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1) The determination and design of the supporting system shall be based on careful consideration of the following: Depth of the cut; anticipated changes in the soil due to air, sun, freezing temperature, water, ground movement caused by vehicle vibration and earth pressures (not only the angle or repose).

2) The Contractors Safety Representative will issue an excavation permit prior to all excavation, digging, trenching or drilling operations and a copy shall be provided to the JEA Project Manager.

3) According to the OSHA Standards, a trench is referred to as a narrow excavation in which the depth is greater than the width, although the width is not greater than 15 feet. An excavation is any man-made cavity or depression in the earth's surface.

4) Requirements are that all trenches and excavations over 5 feet deep be sloped, shored, braced, or otherwise supported. When soil conditions are unstable, excavations lower than 5 feet shall be sloped, supported, or shored. Benching is prohibited for Type C soil.

5) Contractors also may use a trench box - a prefabricated, movable trench shield composed of steel plates welded to a heavy steel frame. OSHA standards permit the use of a trench box as long as the protection it provides is equal to or greater than the protection that would be provided by the appropriate shoring system.

6) Designing Adequate Protection

Some of the considerations the Contractor will take into account when designing a protective system are:

• Soil Structure

• Depth of Cut

• Water Content of Soil

• Changes Due to Weather and Climate

• Superimposed Loads

• Vibrations

• Other Operations in Vicinity

• Overhead Power Lines

• Underground Obstructions

• Air Quality

7) Installing of Protection:

a. Whatever support system is used, workers shall always install shoring, starting from the top of the trench or excavation and working down. When installing the shoring, care shall be taken to place the cross beams or trench jack in true horizontal position and to space them vertically at appropriate intervals. The braces also will be secured to prevent sliding, falling, or kick outs.

b. All materials used for shoring shall be in good condition, free of defects, and of the required size. Timbers with large or loose knots shall not be used.

c. Installation of shoring shall closely follow the excavation work. It is dangerous to allow

the soil will remain at rest. The angle of repose varies with different kinds of soil, and must be determined on each individual project and at each trench or excavation. When an excavation has water conditions, silty material, or loose boulders, or where erosion, deep frost, or slide planes are apparent, the angle of repose will be flattened.

e. Other methods of support include shoring-sheeting, tightly placed timber shores, bracing, trench jacks, piles, or other materials installed in a manner strong enough to resist the pressures surrounding the excavation.

8) Special Precautions

a. The Contractor shall guard against an unstable excavation bottom, such as below the water line. Sheeting may have to be driven below the bottom of such an excavation to add to the soil stability.

b. OSHA standards require that diversion dikes and ditches, or other suitable means, be used to prevent surface water from entering an excavation and to provide adequate drainage of the area adjacent to the excavation. Water causes erosion and softening and shall not be allowed to accumulate in a trench or excavation.

c. In trenches or excavations which employees are required to enter, excavated or other material (this includes materials to be installed) shall be effectively stored and retained at least 2 feet or more from the edge of the trench or excavation.

d. In case of emergency, workers will be able to leave the trench or excavation quickly.

When employees are required to be in trenches that are 4 feet or greater in depth, adequate means of exit, such as ladders or steps, shall be provided and located so as to require no more than 25 feet lateral travel. Ladders will be in good condition, extend from the floor of the trench to 3 feet above the top of the excavation, and be secured at the top by some means to ensure stability.

e. All underground utilities shall be located in advance of excavation and provisions made for their protection.

9) Inspections

a. Excavations and shoring systems will be inspected daily by a competent person.

b. Inspections are required after rain storms or any other change in conditions that can increase the possibility of a cave-in or slide. If dangerous ground movements are apparent, such as tension cracking, all work in the excavation shall be stopped until the problem has been corrected.

10) After the Work is Completed

As soon as work is completed, backfilling shall take place as the shoring is dismantled.

Workers shall remove the shoring from the bottom up, taking care to release jacks or braces slowly. In unstable soil, ropes will be used to pull out the jacks or braces from above.

11) Remember

a. OSHA regulation for trenching and excavations work leaves no room for risk-taking.

Safe working conditions shall be provided for all employees working in excavations.

b. A greater awareness of the safety problems to be overcome in excavation--on the part of the employer who designs the protection and the employee who installs it--will help prevent cave-in hazards in construction.

12) Drilling Operations

a. All Contractors will issue an excavation permit prior to any excavation, digging, trenching or drilling operations commencing.

b. The drilling area shall be inspected for hazards before starting the drilling operation.

c. Drill crews and other employees shall be directed to stay clear of augers or drill stems that are in motion.

d. When drill helpers assist the drill operator during installation or operation of a drilling rig, the helpers shall be in sight of, or in communication with, the operator at all times.

e. While in operation, drilling rigs shall be attended at all times.

f. Drill steel, spare parts, and tools shall be safely stored in racks or receptacles on the drill rig when not in use.

g. Employees shall not drill from positions which hinder their access to the controls or from insecure footing or staging.

h. Drilling equipment shall be inspected at the start of each shift by competent person and any defects noted shall be corrected before the equipment is used.

i. Before each drilling cycle is started, warnings shall be given to workers in the area around the drilling operation.

13) Hazardous Atmospheres

In environments of known chemical or sanitary contamination, or if the potential exists for the development of a hazardous atmosphere produced from equipment operation or near by motor vehicles, the Contractor shall test the atmosphere. Such testing shall qualify the atmosphere in the breathing zone of exposed workers to contain adequate level of Oxygen (>

19.5%), and the absence of flammable/explosive, and or toxic vapors/gases/fumes. The results of this testing shall be documented and made available to the JEA on request.