Showing papers in "Materials protection in 1974"

Soil resistivity-measurement and analysis

Abstract: AN EXTENSIVE RESISTIVITY SURVEY WAS UNDERTAKEN IN SOUTH CENTRAL ONTARIO TO DEVELOP CORRELATIONS OF SOIL CONDITION WITH THE CONDITION OF BURIED GAS PIPELINES. BOTH THE WENNER 4-PIN METHOD AT GRADE AND SOIL BOX WITH SAMPLES AUGERED FROM THE PIPE DITCH WERE USED. COMPARISON OF THE DATA SHOWED THE READINGS OBTAINED FROM THE SOIL BOX MEASUREMENTS TO BE CONSISTENTLY LOWER THAN THOSE PROVIDED FROM THE AT-GRADE SURVEY. READINGS WERE ANALYZED VISUALLY AND STATISTICALLY. READINGS OBTAINED WITH THE SOIL BOX PROVED MORE RELIABLE. DETAILS ARE GIVEN OF THE INVESTIGATION PROCEDURE. MEASUREMENTS WERE MADE IN OPEN SPACES. SOIL SAMPLES WERE OBTAINED FROM GAS COMPANY ROUTINE EXCAVATIONS. IF GROUND WATER WAS PRESENT, THE SAMPLE WAS FULLY MOISTENED WITH IT. IF NO GROUNDWATER WAS PRESENT, THE SAMPLE WAS SATURATED WITH LOCAL TAP WATER. THE SURVEY IN METRO TORONTO IS ALSO DESCRIBED. THE ANALYTICAL PROCEDURES BEST SUITED FOR ANALYSIS OF THE LARGE VOLUME OF DATA IS DESCRIBED. THESE PROCEDURES REQUIRED THAT THE MEASUREMENTS BE RANKED IN ASCENDING ORDER AND ASSIGNED PROBABILITES (ILLUSTRATED IN FIGURE). WHERE POSSIBLE, SOIL BOX DATA WERE COMPARED WITH DATA FROM AT GRADE SURVEYS. RESULTS OF SUCH COMPARISON ARE TABULATED. RECOMMENDATIONS ARE MADE REGARDING THE PERFORMANCE OF RESISTIVITY SURVEYS. SUCH SURVEYS INTENDED TO DETERMINE THE CORROSIVITY OF SOIL IN CONTACT WITH PIPELINES SHOULD BE CARRIED OUT BY RANDOMLY AUGERING SOIL SAMPLES FROM THE PIPE DITCH AT PIPE DEPTH. SOIL MEASUREMENTS SHOULD BE MADE ON FULLY MOISTENED SAMPLES COMPACTED IN A SOIL BOX INCORPORATING SEPARATE ELECTRODES FOR CURRENT AND POTENTIAL MEASUREMENT. WHEN EVALUATION OF SOIL CONDITIONS IS NECESSARY FOR A FUTURE PIPELINE AND RELIABLE DATA FOR THE LOCATION IS NOT AVAILABLE, SOIL TYPES SHOULD BE IDENTIFIED USING A SOIL MAP. WHEN RESISTIVITY DATA IS REPORTED, THE MANNER OF TESTING SHOULD BE SUFFICIENTLY DESCRIBED, PARTICULARY IF SOIL BOX MEASUREMENTS ARE INVOLVED.

Corrosion and cathodic protection of 5086-h32 aluminum coupled to dissimilar metals

Abstract: This study was initiated to determine the corrosion characteristics of 5086-H32 aluminum in sea water. Another objective was to determine whether cathodic protection could prevent the accelerated corrosion of 5086-H32 aluminum coupled to dissimilar metals. This report summarizes and correlates data from specimens exposed for several time periods at different exposure locations. (Author)

Mitigation of induced ac on a buried oil pipeline along power line right-of-way

Abstract: THE REPORT DESCRIBES THE PROBLEMS OF INDUCED AC ENCOUNTERED DURING THE CONSTRUCTION OF A 34-INCH DIAMETER CRUDE OIL PIPELINE ALONG A POWERLINE RIGHT=OF-WAY IN THE CHICAGO AREA. THE MONITORING AND MITIGATION PROGRAM IS DESCRIBED AND THE ONGOING PROBLEMS WHICH FACE THE PIPELINE OPERATOR ARE OUTLINED. MEASURES ARE RECOMMENDED WHICH MAY ACHIEVE THE GOALS OF CORROSION PREVENTION AND HUMAN SAFETY. THESE RECOMMENDATIONS RELATE TO THE MINIMIZING OF RESISTIVE AND INDUCTIVE COUPLING, DANGEROUS AC VOLTAGE LEVELS DURING CONSTRUCTION, ABOVE GRADE METAL STRUCTIRS, THE GROUNDING PROGRAM, THE USE OF MAGNESIUM ANODES AND THE ENERGY LEVELS IN THE OVERHEAD TRANSMISSION LINES.