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2 DAYS Notify CALL BEFORE-U-DIG (800-922-4455) two full days (excluding Saturdays, Sundays, and holidays) prior to an
excavation. Digging cannot commence until all utilities have responded and verified. Public Act 77-350 & 81-146 -
2 FEET Spoils, surcharge or other material or equipment shall be set back from the excavation by at least 2 feet. 1926.651(j)(2)
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2 FEET Excavating no more than 2 feet below the members of the support or shield system shall be permitted, if system is
designed for the full depth of trench, and no loss of soil from behind or below the system. 1926.652(e)(2)(i) and (g)(2)(ii) -
4 FEET Stairways, ladders or ramps are needed in excavations 4 feet or more in depth. 1926.651(c)(2)
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4 FEET For excavations greater than 4 feet, the atmosphere must be tested if oxygen deficiency or a hazardous atmosphere
does, or is reasonably expected, to exist. 1926.651(g)(l)(i) -
5 FEET Excavations less than 5 feet in depth do not require protective systems if the competent person examines and determines
that there is no potential for a cave-in. 1926.652(a)(1)(ii) -
6 FEET Guardrails are required on walkways that are over excavations 6 feet or more above lower levels. 1926.651(l)
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18 IN. In excavations with vertically sided lower portions, the support or shield system must extend 18 inches above the top
of the vertical side. 1926, Subpart P, Appendix B -
19.5 % Where an oxygen deficient atmosphere, less than 19.5%, or a hazardous atmosphere exists, or could exist, the atmosphere
shall be tested before entry for excavations greater than 4 feet in depth. 1926.651(g)(1)(i) -
20 FT. Sloping, benching, or timber and aluminum hydraulic shoring for excavations greater than 20 feet deep shall be designed
by a registered professional engineer. 1926, Subpart P, Table B-1 note 3, Appendix C, Tables C, Note 1, and Appendix D,
Tables D, Note 1 -
20 % Adequate precautions shall be taken, such as ventilation, to prevent employee exposure to atmospheres containing a
concentration of a flammable gas in excess of 20% of the lower flammable limit for that gas. 1926.651(g)(1)(iii) -
24 HRS. Simple slope excavations in Type A soil which are open for 24 hours or less (short term) and which are 12 feet or less in
depth shall have a maximum allowable slope of ½H:1V. 1926, Subpart P, Appendix B, Figure B-1.1, exception -
25 FT. For excavations of 4 ft. or more in depth, ladders, stairways, and ramps are needed so lateral travel for employees is no
more than 25 feet. 1926.651(c)(2) -
34° Maximum allowable slopes (degrees from the horizontal) for excavations less than 20 feet in Type C soil. 1926, Subpart
P, Table B-1 -
45° Maximum allowable slopes for excavations less than 20 feet in Type B soil. 1926, Subpart P, Table B-1
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53° Maximum allowable slopes for excavations less than 20 feet in Type A soil. 1926, Subpart P, Table B-1
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90° Maximum allowable slopes for excavations less than 20 feet in Stable Rock. 1926, Subpart P, Table B-1
Source: Jeff Carter, CONN-OSHA Quarterly