# 30KVA generator on a roof



## five.five-six (Apr 9, 2013)

I have been asked to install a 30KVA 208 generator on a roof with an ATS. It's a 6 story medical building but this generator is only going to be used for backing up deep freezers that store tissue samples from medical trials, there won't be any JCAHO requirements. I don't have the plans yet, I'm waiting for the deposit check before I get the engeneered started, is there anything I need to look out for? I have never done a roof mounted generator before.


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## ponyboy (Nov 18, 2012)

What's the fuel type? You'll have to look into the storage methods of whatever it is and prep to meet any containment and monitoring requirements. 

Edit: just read it closer and see it's only a 30k, probably not much in the way of fuel storage for that

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## five.five-six (Apr 9, 2013)

It's diesel, 57 gallon belly tank keeps the fire marshal happy. Apperantly, at 60 gallons and above is where fire marshal gets involved with containment. It has a 49 HP engine and AQMD gets involved with 50HP and larger..


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## frenchelectrican (Mar 15, 2007)

there will be few suprises when you plan to mount the generator on the roof so there are few issue you will have to address .,,

A ) the roof structure that need to be done by engineers to make sure they can support the generator plus fuel.

B ) with short run it will be ok but with long run peroids how the heck ya going to get diesel fuel from ground level to the generator tank ? I know about the larger units .,, 

with 30 Kva unit generator the fuel useage will be about 3.5 gallons per hour at full load so you should have enough fuel for 24 hour run time but after that ya get back up plans ready.


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## five.five-six (Apr 9, 2013)

The customer is aware they will have to hand carry fule to the roof or hire a contractor (not me) to do it for them. There is an existing similar sized generator right next to where this one is going. It is for egress lighting and my customer had been on it for their freezers, but a new management company kicked them off it. Fire marshal wants a fuling procedure that shuts down that stairwell while fuling is in progress.


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## frenchelectrican (Mar 15, 2007)

five.five-six said:


> The customer is aware they will have to hand carry fule to the roof or hire a contractor (not me) to do it for them. There is an existing similar sized generator right next to where this one is going. It is for egress lighting and my customer had been on it for their freezers, but a new management company kicked them off it. Fire marshal wants a fuling procedure that shuts down that stairwell while fuling is in progress.


Ahh understood it .,, 

what about set up a stand pipe to transfer diesel fuel extitor ( outside ) of building ? I am not too crazy to carry diesel fuel in the medical building due of oxygen in the building so just be aware of that.


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## five.five-six (Apr 9, 2013)

The exterior is all glass, standpipe wouldn't fly. Not too crazy about coring 6 floors up either. I hadn't thought about the O2, but the other generator has been up there for 30+ years and that's how it's always been fuled. 

Helicopter contractor that gave me a price on setting the generator said they would NOT bring fuel up. I guess that's what my apprentice is for LOL.


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## frenchelectrican (Mar 15, 2007)

five.five-six said:


> The exterior is all glass, standpipe wouldn't fly. Not too crazy about coring 6 floors up either. I hadn't thought about the O2, but the other generator has been up there for 30+ years and that's how it's always been fuled.
> 
> Helicopter contractor that gave me a price on setting the generator said they would NOT bring fuel up. I guess that's what my apprentice is for LOL.



Ahh got it .,,

Ya I know but it going be fun try to carry 20 liter jugs up 6 flights I been there with one place with 14 flights up we can deal with 20 liter jugs but no way with 100 or 200 liter barrels .

The helicopter company did bring up a good point about that .,, I think it have to do something about static charge from rotors but it been a while on that part.


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## telsa (May 22, 2015)

frenchelectrican said:


> there will be few suprises when you plan to mount the generator on the roof so there are few issue you will have to address .,,
> 
> A ) the roof structure that need to be done by engineers to make sure they can support the generator plus fuel.
> 
> ...


Truly.

I would've expected natural gas.


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## frenchelectrican (Mar 15, 2007)

telsa said:


> Truly.
> 
> I would've expected natural gas.


Ya I do expected that too but being medical building that will kick the natural gas off the fuel choice so they have to use diesel unit or Propane unit.

If it was nonmedical building then ya you can use Natural gas easy.


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## five.five-six (Apr 9, 2013)

telsa said:


> Truly.
> 
> I would've expected natural gas.


City won't allow municipal natural gas, CNG, yes but no city supplied natural gas. I think they don't want it running 24x7 to supplement PoCo power.


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## glen1971 (Oct 10, 2012)

At French's estimate of 3.5 gallons/hr for the generator, dragging a jerry can up 100 stairs, down to refill and back up will be up there for crap jobs... I'm assuming the poor soul will be switching hands every floor or every other floor at best. You could do 2 at a time, and take more, longer breaks on the way.... Either way, I'll guess that to fill, haul, empty and return will be between 45-60 minutes, at least. With it running, you'll they'll be treading water to keep it filled..


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## sbrn33 (Mar 15, 2007)

I am guessing there just might be an elevator. Which would be on the other gen


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## five.five-six (Apr 9, 2013)

I'll give them 4 cans as a bonus on this job, I'm making pretty good money on it if all goes well.


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## MikeFL (Apr 16, 2016)

Why aren't you using a crane?


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## five.five-six (Apr 9, 2013)

MikeFL said:


> Why aren't you using a crane?


The roof is about 100' above grade, the generator location is about center of the 30,000sqft footprint, that's going to take one heck of a crane. Helicopter came in at about 1/3 the price of a crane with the parking lot shut down for 1 hr as opposed to 12 hrs For crane setup and tear down. 

Don't use a helicopter to set stuff on a gravel roof, don't ask me how I know this 


Plus, the "Archer Sterling" in me just likes the idea of renting a helicopter.


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## five.five-six (Apr 9, 2013)

The whole roof is concrete, how do I flash the penetrations? I am assuming a flat led roofjack.


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## frenchelectrican (Mar 15, 2007)

five.five-six said:


> The whole roof is concrete, how do I flash the penetrations? I am assuming a flat led roofjack.


Do you have few roofing buddies that ya can use ? 

there are few different style of roof jack it avaiable so I do not know if you use rubber sheeting on top of concrete roof or what so I really suggest have a roofing contractor or your roofing buddy do the flashing work for ya because they will know the correct way to flash the penetrations good.


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## five.five-six (Apr 9, 2013)

frenchelectrican said:


> Do you have few roofing buddies that ya can use ?
> 
> there are few different style of roof jack it avaiable so I do not know if you use rubber sheeting on top of concrete roof or what so I really suggest have a roofing contractor or your roofing buddy do the flashing work for ya because they will know the correct way to flash the penetrations good.


Have your read my posts? I don't have any friends LOL.... actually, I do have a customer who had roffing experiance working for his brother. I might reach out to his brother.


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