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<br />crcalc problems with a numi)cr nl
<br />Ic',IS. The rough orange peel surtacc
<br />Ir~nd•; ro retain moisture whlrh ywll
<br />rouse significant problems, especially
<br />with holiday detection.
<br />Until proven otherwise, surface ap-
<br />pearance problems should be consid-
<br />ered indicative of an unxreprahle
<br />coating. The powders stored at 11' C.
<br />and 23" C.. 95`b RH both resulted in
<br />an unacceptahle appearance ITable
<br />21.
<br />Accurate test. The results of this
<br />e•raluauon indicated that the gel-time
<br />test was the only powder test method
<br />that provided speedy and accurate
<br />information relating to the condition
<br />of an FBE powder.
<br />It is somewhat refreshing to note
<br />that, in these days of high technology,
<br />the findings of such simple tests as gel
<br />time or appearance panels can In tact
<br />detect problems with aged powders,
<br />while technically powedul tools such
<br />as the DSC could not accurately pre-
<br />dict or identify powder degradation.
<br />While the industry has widely ac-
<br />cepted the DSC as a most reliable tool
<br />For determining the extent of cure in
<br />an FBE coating, it is clearly not the
<br />panacea for detecting all FBE-powder
<br />characteristics and conditions.
<br />The resultr of this program and pre-
<br />vious research have clearly indicated
<br />that the results of the DSC can be
<br />significantly misleading if one,consid-
<br />ers the ~Tg and OH results to be
<br />absolute reflections of the state or con-
<br />ditions of the coating or powder.' G
<br />The OSC should only be utilized for
<br />tasks (such as cure determination) in
<br />which the method has not only been
<br />clearly defined, but also proven.
<br />Retmmces
<br />I. Temple. D.G., and Coulson. K.E.W . "Pipeline
<br />Coatings, Is it Really aCover-up 6iory! -Pan
<br />II." Paper 756, Corrosion 27, New Orleans.
<br />?. Mills, G.. "The Interpretation of Odiermnal
<br />Thermal analysis Data for fuspn Banded Epoav
<br />Powder Comings." Paper 112. Corrot~on 9J.
<br />Anaheim- [Jh(.
<br />]. Gray. C., Lunn, W H., Jnd MtTrdle. O.. "EVaI-
<br />uaUOn o! Epoxy Powder [omngs Far Vse on
<br />Steel Pipelines," Paper I IB. Corrosion dJ, Ana-
<br />heim, [JII(.
<br />J. iempie. D.G.. Jnd Coulson, K.E.W . "The Use
<br />ni D~Herentul $dJnnmg Calonmetrv to Demr-
<br />minr Coating Cure," Materials Penormaon•.
<br />Vnl. $J, Nu. 11,p I; ,VOVrmtscr IYH6.
<br />5 Canadian StandJrds Assunmion. "CAN([$A-
<br />Z'a6.!0~MR6 EAernal Fusion Bnnd Epoxy
<br />Cua0.d $Icel Pia," Augua IYtl6.
<br />h Dunn, L. 61115, LD., Jnd i'Irvsin. R., "Mnwwc
<br />ai(eai dmded epsxv line mating," DCI. Fcb.
<br />'1, 19H6, pp. G1~77.
<br />USE OGJ REPRIMS
<br />Bepnnis pl any artlRe Or advenlse-
<br />ment appearlnq ~n Od S Gu JOUrnal may
<br />OE purOhBed py EpnldRmq Jpnr Bo~
<br />1Jrtn, Bcronnl Gepl.. Penm4Ell Pu011sn-
<br />inq ro.. Baa 1260. Tulsa, 04 77191 I
<br />200.711-aa67 or 912.875-1161. en
<br />]i9 Mlrumum order: 100 Jlack-an2~
<br />wnrte cpp~es: 500 Ipur~color copies.
<br />
<br />Strain
<br />monitoring
<br />averts line
<br />failure in
<br />Rockies
<br />Bruce Miller
<br />Western Gas Supply Co
<br />5ilverthorne, Colo.
<br />Michal Bukovansky
<br />Golder Associates
<br />Denver
<br />The case history of a landslide in the
<br />U.S. Rocky Mountains shows the po-
<br />tential far pipeline monitoring in geo-
<br />logically sensitive areas, those subject
<br />to landslides and subsidence, for ex-
<br />ample.
<br />A properly installed monitoring sys-
<br />tem monitored by the pipeline opera-
<br />tor, Western Gas Supply Co. (west
<br />Gas), Denver, provided an early
<br />warning of increasing line strains.
<br />Rugged topography. The Vail later-
<br />al supplies natural gas from West Gas'
<br />mainline in the vicinity of Climax,
<br />Colo., to the Vail valley, some 30
<br />miles nonh. The lateral was construct-
<br />ed in 1965.
<br />The pipeline is a•high-pressure, b-
<br />in. line with 0.188 W.T., X4? grade.
<br />The pipeline alignment was devel-
<br />oped in exceptionally rugged topo-
<br />graphic conditions of the Rocky
<br />Mountains, with the line crossing the
<br />~~pn ua\ .. ~\<_ .
<br />p~ ~
<br />"~\,~~~~~~ peP°n
<br />l:untmenwl Dwide. .Much of the
<br />alignment has been developed on
<br />Steep and high slopes, mostly above
<br />the Eagle River. Rug;;ed topographic
<br />conditions, high altitude. and locally
<br />uniavorahle geologic mndinons have
<br />u)ntrlbuted lu accasiunal stability
<br />proi>lems that caused a disruption of
<br />Ihr. Ime In 198.1. Since then, other
<br />stability problems and landslides have
<br />heen encountered along the line.
<br />These have required considerable
<br />mitlgaang efforts durng the last fe•-v
<br />years. It Is interesting to note that no
<br />stability problems were encountered
<br />along the lateral prior to 1984.
<br />The maloriry ai the stability prob-
<br />lems are related to numerous land-
<br />slides that have been crossed by the
<br />alignment.
<br />Most of these landslides are ofd.
<br />having developed many years prior to
<br />construction of the line. Many of [hem
<br />are stable at present and do not en-
<br />danger the integrity of the line.
<br />Some of them have experienced
<br />significant deformations in the past.
<br />Some landslide deformations appear
<br />to have been activated during the last
<br />few years, very probably because of
<br />exceptionally unfavorable climatic
<br />conditions of this period.
<br />The 198•+ landslide occurred during
<br />late winter without warning. Although
<br />it disrupted the line, the gas supply
<br />was maintained.
<br />Following this event, West Gas. de-
<br />cided systematically to evaluate stabil-
<br />ity conditions along the line and to
<br />mitigate the areas with the highest
<br />hazards. Golder Associates assisted
<br />Landslide 7 plan and pipeline deformation
<br />Fig. I
<br />A'
<br />I`\nr .
<br />~
<br />V I Baun(Iary oI WG:LUC
<br /> E. P~ppapl[ IOplian al anyrnn one inSnlbli0n
<br />4 yp I~ ~ 7 One i0fanpn al W vae lOrllor
<br />~ + Suvmsauge ~mm~p~pn
<br />~~ n S. Line nvures ousea ay uruwae
<br />
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