Safety 1st Advancer Manual del operador descargar pdf (Pagina 28)

Environmental Remediation Drilling

Safety Guideline

Page 28 of 132

2.11 - Clearance Methodologies cont.

Proper hand-digging tools and techniques must be used to safely verify the depth of any buried utilities that

must be crossed or are located in close proximity to the work. Several types of direct contact methods

include:

• Hand augers,

• Post hole diggers,

• Steel rods, and

• Hand digging tools.

A backhoe or similar machine may be used to uncover a utility. Clearly, the use of heavy equipment can

produce severe damage to underground structures if not carefully performed. Due to hard soil structure or

dense strata, use of hand tools to locate buried utilities may be precluded. In these instances, the clearance

procedure requires excavation equipment. Extra measures must be taken to locate and identify buried

utilities prior to excavation to protect against injury.

Methods that avoid direct contact:

• Air knifing or water jetting, and

• Vacuum soil excavation or wet vacuuming.

Air knife technology uses compressed air to break soil structure and allow for removal of the soil while

reducing the potential for direct contact between buried utilities and the air knife operator. The compressed

air essentially insulates the operator from directly contacting the buried utility. Compressed air, typically 90

to 100 psig, is converted to a supersonic jet while flowing through a nozzle especially designed for the

purpose. Several nozzles are commercially available.

Figure 2.6 - Using an Air Knife (Photo courtesy of ATC Associates, Inc.)

1 2 ... 23 24 25 26 27 28 29 30 31 32 33 ... 131 132

Sin comentarios

Safety 1st Advancer Manual del operador Pagina 28