40 CFR Part 63, Table 30 — 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 | |
| Unbolted cover, gasketed | 2.9 | 0.41 | 1 | |
| 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 | 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 | |
| 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 | |
| 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 | |
| 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 | 1 | |
| Roof drain (3-in-diameter) | | | | NF7 (Table 31). |
| Open | 0 | 7 | e 1.4 | NF8 (Table 32 f). |
| 90 percent closed | 0.51 | 0.81 | 1 | |
| Roof leg (3-in-diameter) | | | | NF8 (Table 32 f). |
| Adjustable, pontoon area | 1.5 | 0.2 | c 1.0 | |
| Adjustable, center area | 0.25 | 0.067 | c 1.0 | |
| Adjustable, double-deck roofs | 0.25 | 0.067 | 1 | |
| 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 | 0.1 | 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.