User Manual

4 Utility AirSpade Technical Applications Bulletin
A BRIEF HISTORY
During the early 1960s, Brooklyn Union Gas Company first pioneered
using a compressed air powered lance in conjunction with a vacuum
truck as a better way to dig and reduce the costs associated with
approximately 30,000 annual street openings for gas distribution pipe
repair. Compressed air, or “dry excavation” to dig utility “potholes”
proved to be a safe and reliable alternative to manual or mechanical
methods of uncovering buried utility lines without damage.
Success with this methodology quickly led to the development of “small
hole technology” -- now known as “keyhole technology” -- whereby
repairs are made to underground facilities from the roadway surface
using long-handled tools. This technology was first reported in the
1960s as utilities sought ways to reduce the size and cost of utility
excavations and avoid putting “a man in the hole.” Both Philadelphia
Electric (PECO) and Peoples Gas of Chicago were early pioneers in
developing keyhole maintenance techniques to reduce the number of
large street openings that were both a nuisance to the public and
costly to excavate and re-pave.
Early keyholing by PECO included repairs to leaking bell joints and
cathodic protection. The pavement was cut with diamond saw blades
and removed with pneumatic pavement breakers and concrete drills. A
power-driven auger and air jet vacuum removed the spoils, augmented
by a clam-shell post hole digger. These techniques seem rudimentary
compared with today’s rotary coring and vacuum excavators but
resulted in substantial savings to PECO.
Over the next two decades, large dedicated vacuum excavation trucks
and rotary coring devices were introduced at Southern California
Edison as an alternative to traditional pavement breaking. During
this same period, Dravo Corporation of Pittsburgh, PA began the
development of a specialized air lance tool for excavation, later named
“AirSpade”. Throughout the 1980s and 1990s, AirSpade became
widely accepted by other utilities including Baltimore Gas & Electric,
and Pennsylvania-American Water.