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 Code of Federal Regulations (Last Updated: May 6, 2024)
 Title 40 - Protection of Environment
 Chapter I - Environmental Protection Agency
 SubChapter C - Air Programs
 Part 63 - National Emission Standards for Hazardous Air Pollutants for Source Categories
 Subpart G - National Emission Standards for Organic Hazardous Air Pollutants From the Synthetic Organic Chemical Manufacturing Industry for Process Vents, Storage Vessels, Transfer Operations, and Wastewater

  Table 30 to Subpart G of Part 63 - Roof Fitting Loss Factors, KFa, KFb, and m, a and Typical Number of Fittings, NT  

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  • Table 30 to Subpart G of Part 63 - Roof Fitting Loss Factors, KFa, KFb, and m,a and Typical Number of Fittings, NT

    Fitting type and construction details Loss factorsb Typical number of fittings, NT
    KFa (lb-mole/yr) KFb (lb-mole/[mi/hr]m-yr) m (dimensionless)
    Access hatch (24-in-diameter well) 1.
    Bolted cover, gasketed 0 0 c 0
    Unbolted cover, ungasketed 2.7 7.1 1.0
    Unbolted cover, gasketed 2.9 0.41 1.0
    Unslotted guide-pole well (8-in-diameter unslotted pole, 21-in-diameter well) 1.
    Ungasketed sliding cover 0 67 c 0.98
    Gasketed sliding cover 0 3.0 1.4
    Slotted guide-pole/sample well (8-in-diameter unslotted pole, 21-in-diameter well) (d).
    Ungasketed sliding cover, without float 0 310 1.2
    Ungasketed sliding cover, with float 0 29 2.0
    Gasketed sliding cover, without float 0 260 1.2
    Gasketed sliding cover, with float 0 8.5 1.4
    Gauge-float well (20-inch diameter) 1.
    Unbolted cover, ungasketed 2.3 5.9 c 1.0
    Unbolted cover, gasketed 2.4 0.34 1.0
    Bolted cover, gasketed 0 0 0
    Gauge-hatch/sample well (8-inch diameter) 1.
    Weighted mechanical actuation, gasketed 0.95 0.14 c 1.0
    Weighted mechanical actuation, ungasketed 0.91 2.4 1.0
    Vacuum breaker (10-in-diameter well) NF6 (Table 31).
    Weighted mechanical actuation, gasketed 1.2 0.17 c 1.0
    Weighted mechanical actuation, ungasketed 1.2 3.0 1.0
    Roof drain (3-in-diameter) NF7 (Table 31).
    Open 0 7.0 e 1.4 NF8 (Table 32f).
    90 percent closed 0.51 0.81 1.0
    Roof leg (3-in-diameter) NF8 (Table 32f).
    Adjustable, pontoon area 1.5 0.20 c 1.0
    Adjustable, center area 0.25 0.067 c 1.0
    Adjustable, double-deck roofs 0.25 0.067 1.0
    Fixed 0 0 0
    Roof leg (21⁄2-in-diameter) NF8 (Table 32f).
    Adjustable, pontoon area 1.7 0 0
    Adjustable, center area 0.41 0 0
    Adjustable, double-deck roofs 0.41 0 0
    Fixed 0 0 0
    Rim vent (6-in-diameter) 1g.
    Weighted mechanical actuation, gasketed 0.71 0.10 c 1.0
    Weighted mechanical actuation, ungasketed 0.68 1.8 1.0

    a The roof fitting loss factors, KFa, KFb, and m, may only be used for wind speeds from 2 to 15 miles per hour.

    b Unit abbreviations are as follows: lb = pound; mi = miles; hr = hour; yr = year.

    c If no specific information is available, this value can be assumed to represent the most common or typical roof fittings currently in use.

    d A slotted guide-pole/sample well is an optional fitting and is not typically used.

    e Roof drains that drain excess rainwater into the product are not used on pontoon floating roofs. They are, however, used on double-deck floating roofs and are typically left open.

    f The most common roof leg diameter is 3 inches. The loss factors for 21⁄2-inch diameter roof legs are provided for use if this smaller size roof is used on a particular floating roof.

    g Rim vents are used only with mechanical-shoe primary seals.