[TowerTalk] Inspecting tower sections

Mark L. n1lo@hotmail.com
Mon, 06 Dec 1999 14:07:18 GMT


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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