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[TowerTalk] Climbing and working on Rohn 25g/45g towers -

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Subject: [TowerTalk] Climbing and working on Rohn 25g/45g towers -
From: "Richard Elizondo" <>
Date: Sun, 23 Nov 2008 22:43:51 -0600
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Seems there have been several discussions on climbing lately, and since this 
happens to be a subject that I have more then adequate experience in, I 
thought I would share with everyone some of the same info we provide to our 
technicians about the Rohn 25g/45g series towers and fall arrest.

First -  Understanding the difference between fall protection and 

A fall protection/arrest system consists of the following:

A harness with a dorsal (center of back between shoulder blades) D-Ring, and 
means of attachment that can limit the falling force to less than 1800lbs.

The human body can exert several thousand pounds during a fall arrest 
situation. In order to protect the climber most fall arrest lanyards utilize 
a dampener/shock pack to dissipate the fall force to less than 1800lbs. All 
fall protection/arrest lanyards should be double legged/(Y) and be used to 
maintain a 100% attachment to the tower at all times. They should NEVER 
exceed 6' in length.

Positioning devices are used in conjunction with Fall arrest to create a 
working position while on the tower. These are static lanyards and devices 
that do no have shock packs. While in use, these devices should be 
positioned so that a climber can not move more than 18" vertically. As a 
rule of thumb, your primary connection to the tower should always be your 
fall protection, and then your Positioning device.

Now the Numbers:

It is recommended that Fall Protection/Arrest lanyards be anchored to a 
point on tower that can hold 5000 lbs. OSHA claims that the human body 
should not be able to produce more than 5000lbs during a free fall arrest 
with a 6' lanyard.

Positioning devices should be attached in fashion that can hold the weight 
of the climber and rigging with a 10-1 safety factor. (300lbs climber - 3000 
lbs attachment)

Here is the shocking sad truth:

Rohn 25g section shearing strength - 2500lbs (this is the strength of the 
entire section, all three legs and lattice, not just that one leg you may be 
attaching to.

So a Rohn 25g section could fail if a climber falls and the lanyard shock 
pack does not activate, or the climber is using a lanyard without a shock 

Sadly enough the Rohn 45g section is not that much stronger.

Solutions for the Climber:

First and foremost - Never attach to the Z lattice of these towers for any 

Second - Try to use a 3' shock absorbing lanyard for fall protection. The 
reasoning behind this goes back to the numbers. OSHA claims that the human 
body should not be able to produce more than 5000lbs during a free fall 
arrest with a 6' lanyard... so if we limit the fall distance by 1/2 (3' 
instead of 6') the arresting force is also reduced by half. (2500lbs) The 
shorter 3' lanyard also allows you to position the lanyard an arms length 
overhead. By doing this the fall distance is greatly reduced, in many cases 
(depending on body size) to less then 12-18 inches, thusly greatly reducing 
the force to a safe limit for the 25g towers strength. Something to also 
consider, when positioning your fall protection overhead, is the swing zone. 
Should you fall with you lanyard positioned directly overhead (same tower 
face), your dorsal D Ring will pull you forward and swing your upper body 
and head into the tower. For those who do wear hardhats (as you should) this 
should not be a big deal. If however you would like not to have this 
problem, position your lanyard hook overhead and around to another face (to 
your strong side) so that during a fall arrest situation, your shoulder will 
roll onto the tower first and your lead arm either grab the tower or cover 
your face and head.

Third- Never rely on one point of attachment for positioning.  On the 25g 
and 45g tower, it is recommended that the climber choke at least 2 legs with 
a positioning lanyard, to create a solid point of attachment. Another 
recommended procedure is to use two large hooks, one on each side, to 
connect to two different points on the tower. This actually works very well 
and is known as the "gunslinger method" since a climber can attach and 
detach very quickly with this setup.

Working up top - Working on the very top of a 25G/45G tower can provide some 
challenging issues, one of which is positioning. If your harness has a seat, 
do yourself a favor and don't try to use it while at the very top. While 
sitting in the saddle is comfortable, it does not provide enough upper body 
leverage to position or stab a large antenna. Instead use the side D rings 
so that your upper body and arms can be used freely above the tower. When 
attached to the top of this tower, a fall arrest anchorage point also 
becomes an issue. If your work could take some time, use a 4' long choker 
sling to create an attachment point by wrapping it around and choking all 
three legs independently. When used in conjunction with your 3' fall arrest 
lanyard, this setup will create a suitable anchorage point. Also something 
to consider, whenever possible, use a ginpole to help position and hold 
large items over the top of the tower. While it is possible to stack a large 
antenna or even another tower section without a gin pole, using a gin pole 
makes it much easier and safer for the climber.

Richard Elizondo

Senior Consultant

Ionos Communications



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