- Please explain how steel poles can be called equivalent to wood poles, the materials are so different.
The equivalency is based on loading specified by ANSI 05.1 for each wood pole class and then modified by a ratio of overload factors for wood and steel.
- Would you comment on the deterioration of wood verses steel?
Wood being a natural grown material deteriorates with age. It is subject to rot, fungus and decay as well as attack by insects and woodpeckers all of which will reduce the strength of the material. In most utility applications the "normal" life of a wood pole is approximately 30 years. Steel on the other hand has an infinite life span when corrosion is kept in check. The use of galvanizing has proven to be an effective deterrent to corrosion for above ground and many below grade applications. There are some very good coatings which have been developed for below grade protection when soil conditions warrant it. These coatings, in conjunction with galvanizing, can extend the life span of steel considerably.
- Are Steel Distribution poles on the approved RUS (REA) listing of materials?
RUS does not approve material. They have a listing of approved suppliers of material. Valmont-Newmark is on the list as an approved supplier of steel poles. REA co-ops that have used steel distribution poles have indicated in their work plans they are being used "to gain experience and to look to the future". The application of steel distribution poles may require conditional approval for use on RUS funded projects.
- We will use the poles per the A1 and C1 REA applications. Are there any problems using steel distribution poles in these applications?
Structurally, steel distribution poles can be used just like their wood counter parts. In addition, since steel poles are conductive, they offer an added benefit of being an efficient path to ground, which may replace the ground wire used on wood poles. The hardware currently used on wood poles usually works well with steel poles also, but consideration should be given to line reliability issues, such as BIL.
- Do steel poles have a provision for grounding equipment such as transformers, arresters, fuse cut-outs, etc.?
Valmont-Newmark provides one grounding device at the groundline as a standard for all distribution poles. It is very easy to add additional ground nut devices (i.e. at the transformer location) during fabrication should the utility indicate such a need. Valmont-Newmark's standard is a 1/2" diameter threaded insert or TEK50 screw. This detail will also accept the grounding stud used with transformers. Additional threaded inserts can also be added in the field by the utility at the time of pole installation should they be required.
- Can we mount transformer racks directly to the pole?
Because steel poles are round and approximately the same diameter as their wood counterparts, any transformers currently mounted on wood poles should be able to be mounted on steel.
- What precautions are required for installing steel poles during "hot insert" applications?
The same safety procedures and precautions currently being used for wood poles should be used for steel poles in this type of application. Steel poles are conductive and wood poles are generally considered to be conductive during hot line insertion.
- Do you need to guy steel poles; and if so, how do you guy them?
Steel distribution poles would need to be guyed if the wood pole it is replacing would have been guyed. The steel pole can be guyed just as you would a wood pole using the same hardware. By using a stronger class steel pole, though, it may be possible to eliminate the need for guys altogether.
- Can guy attachments be included on steel poles for attaching guy wires?
Steel poles can be guyed using the same hardware currently used for wood poles. Permanent attachments such as vangs can be welded into the poles for attaching guys but this will increase the delivery times and pole costs. The use of your current hardware and construction standards means no additional changes have to be done to enable a utility to start using steel distribution poles. Valmont-Newmark is happy to work with you regarding any specific hardware questions you may have.
- What precautions are required for handling galvanized steel poles?
The preferred method of lifting the poles is to use nylon slings. While a galvanized pole is very tough and abrasion resistant, it is not recommended that chains be used when handling them. During storage in the material yard blocking should be used to keep the poles off the ground and to separate each layer just as you currently are doing with your wood poles.
- Are name plates provided on the poles, and will utilities have problems with tagging the poles with the present lettering systems available?
A tag is attached to the pole with the manufacturers name, pole height and class stamped on it. If the utility wishes to tag the poles with other information they can easily add a tag using self-tapping screws, pop rivets or adhesives.
- How many holes do steel poles come with as a standard?
There is no standard, for the number of holes in a Valmont-Newmark pole. The utility may specify the number and location of holes they would like and Valmont-Newmark will provide them at the time of fabrication. Additional holes can also be easily drilled in the field should they be required.
- How difficult is it to drill holes in steel poles in the field?
Holes can easily be drilled using either a hole saw or stepped "Christmas Tree" style of bit. The rotabroach works best since it requires less force or energy to drill a hole. Twist drill bits are not as easy to use since they use more energy to drill a hole. Drill speed should be limited to about 300 rpm or less.
- Does Valmont-Newmark offer protective coatings for the embedded section? Under what conditions would you recommend this coating?
Valmont-Newmark offers a 100% solids polyurethane coating for below grade protection when it is required. This product replaces the traditional coal tar epoxies and has been successfully used in the transmission industry. The need for below grade protection needs to be determined by the utility as it depends on a number of factors such as how well drained the soil is, and the corrosion potential in the soil. Experience with galvanized ground rods, lighting poles, or transmission/substation structures in the area can be helpful in determining coating requirements.
- Does Valmont-Newmark recommend field application of Shrink-wrap for below grade protection?
Valmont-Newmark does not recommend shrink wrap as a barrier coating due to the possibility of water wicking into the gaps be-tween the wrap and the pole. Valmont-Newmark offers two factory applied barrier coatings for below grade protection. First is a spray-on polyurethane coating, discussed in item 14. The other is a steel ground sleeve.
- What finishes are available?
A variety of finishes are available with steel, including galvanized, paint over galvanized (powder coat or liquid), dulled and darkened galvanizing and weathering steel. Below-grade coatings are available for direct embedded poles. Click here for additional coatings information.
- Our standard practice for deadending 3 phase construction is to deadend the outer phases on the arm and the center phase on the pole. When we do this we take advantage of the insulating properties of the wood. What happens when we go to a steel pole, do we have to go to larger insulators?
In short, if your desired BIL or critical flashover voltage calculations include the insulating properties of the wood pole, then the results will be different with a steel pole. The differences can either be overcome by using different hardware (i.e. larger insulators, bigger air gap, fiberglass material change) or by evaluating the BIL of the steel installation and how it supports your overall reliability goals. We are happy to work with you regarding your particular construction approach and how it might affect overall system performance.
- In the western U.S. there is a great deal of emphasis and effort on raptor protection. Will the use of steel poles pose a threat to raptors?
Utilities that are concerned with electrocution of raptors, or birds of prey, have modified their distribution configuration to minimize the threat to these birds. Typically, this modification on 3-phase construction consist of dropping the crossarm, with the outside phases, 43". This same construction can be used with steel poles. In addition, it may be necessary to field apply a layer of heat shrink wrap just above the crossarm to prevent the possibility of a phase to ground contact. In the case of single phase construction where a bird may sit on top of the pole, Valmont-Newmark can supply a special pole top cap to prevent the bird from coming in contact with the pole.
- What advantages would we as a utility have in purchasing our steel poles from Valmont-Newmark instead of your competitor?
Valmont-Newmark has been in business for over 50 years and has been providing steel poles to the utility industry for more than 28 years. Our engineers are very familiar with industry requirements and are active in several industry organizations such as IEEE and ASCE. Valmont-Newmark has been manufacturing poles similar to the distribution poles for more than 30 years and has supplied several million of them throughout North America. Our multiple manufacturing locations means short delivery times and has resulted in an excellent "on-time" shipping record. We have a network of manufacturer representatives who are local and can answer any questions concerning the product or reply promptly to any concerns the utility may have regarding the product. We constantly invest in new equipment, so we have the latest technology for galvanizing or painting of the poles.
- How do we climb these poles when we have to?
Valmont-Newmark can provide an optional removable climbing safety step which fits into holes in the pole.
- Does Valmont-Newmark coat the inside of the poles with galvanizing or paint?
During the galvanizing process the entire pole is immersed in the bath of molten zinc. Because the pole is immersed in both the cleaning solutions, flux and zinc, the inside surface is adequately cleaned and a good layer of zinc bonds to the pole. This process protects the pole inside and out. On painted poles, only the outside of the pole can be painted. Due to their small size there is no way to mechanically clean the inside of the pole adequately for the paint to bond to the surface. This is why non-galvanized painted steel poles need to be sealed, to prevent moisture from reaching the interior surface and causing corrosion. If paint over galvanizing is specified there is no need to be concerned about the interior as the zinc will provide protection.
- How does the utility determine which class steel poles to use in place of a wood pole?
Since the steel poles are designed to be equivalent to wood poles, they can generally be used on a one for one basis.
- What is the weight of steel poles in comparison to wood poles?
Steel poles weigh 1/3 to 1/2 less than comparable wood poles. (See comparison chart in the technical data section.)
- What prevents a steel pole from sinking into the soil after it has been set in the ground?
All poles come with a welded-on bearing plate to prevent the poles from settling into the soil when a vertical load is applied. This bearing plate is sized to be similar to provide the equipment bearing pressure of an equivalent wood pole.
- What is the maximum weight the steps can handle?
Testing was performed using non-combination loads to determine the ultimate static load capacity for the step. The point load was applied to test specimens at differing locations and directions with the following results:
Load Location
Adjacent to shaft
End of bolt shank
End of bolt shank |
Load Location
Vertical
Vertical
Lateral |
Ultimate Capacity
5000 lbs.
2000 lbs.
5000 lbs. |
- How does the utility order these poles and specify any options?
See the beginning of the quick reference section catalog of Valmont-Newmark's technical binder for ordering options and how to specify poles.
- We presently are using the fiberglass crossarms on our wood construction, will we still be able to use these arms with steel poles?
Typically, all the hardware you are now using will fit on a steel pole also.
- Will we need to purchase different bolts, washers, etc., in order to use steel poles?
The same hardware currently being used for your wood poles should work with steel poles because they are round and of approximately the same diameter.
- What is the delivery lead-time for steel poles?
Because Valmont-Newmark has several manufacturing locations, standard poles can be shipped quickly after receipt of an order. This time may be reduced for emergency situations, or in stocking programs.
- How thick is the pole wall?
Most poles are made from 11 gauge material (0.1196"). Some of the taller poles require 10, 7, or 5 gauge material (0.1345", 0.1793", 0.2092"). See Valmont-Newmark's Distribution Pole Chart in the quick reference section for actual thickness by pole size.
- Will there be a problem with crushing the pole wall due to over tightening of the bolts?
Although it may be possible if excessive force is used, Valmont-Newmark is not aware of this problem occurring when standard practices are followed. This includes using 4" square washers under the heads or nuts of the bolts. Also, since steel poles are dimensionally stable, and don't shrink like wood poles, there is no need to overtighten the hardware anyway. We recommend using a turn of the nut method to attach hardware.
- How many poles come on a truck load?
The number varies depending on the size of the pole. See Valmont-Newmark's Distribution Pole Chart for the truckload quantity for each pole size.
- Does Valmont-Newmark use any special dunnage to separate the poles?
Valmont-Newmark uses wood dunnage between poles to prevent them from rubbing together during shipment and damaging the finish. At your request, we can bundle the poles so they are easily lifted and moved in a group. This eliminates the need to pick each pole up separately, as in wood construction.
- Typical wood construction uses gains between the pole and the arm, is this required for steel poles?
Most utilities who are using steel poles still put a gain between the arm and the pole. The gain provides a good flat surface to mount the arm to and due to its curved surface also provides good bearing surface to the pole. It keeps the arm from rocking on the pole. We know of utilities who have not installed gains. Utilities can use either the standard gain used on wood poles or have switched to a plastic gain which has a smooth surface both against the pole and the arm. Increasingly, braceless construction is being used where the crossarm has it's own gain base. Judging by our customers responses, these crossarms work very well on steel poles.
- Are two piece poles available for use in areas inaccessible by trucks or other equipment?
Yes, two piece poles are available. The two piece pole utilizes a slip fit connection, similar to that used in transmission pole applications.
- Is twisting or turning of a pole a problem?
Normally twisting or turning of a steel pole is not a problem. However, should a utility feel it could occur for their application the utility could easily drill a couple of holes in the base and attach either bolts or other equipment to prevent this from occurring.
