I have been working on inspection lists for new and used tower sections.
With the recent thread, this seems like a good time to ask for further
comment.
here's what I have so far:
INSPECTING NEW TOWER SECTIONS
When picking up new tower sections from a dealer, inspect each section for
defects before accepting them. Look for:
1) Bent or twisted sections (sight along their length).
2) Deformed or bent ends (6 places).
3) Mis-aligned joint sleeves on Rohn 45 & up (3 places).
4) Welds with cracks or multiple pinholes.
5) Gaps, flakes or separations in the galvanizing.
6) Missing assembly bolts. There should be a plastic tube containing the
assembly bolts stuffed into the bottom of one leg.
7) For Rohn 25 only, to make sure you are not accidentally getting Rohn 20,
verify the presence of 8 horizontal rungs, not 7.
8) Bent braces
9) Improperly drilled bolt holes. The holes should be oriented such that the
bolt's axis points toward the geometric center of the tower cross-section.
As an aside, I have also noticed a number of very sharp slag formations on
the rungs of new Rohn 25 sections. This may not necessarily be a defect as
much as a nuisance. Does this indicate inadequate fluxing or some other
problem with the hot dip process? Someone more in the know please comment.
INSPECTING USED TOWER SECTIONS
Take plenty of time to inspect every inch of used tower sections. Tiny
defects may be hard to spot, but they could still seriously weaken the
tower's structure and ability to carry stresses. Watch out for:
1) Bent or twisted sections (sight along their length).
2) Deformed leg ends that have been flattened out-of-round by
over-tightening the joint bolts. Deformed ends may be accompanied by the
presence of bent horizontal braces adjacent to each end of the section,
where excessive jacking force was required to separate the sections.
3) Elongated or drilled-out bolt holes.
4) Cracks and splits anywhere on the 3 legs of each section. Hairline cracks
caused by trapped, frozen water will be thin and run in the same direction
as the leg.
5) Cracks or multiple pinholes in the welds (inspect every weld).
6) Cut and spliced or bent braces.
7) Legs that you cannot see light through, that are clogged with debris.
8) Rust that is more than light, dusty surface rust. If there are flakes of
rust and a scaly appearance of the metal, it is probably deep enough to
weaken the leg. Use a flashlight to peer inside of each leg for interior
rust.
9) Legs that have been repaired or welded to, other than the original
factory brace and joint-sleeve (on R45 & up) welds. These welds are often
easily identified by surface rust where the galvanizing and the temper have
been destroyed.
please offer your additions, comments, and corrections.
--...MARK_N1LO...--
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