Figure: 30 TAC 285.91(8)
Table VIII. OSSF Excavation Length (3 Feet in Width or Less).
Excavation Length (Feet) | |||||||||
Soil Class Ib | Soil Class II | Soil Class III | |||||||
Daily Sewage Flow (Q)2 | For 1.5 Foot Excavation Width3 | For 2.0 Foot Excavation Width | For 3.0 Foot Excavation Width | For 1.5 Foot Excavation Width3 | For 2.0 Foot Excavation Width | For 3.0 Foot Excavation Width | For 1.5 Foot Excavation Width3 | For 2.0 Foot Excavation Width | For 3.0 Foot Excavation Width |
100 | 75 | 66 | 53 | 114 | 100 | 80 | 143 | 125 | 100 |
125 | 94 | 82 | 66 | 143 | 125 | 100 | 179 | 156 | 125 |
150 | 113 | 99 | 79 | 171 | 150 | 120 | 214 | 188 | 150 |
180 | 135 | 118 | 95 | 206 | 180 | 144 | 257 | 225 | 180 |
200 | 150 | 132 | 105 | 229 | 200 | 160 | 286 | 250 | 200 |
225 | 169 | 148 | 118 | 257 | 225 | 180 | 321 | 281 | 225 |
240 | 180 | 158 | 126 | 274 | 240 | 192 | 343 | 300 | 240 |
275 | 207 | 181 | 145 | 314 | 275 | 220 | 393 | 344 | 275 |
300 | 226 | 197 | 158 | 343 | 300 | 240 | 429 | 375 | 300 |
325 | 244 | 214 | 171 | 371 | 325 | 260 | 464 | 406 | 325 |
360 | 271 | 237 | 189 | 411 | 360 | 288 | 514 | 450 | 360 |
375 | 282 | 247 | 197 | 429 | 375 | 300 | 536 | 469 | 375 |
400 | 301 | 263 | 211 | 457 | 400 | 320 | 571 | 500 | 400 |
420 | 316 | 276 | 221 | 480 | 420 | 336 | 600 | 525 | 420 |
450 | 338 | 296 | 237 | 514 | 450 | 360 | 643 | 563 | 450 |
475 | 357 | 313 | 250 | 543 | 475 | 380 | 679 | 594 | 475 |
500 | 376 | 329 | 263 | 571 | 500 | 400 | 714 | 625 | 500 |
1. To determine excavation lengths, greater than 3 feet in
width or where the area and width are known, use the formulas provided in
§285.33(b)(1)(A)(vii).
2. To determine excavation lengths (3 feet or less in width,
but greater than or equal to 1.5 feet in width) for daily sewage flows (Q) not provided in
this table, use the formula provided in §285.33(b)(1)(A) (vii)(III).
3. Minimum excavation width is 1.5 feet for all excavation
lengths.