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New Hampshire Department of Environmental Services

Frequently Asked Questions
  • Do I need a Title V permit for my facility? Is my facility a major source?
    Major source/Title V permitting thresholds are:
    • 100 ton/year of actual TSP emissions statewide,
    • 100 ton/year of actual SO2 emissions statewide,
    • 100 ton/year of actual CO emissions statewide,
    • 50 ton/year of actual VOC emissions statewide,
    • 10 ton/year of actual emissions of any single HAP or 25 ton/year of actual emissions of all HAP's combined, and
    • 50 ton/year of actual NOx emissions in Hillsborough, Merrimack, Rockingham, and Strafford counties or 100 ton/year of actual NOx emissions in all other counties.
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  • My actual emissions are much less than my potential emissions and I will never emit anywhere near my potential emissions. Why do the potential emissions matter?
    The following text is excerpted from the United States Environmental Protection Agency memorandum Options for Limiting the Potential to Emit (PTE) of a Stationary Source Under Section 112 and Title V of the Clean Air Act (Act), dated January 25, 1995 (available on the internetMicrosoft Word Symbol).

    "Many stationary source requirements of the Act apply only to "major" sources. Major sources are those sources whose emissions of air pollutants exceed threshold emissions levels specified in the Act. … To determine whether a source is major, the Act focuses not only on a source's actual emissions, but also on its potential emissions (emphasis added). Thus, a source that has maintained actual emission at levels below the major source threshold could still be subject to major source requirements if it has the potential to emit major amounts of air pollutants. However, in situations where unrestricted operation of a source would result in a potential to emit above major-source levels, such sources may legally avoid program requirements by taking federally-enforceable permit conditions which limit emissions to levels below the applicable major source threshold."

    Essentially, a source with the potential to emit above major source thresholds is considered a major source unless it obtains federally enforceable restrictions to limit its emissions to below major source thresholds. The fact that the facility's historical emissions were below major source thresholds and the company does not plan on increasing emissions above the thresholds is not a federally enforceable limitation. In order to legally avoid major source permitting requirements, the source must have enforceable emission limitations. The most common method of doing this is to obtain a State Permit to Operate which includes emission limitations and recordkeeping and reporting requirements to confirm compliance with the emission limitations.

    In addition to major source requirements, New Hampshire has Reasonable Available Control Technology (RACT) requirements for certain sources of volatile organic compounds (VOCs) and nitrogen dioxide (NO2). Similar to major source thresholds, the applicability of these requirements is based on the source's potential to emit. Therefore, if the source's potential to emit is above an applicable RACT threshold, the source must either obtain a permit specifying the RACT requirements (if actual emissions will be above the RACT threshold), or obtain a permit that limits emissions to below the RACT threshold to 'opt out' of complying with RACT (if actual emissions will be below the RACT threshold).

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  • Which permit application forms do I need?
    Applications for Temporary Permits or State Permits to Operate use "ARD" forms only. Applications for General State Permits use "GSP" forms only.

    Each application for a Temporary Permit or State Permit to Operate must have one form ARD-1, General Information - All Permit Applications. In addition, the application must include a separate device/process form for each device/process that is being applied for. For example, an application for a facility that contains two boilers, one emergency generator, and one paint spraying process would need to include:

    • One form ARD-1 with information on the entire facility;
    • Three forms ARD-2, Fuel Burning Equipment Registration, one for each boiler and one for the emergency generator; and
    • One form ARD-3, Process and Manufacturing Equipment Registration, for the paint spraying process.

    Please note that, in the example above, the emergency generator will be included in the facility-wide Temporary Permit or State Permit to Operate as opposed to the emergency generator having a separate General State Permit. If the only devices at the facility that need to be permitted are emergency generators, the applicant may (and DES suggests) apply for a General State Permit as described below.

    Each application for a General State Permit must have one form GSP-1, General Facility Information All Registrations. In addition, the application must include forms GSP-2, Internal Combustion Engines Used as Emergency Generators, or GSP-2, Nonmetallic Mineral Processing Plants, as appropriate. Please note that up to three emergency generators may be included on one form GSP-2. If the facility has more then 3 emergency generators, fill out as many additional form GSP-2s as needed.

    All of these application forms are available for download.

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  • What is air quality modeling and when is it needed?
    Air quality modeling is a method of analyzing air quality impacts from pollution sources and is usually done by means of a computer. For criteria air pollutants such as SO2, NOx, particulate matter and CO, a modeling analysis is required if it has been determined that a permit is necessary for the particular device. For Title V sources, this only applies when a new device or modification is involved. In the case of toxic air pollutants, modeling is normally required, even if no permit is issued.
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  • When calculating emissions for my coating operation, if I assume that I just spray my gun at maximum capacity 24-hours per day, 365 days a year (8760 hours per year), my resulting potential to emit is unrealistically high. There's no way I would do that. Do I need to use that method to calculate my theoretical potential to emit (TPE), or can I make some reasonable assumptions?
    Theoretical potential to emit (TPE) should be calculated based on the physical capacity of the process to operate and emit pollutants. For a boiler with a fuel input capacity of 12 gallons per hour, its annual capacity for fuel consumption is 12 gallons per hour x 8,760 hours per year = 105,120 gallons per year. Even though the boiler is probably not actually operated at this capacity, it has the potential to and many air related regulatory thresholds are based on potential to emit.

    For coating sources, some reasonable factors relative to the capacity of the operations can be incorporated into TPE calculations. Here are 2 examples:

    Example 1: An automobile body shop has one spray booth and one spray gun used to paint vehicles. The spray gun has a capacity to spray 4 gallons of paint per hour. The spray gun, if operated at maximum capacity for 8,760 hours per year, could spray 35,040 gallons of paint per year. However, each vehicle needs to be prepared in the spraybooth (e.g., sand, clean, tape trim, etc) prior to painting. It takes approximately 1 hour to prepare a vehicle for painting. It takes approximately 2 hours to paint a vehicle. Once the vehicle is painted, it must dry in the spraybooth for at least 1 hour prior to being moved. Based on the above, it takes 4 hours to paint a vehicle, during which time the spray gun can only be used for 2 hours - or 50% of the time. Therefore, the facility only has the potential to spray 17,520 gallons of paint per year.

    Example 2: A company produces metal computer cases. The cases are hung on racks, then painted in one of three spray booths. Each spray booth is equipped with a spray gun capable of spraying 3 gallons of paint per hour. The three spray guns together, if operated at maximum capacity for 8,760 hours per year, could spray 78,840 gallons of paint per year. It takes approximately 1 hour to paint one rack of cases. The second part of the painting process involves moving the racks into a vented, dust controlled room to dry for 24 hours. The drying room can hold 40 racks of cases. Due to the necessary drying time and the size limitation of the drying room, only 40 racks of cases can be painted in a 24-hour period. Since it takes approximately 1 hour to paint a rack of cases, this means that the 3 guns together can spray only 40 hours in any 24-hour period - at which point production needs to stop because the drying room would be full (as opposed to 72 hours of spraying for the 3 guns spraying for 24 hours each). Therefore, the facility only has the potential to spray 43,800 gallons of paint per year.

    The above are examples of actual physical and/or operational conditions that limit the potential of the facility to spray paint and emit pollutants. These types of restrictions may be included when calculating a facility's potential to emit. Please note that changes in the facility that remove some of these restrictions may increase the facility's potential to emit, even though additional emitting equipment will not be installed. For example, if the company in Example 2 put an addition on the drying room to allow more racks to be dried, it has increased its potential to emit, even though it hasn't added more spray guns. This is commonly referred to as 'debottlenecking.' Debottlenecking projects need to be reviewed to evaluate whether air permitting thresholds have been triggered.

    Please note that the fact that a facility only operates 2 shifts per day (16 hours of working time) does not limit the potential to emit. The equipment at the facility has the potential to operate 24 hours per day, and therefore potential to emit calculations must be based on operating 24 hours per day, 365 days per year.

    If you have any questions about calculating your potential to emit, please contact DES for assistance.

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For more information, please see the Info on Permits and Permitting Process section of this web site.

NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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