January / February 2009 - Volume 15, Number 1January / February 2009 - Volume 15, Number 1January / February 2009 - Volume 15, Number 1January / February 2009 - Volume 15, Number 1January / February 2009 - Volume 15, Number 1

Fire Scene Forensics 42 Transformers 48 Composite Poles 54 Industrial Lighting 60, 64

Composite Poles 8/12/09 12:25 AM Page 1

Utilities have been working with sev-eral composite pole manufacturers anddeploying various types of compositepoles to service locations as pilot proj-ects to evaluate composite pole per-formance. Recent winter storms haveshown that composite utility poles havesome important advantages over wood,concrete and steel structures.

The storms that blasted acrossCanada and the northern tier of the

United States this past winter often leftbehind a beautiful blanket of snow andice. Only with some of these storms, thepeace and tranquility that normallyaccompanies the end of a gentle snowfall was instead punctuated by loudperiodic “cracks” and “booms;” thesounds of wood poles snapping liketoothpicks, felled by trees that col-lapsed under the weight of massiveamounts of ice and snow.

In several instances, composite utilitypoles were installed as pilot projects inamongst the old wood pole infrastruc-ture. To the amazement and pleasure ofthe host utilities, none of the compositeutility poles came down or were signif-icantly damaged. The various compos-ite pole manufacturers could not haveasked for a better test to prove the dura-bility of their innovative poles.

What is now becoming increasingly

By Kevin C. Coates

Composite Poles...Proving Their Worth

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obvious to the electric power industry isthat some composite utility poles havefinally matured into the “ready fordeployment stage” where they can nowbe accepted as part of a utility’sreplacement pole inventory. And, smallwonder considering the potential costsavings that composite poles representfor utility pole installation, mainte-nance, repair, replacement, life cycles,and disposal.

The effects of weathering, termites,woodpeckers, rusting, high winds, andfires take a toll on pole infrastructureevery year, which of course drives upmaintenance costs, and reduces overallsystem reliability. The new generationof composite poles effectively mitigatethese negative effects.

Significant advancements have beenmade in the design and manufacture oftransmission and distribution polesusing new high-strength E-Glass fibresand polyurethane resins. Utilities arebeginning to recognize that compositepoles manufactured with these newmaterials hold promise for dramaticallyreducing pole life cycle maintenanceand the need for frequent pole replace-ments, even for reasons other than age.These improvements also hold promiseto reduce the initial cost of setting apole as well as reducing the need forpole replacements.

BackgroundThe first poles used to support tele-

graph lines in the 19th century were fromold growth or ancient forests and typi-cally came from very dense and resilienthard woods. Over the years, old growthforests were decimated and ceased to bethe primary source for transmission anddistribution poles. Today’s rapid growthtree farms now produce, over decades, apole with somewhat degraded properties;mainly, reduced durability, stiffness, and

longevity. This means new wood polesare less robust and do not resist insectinfestation or wood rot as well as theolder generation poles. Service life islogically shorter.

To enhance pole longevity, today’swood poles are treated with pen-tachlorophenol (a known carcinogen)suspended in a light oil (creosote) toenhance pole treatment. This eventuallypresents a handling and disposal chal-lenge for utilities at the end of a pole’sservice life. Environmental regulationsnow consider treated wood poles ashazardous waste; a significantly moreexpensive proposition than normallandfill disposal.

Wood poles have another vulnerabil-ity that is especially problematic inforested areas – they burn. This iswhere composite poles have a distinctadvantage – they resist fire and will notsupport combustion without the addi-tion of an external heat source.

Composite CharacteristicsWhile not fireproof, composite poles

are extremely fire resistant; especially,when coated with fire retardant. Apropane flame can cause a compositepole to smolder with a limited amountof flame when applied directly to thesurface of the pole, but as soon as theflame is removed, the composite mate-rial ceases to smolder or produce flame.This makes composite poles ideal fordeployment in forested areas. More

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Rapid growth tree farms produce poles that are less robust and do not resist insectinfestation or wood rot as well as older generation poles.

Environmental regulations now consider treated wood poles as hazardous waste.

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56 ELECTRICAL LINE January / February 2009

importantly, after exposure to fast moving brush fires, thepoles will not likely require replacement and will continue tosupport the lines and equipment with no loss of strength.

The resilience of composites is one of their more desirablefeatures. Composites allow strength parameters to be accurately“dialed-in” during manufacturing to meet the job specification.This saves time and money and eliminates waste. The servicelife of a composite pole is conservatively rated at 70 years onaverage. In addition, composite poles are extremely lightweight, strong, and do not lose their strength over their lifetime.

Industry AcceptanceObviously, any new product or technology offered to the

electric power industry needs to be thoroughly tested beforeit can be deployed to a live grid. To better evaluate new elec-tric power technologies that might enhance grid reliabilityand/or lower service costs, Southern California Edison (SCE)created a new section on their grid in San Bernardino knownas the “Circuit of the Future.”

Southern California Edison worked closely with a number ofcomposite pole manufacturers to help them design and manu-facture a series of composite poles that meet SCE’s needs interms of strength, durability, serviceability, and service life.

Each composite pole company has its own patentedmethod of production, which means each type of pole has aunique set of characteristics.

The chemical composition of the resins, types and amounts

of E-Glass, winding patterns and tensions vary significantlyfrom one manufacture to another and account for various per-formance characteristic. These various manufacturingprocesses are naturally tightly held secrets.

Hardware DesignAttaching equipment to hollow composite poles, rather

than solid wood poles, requires different hardware and meth-ods. In most cases, hardware installation is very straightfor-ward. For instance, rather than drilling holes and then bolt-ing brackets directly into wood, a composite pole requiresthat a hole be drilled completely through both sides of thepole with the equipment brackets being attached by longthrough bolts, nuts, and plate washers (flat washers for pul-truded poles and curved washers for round filament woundpoles) on both sides to evenly disperse the clamping force.

One of the tasks composites have made less strenuous onlinemen, if not easier, is cross arm replacement. Wood crossarms are routinely replaced as a result of wood deteriorationor mechanical damage. Traditional wood cross arms areheavy and can be unwieldy when being handled by a linemanworking at the top of a pole. Unfortunately this work oftenresults in back strains and days of lost work for linemen. Thepotential for injuries and time lost from work is substantiallyreduced when composite cross arms are substituted for woodarms because the composite weight is significantly less, thusmaking the composite arm easier to handle at the top of pole.

SCE pilot project pultruded transmission pole (left); and at right, modular composite pole for SCE’s “Circuit of the Future”.

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More Installation OptionsHollow composite poles allow more flexibility during

pole erection. This is especially true when erecting polesalong constricted rights of way that require poles to be set byhand or with heavy cranes. Because composite poles areavailable in two forms; one form being single length polesand the second being modular poles that are stacked togetherto the desired height. The second form makes it possible forthe pole to be erected by a line crew using hand tools andequipment because the line crew is working with a series ofshorter and lighter modules rather than a single heavierlength pole.

Modular poles are inherently much more versatile thaneither the single length wood or composite poles and areshipped nested one inside the other so that when unloaded,taken apart and assembled, will yield a pole of specific lengthand class. This flexibility makes for faster response times inemergency disaster relief efforts because assembly can be per-formed by a utility at their own facility or in the field. Anemergency situation might require a pole of a specific lengthand class in order to be able to return service to an area. How-ever, there may not be any poles available in inventory to meetthe length and class requirements for the job. Rather thandelay the job or erect a costly temporary work-around thatwill, at some point, require removal, it would be more effi-cient and cost effective to separate some of the existing polebundles and pick out the specific modules needed to assemble

a pole that meets the job requirements. Resin Systems buildsseveral different length and strength pole modules which canbe assembled in several combinations to create a pole of adesired length and class and is the only company to date offer-ing this design option.

In mountainous areas, distribution poles are frequentlydamaged during heavy annual snow storms. A commonproblem from these storms is that the snow laden trees willfall across distribution lines which can and often does resultin a pole breaking off 5 to 8 feet above the ground line.Many of these pole breaks are in remote locations whichmeans that most of the repair/replacement work will have tobe performed by hand. To make matters worse, these polesare often set in very rocky soil that makes it very difficultand time consuming to exhume the buried pole section.

According to Mikel Rodin, formerly a senior engineer withSCE, the timely and cost effective method to effect a repairin rocky terrain is by trimming the damaged pole down to apoint where there are about 2 metres of undamaged solid stubremaining. By using an equivalent length and class of com-posite sectional pole trimmed to remove the bottom portionof the module equal to the length of the embedded portion ofthe wood pole, a composite module can be set down over thewood stub and secured with through bolts after cross drillingthrough both pole modules approximately 1 metre abovegrade. Then, a closed cell foam is injected to fill any existingvoid between the stub and the bottom composite pole mod-ule. The remaining composite modules are used to finisherecting the new pole combination.

Over the past 10 years, there have been a number of in-depth studies performed by both E-Glass/resin manufacturesand independent laboratories. All have concluded there areno negative health issues that will result from working withcomposite poles (i.e., activities such as handling, cutting,drilling and sanding, etc.).

Major BenefitsTo appreciate the real value of composite poles, which typ-

ically can range from one and a half to twice the price of acomparable wood pole, utilities need to look past the initialcapital and focus on the comparison between the actual lifecycle costs associated with each type of pole. Such compar-isons will identify areas where a utility could realize signifi-cant savings for the maintenance side of the business.

Over the life of a composite pole (rated conservatively at aminimum of 70 years), at least two wooden poles would needto be purchased, which is an obvious value proposition juston the purchase price alone, since the cost of only one instal-lation would be required instead of two. Because compositepoles are not affected by such things as insect infestations,wood peckers, fungi, outer shell cracking, or loss of heart-wood as a result of decay, they do not require periodic intru-sive inspections or internal chemical treatments which can bevery costly over the life of the wood pole.

Kevin C. Coates is a Washington-based energy, electricutility and transportation consultant and technology writer.

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