I have been telling the architect that the utility transformer and the building generator should be physically separated with a fire resistant block wall, but he's fighting me on it. I tell him that it's good design practice so that a non-passive failure of the generator doesn't also take out the entire building's transformer (or visa versa). He's not biting. Is there a regulation that I can cite? What should the min. separation be if there's no block wall?
Utility transformer/ building generator separation
- Thread starter LeslieB
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- Massachusetts
There is a large difference between code minimum and good design.
I don't believe there is any code requirement for physical separation of a utility transformer and a generator.
I am trying to imagine a generator failure that would physically damage items around it or a utility transformer failure that would physically damage a generator.
If we assume a POCO transformer is a potential bomb shouldn't we place them in block walls to protect personal?
Pad mount utility transformers are often placed in public areas.
I don't believe there is any code requirement for physical separation of a utility transformer and a generator.
I am trying to imagine a generator failure that would physically damage items around it or a utility transformer failure that would physically damage a generator.
If we assume a POCO transformer is a potential bomb shouldn't we place them in block walls to protect personal?
Pad mount utility transformers are often placed in public areas.
Thanks both of you. Yes, the generator is an NEC 700 generator, but I was worried more about the potential of explosion taking out other equipment. Are you designers? I was telling the architect we needed 6' min separation and a block wall between the devices.
As far as transformers exploding, it?s a real possibility and it does happen. Here is a news article about one that happened:
http://www.sergi-france.com/html/documents/ffTPoeaa.pdf
Here is an article that talks about how transformer failures are on the rise from an insurer?s perspective:
http://www.rgj.com/news/stories/html/2003/07/29/48134.php?sp1=rgj&sp2=Umbrella&sp3=Umbrella
As far as transformers exploding, it?s a real possibility and it does happen. Here is a news article about one that happened:
http://www.sergi-france.com/html/documents/ffTPoeaa.pdf
Here is an article that talks about how transformer failures are on the rise from an insurer?s perspective:
http://www.rgj.com/news/stories/html/2003/07/29/48134.php?sp1=rgj&sp2=Umbrella&sp3=Umbrella
There are separation requirements for health care generators. I don't remember if its an Illinois thing, or a NFPA thing. If its a NFPA thing, it might be in 110 or 99. I also don't remember if its for health care only, or for all required generators.
Sorry I'm not more help.
Steve
Sorry I'm not more help.
Steve
- Location
- Massachusetts
LeslieB said:
Nope.
You where telling the architect in your opinion you needed 6' min separation and a block wall between the devices.
Of course that can happen but IMO it is not assumed by the NEC or the NFPA that it will happen.
This is where a designers knowledge and experience come into play. It is up to the designer to weigh the pros and cons against the owners money and desires.
Anyway you asked if there was a code you could cite and I am not aware of one.
99% of the Article 700 generators I work on are located inside or on the roof of the building they protect, you could argue that if the buildings burning having the generator inside is a poor choice.
In my state there is an amendment to the NEC that requires the emergency supply and distribution equipment be protected by a 2 hour fire resistant enclosure
Depending upon the local jurisdiction and the Code in force there is a requirement for fire seperation. In Mass, (for example) there is a requirement for seperation of equipment (normal from emergency).
In NFPA 110 (I think section 7.2 Locations) the Emg Sys Eq must be (generally) seperated from normal power equipment.
With out regard to potential catastorphic failure, NFPA 110 in and of itself should support the general seperation requirments you are attempting to achive.
In NFPA 110 (I think section 7.2 Locations) the Emg Sys Eq must be (generally) seperated from normal power equipment.
With out regard to potential catastorphic failure, NFPA 110 in and of itself should support the general seperation requirments you are attempting to achive.
- Location
- Massachusetts
cpal said:
Charlie wouldn't NFPA 110 have to be specifically adopted to use it as a code cite for any application?
Without specific adoption isn't it more of a suggestion like BICSI for data?
700.12 NFPA 70-2005: "Equipment shall be located so as to minimize the hazards that might cause complete failure due to flooding, fires,icing , and vandalism."
450.27 NFPA 70-2005: "Combustible material, combustible buildings, and parts of buildings, fire escapes, and door and window openings shall be safeguarded from fires originating in oil-insulated transformers installed on roofs, attached to or adjacent to a building or combustible material."
The code recognizes the fire hazards associated with oil-insulated transformers. I have personally witnessed two incidents where pad-mounted transformers caught fire. I also know that fuel-oil is a combustible material.
Unlike most NEC requirements the above referenced code sections are performance based rather than presciptive. In my opinion, space separation or fire-resistant-rated construction is necessary to protect the alternate power source from fires originating in the normal source.
450.27 NFPA 70-2005: "Combustible material, combustible buildings, and parts of buildings, fire escapes, and door and window openings shall be safeguarded from fires originating in oil-insulated transformers installed on roofs, attached to or adjacent to a building or combustible material."
The code recognizes the fire hazards associated with oil-insulated transformers. I have personally witnessed two incidents where pad-mounted transformers caught fire. I also know that fuel-oil is a combustible material.
Unlike most NEC requirements the above referenced code sections are performance based rather than presciptive. In my opinion, space separation or fire-resistant-rated construction is necessary to protect the alternate power source from fires originating in the normal source.
kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
My understanding is that it's a building code requirement to have 2 hour fire wall between the transformer and building if it has more then 500 gal of oil, if not at least 25ft away. If it's 25 ft or fartehr away, or less then 500gal of oil, then I don't think you have to do anything.
See the last paragraph of 700.12 before 700.12(A). It says in some cases the generator must be in a space protectd by sprinklers, or in a space with a 1 hour rating.
Also, per NFPA 110:
7.2 Location.
7.2.1 The EPS shall be installed in a separate room for Level 1 installations. EPSS equipment shall be permitted to be installed in this room.
7.2.1.1 The room shall have a minimum 2-hour fire rating or be located in an adequate enclosure located outside the building capable of resisting the entrance of snow or rain at a maximum wind velocity required by local building codes.
7.2.1.2 No other equipment, including architectural appurtenances, except those that serve this space, shall be permitted in this room.
7.2.2* Level 1 EPSS equipment shall not be installed in the same room with the normal service equipment, where the service equipment is rated over 150 volts to ground and equal to or greater than 1000 amperes.
Iwire:
In principle, you are probably right. But there are a lot of "acceptable to the AHJ" paragraphs in article 700 of the NEC. I wouldn't want to be the one to try and convince the AHJ that something that doesn't follow 110 is acceptable.
Steve
Also, per NFPA 110:
7.2 Location.
7.2.1 The EPS shall be installed in a separate room for Level 1 installations. EPSS equipment shall be permitted to be installed in this room.
7.2.1.1 The room shall have a minimum 2-hour fire rating or be located in an adequate enclosure located outside the building capable of resisting the entrance of snow or rain at a maximum wind velocity required by local building codes.
7.2.1.2 No other equipment, including architectural appurtenances, except those that serve this space, shall be permitted in this room.
7.2.2* Level 1 EPSS equipment shall not be installed in the same room with the normal service equipment, where the service equipment is rated over 150 volts to ground and equal to or greater than 1000 amperes.
Iwire:
In principle, you are probably right. But there are a lot of "acceptable to the AHJ" paragraphs in article 700 of the NEC. I wouldn't want to be the one to try and convince the AHJ that something that doesn't follow 110 is acceptable.
Steve
Yes, I was saying *in my opinion* there needs to be a separation between the emergency generator and the transformer, based on my experience and the experience of my peers at my company.
Thank you for mentioning the amendment to the NEC in your state. I think it's interesting that some jurisdictions recognize that there are safety concerns about having the two separated.
I was asking about if you are designers just out of curiousity. I wasn't passing judgement or weighing your advice differently based on the answer. I'm new to the forum and don' t know whether there is a majority of designers or contractors or electricians here.
In my case, both the life safety generator and the utility transformer are pad mounted on the exterior of the building. There will also be a tenant standby generator in the vicinity.
Thank you for mentioning the amendment to the NEC in your state. I think it's interesting that some jurisdictions recognize that there are safety concerns about having the two separated.
I was asking about if you are designers just out of curiousity. I wasn't passing judgement or weighing your advice differently based on the answer. I'm new to the forum and don' t know whether there is a majority of designers or contractors or electricians here.
In my case, both the life safety generator and the utility transformer are pad mounted on the exterior of the building. There will also be a tenant standby generator in the vicinity.
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