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Masts, poles and sign gantries
Materials / coatings used in the utility pole
market – summary of a 2006 survey
The following summary of the different
materials used, was taken from a report
produced in 2006 of the Utility Pole
Market.
Photo 1: Without the correct treatment
timber light poles can rot at the base.
Lighting poles
The market estimate for steel lighting
poles in 2006 was about 4 000 tpa.
However, it was expected that substantial
growth in this market (mainly
infrastructural (township) development
and replacement – accidents,
corrosion, etc.) was likely to occur.
Competitor materials are wood,
concrete and fibreglass. Over 70% of
the steel poles are of standard length.
Market control is via the tender system
with 90% of the municipalities
specifying steel. Most steel poles are
hot dip galvanized and then solution
painted or powder-coated for use in
aggressive conditions. Current
specification control is either local
municipality or SABS 0225.
For the total market it is estimated
that steel represents 64%, concrete
18%, fibreglass 18%. Further
information is available from the
Institute of Lighting Engineers.
Discussions with specifiers/users and
fabricators indicated that the following
material issues were important.
Wood
◆ Municipalities only really use wood if
they have a lot of it currently in stock.
◆ Wood has to be treated and bitumen
is applied at the base, to prevent rot.
See photo 1.
◆ Problem with cable access (need to
cut a groove or strap a conduit).
◆ Need to cut a housing.
◆ Life considered good.
◆ Good structural reliability (often
reused).
◆ Slightly cheaper than steel.
◆ Easy to transport, but heavier than
steel.
◆ Problems are with attachments
(outreach arms, etc), which tend to be
made of hot dip galvanized steel.
Photo 2: Outreach arms are usually hot dip
galvanized steel. Care should be taken that
fasteners also be hot dip galvanized for long
term corrosion control.
Photo 3: GRP light post with stainless steel
sleeve.
Photo 4: GRP light post where outer fibres
have been exposed in the premature
breakdown of the pole.
Photo 5: Outreach arms on concrete poles are
usually hot dip galvanized steel. Ensure all
fasteners are hot dip galvanized and not zinc
electroplated for long maintenance free life.
Photo 6: Cables are attached to the outside
faces of the concrete pole, limiting its
aesthetical appeal.
Photo 7: Concrete poles often need outside
junction boxes to accommodate incoming
cables.
24 Hot Dip Galvanizing Today Volume 4 Issue 3 2007