N.Y. Comp. Codes R. & Regs. tit. 12, § 23-4.4 – Sheeting, shoring and bracing.

(a) Where any excavation is not protected by sloped sides or banks in compliance with Table I of this Subpart, any person in such excavation shall be protected by sheeting, shoring and bracing in compliance with Tables II, III and IV of this Subpart. Sizes of materials listed in the tables are nominal or trade dimensions.
TABLE II
MAXIMUM HORIZONTAL DISTANCE BETWEEN EDGES OF SHEETING
Excavation Depth
Type of Soil 5 to 10 ft. Over 10 to 15 ft. Over 15 to 20 ft.
Stiff cohesive soil Tight Tight Tight
Noncohesive soil 2 feet Tight Tight
Soft cohesive or wet flowing soil Tight Tight Tight
(b) Shores, struts and braces, whether horizontal or inclined, shall be of adequate size to provide stiffness and adequately braced to withstand the loads intended to be imposed thereon. The ends of all braces shall be individually anchored and fastened to fully resist all imposed forces and to prevent such braces from shifting or slipping. The placing of any inclined shores, struts or braces at any angle exceeding 30 degrees from the horizontal is prohibited.

Excavation Depth

Stiff cohesive soil	Tight	Tight	Tight
Noncohesive soil	2 feet	Tight	Tight
Soft cohesive or wet flowing soil	Tight	Tight	Tight

(c) Each earth-supported shore, strut or brace shall bear against a footing of sufficient area and stability to prevent any subsidence, yield or shifting of such shore, strut or brace.

TABLE III

MINIMUM SIZES OF STRINGERS AND BRACES

Narrow Trenches—Horizontal Cross-Braces Not Longer Than Four Feet

Trench Depth	Type of Soil	Vertical Spacing of Stringers	Horizontal Spacing of Cross–Braces
4 Feet	6 Feet
			Stringers	Braces	Stringers	Braces	Stringers	Braces	Stringers	Braces
5 to 10 ft.	Stiff cohesive	4 ft. max.	4 × 4	4 × 4	6 × 6 or 4 ×8	4 × 4	6 × 6	4 × 4	8 × 8	4 × 6
	Noncohesive	4 ft. max.	6 × 6 or 4 ×8	4 × 4	6 × 6	4 × 4	6 × 8	4 × 4	8 × 10	6 × 6
	Soft cohesive and wet flowing	4 ft. max.	6 × 6	4 × 4	6 × 10	4 × 6	8 × 10	6 × 6	10 × 12	6 × 8
Over 10 to 20 ft.	Stiff cohesive and noncohesive	4 ft. max.	4 × 6	4 × 4	6 × 6	4 × 4	8 × 8 or 6 ×10	4 × 6	10 × 10	6 × 6
	Soft cohesive and wet flowing	4 ft. max.	6 × 8	6 × 6	8 × 10	6 × 8	10 × 12	8 × 8	^*	^*
Over 20 ft.	For any trench over 20 feet in depth the sheeting, shoring and bracing systems shall be designed by a professional engineer licensed to practice in the State of New York. A copy of the plans and specifications for any such bracing system shall be kept at the job site available for examination by the commissioner.

Sizes of timber for such conditions become excessive. A special structure designed by a professional engineer licensed to practice in the State of New York shall be constructed and used for the specific condition involved.

Note: Timber sizes are nominal or trade dimensions.

(d) Each end of each stringer shall be individually braced. Where stringers are terminated to form individual panel type sheeting, each such panel shall be braced at either end.
(e) In lieu of sheeting and shoring and where conditions permit, a self-supporting movable shield of timber or metal may be used and moved ahead as the excavation and construction progresses. The supporting capacity of such a shield shall be equal in all respects to the sheeting and shoring set forth in Tables II, III and IV of this Subpart. When any person is located in such excavation at any point not protected by such shield, sheeting and shoring as set forth in Tables II, III and IV of this Subpart shall be provided.
(f) In lieu of wood, screw jacks of adequate size and stability may be used as cross bracing in the sheeting and shoring of any excavation. Any type of cross bracing used shall be in a true horizontal position, shall be securely fastened and shall be prevented from shifting or slipping by adequately fastened scabs or blocks.
(g) When the depth of an excavation requires the use of two vertical lengths of sheeting, one above the other, the lower sheeting shall be set inside the bottom stringers of the upper sheeting and shall be driven down and braced as the excavation continues.
(h) Excavations which are generally parallel to existing underground pipe lines, utilities or structures of any kind shall be tightly sheeted and shored alongside such pipe lines, utilities or structures where they are exposed by such excavations.
(i) Timber sheeting shall consist of structurally sound hardwood at least two inches by six inches in size or of lumber of equivalent strength. The actual thickness of such timber sheeting shall be consistent with the size of the supporting timbers and the depth of the excavation.

Excavation Depth
Type of Soil	5 to 10 ft.	Over 10 to 15 ft.	Over 15 to 20 ft.

Stiff cohesive soil	Tight	Tight	Tight
Noncohesive soil	2 feet	Tight	Tight
Soft cohesive or wet flowing soil	Tight	Tight	Tight