Main Break: 21st and Bainbridge

SOSNA Sponsored Community MeetingAugust 22, 2012

• Break in 48-inch transmission main on Sunday, July 22

• Resulting in washout of intersection and flooding to approximately 70 properties

• PWD pumped basements, cleaned sidewalks and streets with the assistance of the Streets Department and replaced hot water and house heaters as needed

• PWD Claims representatives worked with residents/businesses

WHAT HAPPENED?

Philadelphia Water Department

• Analysis performed by an independent consultant on the broken section of pipe showed that age/corrosion was not a factor

• Forensic evidence to pinpoint contributing factors not available as pre-existing underground conditions washed out with break

WHY DID IT BREAK?

Philadelphia Water Department

WHY DID IT BREAK?

• PWD “first in” to make repairs

• PECO, PGW, Verizon are following

• Restoration of damaged streets and sidewalks last component

Philadelphia Water Department

RESTORING THE INTERSECTION AND THE COMMUNITY

The break occurred at the intersection of two large transmission mains.

A close-up of the break location.

A variety of utilities lie beneath the street.

Workers prepare to remove a section of 36” main to access the broken 48” main.

A worker begins sawing through the bolts of the 36” pipe joint.

A worker slices through the 48” inch main that ruptured.

The 36” pipe is strapped so it can be hoisted from the washout.

The 36” main has been cut into several sections in order to be removed

Machines aid workers, but this is still a very dangerous job.

A broken strap could result in serious injury and further damage to infrastructure.

With the 36” main out of the way, workers attach strapping to the 48” main.

A good view of the blow out on the 48” cast iron transmission main.

• Water mains fail when the stresses placed upon them are greater than the strength of the pipe.

• External forces on a water main may increase over time due to traffic loading, temperature changes, other underground work that impacts the water main either immediately from direct contact or over time from movement or bearing on the main.

Philadelphia Water Department

WHY WATER MAINS BREAK

• 50% of all water main breaks occur during the winter months of December, January and February.

• Water temperatures in the main and the ambient air temperature drops dramatically and cause smaller mains to contract and become brittle. In addition, the ground freezes and expands exerting additional stress on the main.

• Transmission mains are large, thick walled pipes that are not impacted as much from the cold weather

• Philadelphia experiences less than 5 transmission main breaks (pipes16-inches and greater) on average a year.

WHY WATER MAINS BREAK CONTINUED…

Philadelphia Water Department

WHY WATER MAINS BREAK CONTINUED…

• Philadelphia has been monitoring main breaks for decades. The number of main breaks occurring each year is highly dependent on the severity of the winter weather; milder winters mean fewer breaks.

• The national annual average for water main breaks is 270 breaks per 1,000 miles of main. PWD’s current average is 230 breaks per 1,000 miles of main annually, less than the national average.

• This lower rate is due to a water main replacement program begun thirty years ago and PWD’s leak survey and corrosion control programs.

WHY WATER MAINS BREAK CONTINUED…

Philadelphia Water Department

WHY WATER MAINS BREAK CONTINUED…

• Leak Detection

• Water Main Replacement

• Cathodic protection

• Corrosion testing

• PWD just conducted a focused leak detection program in this community and found one leak on a hydrant which is scheduled for repair

Philadelphia Water Department

HOW ARE WATER MAIN BREAK AVOIDED?

• PECO began work on August 13 – date PWD completed their work. Work includes: removal of damaged conduit, installation of new conduit and installation of new manhole

• PGW will begin work once PECO manhole installed. Work includes: relocate gas main along north footway on Bainbridge Street

• Verizon - Work includes: installation of new conduit in intersection. Completed work on August 21

Philadelphia Water Department

PECO, PGW & VERIZON

7/22-8/13 8/13-8/19 8/20-8/26 8/27-9/2 9/3-9/9 9/10-9/16 9/17-9/23

PWD Repair Mains, etc.

Complete

PECO RemoveConduit

Install New Conduit &Manhole

PGW Relocate New

Gas Main

Verizon ServiceRestored

Removed Damaged Facilities

Conduit Replacement Scheduled

PWD Paving Restoratio

n

Restoration of Streets and Sidewalks

Repair Timeline

REPAIR TIMELINE

Philadelphia Water Department

CLAIMS PRESENTATION BY CITY RISK MANAGEMENT DIVISION

Visit us on line at:

www.phillywatersheds.org/alerts

Philadelphia Water Department

MORE INFORMATION