STAFF REPORT - CITY COUNCIL/SUCCESSOR AGENCY/PUBLIC FINANCE AUTHORITY

City Council is recommended to approve the purchase and installation of 13 remote rectifier monitoring units (RMU’s) to allow operation of the city’s natural gas system in compliance with federal safety standards.

Coalinga’s gas distribution system consists of a combination of steel pipe and polyethylene (plastic) pipe.  The steel pipe is protected from corrosion (rust deterioration) by a series of 13 rectifiers that induce a positive charge on the pipe to prevent corrosion.  The rectifiers are inspected every two months for proper operation.  Once a year a survey is conducted of pipe-to-soil voltage potential to assure a positive charge is maintained along the steel pipes.  The annual survey also requires a test of “IR drop,” which is the voltage drop through the soil between the underground pipe and the test instrument measuring the potential at the soil surface. 

The Pipeline and Hazardous Materials Safety Administration (PHMSA) specifies criteria for IR drop measurement in the Code of Federal Regulations, (CFR) 49, Part 192.463.   Prior to 2016, the city had not been conducting the IR drop survey.  In 2017, the city’s survey contractor attempted to measure IR drop, but could not do so with the rectifiers operating continuously.  This item was discussed with PHMSA inspectors on their visit to Coalinga in August 2018.   The item is outstanding and must be addressed.

After consultation with corrosion experts from Farwest Corrosion Control Company, the proposed solution is to install 13 RMU’s that will allow simultaneous cycling of the rectifiers.  These units also allow remote access to determine the operating status of the rectifiers.  The specific device is a “WatchDog Scout RMU,” made by Elecsys Corporation.  These devices are widely used by Southern California Gas Company.

After contacting Elecsys, staff recommends purchasing the rectifiers from Farwest.  The price is the same from either source, and the folks from Farwest have provided valuable information regarding a solution to the IR Drop survey.  The cost of the units is $2,095 each.

Staff recommends utilizing a local electrician, assisted by Operator Qualified Coalinga gas personnel, to install the units in the field.  The quote from Solomon Electric & Data Inc. is $4,225.00, based on $325 per unit to install.  (The quote from Farwest for installation was over $12,000, partially high because Farwest employees would have to travel to Coalinga.)

The budgeted amount for this work is:

There will also be an ongoing monthly cost for operations of the units:

The alternative is to manually cycle the rectifiers, but doing so would require 13 operator qualified personnel, one at each rectifier with group communication, and would require them to be there for several hours as the tests progressed around the system. This alternative is not practical.

The fiscal impact will be to the natural gas enterprise, which has enough funds to cover the costs.  This item is covered under budgeted expenses for natural gas.  The installation of the units is a capital improvement to the gas system. There will be no fiscal impact to the General Fund.