Code of Federal Regulations > Title 40 > Chapter I > Part 63 > Subpart G > Appendix - Table 30 to Subpart G of Part 63—Roof Fitting Loss Factors, KFa, KFb, and m, a and Typical Number of Fittings, NT

Regulations last checked for updates: May 18, 2024

Title 40 - Protection of Environment last revised: May 16, 2024

Appendix - 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
Fitting type and construction details	KFa (lb-mole/yr)	KFb (lb-mole/[mi/hr] ^m-yr)	m (dimensionless)	Typical number of fittings, NT
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 (2 1/2-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 2 1/2-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.

authority: 42 U.S.C. 7401

source: 57 FR 61992, Dec. 29, 1992, unless otherwise noted.