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r` ~T create problems with a numF3er of tests. The rough orange peel sudace tends Io retain moisture which will cause significant problems, especially with holiday detection. Until proven otherwise, surface ap- pearance problems should be consid- ered indicative of an unacceptable coating. The powders stored at 41° C. and Z3° C., 95% RH both resulted in an unacceptable appearance (Table 21. Accurate test. The results of this evaluation indicated that the gel-time test was the only powder test method that provided speedy and accurate information relating to the condition of an FBE powder. It is somewhat refreshing to note that, in these days of high technology, the findings of such simple tests as gel time or appearance panels can in fact detect problems with aged powders, while technically powerful tools such as the DSC could not accurately pre- dict or identify powder degradation. While the industry has widely ac- cepted the DSC as a most reliable tool for determining the extent of cure in an FBE coating, it is clearly not the panacea for detecting all FBE-powder characteristics and conditions. The results of this program and pre- vious research have clearly indicated that the results of the OSC can be significantly misleading if one consid- ers the GTg and ~H results to be absolute reflections of the state or con- ditions of the coating or powder.' b The DSC should only be utilized for [asks (such as cure determination) In which the method has not only been clearly defined, but also proven. References 1. Temple, D.G., and Coulson, K E.W , "Pipeline Coatings, Is 11 Really aCover-up Story! -Pan II," Paper 356, Corrosion B9, New prleans. 2. Mills, G., "The Inierprelaiion of D~ffcreniial Thermal Analysis Dasa for Fusion Bonded Epoxy Powder Coatngs," Paper 112. Corosion 83, Anaheim, Calif. 3 Gray, C., Lunn, W H.. and McArdle, U . "Eval- uabon of Epoxy Powder Coatings for Use un Steel Pipelines." Paper 1IB. Cwrosipn B3, Aw- heim, Calf. 4. Temple, D G., and Coulson. K.E.w.. "The Use of DiHeremial Scanning Calorimelry to Deter- mine Cmring Cure," Maienals Pedormancc, vol. 24, No. I I, pp. l7, November 19tl6. S Canadian Aandards Assuoaiiun. "CANIC6A~ Z295.20~M8b External Fusion Bnnd Egiry Coated 9cel Pipe," August 1986 6. Dunn, I , S~IIs. I D., and Pleysicr, R . "MUisture aHecis bonded epovy line coaling," (1(:I. Feb 29, 19tlh, pp. 61.77 USE OGJ REPRIHrS Repnnls of any ankle or aovedise- ment appeannq In Oe d Gas Journal may be Durcnasetl by mntacrinq June Bo- rarth. Bepnn[ Oept . PenriWell Publish- ing Co., Box 1260. Tulsa. Ok. X101, t- 600~331-1963 or 918.635-3161, ert 379. Mlnlmum prder 100 black-and- whne copies: 500 lour-cglar copies. L Strain monitoring averts line failure in Rockies Bruce Miller Western Gas Supply Co. Silverthorne, Colo. Michal Bukovansky Golder Associates Denver The case history of a landslide in the U.S. Rocky Mountains shows the po- tential for pipeline monilonng in geo- logically sensitive areas, those subject to landslides and subsidence, for ex- ample. A properly installed monitoring sys- tem monitored by the pipeline opera- tor, Western Gas Supply Co. (West Gas), Denver, provided an early warning of increasing line strains. Rugged topography. The Vail later- al supplies natural gas from West Gas' mainline in the vicinity of Climax, Colo., to the Vail valley, some 30 miles north. The lateral was construct- ed in 1965. The pipeline is ahigh-pressure, b- in. line with 0.188 W.T., X42 grade. The pipeline alignment was devel- oped in exceptionally rugged topo- graphic conditions of the Rocky Mountains, with the line crossing the ~e~:f~.~r O e ~~~ ,._Pepp~ ~~ Continental Divide. Much of the alignment has been developed on sleep and high slopes, mostly above the Eagle River. Rugged topographic conditions, high altitude, and locally unfavorable geologic conditions have contributed to occasional stability problems that caused a disruption of the bite ria 1984. Since then, other stability problems and landslides have been encountered along the line. These have required considerable mitigating efforts during the last few years. It is interesting to note that no stability problems were encountered along the lateral prior to 1984. The majority of the stability prob- lems are related to numerous land- slides that have been crossed by the alignment. Most of these landslides are old, having developed many years prior to construction of the line. Many of them are stable at present and do not en- danger the integrity of the line. Some of them have experienced significant deformations in the past. Some landslide deformations appear to have been activated during the last few years, very probably because of exceptionally unfavorable climatic conditions of this period. The 1984 landslide occurred during late winter without warning. Although it disrupted the line, the gas supply was maintained. Following this event, West Gas de- cided systematically to evaluate stabil- ity conditions along the line and to mitigate the areas with the highest hazards. Golder Associates assisted Landslide 7 plan and pipeline deformation Fig. I A' I aqun9ary °I IanCSlae ~~UP' . 2. PrgWbl! I°G4gn pl anginal line insUlldLgn a sg iao qqp ] Line Ionian est. °v q~qe lonmr a Sven gauge initllldtan ~~ ° 5. Line Ikaures nusen OY Ian9Lide