Petroleum systems inspection and maintenance. . - Arema News - Part 1 of 2

Railway Track and Structures, April, 2001 by Preston E. Sargent

(Part 1 of 2)

Prior to the current escalation of petroleum costs it was estimated that North American railroads spent in excess of $20 million per year on diesel fuel that was captured at wastewater treatment plants. The cost for spilled fuel that did not get captured by the industrial waste system is considerably higher. With the rising costs of petroleum products and the already high costs associated with environmental remediation and waste-water treatment plant operations, railroads should put more emphasis on leak and spill reduction of petroleum products. These petroleum systems include diesel fuel, lube oil, compressor oil, traction motor oil and drained oil.

The primary element required to achieve these reductions is maintenance of the petroleum systems. An essential part of the maintenance function is a program of inspection and testing of existing petroleum systems.

The basic components of a petroleum system are the storage tanks, piping, and equipment. This article will touch briefly on each of the components of the system and attempt to provide information concerning important areas where inspection and maintenance can have a positive impact on the environment, the bottom line of the railroad and the public/employee perceptions of railroads.

Storage tanks

Most railroads have a large number of tanks. Many of them are more than 20 years old and erected when the typical installation called for the tanks to be set on an asphalt or "oiled sand or gravel" base placed on an unprepared earth surface. Many of the tanks were installed with no cathodic protection.

Compared to today's construction standards these tanks are suspect in their ability to prevent leakage of the contained product and need to be inspected. Most railroads own a large number of tanks and it is suggested that an American Petroleum Institute (API) 653 inspection program be developed. The API standard 653 is for Tank Inspection, Repair, Alteration and Reconstruction of tanks constructed to API 650 standards. API 650 tanks are usually considered to be large field-erected tanks. API 653 section 4.1.0.1 provides a list of requirements to be a qualified inspector. These requirements, as well as the specialized equipment knowledge and training, will usually preclude the use of railroad people for this part of the program, although we will have to do the planning, coordination, and possibly provide temporary facilities to be able to do the inspection. To perform the inspection will require that the tank be pumped down and cleaned. Of course, all work done inside the tank is considered confined-space wor k and all the pertinent safety regulations and practices must be observed. This particular portion of a tank inspection program entails the testing of the floor and first ring plates, usually using magnaflux exclusion equipment on the floor and ultrasonic measurements coupled with a visual inspection for the shell plates and critical weld areas. The plate testing can detect loss of section, fractures and pinholes. The information gathered by this inspection can be used to determine what, if any, repairs are needed and can be used as a predictive measure for remaining tank life, preventive maintenance schedules and suggest remedial actions to prolong the service life.

The cycle for API 653 testing is dependent on a number of variables such as interior coatings, decanting process, soil conditions, containment drainage, paint condition and other factors relevant to each tank. API recommends a professional external inspection at a maximum of five year intervals and an internal inspection at 20 years. My personal opinion is that the external inspection should be part of a monthly in-house process and the internal inspection on a 10-year cycle.

Although the API 653 inspection is typically outside the expertise of railroad employees, there are a number of crucial inspections that railroad employees can perform. It is suggested that on a monthly basis a railroad employee visit every petroleum tank and visually inspect it. This inspection is for signs of leakage and/or straining around the tanks on the shell or piped connections, movement (does the tank show signs of tilting out of plumb?), signs of cracking or settlement of the foundation, indications of overfilling, condition of the containment structure, plate buckling, or severe surface pitting and corrosion, as well as checking for vandalism or illegal connections to the tank and piping.

While doing this monthly site visit it is suggested that the inspector "tape or stick" the tank and compare the reading to the automatic gauges, verify any floats used by the automatic gauges are free and not hung up or that a guide wire hasn't broken.

This is also an opportune time to check the tank vents for obstructions, decant the water from the tank, test the cathodic protection system and verify that the overfill-prevention controls perform as required and that any and all alarms are initiated at the proper set points.