WALKING AND MOBILE GAS (METHANE) LEAK SURVEYS

The purpose of this request is to secure a Professional Services agreement with a qualified Consultant to conduct mobile and walking natural gas (methane) leak surveys of the City of Palo Alto Utilities gas distribution system (mains, services and meters). The leakage surveys shall be in compliance with the Department of Transportation Code of Federal Regulations, Title 49, Part 192 & Part 199 minimum safety regulations and the Utilities Department Operations & Maintenance Manual. The term of this agreement is expected to be for three years.

The City of Palo Alto owns and operates its own utilities (water, gas, wastewater collection and treatment, and electric and fiber) and delivers natural gas to over 24,000 meters. The Utilities Department maintains and operates over 210 miles of distribution main and approximately 17,395 individual gas service pipelines with an average service length of 61 feet.

A leak survey of the entire gas distribution system is completed once every two years and is conducted between the months of March through November. The city is divided into two sections, the northern and southern section. A complete annual gas leak survey of the city is broken up using the following four methods:

• Mobile Survey: The mobile survey is conducted annually on all gas mains throughout the city. The survey is conducted using a mounted vehicle leak survey device and, in some locations, requires a walking survey of the mains to be completed when access using a vehicle is not feasible. The survey starts in the beginning of May and is completed by the end of May each year.
• Business Districts: There are 14 Business Districts in the City, consisting of over 1,870 gas services. A walking leak survey of the gas service from the main to the gas meter, including the gas meter, is performed annually in both the northern and southern sections of the city. The survey starts in the beginning of April and is completed by the end of May each year.
• Walking Survey: A walking leak survey is completed either in the northern section of the city or the southern section of the city, excluding the gas services already walked within the business districts. Only one section of the city is completed each year. A walking leak survey of the existing gas service from the main to the gas meter, including the gas meter, is performed. The survey starts the beginning of June and is completed by the end of November each year.
• Existing Gas Leaks (Re-checks): A walking leak survey of all carry-over gas leaks from the previous year is conducted annually. There are approximately 100 carry-over gas leaks to be surveyed annually. The re-check evaluates the existing gas leak and requires an updated grading of each leak. The survey starts in the beginning of March and is completed by the end of April each year.