cell tower on building concerns

[malachi constant]

Hi all,

I've been asked by a client to review plans for installation of cellular utility equipment on their existing building. The facility is mainly an office environment, no elevated security or data protection concerns, other than the organization's campus data center is located within.

The scope of my review is limited to how the installation will affect their existing electrical and communication systems. The scope of the new installation is four antennaes ranging from roughly 4' to 8' in height, plus equipment pad, utility transformer feed, etc. The installation does not penetrate into the building or connect to the building's electrical system.

I have some (limited) experience with cell equipment. Enough to know that I expect my review to basically say "this isn't a big deal" - especially now that I have the utility's plans in hand that show the equipment being fed from the utility, not eating up distribution space. And this equipment is tiny compared to what I've seen and dealt with on other facilities.

Can you think of anything I should be concerned about regarding electrical systems? Lighting protection, grounding... Is there a potential for the cell frequencies to affect existing equipment? No one is expecting a lengthy report from me but I figured I could at least get a paragraph or two in about distribution loading...looks like that is irrelevant now...

Thanks!

 

[ActionDave]

Your right, it shouldn't be a problem. The only thing we had to do different for cell sites on buildings was use chemical ground rods to meet cell company specs.

 

[Sahib]

You need to see to it that a lightning current from the tower does not find an easier path through their campus data center.

 

[ron]

Do you need to evaluate possible EMI interference? That would be a tough one to have definitive results.

 

[mgookin]

Hi all,

I've been asked by a client to review plans for installation of cellular utility equipment on their existing building. The facility is mainly an office environment, no elevated security or data protection concerns, other than the organization's campus data center is located within.

The scope of my review is limited to how the installation will affect their existing electrical and communication systems. The scope of the new installation is four antennaes ranging from roughly 4' to 8' in height, plus equipment pad, utility transformer feed, etc. The installation does not penetrate into the building or connect to the building's electrical system.

I have some (limited) experience with cell equipment. Enough to know that I expect my review to basically say "this isn't a big deal" - especially now that I have the utility's plans in hand that show the equipment being fed from the utility, not eating up distribution space. And this equipment is tiny compared to what I've seen and dealt with on other facilities.

Can you think of anything I should be concerned about regarding electrical systems? Lighting protection, grounding... Is there a potential for the cell frequencies to affect existing equipment? No one is expecting a lengthy report from me but I figured I could at least get a paragraph or two in about distribution loading...looks like that is irrelevant now...

Thanks!

I'd suggest a contract clause that any adverse effect on existing electrical, data and communications systems shall be abated at the expense of the tenant. Sort of a FCC Part 15 disclaimer. You never know what might come up. I remember back with the old CRT's my monitor would give me advance notice that my Blackberry had incoming and that's just a handheld unit.
IIRC you're also going to have to post signage at each service indicating "Service 1 of 2. Other service located ..."
And of course all this has to go through structural but it sounds like that's not under your scope of services.

 

[malachi constant]

I'm going to resurrect this thread with some new information. Upon further review of the plans and walking the site the feed from utility transformer to roof equipment DOES pass through the building. I assume I do not need to be overly concerned about communication interference coming back down the feeder into the building, but it does present a lightning path. I am not TOO concerned about that either, as there are already a dozen or so antennas on the roof. What does concern me is in looking at the plans I can't find any grounding called out w/ respect to the new antennas. I see mention of grounding at the roof-mounted equipment platform. I see a spec note that says something to the effect of "contractor shall familiarize themselves with (cellular utility) grounding standard, and provide grounding per grounding details". I think it reasonable to assume this utility has a good understanding of grounding theory (probably better than I do), but that more details should be provided for the installing contractor. If anyone has anything to add to that let me know.

And mgookin - thank you for the clause suggestion. (Thanks to everybody, really.)

 

[ActionDave]

....What does concern me is in looking at the plans I can't find any grounding called out w/ respect to the new antennas. I see mention of grounding at the roof-mounted equipment platform. I see a spec note that says something to the effect of "contractor shall familiarize themselves with (cellular utility) grounding standard, and provide grounding per grounding details". I think it reasonable to assume this utility has a good understanding of grounding theory (probably better than I do), but that more details should be provided for the installing contractor. If anyone has anything to add to that let me know.

And mgookin - thank you for the clause suggestion. (Thanks to everybody, really.)

There's going to be some grounding. Look up Motorola R56. That's the standard.

 

[mgookin]

I'm going to resurrect this thread with some new information. Upon further review of the plans and walking the site the feed from utility transformer to roof equipment DOES pass through the building. I assume I do not need to be overly concerned about communication interference coming back down the feeder into the building, but it does present a lightning path. I am not TOO concerned about that either, as there are already a dozen or so antennas on the roof. What does concern me is in looking at the plans I can't find any grounding called out w/ respect to the new antennas. I see mention of grounding at the roof-mounted equipment platform. I see a spec note that says something to the effect of "contractor shall familiarize themselves with (cellular utility) grounding standard, and provide grounding per grounding details". I think it reasonable to assume this utility has a good understanding of grounding theory (probably better than I do), but that more details should be provided for the installing contractor. If anyone has anything to add to that let me know.

And mgookin - thank you for the clause suggestion. (Thanks to everybody, really.)

An engineer wrote that? Seems pretty lame. In Florida you can reference a code or standard but that reference can not be a substitute for specifics. It's the engineer's job to design per those referenced standards and codes. What he's doing is passing the buck on liability.

You could say you want the grounding plan reviewed, signed and sealed by a professional engineer. You can also require an engineer's certification of substantial completion/ compliance (of the whole job) at the end of the job.

 

[jumper]

There's going to be some grounding. Look up Motorola R56. That's the standard.

You trying to put the guy in a coma. That there doc is dangerous.

 

[don_resqcapt19]

I'm going to resurrect this thread with some new information. Upon further review of the plans and walking the site the feed from utility transformer to roof equipment DOES pass through the building. I assume I do not need to be overly concerned about communication interference coming back down the feeder into the building, but it does present a lightning path. I am not TOO concerned about that either, as there are already a dozen or so antennas on the roof. What does concern me is in looking at the plans I can't find any grounding called out w/ respect to the new antennas. I see mention of grounding at the roof-mounted equipment platform. I see a spec note that says something to the effect of "contractor shall familiarize themselves with (cellular utility) grounding standard, and provide grounding per grounding details". I think it reasonable to assume this utility has a good understanding of grounding theory (probably better than I do), but that more details should be provided for the installing contractor. If anyone has anything to add to that let me know.

And mgookin - thank you for the clause suggestion. (Thanks to everybody, really.)

That will require a service disconnect and OCPD outside the builing or inside nearest the point of entry of the service conductors.

 

[malachi constant]

When googling I found this brilliant suggestion on another site (slashdot):
Have your lawyers write up a separate page of the lease in which the cell-phone company agrees not to use the tower to mind control you, your employees, or your families. Frame it on your office wall next to your college degree.

Back to this project, it does have a service disconnect, and the drawings are prepared by a licensed engineer. I'm making it a point that the construction documents need revised to include more grounding information (details, diagrams, etc).

Thanks all!!

 

[ActionDave]

You trying to put the guy in a coma. That there doc is dangerous.

Reading it is amazing. Seeing it is a whole 'nother kind of wow.