Lightning Protection for Tall Buildings - Mandatory?

[Aaron407]

Hi everybody,

I'm not sure if this is the right group to post this in (correct me if
it's not), but I could really use some help. I'm an electrical engineer
looking into lightning protection for buildings, but in my search I
have found the information to be quite ambiguous as to whether
lightning protection is actually mandatory or not. I am looking at a
possible install on a mill building about 150' tall at a potash mine
here in Saskatchewan, Canada.

Could anyone direct me to any resources (American or Canadian) which
state cut and dried if/when lightning protection is mandatory? I have
looked through the CAN/CSA-B72-M87 and NFPA 780, but both avoid
explicitly saying anything along the lines of "lightning protection is
not mandatory, but highly recommended...". They use terms at the
beginning like 'required', but continue with words such as
'recommended' and 'should', which have confused me to this point.

Can anyone enlighten me? It would be greatly appreciated.

Thanks.

-407

 

[Michael A. Terrell]

Hi everybody,

I'm not sure if this is the right group to post this in (correct me if
it's not), but I could really use some help. I'm an electrical engineer
looking into lightning protection for buildings, but in my search I
have found the information to be quite ambiguous as to whether
lightning protection is actually mandatory or not. I am looking at a
possible install on a mill building about 150' tall at a potash mine
here in Saskatchewan, Canada.

Could anyone direct me to any resources (American or Canadian) which
state cut and dried if/when lightning protection is mandatory? I have
looked through the CAN/CSA-B72-M87 and NFPA 780, but both avoid
explicitly saying anything along the lines of "lightning protection is
not mandatory, but highly recommended...". They use terms at the
beginning like 'required', but continue with words such as
'recommended' and 'should', which have confused me to this point.

Can anyone enlighten me? It would be greatly appreciated.

Thanks.

-407

I would check with the local government's building & zoning people.
They are the people you have to satisfy, anyway.

is a group that deals more in the
power distribution side of EE.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Rich Grise]

Hi everybody,

I'm not sure if this is the right group to post this in (correct me if
it's not), but I could really use some help. I'm an electrical engineer
looking into lightning protection for buildings, but in my search I have
found the information to be quite ambiguous as to whether lightning
protection is actually mandatory or not. I am looking at a possible
install on a mill building about 150' tall at a potash mine here in
Saskatchewan, Canada.

Could anyone direct me to any resources (American or Canadian) which state
cut and dried if/when lightning protection is mandatory? I have looked
through the CAN/CSA-B72-M87 and NFPA 780, but both avoid explicitly saying
anything along the lines of "lightning protection is not mandatory, but
highly recommended...". They use terms at the beginning like 'required',
but continue with words such as 'recommended' and 'should', which have
confused me to this point.

Can anyone enlighten me? It would be greatly appreciated.

Whether it's mandatory or not is irrelevant. Do it anyway. Just put some
sharp spikes on the roof, and then either bond them to the steel frame
or to some heavy cable to a good ground.

The reason for the lightning rods isn't to absorb a strike - it's to
dissipate the charge above the building before it builds up enough
to cause a strike; that's why you use pointy ends - the corona drains
off the charge, at least right above your structure.

Good Luck!
Rich

 

[Howard Eisenhauer]

Building lightning protection requirements vary by province, each with
their own idea of which department is responsible. Could be part of
the electrical, fire, building codes, or something else completely.
I'd suggest contacting one of the companies doing rooftop antenna
installations such as Radian or Westower & ask them who does the
inspections on the lightning protection systems they install, that
should point you in the right direction. If you don't have experience
with these systems I'd seroiusly suggest farming it out to someone who
does, for supposedly simple systems theres a lot of little "gotchas"
in there.

H.

 

[jasen]

Whether it's mandatory or not is irrelevant. Do it anyway. Just put some
sharp spikes on the roof, and then either bond them to the steel frame
or to some heavy cable to a good ground.

The reason for the lightning rods isn't to absorb a strike - it's to
dissipate the charge above the building before it builds up enough
to cause a strike; that's why you use pointy ends - the corona drains
off the charge, at least right above your structure.

that sounds like a load of crap to me.

If you put ions into the air above a structure that'll attract lightning
in much the same way as making it taller would.

Bye.
Jasen

 

[Rene Tschaggelar]

Hi everybody,

I'm not sure if this is the right group to post this in (correct me if
it's not), but I could really use some help. I'm an electrical engineer
looking into lightning protection for buildings, but in my search I
have found the information to be quite ambiguous as to whether
lightning protection is actually mandatory or not. I am looking at a
possible install on a mill building about 150' tall at a potash mine
here in Saskatchewan, Canada.

Could anyone direct me to any resources (American or Canadian) which
state cut and dried if/when lightning protection is mandatory? I have
looked through the CAN/CSA-B72-M87 and NFPA 780, but both avoid
explicitly saying anything along the lines of "lightning protection is
not mandatory, but highly recommended...". They use terms at the
beginning like 'required', but continue with words such as
'recommended' and 'should', which have confused me to this point.

Can anyone enlighten me? It would be greatly appreciated.

Beside mandatory or not, there could be the case when
an insurance refuses to pay if not installed...

Rene

 

[Rich Grise]

that sounds like a load of crap to me.

If you put ions into the air above a structure that'll attract lightning
in much the same way as making it taller would.

Well, I'll be. According to howstuffworks.com, you're right. It doesn't
dissipate the charge, it just diverts the stroke so it doesn't burn the
house down.

If you learn something new every day, does that mean I can go back to bed
now? ;-)

Thanks!
RIch

 

[[email protected]]

Well, I'll be. According to howstuffworks.com, you're right. It doesn't
dissipate the charge, it just diverts the stroke so it doesn't burn the
house down.

If you learn something new every day, does that mean I can go back to bed
now? ;-)

Thanks!
RIch

I inspected some toll booths at exit 99 on I-75 in Florida. They were
planning on these little boxes getting hit with people in them. The
biggest thing they did was be sure it was a great grounding system.and
all the metal was bonded to it.

 

[Michael A. Terrell]

I inspected some toll booths at exit 99 on I-75 in Florida. They were
planning on these little boxes getting hit with people in them. The
biggest thing they did was be sure it was a great grounding system.and
all the metal was bonded to it.

Yes, lightning loves all kinds buildings here in Florida. It hit one
of those old fashioned concrete awnings that was built in a restaurant
parking lot for the car hops to stay dry. It also hit the corner of the
main building, and the small STL tower in the parking lot and two C-band
sat dishes where I lost all the LNAs and the CARS (STL) transmitter.

It vaporized the rebar and the large threaded rods that held the roof
panels on the concrete columns. It exploded damp concrete in both
structures which went through the various breaker boxes and electronics
while destroying almost everything electrical, after some of the old
building grounds failed.

It was in Leesburg, and was the original studio and offices of WACX
TV, Ch 55. It took weeks to repair all the damage, but I managed to
have the phones and lights working an hour after the office opened, then
got on the phones to arrange for rental equipment to keep the station on
the air.

I replaced the entire ground system, and redid all the cabling into
bonded steel conduit. It cost a wad of money, and we were self insured.

On top of that it was my first day as the only engineer on staff.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[[email protected]]

It vaporized the rebar and the large threaded rods that held the roof
panels on the concrete columns. It exploded damp concrete in both
structures which went through the various breaker boxes and electronics
while destroying almost everything electrical, after some of the old
building grounds failed.

This stuff happens when the bonding/grounding is not secure. If you
give the lightning a clean path to ground, that is where it goes. I
bet they did not have all that rebar tied together and it was just
stuck in the wet mud at the top of the columns.
At MM99 we probably had close to a half mile of 1/0 copper ground ring
along with a bunch of 40' rods around the ring and Ufers on all the
buildings, tied to the steel in the roadbed and duct banks. Any
significant chunk of metal was bonded along with the normal bonding of
"building steel". They did ground testing on every rod and they shot
so many CadWelds it was like the 4th of July for a week around there.
There were no clamps used on any buried ground connection in the
concrete or underground
I was surprised at all the engineering that goes into a toll booth and
the systems they use. For one thing there is 5 tons of "fresh air
makeup" A/C blowing into the booths pulling air from the woods behind
the service building. It keeps the CO down in the booth. The duct
banks for the electrical, computer and control systems are about 8
feet down to protect them from the traffic. I really didn't have much
to look at as an electrical inspector since everything was supervised
by an engineer and inspected by about 3 other guys before I saw it.
Things were so far above and beyond the NEC it was just a sight seeing
trip.

 

[Michael A. Terrell]

This stuff happens when the bonding/grounding is not secure. If you
give the lightning a clean path to ground, that is where it goes. I
bet they did not have all that rebar tied together and it was just
stuck in the wet mud at the top of the columns.
At MM99 we probably had close to a half mile of 1/0 copper ground ring
along with a bunch of 40' rods around the ring and Ufers on all the
buildings, tied to the steel in the roadbed and duct banks. Any
significant chunk of metal was bonded along with the normal bonding of
"building steel". They did ground testing on every rod and they shot
so many CadWelds it was like the 4th of July for a week around there.
There were no clamps used on any buried ground connection in the
concrete or underground
I was surprised at all the engineering that goes into a toll booth and
the systems they use. For one thing there is 5 tons of "fresh air
makeup" A/C blowing into the booths pulling air from the woods behind
the service building. It keeps the CO down in the booth. The duct
banks for the electrical, computer and control systems are about 8
feet down to protect them from the traffic. I really didn't have much
to look at as an electrical inspector since everything was supervised
by an engineer and inspected by about 3 other guys before I saw it.
Things were so far above and beyond the NEC it was just a sight seeing
trip.

The building was an old restaurant, converted into the studios and
offices of a low power UHF TV station. it all happened before I was
hired, and from the look of things it had survived several previous
strikes without damage, but it appeared that there were multiple strikes
that morning and there wasn't time for the copper bonding to cool down
between strikes. That was in 1988, and as far as I know, there has been
no new damage since then. The studio and control room was bonded with
1/8" * four inch copper, but the multiple power panels were not well
bonded, so the ground potential flowed though them and melted them. The
main grounding was at the tower and sat dishes. They survived, but the
older parts didn't. They were about 40 years old at the time, and
probably not up to code for new work. Just a couple miles away WLBE's
towers sit in a swamp and get multiple strikes on a regular basis. The
engineer has had to replace the conduits to the towers several times
because there was so much crap fused to the walls that they couldn't
replace the wires, again. When I lived in lake County I could see the
lightning heading for the towers, then it would split and hit all of
them. Sometimes the strikes were just seconds apart. On the other hand,
the new WACX tower in Orange City is 1749 feet of steel that has been
hit, but hadn't suffered any damage that I know of. It was over a
million dollars to build and it gets annual maintenance where bolts are
inspected and replaced, as needed. There is a freight elevator to the
top, but I never had the two hours needed to go up, and back down while
I was there doing weekly transmitter maintenance.

They had just installed equipment from Innovative Technology
http://www.itvss.com/ to protect the electrical and data systems at all
four sites when I left the station to build Ch 58 in Destin, Florida.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[joseph2k]

This stuff happens when the bonding/grounding is not secure. If you
give the lightning a clean path to ground, that is where it goes. I
bet they did not have all that rebar tied together and it was just
stuck in the wet mud at the top of the columns.
At MM99 we probably had close to a half mile of 1/0 copper ground ring
along with a bunch of 40' rods around the ring and Ufers on all the
buildings, tied to the steel in the roadbed and duct banks. Any
significant chunk of metal was bonded along with the normal bonding of
"building steel". They did ground testing on every rod and they shot
so many CadWelds it was like the 4th of July for a week around there.
There were no clamps used on any buried ground connection in the
concrete or underground
I was surprised at all the engineering that goes into a toll booth and
the systems they use. For one thing there is 5 tons of "fresh air
makeup" A/C blowing into the booths pulling air from the woods behind
the service building. It keeps the CO down in the booth. The duct
banks for the electrical, computer and control systems are about 8
feet down to protect them from the traffic. I really didn't have much
to look at as an electrical inspector since everything was supervised
by an engineer and inspected by about 3 other guys before I saw it.
Things were so far above and beyond the NEC it was just a sight seeing
trip.

Maybe it was above the NEC at the time, you should see the changes between
1999 and 2002 editions on grounding and bonding, and ampacity.

 

[joseph2k]

Beside mandatory or not, there could be the case when
an insurance refuses to pay if not installed...

Rene

Actual legal requirements do vary some from jurisdiction to jurisdiction.
Complying with the requirements in NFPA 70, ANSI/IEEE C2 and similar is
often required to buy affordable insurance. I do not have my reference
list with me.