On June 28, 1993, natural gas leaked from a 12-inch high-pressure
cast iron natural gas line at Pennsylvania Avenue and 30th Street,
SE. Fire, followed by an explosion, apparently caused by a spark
from a stalled van's starter motor, resulted in one fatality and
several injuries. As a result of the incident, the Commission directed
Washington Gas Light officials and Commission staff to develop a
Cast Iron Replacement Program ("CIRP") to rapidly retire
8-inch and 12-inch high pressure cast iron pipes, which are more
susceptible to failures. Although WGL already had a pipe replacement
program, the CIRP was in addition to the existing pipe replacement
program.
Washington Gas Light submitted a ten-year plan for the CIRP in November
1994. The plan called for the replacement of the 8-inch and 12-inch
cast iron pipes to be completed by the year 2004. Charts A, B, C &
D show the status of the CIRP*.
* Current year data is
not available until April of next year.
Washington Gas Light's HP Cast Iron Replacement
- DC (12" & 8" Daimeter Mains) - In Miles
Length (in miles of CIRP) Replaced per Calendar Year
1994
1.01
1995
3.20
1996
0.12
1997
3.20
1998
2.54
1999
1.09
2000
0.78
2001
0.39
2002
2.08
2003
0.55
2004
0.82
Washington Gas Light's HP Cast Iron Replacement
- DC (12" and 8" Diameter Mains) - Cumulative Total of CIRP Replaced
Cumulative Total of CIRP Replaced
1994
1.01
1995
4.21
1996
4.33
1997
7.53
1998
10.08
1999
11.18
2000
11.96
2001
12.36
2002
14.41
2003
14.96
2004
15.78
Washington Gas Light's HP Cast Iron Replacement
- DC (12" and 8" Diameter Mains) - Distribution per Mile for Each
Quadrant
Calendar Year 2003
DC Area
Miles of Cast Iron
NW
0.55
NE
0.00
SW
0.00
SE
0.00
Washington Gas Light's HP Cast Iron Replacement
- DC (12" and 8" Diameter Mains) - Distribution per Mile for Each
Quadrant
Calendar Year 2004
DC Area
Miles of Cast Iron
NW
0.30
NE
0.00
SW
0.00
SE
0.52
In its continued
efforts to enhance the reliability and safety of its natural gas
distribution system, Washington Gas Light is implementing an on-going
program of replacing small diameter (less than 8 inches in diameter)
cast iron pipes with plastic insertion or direct burial.
A chart of
the status of the smaller diameter cast iron (CI) pipe replacement
program, together with the status of the Commission mandated replacement
program, is shown below.
The table and
chart below represent all cast iron pipes of different diameters
for both low pressure and high pressure. As of October 2004, all
high Pressure CI pipes between 8" and 12" diameters have
been replaced for the CIRP.
Trend in Washington Gas Light's Cast Iron Replacement
Program - Miles of Cast Iron Pipe in System
