Federal regulations · Through 2026-08-25 · Newer source version available

40 CFR Table 30 to Subpart G of Part 63: 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 factors b 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 32 f).
90 percent closed 0.51 0.81 1.0
Roof leg (3-in-diameter) NF8 (Table 32 f).
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 32 f).
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) 1 g.
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.

Where this section sits in the code

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 Hazardous Air Pollutants From the Synthetic Organic Chemical Manufacturing Industry for Process Vents, Storage Vessels, Transfer Operations, and Wastewater

Fitting type and construction details Loss factors b 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 32 f).

90 percent closed 0.51 0.81 1.0

Roof leg (3-in-diameter) NF8 (Table 32 f).

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 32 f).

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) 1 g.

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.

Collected 2026-08-27T02:26:04Z. Source file · JSON

Browse this collection