Page:NTSB - Railroad Accident Report - Derailment on May 25, 1989.djvu/65

 not provided to its enforcement personnel any guidance indicating that check valves do not have to comply with the maintenance requirements; however, the OPS representative stated that this position reflected what OPS has been doing from an enforcement policy.

The Calnev manager of operations further testified that, based on the amount of product eventually required to refill the line, at the time of the rupture, the check valve at MP 6.9 did not close, the valve at MP 14.9 "must have come closed at some point," and that check valve at MP 19.2 "probably has at minimum leaking seats."

.—Remotely operated block valves were installed on the Calnev pipeline at MP 35.4 and MP 46.7. A manually operated block valve was installed at MP 25.7. According.to the testimony of the incident commander (the deputy fire chief) and Calnev’s manager of operations, the deputy fire chief requested after the train derailment that a block valve be installed just north of where the derailment occurred. According to Calaev’s manager of operations, "With a block valve you have the ability for positive shut-off. You can turn a crank and tighten it and possibly have a more certain measure that your pipeline is shut off at that point. I think the chief felt that given the difficulty we had in getting that check valve to seat during our drain-down, that that might be a good idea given the population in the area.…We were basically in agreement with the chief that that would be a good idea." He further stated, "There is a fair amount of lead-time in ordering such an item and a fair amount of time to set up an installation such as that one." Subsequent to the pipeline rupture, a remotely operated block valve was installed at MP 6.9.

.—The pipeline system is controlled by dispatchers from a dispatch center at the Colton Pump station. The system is equipped with a monitoring system that scans selected system parameters, such as pipe pressures and motor drive amperages, every 13 seconds, compares the data with programmed acceptance values, and through visual and audible alarms, alerts the dispatcher to changes to operating conditions in the system and abnormal or unacceptable occurrences. The audible alarm indicates that a change has occurred; however, this does not necessarily indicate that there is an emergency or that any action is required on the part of the dispatcher other than to acknowledge the alarm by pressing a key on his terminal keyboard. The visual alarms are presented in the form of numerical values flashing on a colored background. The background color varies depending on the measured value for the particular operating parameter. Background colors range from shades of white and blue, representative of the range of low pressure conditions, to yellow and red, representative of the range of high pressure conditions. Normal ranges are presented on a green background.

A computer printout of the monitoring system indicated that on the day of the accident, the dispatcher on duty received both a low suction and a low discharge pressure alarm on his computer terminal screen. The dispatcher did not detect the low discharge pressure alarm, and by one stroke on his terminal keyboard, he silenced the audible alarm, caused the flashing word "alarm" to disappear from his screen, and caused the flashing numerical information regarding the low suction pressure and the low discharge pressure