.

 The cumulative quantity of H2S and SO2 released into the atmosphere. For releases 

controlled by flares, assume 99 % conversion of TRS to SO2.

 The steps taken to limit the emissions during the discharge.

 Statement as to whether the discharge resulted from the same root cause(s) identified in 

previous RCAs.

 Description of the recommended corrective action(s) or an explanation of why corrective 

action is not necessary.

 If the discharge was a result of a planned startup or shutdown of a refinery process unit or 

ancillary equipment connected to the affected flare, a statement that an RCA is not 

necessary because the facility followed the FMP. For further information on the 

procedures to minimize flaring during planned startup and shutdown, see Section 3.4.
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4.2 Corrective Action Analyses

As defined in the NSPS Ja 60.101a, a Corrective Action is

“the design, operation and maintenance changes that one takes consistent with good 

engineering practice to reduce or eliminate the likelihood of the recurrence of the primary 

cause and any other contributing cause(s) of an event identified by a root cause analysis 

as having resulted in a discharge of gases to an affected flare in excess of specified 

thresholds”

An identification of corrective action(s) must be performed as the final step of an RCA per 

60.103a(d). The purpose of documenting the corrective action(s) in the internal RCA Report is 

to systematically identify changes that could be made to reduce or, if possible, eliminate the 

possibility of the recurrence of the causes of the flaring event that caused an exceedance of one 

or both of the RCA thresholds. The identification of corrective actions should incorporate 

rationale regarding economic or technical feasibility or other potential limiting factors. The 

purpose of identifying corrective actions is to determine, based upon good engineering practices, 

potential changes that could rectify the cause(s) of the flaring event that was/were identified by 

the RCA. 

According to the rule, a Corrective Action Analysis is

“a description of all reasonable interim and long-term measures, if any, that are available, 

and an explanation of why the selected corrective action(s) is/are the best alternative(s), 

including, but not limited to, considerations of cost effectiveness, technical feasibility, 

safety and secondary impacts.”

The Corrective Action Analysis is the process to determine which of the identified corrective 

actions presents the most plausible argument for implementation. It is during this analysis that 

rationale regarding economic and technical feasibility, along with other potential limiting factors, 

are taken into consideration. If the facility concludes that a corrective action should not be 

conducted, the facility must document the decision and include the basis for the conclusion.

All corrective actions must be implemented within 45 days of the discharge for which the RCA 

and corrective action analyses were required or as soon as practicable. If it is determined that a 

corrective action should not be implemented, the explanation of the basis of that decision must 

be recorded no later than 45 days following the discharge. Because the Corrective Action 

Analysis is a consequence of the RCA, it is imperative to commence the RCA as soon after the 

discharge as possible in order to allow for the maximum amount of time to be allotted to the 

determination and implementation of the most beneficial corrective action. However, if a 

corrective action cannot be fully implemented within 45 days, the facility must develop an 

implementation schedule to complete the corrective action as soon as feasible.

Once the 45-day period following the discharge has passed, the rule specifies that certain items 

must be included in the internal RCA Report for each Correct Action Analysis. At minimum, 

each internal report must include the following items:

 If it is determined that a corrective action should not be implemented, an explanation of 

the basis of that decision.
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 A description of the corrective action(s) completed within the first 45 days following the 

discharge. 

 For corrective actions not completed within 45 days, a schedule for implementation, 

including proposed commencement and completion dates.

According to 60.103a(d)(3), if the discharge was a result of a planned startup or 

shutdown of a refinery process unit or ancillary equipment connected to the affected 

flare, a statement that a Corrective Action Analysis is not necessary because the facility 

followed the FMP. For further information on the procedures to minimize flaring during 

planned startup and shutdown, see Section 3.4.
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APPENDIX A

PLAN REVISION LOG
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Revision Log

Suncor Energy (U.S.A.) Inc.

Commerce City, Colorado

NSPS Subpart Ja – GBR Flare Management Plan

This Flare Management Plan (FMP) fulfills the requirements for NSPS Subpart Ja for the 

GBR Flare at the Commerce City Refinery. Any changes to the original plant should be 

documented in the table below.

Revision 

No.

Revision 

Date

Revision Author 

(name, company) Reason for Revision

Requires 

Submission to 

the EPA? (See 

section 1.3 of 

FMP)

0 11/13/12 Sage Environmental 

Consulting Original Submittal to EPA Yes

1 7/16/13 Craig Neuman 

(Suncor) Updated baseline flow limits Yes

2 4/7/14

Bernd Haneke 

(Suncor)

Updates to Section 2.13.1

Updates to Section 2.13.2 Yes
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APPENDIX B

NSPS Ja CROSS-REFERENCE TABLE
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FMP Manual Section

60.103a(a)

Appendix D

1.1, Appendix D

1.1, Appendix D

60.103a(a)(2) 3.2

60.103a(a)(3)(i)

Flare type 2.1

Assist system 2.7

Flare tip 2.2

Flare header system 2.3

Flare Gas Recovery System 2.5

60.103a(a)(3)(ii)

Flare tip 2.2, Appendix D

KO drum 2.4, Appendix D

Flare header & subheader 2.3, Appendix D

Assist system 2.7, Appendix D

Ignition system 2.9, Appendix D

60.103a(a)(3)(iii)

Maximum vent gas flow rate 2.1

Minimum sweep gas flow rate 2.11

Minimum purge gas flow rate N/A

Maximum supplemental gas flow rate N/A

Maximum pilot gas flow rate 2.8

Minimum total steam flow rate 2.2

60.103a(a)(3)(iv)

Flare header 2.3, Appendix D

Purge gas N/A

Sweep gas 2.11, Appendix D

Supplemental gas N/A

Pilot gas 2.8, Appendix D

60.103a(a)(3)(v) 2.13

60.103a(a)(3)(vi)

Description of water seal N/A

Designation of monitoring option N/A

60.103a(a)(3)(vii) N/A

60.103a(a)(4) 3.3

60.103a(a)(5) 3.4

60.103a(a)(6) 3.5

60.103a(a)(7) N/A

60.103a(b)(1) 1.2

60.103a(b)(2) 1.3

60.103a(c)(1) 4.1

60.103a(d) 4.1

60.103a(e) 4.2

60.103a(f) 4.2

60.103a(g) N/A

60.103a(h) 2.13.2

60.107a(a)(2) 2.13.2

60.107a(a)(3) 2.13.2

60.107a(b) 2.13.2

60.107a(e) 4.1.2

60.107a(f) 4.1.1

60.107a(g) 2.13, 4.1

60.108a(a) - (c) 1.2, Appendix A

Monitoring of flow rates for RCA

Monitoring alternatives for Sulfur Content and Flow Rate for RCA

Required notifications and records

Applicability of flares to < 162 ppmv H2S concentration limit in flare 

Requirements for monitoring flare gas H2S concentration

Exemptions for flare gas H2S concentration monitoring

Procedures to exempt streams from flare gas H2S concentration 

monitoring

Monitoring of sulfur content for RCA

Procedures to minimize or eliminate discharges during planned 

shutdown and startup

Procedures to reduce flaring in cases of fuel gas imbalance

Submission timeline for initial FMP

Conditions which Trigger a Root Cause Analysis for a Flaring Event

Specific requirements for flares located in the BAAQMD and 

SCAQMD

Design parameters

Description and simple PFD of flow meters and sulfur content 

Manufacturer's specifications for each monitor/analyzer identified in 

60.103a(a)(3)(iv)

Description of FGRU, FGRU monitoring parameters, and compressor 

system logistics

Baseline flow evaluation

List of ancillary equipment

List of fuel gas systems

Minimization assessment

General description

Description and simple PFD

NSPS Ja Cross-Reference Table

Events which trigger a re-submittal of the FMP

Timeline to conduct Root Cause Analysis and Corrective Action 

Records to be maintained for Corrective Action Implementation

Timeframe for initial compliance for Root Cause Analysis and 

Corrective Action Implementation Programs

For emergency flares, secondary flares, and flares with FGRUs that are 

designed to capture all normal flows

Procedures to minimize frequency and duration during FGRU outages 

and to minimize flaring during FGRU outages

Regulatory Citation

60.103a(a)(1)

Items to be included in the Flare Management Plan

List of process units
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Suncor Energy (U.S.A.) Inc.

July 2013 GBR - Flare Management Plan 

APPENDIX C 

PROCESS FLOW DIAGRAMS 

 
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Seal Pots

•24P2410B

24P2410B

•24P2420B

24P2420A

24TW2410 Overhead•Relief Valve ‐ 24RV2410

Sweep Gas  (

Seal Pots•24P2410B•24P2410B•24P2410A•24P2410A•24P2400B•24P2400A•P‐3924 SealSump

•24P2420B•24P2420A•24P2415B•24P2425A•24P2430A•24P2430B

Guard Beds•Light Reformate (LR) Guard Beds ‐ 24D242•LR Relief Valve ‐ 24RV2420A•LR Relief Valve ‐ 24RV2420B•H2 Guard Bed Relief Valves ‐ 24RV2412A/

24TW2410 Overhead•Relief Valve ‐ 24RV2410B Analyzer Building•24AAX3002•PC 1108

Purge Gas  (Sam

s  (City Gas)

Sample Port)

Vent Gas

)

BERT• Overhead•Tower Overhead Drum Relief Valve ‐ 24RV2430•Tower Reflief Valve ‐ 24RV2425

Fuel Gas Knock Out Drum•Drain ‐ 24D2405

Splitter Overhead Drum•Drum ‐ 24D2415

•Relief Valve ‐ 24RV2415

Sweep Gas(City Gas)

FIGURE C 1 GBR Fl FLR 6 H d

•Tower Overhead Drum Relief Valve ‐ 24RV2430•Tower Reflief Valve ‐ 24RV2425

•Relief Valve ‐ 24RV2415

Swe

FIGURE C‐1. GBR Flare FLR‐6 Header

Suncor Energy ‐ Commerce City, Colora

Suncor Energy (U.S.A.) Inc.

DATE: N

PROJECT N
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Gas Mix

LowFlowRange

Ignition Tubes 4" Upper Ring Steam Line

PCV 2407

PCV 2401

Flame Front Ignition

Chamber

PCV 2402

1 5" C t

Fuel Gas Line

Vent Gas

FlareGas from GBR Unit

Instrument Air

PilotsThermocouplesTE2401‐TE2406(2 / pilot)

Sweep Gas

Globe

Valve FV 2401A

FT 2402

FT 2401A

Flare Vent Gas

Natural Gas

SteamInstrument Air

1.5" Center

Suncor Energy (U.S.A.) Inc.

DATE

PROJECT 

FIGURE C‐2. GBR Flare FLR‐6

Suncor Energy ‐ Commerce City, Colo

Flare Drawing Color Legend

Knock Out Drum

D‐3924

Steam Line

FlareGas from GBR Unit
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Suncor Energy (U.S.A.) Inc.

July 2013 GBR - Flare Management Plan 

APPENDIX D 

FLARE TIP DRAWING 
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Suncor Energy (U.S.A.) Inc.

April 2014 GBR - Flare Management Plan

APPENDIX E

ALT. TEST METHOD 099
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