Boiler 

Environmental 

Certification Workbook 

For use with MassDEP’s Environmental Results 

Program 

Massachusetts Department of Environmental Protection 
2

THE 

ENVIRONMENTAL 

RESULTS PROGRAM 

INTRODUCTION 

The Massachusetts Environmental Results Program (ERP) is an on-going environmental 

performance enhancement and measurement initiative that seeks to cost-effectively 

improve the environmental performance of whole small business sectors. In this 

regulatory system, comprised of a unique set of linked regulatory tools, small businesses 

are educated about their environmental impact and obligations, are required to selfevaluate and certify compliance, and are tracked to measure environmental performance 

changes. The Massachusetts Department of Environmental Protection (MassDEP) uses a 

statistical approach to track individual facility and whole-group performance results to 

identify poor performance areas and to effectively target limited agency compliance 

assistance and enforcement resources. 

The Boiler ERP replaces permits with performance standards that include the use of clean 

fuels, equipment maintenance, and record keeping requirements for new boilers with a 

heat input rating between 10,000,000 and 40,000,000 Btu per hour. You must submit an 

initial certification that you are meeting the environmental performance standards. By 

simplifying and clarifying the regulatory process, MassDEP hopes to reduce the cost and 

time required for compliance, while maintaining effective standards and improving 

environmental results. This workbook provides the information you must understand to 

meet your environmental obligations.
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Table of Contents 

Getting Started 

1.1 Who is Subject 

1.2 Who Should Read This Workbook 

1.3 Key Things You Should Know as a Facility Owner/Administrator 

Air Quality Requirements 

2.1 Fuel Requirements 

2.2 Emission Limits 

2.3 Performance Standards 

2.4 Recordkeeping 

2.5 Stack Design 

Industrial Waste Water Requirements 

3.1 Sewer 

3.2 Septic System 

3.3 Surface Water 

3.4 Ground Water 

3.5 Holding Tanks 

Related Activities 

4.1 Asbestos Removal 

4.2 Underground Storage Tanks 

Definitions and Terms 

Appendix 1: Information Needed for Air Dispersion Modeling 
4

GETTING STARTED 

[1.1] WHO IS SUBJECT TO ERP FOR BOILERS? 

Any individual boiler with a heat input rating between 10 million and 40 million Btu per 

hour (approximately 70 to 280 gallons of distillate fuel oil or 10,000 to 40,000 standard 

cubic feet (scf) of natural gas per hour) installed after September 14, 2001 is subject to 

the requirements of the Environmental Results Program (ERP) for boilers (Boiler ERP). 

For example, if a facility installs: 

o One 25 million Btu per hour boiler, the boiler IS subject to Boiler ERP 

o One 10 million Btu per hour boiler and one 30 million Btu per hour boiler, both 

boilers ARE subject to Boiler ERP 

o One five million Btu per hour boiler and one 15 million Btu per hour boiler, only 

the 15 million Btu per hour boiler is subject to Boiler ERP 

o Three five million Btu per hour boilers, the facility is not subject to Boiler ERP 

Please Note: Boilers larger than 40 million Btu per hour are subject to the requirement to 

obtain a plan approval from MassDEP. See: 

http://www.mass.gov/dep/air/approvals/aqforms.htm#airpapp 

Also Note: if you replace only the burner in a boiler you are not subject to Boiler ERP. 

[1.2] WHO SHOULD READ THIS WORKBOOK? 

Boiler Installer:

All boilers with a heat input rating between 10 million and 40 million Btu per hour 

installed after September 14, 2001 must meet the air emission limits specified in the 

boiler ERP regulation [310 CMR 7.26(33)] and outlined in this workbook. Therefore, it 

is crucial that you understand the requirements to ensure that the boiler you install is 

capable of meeting the standards. You are also a primary source of technical expertise to 

your customers. Providing the information and service that your customer needs to 

operate and maintain the boiler as efficiently and cleanly as possible not only minimizes 

emissions but is a good business practice as well. 

Facility Owner/Administrator:

As the owner or chief administrator of the facility, it is important that you understand the 

regulatory requirements described in this workbook. It is your responsibility to ensure 

that your new boiler is operated in compliance with the applicable environmental 
5

regulations. By ensuring that the “hands-on” person who operates the boiler understands 

the material in this workbook, you can make sure that the new boiler is run cleanly and 

efficiently, with minimal impact to the environment. You will also be confident that the 

compliance certification you sign is completed accurately and truthfully. 

In addition to focusing on reducing combustion emissions, the workbook also describes 

your options for managing boiler-related wastewater (boiler blowdown). Under the 

heading "Related Activities" this workbook provides information you may need if you 

remove an old boiler, or if underground petroleum storage tanks are located on your 

property. 

Boiler Operator:

As the boiler operator, it is equally important that you understand the material in this 

workbook. You are the “hands-on” person who has the daily responsibility to operate 

and maintain the boiler properly. To ensure compliance you must understand the fuel, 

stack, operational and record keeping requirements. You should also read the Related 

Activities section beginning on page 13 if you must dispose of an old boiler or if you 

manage underground petroleum storage tanks. 

[1.3] KEY THINGS YOU SHOULD KNOW AS A FACILITY OWNER / 

ADMINISTRATOR

• You must install a boiler that is capable of meeting the emissions standards 

specified in Section 2-2 of this workbook. 

• You must use specified clean fuels: The cornerstone of the Boiler ERP is the use 

of the following fuels: 

On or before July 1, 2009 - natural gas and/or distillate fuel oil (no more than 

0.05% sulfur by weight). 

After July 1, 2009 – natural gas or ultra low sulfur (no more than .0015% sulfur 

by weight) distillate (ULSD) fuel oil. 

 Natural gas-fired boilers emit significantly lower levels of particulate matter 

(PM), nitrogen oxides (NOx), and sulfur oxides (SOx) than boilers fired with 

other fuels. An example of the differences in potential emissions is shown in 

Tables 1a and b on page 7 in this workbook. Although the use of distillate or 

ULSD fuel oil results in slightly higher emissions than natural gas, they are 

significantly cleaner than other grades of oil or solid fuels. For example, the 

sulfur contents allowed in #2 distillate (“home heating oil”) and #6 residual fuel 

are 0.3% and up to 2.2% sulfur by weight, respectively. 

• Using these fuels and boilers protects public health: The air pollutants emitted 

by boilers have significant health impacts, especially to the very young, the 

elderly, and the people suffering from respiratory illnesses. Particulate matter, 

especially the small-sized particulate matter generated by fuel combustion, can 

cause and contribute to serious respiratory problems. SO2 and NOx are 
6

respiratory irritants and key ingredients in the formation of acid rain. NOx is 

also a major contributor to summertime smog. 

• You must submit the certification prior to the installation of the boiler. This 

is a one-time certification. Certification Forms are available through MassDEP’s 

web site at http://www.state.ma.us/dep/erp.

• N.B. MassDEP eliminated the requirement to file an annual certification. 

• If you are otherwise required to submit a source emissions report under 310 CMR 

7.12, you must include the boiler(s) installed under the ERP regulation in your 

next required submittal. 

• If you are uncertain how to file a Source Registration, you should go to the 

Source Registration website at: 

http://www.mass.gov/dep/service/compliance/srfaq.htm. Under the heading: 

Important Information for New Facilities, you will find guidance on how to 

file a Source Registration. 

• There is no fee associated with the certification. Please note that your facility 

still may be subject to other MassDEP fees, such as the annual air quality or 

hazardous waste compliance assurance fees. 

• The Boiler ERP regulation has three exemptions: 

1. New wood fuel boilers: you must submit a plan application under the 

permitting regulations, and receive written approval from MassDEP before 

the boiler can be installed and operated. 

2. Facilities subject to the Air Operating Permit program under 310 CMR 7.00 

Appendix C are exempt from Boiler ERP. If your facility has one or more 

boilers certified under ERP when it becomes subject to Appendix C, you must 

continue to comply with the ERP boiler performance standards and document 

compliance in the semi and annual operating permit certifications. 

3. Temporary boilers installed in accordance with 310 CMR 7.03(23) are exempt 

from Boiler ERP. 

• Installation of a new boiler can increase facility-wide potential emissions 

above regulatory thresholds. 

Potential emissions of the new boiler may cause total emissions from your facility 

to exceed an emission cap contained in one of the following approvals that your 

facility obtained previously from MassDEP: 

 Limited or Comprehensive Plan Application 

 50% / 25% Facility Emission Cap 

 Restricted Emission Status 
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Potential emissions of the new boiler may also cause the total potential emissions 

from your facility to exceed thresholds for other air pollution control 

requirements, including: 

 New Source Review (NSR) 

 Operating Permits 

 Prevention of Significant Deterioration (PSD). 

Tables 1a and 1b display the potential emissions of criteria pollutants generated 

by several fuel burning scenarios in order to help you determine if your new 

boiler could cause your facility to exceed an emissions cap or threshold. 

Emissions are calculated for the smallest and largest size boilers that are subject 

to ERP. Potential emissions resulting from burning #6 residual fuel (1% sulfur) 

are included to demonstrate the differences between burning “clean” fuels under 

ERP and 1% sulfur fuel, #6 residual fuel. 

Table 1a 

Potential1 Emissions in Tons Per Year (10 MMBTU / Hour Capacity Boiler) 

Fuel NOx SOx VOC PM CO 

Natural Gas 

12 Months 

1.5 0.03 1.3 0.44 3.5 

ULSD 

12 Months 

6.6 0.03 1.3 0.88 3.5 

Natural Gas-9 Months 

ULSD-3 Mo. 

2.8 0.03 1.3 0.55 3.5 

#6 Residual Fuel 

12 Months 

13.1 47.4 *0.34 *2.14 *1.5 

Major Source Threshold 50 100 50 100 100 

1

 Potential emissions mean the maximum capacity of a boiler to emit a pollutant 

while operating continuously, i.e., 8,760 hours per year. 

* These potential emissions are calculated using EPA AP-42 emission factors. 

The other potential emissions are calculated using regulatory emission limits 

established in boiler ERP. 

Table 1b 

Potential1 Emissions in Tons Per Year (40 MMBTU / Hour Capacity Boiler) 

Fuel NOx SOx VOC PM CO 

Natural Gas - 12 Months 6.1 0.11 5.3 1.75 14 

ULSD - 12 Months 26.3 0.13 5.3 3.5 14 
8

Natural Gas-9 Months 

 ULSD-3 Mo. 

11.1 0.11 5.3 2.18 14 

#6 Residual Fuel - 12 Months 52.6 190 *1.36 *8.56 *6.0 

Major Source Threshold 50 100 50 100 100 

If you have any questions concerning whether or not your facility is subject to any 

of these programs, please call your MassDEP Regional Service Center for 

additional information and guidance. See the following link: 

http://mass.gov/dep/about/region/findyour.htm . 

Compliance with the requirements of Boiler ERP does not relieve you of the 

responsibility of complying with other regulations, i.e., federal 40 CFR 63 Subpart 

DDDDD – Boiler MACT and federal 40 CFR 60 Subpart Dc – Standards of Performance 

for Small Industrial-Commercial Steam Generating Units, which requires notification, 

record keeping, and reporting to the U.S. EPA. The EPA Customer Service Center may 

be called at (617) 918-1111. 

The following sections describe the specific air quality and industrial wastewater 

requirements. 

AIR QUALITY REQUIREMENTS 

[2.1] FUEL REQUIREMENTS 

Boiler ERP limits the types of fuel that can be used to certain clean fuels. Note that the 

as of July 1, 2009 the types of allowed fuels change. 

• Before July 1, 2009 

o Natural Gas must be the primary fuel for boilers subject to ERP, if a 

natural gas pipeline, having sufficient capacity, exists beneath a street or 

sidewalk adjacent to the property. 

o If a natural gas pipeline having sufficient capacity does not exist adjacent 

to the property distillate fuel oil may be burned as the primary fuel. 

o Boilers required to burn natural gas as the primary fuel may burn distillate 

fuel oil for up to a maximum of 180 days per calendar year. Annual 

distillate fuel use (gallons/year) allowed is calculated by multiplying 90 

days/yr x 24 hours/day x maximum firing rate (gals/hour) per boiler. 

Records must be established and maintained up to date in accordance with 

310 CMR 7.26(36) Recordkeeping and Reporting as explained in Section 

2.4.
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• On and After July 1, 2009 

Only natural gas and ULSD, as defined in 310 CMR 7.26(31), are allowed 

(delivery of distillate fuel oil accepted after July 1, 2009 must be ULSD. 

However, you may use your remaining supply of distillate fuel oil, if its sulfur 

content is less than 0.05% sulfur by weight). 

Boilers equipped with dual fuel capability may burn natural gas or ULSD in any 

combination. These fuels are defined in this workbook on pages 14 and 15.

Fuel additives may only be used according to the manufacturer’s instructions. 

[2.2] EMISSION LIMITS 

Each owner or operator must: 

o Install a boiler that is able to comply with emission limits specified in Table 2. 

o Keep documentation that the boiler as designed and installed will comply with 

the emission limits specified in Table 2. 

(The documentation may be in the form of a written statement from the 

manufacturer or actual emission test results. The emission limits are in pounds of 

pollutant per million Btu of fuel input. The boiler industry often specifies 

emissions in units of “parts per million” (ppm). Therefore, the nitrogen oxides 

(NOx) and carbon monoxide (CO) emission limits are also listed, in brackets, in 

equivalent units of ppm in Table 2.) 

o Operate the boiler in accordance with the manufacturer’s instructions. 

Table 2 

Natural Gas Distillate 

(lbs. per mmBtu) [ppm] (lbs. per mmBtu) [ppm] 

NOx 0.035 [30] 0.15 [116] 

Particulate mattter 0.01 0.02 

Carbon Monoxide* 0.08 [100] 0.08 [100] 

VOC’s 0.03 0.03 

* The carbon monoxide emission limits for natural gas and ULSD fuel do not apply to 

high turndown boilers while they are operating at less than 25 % of their maximum input 

rating. 

Sulfur dioxide emissions are established by limiting the sulfur content of the fuel. The 

sulfur content of the fuel, as certified by the fuel supplier, is limited to: 

 1. Natural Gas N/A 

2. ULSD Fuel Oil 0.0015% by weight 
10

 Visible emissions may not exceed 10% opacity at any time during boiler operation. 

Visible emissions do not include water vapor. 

[2.3] PERFORMANCE STANDARDS 

• Boilers must be operated and maintained according to the manufacturer's 

instructions, in order to ensure efficient combustion and compliance with the 

emissions standards. 

• One tune-up per year is required because tune-ups are considered crucial to 

efficient, clean operation. 

• Tune-ups must incorporate an efficiency test. Efficiency tests must include at 

least a smoke spot reading, measurement of carbon monoxide, carbon dioxide, 

oxygen concentrations, and flue gas temperature. 

• Boilers equipped and operated with an automated combustion control system (see 

Definitions section) must be maintained and serviced as specified by the 

manufacturer. 

[2.4] RECORDKEEPING REQUIREMENTS 

• The following records must be kept onsite for at least three years. This means that 

each individual record must be retained onsite for three years from the date it was 

“generated”. 

o A record of the type and the amount of fuel used each month, in gallons or 

cubic feet, as appropriate. 

o Fuel sulfur content (percent), as certified by your fuel supplier for each 

shipment or in other supporting documentation. 

o Results of tune-up(s) including efficiency test results. 

o All purchase orders and invoices related to the boiler operation and 

maintenance. 

• The following items must be kept onsite for the life of the ERP boiler(s). 

o Manufacturer’s operating instructions. 

o Documentation from the manufacturer that the boiler as designed and 

installed meets the required emission limits when operated according to 

the manufacturer’s instructions. 

o If applicable, the results of an air quality model run which demonstrates 

that boiler emissions have not caused an exceedence of the National 

Ambient Air Quality Standards (NAAQS). 
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[2.5] STACK DESIGN REQUIREMENTS 

Proper stack design addresses location, height, and exit velocity. 

There are three basic requirements for stack design: 

[2.5.a] To minimize plume entrapment in wakes caused by obstructions to air streams, 

the height of your stack must be at least 1.5 times the height of your building

from ground level. 

If this condition cannot be met, OR if any adjacent structures (see adjacent 

structure in Definitions) are taller than your stack then Air Quality Modeling 

MUST be performed to document that the NAAQS will not be exceeded. 

Appendix 1 lists the minimum data inputs that would be needed to execute an 

EPA Screen3 Model run. Modeling information is available at the following EPA 

website: http://www.epa.gov/scram001/dispersion_screening.htm. If 

you need assistance, call the BWP Air Planning & Evaluation Branch at 617-292-

5607. 

[2.5.b] The stack must discharge exhaust gas vertically upwards. 

[2.5.c] Stack heads, devices used to prevent precipitation from entering the stack, must 

not restrict the vertical flow of the exhaust gas stream. Devices such as “shanty 

caps” and “egg beaters” are prohibited. Coning of the top of the stack and rain 

sleeves are acceptable. No more than a one-inch change in diameter to every five 

inches in length of cone is recommended in order to avoid serious backpressure 

that may affect air flow at the point of origin. 

Although not specifically required, MassDEP also recommends the following: 

• There should be no fresh air intakes near the stack. 

• The flue gas exit velocity should be at least 40 feet per second. 

• The construction material can affect the acid dew point and ultimately the life of the 

stack. Therefore, it is wise to invest in a new stack at the time the boiler is being 

replaced, if the existing stack does not meet the general standards listed above. 

INDUSTRIAL WASTEWATER REQUIREMENTS

"Boiler blowdown" is the wastewater stream associated with boilers. It is water released 

periodically from a boiler to remove impurities and sediment. It is regulated as industrial 

wastewater. The purpose of releasing blowdown is to limit the buildup of contaminants 

in the boiler water that may degrade boiler performance and increase maintenance costs. 

Contaminants may include one or more of the following: dissolved/suspended minerals, 

heavy metals (iron, copper), corrosion inhibitors, oil, or algicides. 

Boiler blowdown can degrade groundwater or surface water quality, and therefore, must 

be properly managed. Your options for managing blowdown are briefly described below. 
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[3.1] Boiler blowdown can be discharged to a sewer. Contact your local sewer 

authority to determine if there are any special requirements for boiler blowdown. 

Contact information: Massachusetts Water Pollution Control Association 

(www.mwpca.org or call 781-939-0918). 

[3.2] Boiler blowdown MAY NOT be discharged to a septic system. If discharge to a 

sewer is not possible, you must obtain a groundwater or surface water discharge 

permit, or store your boiler blowdown in a holding tank or container (see section 

3.5 below). 

[3.3] Discharge to a surface water body (e.g., storm drain, river, lake, or stream) 

requires a National Pollutant Discharge Elimination System (NPDES) permit 

issued by the U.S. Environmental Protection Agency (EPA). For more 

information, call the EPA at (617) 918-1111 (Customer Service Center). 

[3.4] Discharge to groundwater or directly on the ground requires a groundwater 

discharge permit issued by MassDEP. The permit, BRP WP 10 - Other 

Groundwater Discharges, is reviewed and approved by MassDEP’s Bureau of 

Resource Protection, Water Pollution Control Program. There is an application 

fee, and more detailed information can be obtained on the MassDEP website. 

The permit application package is available through the MassDEP website at: 

http://www.mass.gov/dep/water/approvals/surffms.htm#groundwater . 

[3.5] Storage of boiler blowdown or other non-hazardous industrial wastewater in a 

holding tank requires compliance with design and operating standards and 

submission of a one-time compliance certification to MassDEP. Holding tank 

certification packages are available at: 

http://www.mass.gov/dep/service/online/erpforms.htm#holdingt 

 If you store boiler blowdown in a container you must comply with design and 

operating standards, but you need not submit a compliance certification form for 

the holding tank. Call the appropriate MassDEP regional office for information

(http://mass.gov/dep/about/region/findyour.htm ). 

You may use an evaporator to reduce the volume of boiler blowdown before 

shipping it offsite. A permit is not required. Test evaporator sludge to determine 

if it is a hazardous waste and needs to be handled as such. If you have samples of 

evaporator sludge tested, the results should be kept on file. 

IF boiler blowdown contains a layer of oil (more than a sheen), it must be stored 

and disposed of as a waste oil. 

RELATED ACTIVITIES 

[4.1] Asbestos removal and related construction and/or demolition: 
13

Asbestos is a known carcinogen and has been linked to a variety of respiratory 

ailments such as asbestosis, mesothelioma and lung cancer. Tiny microscopic 

asbestos fibers from loose or crumbling asbestos can be suspended in air, inhaled 

and remain in the lungs causing severe health effects during removal or 

demolition operations. 

o Any removal, disturbance, encapsulation or enclosure of these asbestos 

materials requires notification to the MassDEP (Asbestos Notification 

Form - ANF 001) at least ten working days in advance.

o Any related construction and/or demolition activity requires notification to 

the MassDEP (Notification Prior to Construction or Demolition - BWPAQ 06) at least ten days in advance. These notification forms and 

information on the associated fee are available through the MassDEP Web 

site at http://www.state.ma.us/dep. 

o All materials containing asbestos, such as may be found around ducts and 

old boilers, must be wetted, containerized, labeled and removed by a statecertified contractor in accordance with MassDEP regulations. 

[4.2] Underground petroleum storage tanks: 

Single wall, bare steel underground storage tanks containing petroleum products, 

including those resting on the ground, were required to meet leak detection and 

corrosion protection standards, or be replaced, as of December 22, 1998. For 

more information, contact your local fire department. 

DEFINITIONS AND TERMS 

Acid dew point: temperature at which the flue gas condenses on the stack surface.

Adjacent structure: means a structure that is within 5L of the stack. 5L means five times 

the lesser dimension (height or maximum horizontal width) of the structure. 

Air contaminant: volatile organic compounds (VOC’s), sulfur dioxide (SO2), nitrogen 

oxides (NOx), carbon monoxide (CO), and particulate matter are contaminants of concern 

in achieving air quality standards in the United States. Each geographic area is required to 

meet specific limits for each contaminant. 

Automated Combustion Control System: a system that self adjusts burner/boiler operation 

to maximize energy efficiency. It must include at least the following capabilities: fuel/air 

ratio adjusted automatically, fuel flow metered/monitored, and continuous monitoring of 

nitrogen oxides and carbon monoxide. 

Boiler: a device that combusts any fuel and produces steam or heats water. 
14

Boiler blowdown: water released from a boiler to remove impurities and sediment.

Container: means any portable device used to accumulate, store, treat and transport 

industrial wastewater, which is movable without any motorized mechanical device 

(including but not limited to forklifts). Containers requiring motorized mechanical 

devices for movement are classified as holding tanks.

Distillate Fuel Oil: for the purposes of 310 CMR 7.26(30) means fuel oil that complies 

with the specifications for fuel oil numbers 1 or 2 as defined by the American Society for 

Testing and Materials in ASTM D396-98, “Standard Specification for Fuel Oil” dated 

September 1998 and has a sulfur content not to exceed 0.05% by weight or D6751 for 

bio-diesel and has a sulfur content not to exceed 0.0015% by weight. 

Emission: any discharge or release of an air contaminant to the ambient air

Holding Tank: means a stationary device, constructed of non-earthen materials (e.g. 

concrete, steel or plastic), that provide structural support, used to accumulate and store 

industrial wastewater. Containers requiring motorized mechanical devices for movement 

are classified as holding tanks. Tanks that are transportable but not mounted on a truck, 

or placed on or mounted on a trailer are considered holding tanks. The term holding tank 

does not include mobile tanks as described under these regulations.

National Ambient Air Quality Standards: Massachusetts is subject to national standards 

that deal with six criteria pollutants: particulate matter (PM), nitrogen oxides (NOx), 

sulfur dioxide (SOx), ozone, carbon monoxide (CO) and lead. 

Natural Gas: a naturally occurring mixture of hydrocarbon gases found in geologic 

formations beneath the earth’s surface, of which the principal constituent is methane, or 

liquid petroleum gas (LPG), as defined by the American Society for Testing and 

Materials. LPG includes propane, butane, or a combination of propane and butane. 

Source Registration/Emission Statement: Any person who operates a new boiler subject 

to this ERP program is required to submit a Source Registration and Emission Statement, 

including BWP AQ AP-1 form to MassDEP. 

Ultra Low Sulfur Distillate (ULSD): any fuel oil or other fuel, excluding used oil fuel 

and hazardous waste fuel, which complies with the applicable U.S. Environmental 

Protection Agency sulfur limits for fuel pursuant to 40 CFR 80.29, 40 CFR 80.500, and 

40 CFR 80.520(a) and (b) as in effect on January 18, 2001 and either complies with the 

specifications for fuel oil numbers 1 or 2 as defined by the American Society for Testing 

and Materials (ASTM) in ASTM D-396-98 or D6751 for bio-diesel. 

Appendix 1 
15

Minimum Data Inputs Required for an EPA Screen3 Model Run 

1. Stack height (feet) => 

2. Stack inside diameter (feet) => 

3. Stack gas exit temperature (o F) => 

4. Stack flow rate (cubic feet per minute) => 

5. Building height (feet) => 

6. Minimum horizontal building width (feet) => 

7. Maximum horizontal building width (feet) => 

8. Type of fuel (natural gas or red dye distillate fuel oil) => 

9. Millions of Btu per hour of fuel input => 

10. Emission rate (grams per second) =>