7-2
RedMAX Administration and Maintenance Guide
Redline Communications Inc. Confidential and Proprietary
Lightning Strike
Lightning damage may occur either as a result of a direct lightning strike to the building or
tower or more commonly, as a result of the induced effects of a lightning strike some
distance away. Lightning which strikes kilometres away may cause electrical surges which
travel long distances on power and telecommunications lines.
When preparing a disaster recovery plan for a lightning strike you may first want to look up
the lightning ground-flash density (LGD) of your area. This is the average number of direct
lightning strikes per square kilometre of your area in one year.
The next step is to investigate the geography of your area and use the rules outlined in the
applicable standards to determine what percentage of those strikes to your area are likely
to terminate on your building and what percentage are likely to cause induced surges.
Quantifying the risk will allow you to make an informed decision about the lightning
protection measures which need to be employed at your site.
If you are not able to investigate this issue, consider contacting a lightning protection
company who can provide both a a lightning protection system and a disaster recovery
plan.
No matter how comprehensive your lightning protection system is, your network equipment
may still incur damage from a lightning strike.
Step 1
When it is safe to access the outdoor equipment, you need to inspect all of the outdoor
equipment as outlined in “Verifying Power and RF Signal Cabling” on page 4-6.
Step 2
You will need to compile a list of required replacement equipment. Ideally, the required
replacement items will be among your available spares, possibly reducing network
downtime. See “Planning/Scheduling Equipment Maintenance” on page 2-14.
Wind Damage
In most cell planning designs, your antenna needs to be installed at the highest point in a
given area. However, gusting wind will also be a common occurrence at this same location
and it is therefore, important to take wind loading into consideration.
As with the lightning example above, preparing a disaster recovery plan for wind damage
should start with characterizing the your site exposure to excessive wind. For example a
site located in a coastal area will have increased exposure to wind and corrosion than a
site that is inland.
Wind loading specifications are provided with the antenna. You may want to perform you
own calculations based on your proposed antenna locations.
Another consideration is repetitive strain on antenna mounting hardware and brackets. If
your antenna is subject to constant windy conditions, you will need to check your outdoor
installation regularly and ensure all connections are secure. Additional strain from ice
buildup or sand abrasion will also contribute to metal failure. To avoid failure due to metal
fatigue you may need to replace mounting hardware every few years.
