
| Structural members | Light duty (UP to 25 pounds per square foot) -- Height in feet | Heavy duty (25 to 75 pounds per square foot) -- Height in feet | ||||
| 24 or less | 24-40 | 40-60 | 24 or less | 24-40 | 40-60 | |
| Poles or uprights (in inches) Bearers (in inches) Ledgers (in inches) Stringers (not supporting bearers) (in inches) Braces (in inches) Pole spacing -- longitudinally (in feet) Pole spacing -- transversely (in feet) Ledger spacing -- vertically (in feet) |
2 x 4 2 x 6 2 x 6 2 x 6 1 x 6 1 x 4 7 1/2 6 1/2 min 7 |
3 x 4 or 2 x 6 2 x 6 1 x 6 1 x 6 7 1/2 7 1/2 min 7 |
4 x 4 2 x 6 2 x 6 1 x 6 1 x 6 7 1/2 8 1/2 min 7 |
3 x 4 2 x 8 2 x 8 1 x 6 1 x 6 7 6 1/2 4 1/2 |
4 x 4 2 x 8 2 x 8 1 x 6 1 x 6 7 10 4 1/2 |
4 x 6 2 x 10 2 x 8 1 x 6 1 x 6 7 10 4 1/2 |
| Length (in feet) | Cross section (in inches) | |
| At ends | At center | |
| 15 16 18 20 24 |
1 7/8 x 2 3/4 1 7/8 x 2 3/4 1 7/8 x 3 1 7/8 x 3 1 7/8 x 3 |
1 7/8 x 3 3/4 1 7/8 x 3 3/4 1 7/8 x 4 1 7/8 x 4 1 7/8 x 4 1/2 |
| Structural members | Height in feet | ||
| Up to 10 | 10 to 16 | 16 to 20 | |
Legs Bearers or headers Crossbraces Longitudinal braces |
inches 2 x 4 2 x 6 2 x 4 or 1 x 8 2 x 4 |
inches 3 x 4 2 x 8 2 x 4 2 x 6 |
inches 4 x 6 4 x 6 2 x 6 2 x 6 |
| Span in feet | Lumber dimensions in inches | |||||||||
| A | B | A | B | A | B | A | B | A | B | |
| 2 x 10 | 1 5/8 x 9 1/2 | 2 x 12 | 1 5/ 8 x 11 1/ 2 | 3 x 8 | 2 5/ 8 x 7 1/2 | 3 x 10 | 2 5/ 8 x 9 1/2 | 3 x 12 | 2 5/ 8 x 11 1/ 2 | |
| 6 8 10 12 14 16 |
256 192 153 128 110 |
309 232 186 155 133 116 |
526 395 316 263 225 197 |
667 500 400 333 286 250 |
807 605 484 404 346 303 |
|||||
| Circumferences | Diameter in inches | Single leg | 60° bridle | 45° bridle | 30° bridle |
| 3/4 1 1 1/8 1 1/4 1 3/8 1 1/2 1 3/4 2 2 1/4 2 1/2 2 3/4 3 3 1/4 3 1/2 3 3/4 4 4 1/2 5 5 1/2 6 6 1/2 |
1/4 5/16 3/8 7/16 1 15/3 2 1/2 9/16 5/8 3/4 1 13/16 7/8 1 1 1/16 1 1/8 1 1/4 1 5/16 1 1/2 1 5/8 1 3/4 2 2 1/8 |
lbs. 120 200 270 350 450 530 690 880 1080 1300 1540 1800 Tons 1.0 1.2 1.35 1.5 1.8 2.25 2.6 3.1 3.6 |
lbs. 204 346 467 605 775 915 1190 1520 1870 2250 2660 3120 Tons 1.7 2.1 2.3 2.6 3.1 3.9 4.5 5.4 6.2 |
lbs. 170 282 380 493 635 798 973 1240 1520 1830 2170 2540 Tons 1.4 1.7 1.9 2.1 2.5 3.2 3.7 4.4 5.1 |
lbs. 120 200 270 350 450 530 690 880 1080 1300 1540 1800 Tons 1.0 1.2 1.35 1.5 1.8 2.25 2.6 3.1 3.6 |
| Rope diameter | Single leg | |||||
| Vertical | Choker | |||||
| A | B | C | A | B | C | |
| 6 x 19 Classification | ||||||
| 1/4" 3/8" 1/2" 5/8" 3/4" 7/8" 1" 1 1/8" |
.59 1.3 2.3 3.6 5.1 6.9 9.0 11 |
.56 1.2 2.2 3.4 4.9 6.6 8.5 10 |
.53 1.1 2.0 3.0 4.2 5.5 7.2 9.0 |
.44 .98 1.7 2.7 3.8 5.2 6.7 8.5 |
.42 .93 1.6 2.5 3.6 4.9 6.4 7.8 |
.40 .86 1.5 2.2 3.1 4.1 5.4 6.8 |
| 6 x 37 Classification | ||||||
| 1 1/4" 1 3/8" 1 1/2" 1 3/4" 2" 2 1/4" |
13 16 19 26 33 41 |
12 15 17 24 30 38 |
10 13 15 20 26 33 |
9.9 12 14 19 25 31 |
9.2 11 13 18 23 29 |
7.9 9.6 11 15 20 25 |
| Rope diameter | Two-leg bridle or basket hitch | |||||||||||
| Vertical | 60° Bridle | 45° Bridle | 30° Bridle | |||||||||
| A | B | C | A | B | C | A | B | C | A | B | C | |
| 6 x 19 Classification | ||||||||||||
| 1/4" 3/8" 1/2" 5/8" 3/4" 7/8" 1" 1 1/8" |
1.2 2.6 4.6 7.2 10 14 18 23 |
1.1 2.5 4.4 6.8 9.7 13 17 21 |
1.0 2.3 3.9 6.0 8.4 11 14 18 |
1.0 2.3 4.0 6.2 8.9 12 15 19 |
97 2.1 3.8 5.9 8.4 11 15 18 |
.92 2.0 3.4 5.2 7.3 9.6 12 16 |
.83 1.8 3.2 5.1 7.2 9.8 13 16 |
.79 1.8 3.1 4.8 6.9 9.3 12 15 |
.75 1.6 2.8 4.2 5.9 7.8 10 13 |
.59 1.3 2.3 3.6 5.1 6.9 9.0 11 |
.56 1.2 2.2 3.4 4.9 6.6 8.5 10 |
.53 1.1 2.0 3.0 4.2 5.5 7.2 9.0 |
| 6 x 37 Classification | ||||||||||||
| 1 1/4" 1 3/8" 1 1/2" 1 3/4" 2" 2 1/4" |
26 32 38 51 66 83 |
24 29 35 47 64 76 |
21 25 30 41 53 66 |
23 28 33 44 57 72 |
1 25 30 41 53 66 |
18 22 26 35 46 57 |
19 22 27 36 47 58 |
17 21 25 33 43 54 |
15 18 21 29 37 47 |
13 16 19 26 33 41 |
12 15 17 24 30 38 |
10 13 15 20 26 33 |
| Rope diameter | Two-leg bridle or basket hitch | |||||||||||
| Vertical | 60° Bridle | 45° Bridle | 30° Bridle | |||||||||
| A | B | C | A | B | C | A | B | C | A | B | C | |
| 6 x 19 Classification | ||||||||||||
| 1/4" 3/8" 1/2" 5/8" 3/4" 7/8" 1" 1 1/8" |
1.1 2.4 4.3 6.7 9.5 13 17 21 |
1.0 2.2 3.9 6.2 8.8 12 15 19 |
.99 2.1 3.7 5.6 7.8 10 13 17 |
.95 2.1 3.7 5.8 8.2 11 14 18 |
.88 1.9 3.4 5.3 7.6 10 13 16 |
.85 1.8 3.2 4.8 6.8 8.9 11 14 |
.77 1.7 3.0 4.7 6.7 9.1 12 15 |
.72 1.6 2.8 4.4 6.2 8.4 11 13 |
.70 1.5 2.6 4.0 5.5 7.3 9.4 12 |
.55 1.2 2.1 3.3 4.8 6.4 8.4 10 |
.51 1.1 2.0 3.1 4.4 5.9 7.7 9.5 |
.49 1.1 1.8 2.8 3.9 5.1 6.7 8.4 |
| 6 x 37 Classification | ||||||||||||
| 1 1/4" 1 3/8" 1 1/2" 1 3/4" 2" |
25 30 35 48 62 |
22 27 32 43 55 |
20 24 28 38 49 |
21 26 30 41 53 |
9 23 27 37 48 |
17 20 24 33 43 |
17 21 25 34 43 |
16 19 22 30 39 |
14 17 20 27 35 |
12 15 17 24 31 |
11 13 16 21 28 |
9.8 12 14 19 25 |
| Rope diameter | Single leg | |||||
| Vertical | Choker | |||||
| A | B | C | A | B | C | |
| 6 x 19 Classification | ||||||
| 1/4" 3/8" 1/2" 5/8" 3/4" 7/8" 1" 1 1/8" |
.55 1.2 2.1 3.3 4.8 6.4 8.4 10 |
.51 1.1 2.0 3.1 4.4 5.9 7.7 9.5 |
.49 1.1 1.8 2.8 3.9 5.1 6.7 8.4 |
.41 .91 1.6 2.5 3.6 4.8 6.3 7.9 |
.38. 85 1.5 2.3 3.3 4.5 5.8 7.1 |
.37 .80 1.4 2.1 2.9 3.9 5.0 6.3 |
| 6 x 37 Classification | ||||||
| 1 1/4" 1 3/8" 1 1/2" 1 3/4" 2" |
12 15 17 24 31 |
11 13 16 21 28 |
9.8 12 14 19 25 |
9.2 11 13 18 23 |
8.3 10 12 16 21 |
7.4 8.9 10 14 18 |
| Improved plow steel, rope diameter, inches | Number of clips | Minimum spacing, inches | |
| Drop forged | Other material | ||
| (1) 1/2 5/8 3/4 7/8 1 1 1/8 1 1/4 1 3/8 1 1/2 |
3 3 4 4 4 5 5 6 6 |
4 4 5 5 6 6 7 7 8 |
3 3 3/4 4 1/2 5 1/4 6 6 3/4 7 1/2 8 1/4 9 |
| Nominal size chain stock | Single leg | 60° bridle | 45° bridle | 30° bridle |
| 1/4"1 5/16"1 3/8"1 7/16"1 1/2" 9/16"1 1 5/8" 3/4" 7/8" 1" 1 1/8" 1 1/4" 1 1/2" 1 5/8" 1 3/4" 1 7/8" 2" |
1060 1655 2835 3250 2.1 2.7 3.3 4.8 6.5 8.5 10.0 12.4 15.0 17.8 20.9 24.2 27.6 31.6 |
1835 2865 2.1 2.8 3.7 4.6 5.7 8.3 11.2 14.7 17.3 21.4 25.9 30.8 36.2 42.0 47.9 54.8 |
1500 2340 3370 2.3 3.0 3.8 4.7 6.7 9.2 12.0 14.2 17.5 21.1 25.2 29.5 34.3 39.1 44.8 |
1060 1655 2385 3250 2.1 2.7 3.3 4.8 6.5 8.5 10.0 12.4 15.0 17.8 20.9 24.2 27.6 31.6 |
| Nominal size chain stock | Single leg | 60° bridle | 45° bridle | 30° bridle |
| 1/4" 3/8" 1/2" 5/8" 3/4" 7/8" 1" 11/8" 11/4" 13/8 11/2" 15/8" 13/4" |
1.62 3.30 5.62 8.25 11.5 14.3 19.3 22.2 28.7 33.5 39.7 42.5 47.0 |
2.82 5.70 9.75 14.25 19.9 24.9 33.5 38.5 49.7 58.0 68.5 73.5 81.5 |
2.27 4.65 7.90 11.65 16.2 20.3 27.3 31.5 40.5 47.0 56.0 59.5 62.0 |
1.62 3.30 5.62 8.25 11.5 14.3 19.8 22.2 28.7 33.5 39.7 42.5 47.0 |
| Chain size in inches | Maximum allowable wear in fraction of inches |
| 1/4 (9/32) 3/8 1/2 5/8 3/4 7/8 1 11/8 11/4 13/8 11/2 13/4 |
3/64 5/64 7/64 9/64 5/32 11/64 3/16 7/32 1/4 9/32 5/16 11/32 |
| Chain size in inches | Maximum allowable wear in fraction of inches |
| 1/4 (9/32) 3/8 1/2 5/8 3/4 7/8 1 11/8 11/4 13/8 11/2 13/4 |
3/64 5/64 7/64 9/64 5/32 11/64 3/16 7/32 1/4 9/32 5/16 1 1/32 |
| Material size (inches) | Pin diameter (inches) | Safe working load |
| 1/2 | 5/8 | 1.4 |
| 5/8 | 3/4 | 2.2 |
| 3/4 | 7/8 | 3.2 |
| 7/8 | 1 | 4.3 |
| 1 | 11/8 | 5.6 |
| 11/8 | 11/4 | 6.7 |
| 11/4 | 13/8 | 8.2 |
| 13/4 | 11/2 | 10.0 |
| 11/2 | 15/8 | 11.9 |
| 13/4 | 2 | 16.2 |
| 2 | 1/4 | 21.2 |
| Operation | Shade No. |
| Soldering | 2. |
| Torch Brazing | 3 or 4. |
| Light cutting, up to 1 inch | 3 or 4. |
| Medium cutting, 1-6 inches | 4 or 5. |
| Heavy cutting, over 6 inches | 5 or 6. |
| Light gas welding, up to 1/8 inch | 4 or 5. |
| Medium gas welding, 1/8 -1/2 inch | 5 or 6. |
| Heavy gas welding, over 1/2 inch | 6 or 8. |
| Shielded Metal-Arc Welding 1/16 to 5/32-inch electrodes | |
| 10. | |
| Inert-gas Metal-Arc Welding (Non-ferrous)1/16- to 5/32-inch electrodes | |
| 11. | |
| Shielded Metal-Arc Welding: | |
| 3/16- to 1/4-inch electrodes | 12. |
| 5/16- and 3/8-inch electrodes | 14. |
| Operations | Electrode size 1/32 in. | Arc current | Minimum protective shade |
| Shielded metal arc welding | Less than 3 3-5 5-8 More than 8 |
Less than 60 60-160 160-250 250-550 |
7 8 10 11 |
| Gas metal arc welding and flux cored arc welding | Less than 60 60-160 160-250 250-500 |
7 10 10 10 |
|
| Gas Tungsten arc welding | Less than 50 50-150 150-500 |
8 8 10 |
|
| Air carbon | (Light) | Less than | 10 |
| Arc cutting | (Heavy) | 500 500-1000 |
11 |
| Plasma arc welding | light)** | Less than 300 | 8 |
| medium)** | 300-400 | 9 | |
| heavy)** | 400-800 | 10 | |
| Torch brazing | 3 | ||
| Torch soldering | 2 | ||
| Carbon Arc welding | 14 |
| Operations | Plate thickness in. | Plate thickness mm | Minimum* protective shade | |
| Gas welding: | ||||
| Light | Under 1/8 | Under 3.2 | 4 | |
| Medium | 1/8 to 1/2 | 3.2 to 12.7 | 5 | |
| Heavy | Over 1/2 | Over 12.7 | 6 | |
| Oxygen cutting: | ||||
| Light | Under 1 | Under 25 | 3 | |
| Medium | 1 to 6 | 25 to 150 | 4 | |
| Heavy | Over 6 | Over 15 | 5 | |
| Airborne concentration of asbestos or conditions of |
Required respirator use Half-mask air purifying respirator. Not in excess of 1 f/cc |
| (10 X PEL), or other than a disposable respirator, otherwise as required equipped with high efficiency filters. independent of exposure pursuant to paragraph (h)(2)(iv) of this section. | Not in excess of 5 f/cc |
| (50 X PEL) | Full facepiece air-purifying respirator equipped with high efficiency filters. Not in excess of 10 f/cc |
| (100 X PEL) | Any powered air-purifying respirator equipped with high efficiency filters or any supplied air respirator operated in continuous flow mode. Not in excess of 100 f/cc |
| (1,000 X PEL) | Full facepiece supplied air respirator operated in pressure demand mode. Greater than 100 f/cc |
| (1,000 X PEL) or unknown concentration | Full facepiece supplied air respirator operated in pressure demand mode, equipped with an auxiliary positive pressure self-contained breathing apparatus. |