Surge Protection Devices in Hospitals

[Shujinko]

I have a project renovation to an existing lab in a hospital in Florida. There are several units of HVAC equipment located on the roof. I am electrically feeding these branch circuits from panels located in a mechanical room adjacent to the roof area. However, looking at the Florida Building Code (FBC) requirement for hospitals each branch circuit entering or exiting the structure requires a surge protection device (SPD). The HVAC equipment circuits are either 120V/1ph or 480V/3ph. What would be the best product to use for these SPDs at each location where the circuits enter/exit the building? How would this be wired? Via a disconnect? Thanks.

FBC 449.3.15.6
All low-voltage system main or branch circuits entering or exiting the structure shall have surge suppressors installed for each pair of conductors and shall have visual indication for protector failure to the maximum extent feasible.

 

[Brian_ZSI]

Surge Protection Devices in Hospitals

What would be the best product to use for these SPDs at each location

You are going to have every single SPD manufacturer telling you different stories of which product is better, but calling sales, asking questions, then comparing is highly suggested.

Might I suggest reading the Wiki? https://en.wikipedia.org/wiki/Surge_protector

 

[kwired]

I say look into the intentions of the requirement a little harder.

If they literally mean every penetration of wiring to the exterior side then you should be installing surge protectors on all exterior luminaires, signs, receptacles, exhaust fans, etc.

Is possible the intention is for circuits that actually go to separate structures?

IMO surge protection on a roof top mounted unit doesn't accomplish much. If it gets struck by lightning - so what? Chances are the lightning doesn't even do anything to the unit internally - it probably follows the frame and gets into other objects that are either bonded or in close enough proximity to arc over to. Properly installed lightning protection systems would be much more worth the efforts.

 

[steve66]

I say look into the intentions of the requirement a little harder.

If they literally mean every penetration of wiring to the exterior side then you should be installing surge protectors on all exterior luminaires, signs, receptacles, exhaust fans, etc.

Is possible the intention is for circuits that actually go to separate structures?

IMO surge protection on a roof top mounted unit doesn't accomplish much. If it gets struck by lightning - so what? Chances are the lightning doesn't even do anything to the unit internally - it probably follows the frame and gets into other objects that are either bonded or in close enough proximity to arc over to. Properly installed lightning protection systems would be much more worth the efforts.

I assume they mean one suppressor for each branch circuit or feeder that enters or leaves the building. Not one at every point where the wiring enters or leaves.

But who knows. Florida is the lighting capital. If I remember right, Tampa was a native word for lightning.

Anyhow, that the problem with local rules - they are usually not written very well.

 

[mgookin]

I have a project renovation to an existing lab in a hospital in Florida. There are several units of HVAC equipment located on the roof. I am electrically feeding these branch circuits from panels located in a mechanical room adjacent to the roof area. However, looking at the Florida Building Code (FBC) requirement for hospitals each branch circuit entering or exiting the structure requires a surge protection device (SPD). The HVAC equipment circuits are either 120V/1ph or 480V/3ph. What would be the best product to use for these SPDs at each location where the circuits enter/exit the building? How would this be wired? Via a disconnect? Thanks.

FBC 449.3.15.6
All low-voltage system main or branch circuits entering or exiting the structure shall have surge suppressors installed for each pair of conductors and shall have visual indication for protector failure to the maximum extent feasible.

I just went through and read the code (as I see you have cited verbatim). Two things I take issue with are "...for each pair of conductors..." and "...to the maximum extent feasible."

Show me a pair when you have a 3p delta??? So let's just assume you need protection on all conductors.

As to max extent feasible, that's as open ended as could be. If you put 5,000 SPD's on that circuit someone could argue you could have had 5,001. So let's look at the objective. They want to protect life and property and they want the facility to continue running because it's an essential facility.

Are you doing the lightning protection for this project? If not, can that engineer assist you with meeting your requirement? He's certainly a qualified expert in mitigating "too much energy".

 

[gadfly56]

Does that modifier "All low-voltage system" actually refer to fire alarm circuits and such?

 

[kwired]

I assume they mean one suppressor for each branch circuit or feeder that enters or leaves the building. Not one at every point where the wiring enters or leaves.

But who knows. Florida is the lighting capital. If I remember right, Tampa was a native word for lightning.

Anyhow, that the problem with local rules - they are usually not written very well.

So is a rooftop HVAC unit considered to be leaving the building? Or is it just an accessory/part of the building that happens to be on one of the exterior surfaces of the building? If the HAVC system were actually in a separate, able to stand alone, building/structure might it be treated differently?

 

[steve66]

So is a rooftop HVAC unit considered to be leaving the building? Or is it just an accessory/part of the building that happens to be on one of the exterior surfaces of the building? If the HAVC system were actually in a separate, able to stand alone, building/structure might it be treated differently?

I'd say the walls and roof and floor define the building, so any of the above is considered leaving the building (although I'm not really sure how any of that is any different than a metal covered penthouse, which seems like it would still be inside the building?).

But don't ask me - ask Florida.

 

[kwired]

I'd say the walls and roof and floor define the building, so any of the above is considered leaving the building (although I'm not really sure how any of that is any different than a metal covered penthouse, which seems like it would still be inside the building?).

But don't ask me - ask Florida.

So if that is "leaving the building" then isn't exterior lights, exterior receptacles, maybe an exhaust fan or items of the nature of those I just mentioned also "leaving the building"?

I don't see the need to require surge protection on any of those mentioned items, and have to say it is either a stupid requirement, is poorly written, is misunderstood, or a little of each.

 

[steve66]

So if that is "leaving the building" then isn't exterior lights, exterior receptacles, maybe an exhaust fan or items of the nature of those I just mentioned also "leaving the building"?

I don't see the need to require surge protection on any of those mentioned items, and have to say it is either a stupid requirement, is poorly written, is misunderstood, or a little of each.

Yes, its poorly written, but you are reading something into the requirement that simply isn't there. Here it is again:

FBC 449.3.15.6
 All low-voltage system main or branch circuits entering or exiting the structure shall have surge suppressors installed for each pair of conductors and shall have visual indication for protector failure to the maximum extent feasible.

It says each main or branch circuit shall have surge suppressors for each pair of conductors. Nowhere does it say surge suppression is required every time a circuit enters or leaves a building.

 

[kwired]

Yes, its poorly written, but you are reading something into the requirement that simply isn't there. Here it is again:

FBC 449.3.15.6
 All low-voltage system main or branch circuits entering or exiting the structure shall have surge suppressors installed for each pair of conductors and shall have visual indication for protector failure to the maximum extent feasible.

It says each main or branch circuit shall have surge suppressors for each pair of conductors. Nowhere does it say surge suppression is required every time a circuit enters or leaves a building.

Still poorly written. Which two conductors (pair) should we provide surge suppression to on a three phase three wire circuit?

My guess is this is still mostly about lightning and I think it is pointless to do this for a rooftop HVAC unit. A better investment is properly designed and installed lightning protection system for the entire building - to which the HVAC unit very well may have a bonding conductor run to the system.

 

[Jennifer Aldrich]

Hospital Exterior Load Surge Protection for the circuits

Hospital Exterior Load Surge Protection for the circuits

Still poorly written. Which two conductors (pair) should we provide surge suppression to on a three phase three wire circuit?

My guess is this is still mostly about lightning and I think it is pointless to do this for a rooftop HVAC unit. A better investment is properly designed and installed lightning protection system for the entire building - to which the HVAC unit very well may have a bonding conductor run to the system.

Agreed! The FBC verbiage is unclear, but we have been using PQ Protection brand SPD's for this specific application on many Florida Hospitals. You can choice your voltage configuration, number of circuits and AWG wiring to build the product you need. IT's also UL 1449 listed which is another thing that AHCA requires.

 

[steve66]

Still poorly written. Which two conductors (pair) should we provide surge suppression to on a three phase three wire circuit?

My guess is this is still mostly about lightning and I think it is pointless to do this for a rooftop HVAC unit. A better investment is properly designed and installed lightning protection system for the entire building - to which the HVAC unit very well may have a bonding conductor run to the system.

Yes, its about lightning. But I don't see why its pointless to do for a RTU. Even with lighting protection, I would still provide surge protection to take care of any inducted currents.

 

[kwired]

If every circuit entering or leaving the structure needs a surge protector, then not only will roof top HVAC units need it, so will every outside luminaire, receptacle, signs, etc. I also don't like how they say every "pair" some circuits contain more then a "pair" of conductors.

 

[steve66]

If every circuit entering or leaving the structure needs a surge protector, then not only will roof top HVAC units need it, so will every outside luminaire, receptacle, signs, etc. I also don't like how they say every "pair" some circuits contain more then a "pair" of conductors.

You are still reading something into the requirement that isn't there.

It says every circuit shall have surge protection if the circuit enters or leaves the building. It does not say the circuit needs surge protection every time it enters or leaves the building. I don't think you have to put 5 surge suppressors on a circuit just because the circuit exits the building at 5 different lights. You put one suppressor on the circuit, probably at the source, or the first time it leaves the building.

I also don't see your issue with every "pair". That's standard for surge suppressors. Yes, some circuits have more than a pair. Take a 3 phase circuit with neutral and ground. It would require modules to suppress L-N, L-G, L-L and N-G surges. Its basically one suppressor with 10 surge suppression modules installed.

 

[kwired]

You are still reading something into the requirement that isn't there.

It says every circuit shall have surge protection if the circuit enters or leaves the building. It does not say the circuit needs surge protection every time it enters or leaves the building. I don't think you have to put 5 surge suppressors on a circuit just because the circuit exits the building at 5 different lights. You put one suppressor on the circuit, probably at the source, or the first time it leaves the building.

I also don't see your issue with every "pair". That's standard for surge suppressors. Yes, some circuits have more than a pair. Take a 3 phase circuit with neutral and ground. It would require modules to suppress L-N, L-G, L-L and N-G surges. Its basically one suppressor with 10 surge suppression modules installed.

I maybe failed to see that it is a Florida building code, possibly the lightning capital of the US, otherwise sure seems overkill for around here.

 

[mgookin]

I maybe failed to see that it is a Florida building code, possibly the lightning capital of the US, otherwise sure seems overkill for around here.

We get lotsa lightning!

Florida Power & Light has a lightning simulator at HQ in Juno Beach to blow stuff up and see which device or design is most durable. I've been there and it's fun!

www.fpl.com/lightninglab