# emergency generator location



## Yikes

A client was asking me recently about the code parameters for locating an exterior skid-mount emergency generator ( http://www.cat.com/cda/layout?f=413765&m=39280&x=7 ) on his site.  I assume the main issues for an outdoor installation are exhaust location.  where should I look in the code?

This is California, based on the 2009 Uniform Mechanical Code.


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## cda

Is the diesel tank part of the skid??

Exhaust should be not be a problem, unless they want to put it against a building??


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## Yikes

Yes, it's an all-in-one package - -the diesel tank is on the skid.  The whole thing just bolts down to a concrete pad.

The site is small, so they need to know how far away from property lines, air intakes and windows, exterior exit stairs, and ground level exterior exit paths-of-travel.

This is a retail building material facility.


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## mtlogcabin

2009IBC

1707.7 Mechanical and electrical components.

Special inspection for mechanical and electrical equipment shall be as follows:

1. Periodic special inspection is required during the anchorage of electrical equipment for emergency or standby power systems in structures assigned to Seismic Design Category C, D, E or F;

[F] 2702.1 Installation.

Emergency and standby power systems required by this code or the International Fire Code shall be installed in accordance with this code, NFPA 110 and 111.

Don't have NFPA 110 or 111


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## Yikes

Is there any exhaust discharge requirements for parkign garages, I assume a generator exhaust location would be a similar issue.


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## north star

*@ @ @ @*

Some other issues to consider are:  *(1)* the noise level - typically, not desirable near

a retail facility,......*(2)* the ability to refill the diesel tank by a fuel truck. 

The ability of the fueling truck to be able to pull up next to the generator itself

and refill, or will they have to connect fueling hoses, .....*(3) * if an event occurs

that requires the generator to run for extended periods of time, will a continuous

supply of diesel fuel be available,...and *(4)* with the prices of diesel fuel these days,

natural gas is a cleaner, more affordable option  -  IMO!

*@ @ @ @*


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## peach

emergency generators are only required to have fuel for 2 hours.  Even when the generator is on the room, the fuel port location sometimes causes issues.


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## FyrBldgGuy

Hey, Peach!

Emergency Diesel Generator run time is based on NFPA 110.  Depending on Class, Type and Level.  But if it is a Level 1 then you have a 96 hour run time if you are in a Seismic Zone C, D, E or F.

Next look at the tables in NFPA 30 and CFC for distance to building and property line.


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## rktect 1

Dont forget the Manufacturers specs.

Generac installers are notorious for ignoring their own requirements.  They aren't even printed with the brochures.  I have had to call the Generac company to have them emailed to me.


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## Yikes

north star - I agree about the natural gas being easier.  The problem is that Southern California is earthquake country and in a seismic event, the gas' seismic shutoff valves activate, so you can't use the generator just when you need it most!


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## FyrBldgGuy

NFPA 110 does not allow natural gas for emergency generators for that reason.


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## Dr. J

There will be some fire code related issues for liquid fuel.  Most of these should be covered by a listed packaged unit, such as fuel fill spill containment, venting, and secondary containment.  One thing to watch out for is the normal atmospheric vent.  It is supposed to be 12' above grade, but the packaged unit may not be that tall, so someone has to extend it - commonly missed.


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## Yikes

Dr. J - thanks, that's exactly the info I'm looking for.  Where can I find a code reference for the 12' above grade requirement?  Most package units are about  4-5 feet tall.

Also, I'm concerned that the owner may place the generator close to an emergency exit stair, in which case 12' above grade exhaoust may actually be blasting diesel exhaust into the exit path of travel, right at eye level.  What code would cover this issue?


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## Dr. J

In the IFC, it is in Ch. 34.  Don't know about CA codes.

_3404.2.7.3.3 Vent pipe outlets._

_Vent pipe outlets for tanks storing Class I, II or IIIA liquids shall be located such that the vapors are released at a safe point outside of buildings and not less than 12 feet (3658 mm) above the adjacent ground level. Vapors shall be discharged upward or horizontally away from adjacent walls to assist in vapor dispersion. Vent outlets shall be located such that flammable vapors will not be trapped by eaves or other obstructions and shall be at least 5 feet (1524 mm) from building openings or lot lines of properties that can be built upon. Vent outlets on atmospheric tanks storing Class IIIB liquids are allowed to discharge inside a building if the vent is a normally closed vent._


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## Dr. J

I don't think internal combustion exhaust is specifically covered in the I codes.  One could stretch the scope of the Venting requirements of the IMC (slightly more applicable than the IFGC since IMC covers oil).

_SECTION 804_

_DIRECT-VENT, INTEGRAL VENT AND_

_MECHANICAL DRAFT SYSTEMS_

_804.1 Direct-vent terminations._

_Vent terminals for direct-vent appliances shall be installed in accordance with the manufacturer’s installation instructions_

_804.2 Appliances with integral vents._

_Appliances incorporating integral venting means shall be installed in accordance with their listings and the manufacturer’s installation instructions._

_804.2.1 Terminal clearances._

_Appliances designed for natural draft venting and incorporating integral venting means shall be located so that a minimum clearance of 9 inches (229 mm) is maintained between vent terminals and from any openings through which combustion products enter the building. Appliances using forced draft venting shall be located so that a minimum clearance of 12 inches (305 mm) is maintained between vent terminals and from any openings through which combustion products enter the building._

_804.3 Mechanical draft systems._

_Mechanical draft systems of either forced or induced draft design shall comply with Sections 804.3.1 through 804.3.7._

_804.3.1 Forced draft systems._

_Forced draft systems and all portions of induced draft systems under positive pressure during operation shall be designed and installed so as to be gas tight to prevent leakage of combustion products into a building._

_804.3.2 Automatic shutoff._

_Power exhausters serving automatically fired appliances shall be electrically connected to each appliance to prevent operation of the appliance when the power exhauster is not in operation._

_804.3.3 Termination._

_The termination of chimneys or vents equipped with power exhausters shall be located a minimum of 10 feet (3048 mm) from the lot line or from adjacent buildings. The exhaust shall be directed away from the building._

_804.3.4 Horizontal terminations._

_Horizontal terminations shall comply with the following requirements:_

_1.	Where located adjacent to walkways, the termination of mechanical draft systems shall be not less than 7 feet (2134 mm) above the level of the walkway._

_2.	Vents shall terminate at least 3 feet (914 mm) above any forced air inlet located within 10 feet (3048 mm)._

_3.	The vent system shall terminate at least 4 feet (1219 mm) below, 4 feet (1219 mm) horizontally from or 1 foot (305 mm) above any door, window or gravity air inlet into the building._

_4.	The vent termination point shall not be located closer than 3 feet (914 mm) to an interior corner formed by two walls perpendicular to each other._

_5.	The vent termination shall not be mounted directly above or within 3 feet (914 mm) horizontally from an oil tank vent or gas meter._

_6.	The bottom of the vent termination shall be located at least 12 inches (305 mm) above finished grade._

_804.3.5 Vertical terminations._

_Vertical terminations shall comply with the following requirements:_

_1.	Where located adjacent to walkways, the termination of mechanical draft systems shall be not less than 7 feet (2134 mm) above the level of the walkway._

_2.	Vents shall terminate at least 3 feet (914 mm) above any forced air inlet located within 10 feet (3048 mm) horizontally._

_3.	Where the vent termination is located below an adjacent roof structure, the termination point shall be located at least 3 feet (914 mm) from such structure._

_4.	The vent shall terminate at least 4 feet (1219 mm) below, 4 feet (1219 mm) horizontally from or 1 foot (305 mm) above any door, window or gravity air inlet for the building._

_5.	A vent cap shall be installed to prevent rain from entering the vent system._

_6.	The vent termination shall be located at least 3 feet (914 mm) horizontally from any portion of the roof structure_

I can tell you from experience that diesel exhaust will be smell-able at very low concentrations and can find any building opening.


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## Yikes

In California, we're still on the 2009 Uniform Mechanical Code.


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## FyrBldgGuy

Dr. J has good information.  The 2010 California Fire Code has the same section as listed above.


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## Yikes

Wait, I think I just found it:

_CMC / UMC 506.9 Exhaust Outlets. The termination point for exhaust ducts discharging to the atmosphere shall be not less than the following:_

_506.9.1 Ducts conveying explosive or flammable vapors, fumes, or dusts: thirty (30) feet (9,144 mm) from property_

_line; ten (10) feet (3,048 mm) from openings into the building, six (6) feet (1,829 mm) from exterior walls or roofs; thirty (30) feet (9,144 mm) from combustible walls or openings into the building that are in the direction of the exhaust discharge; ten (10) feet (3,048 mm) above adjoining grade._

_506.9.2 Other product-conveying outlets: ten (10) feet (3,048 mm) from property line; three (3) feet (914 mm) from exterior wall or roof; ten (10) feet (3,048 mm) from openings into the building; ten (10) feet (3,048 mm) above adjoining grade._

I assume that diesel exhaust would qualify under 506.9.2.


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## FyrBldgGuy

CMC 2010

802.2.6 Appliances with Integral Vents.

NFPA 54: 12.3.6


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## earshavewalls

I remember a VA Ambulatory Care facility in Las Vegas that had a diesel generator. They installed it 10 feet from the building, but that location was where the intake louvers for outside air for the surgery center were. They were "code compliant" but in reality, the fumes came straight into the louvers and into the air system...........it was funny that nobody noticed or said anything until time to test the genset.......yep, 2-week delay to move the genset another 10 feet away from the building and re-oriented so that the exhaust was as far away from the building as possible. It was a pretty good sized change order!

Code means a lot, but a little uncommon-common sense goes a long way!


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## Frank

Not in the basement, if you are in or near a tsunami or hurricaine storm surge flood zone and continued power is critical for the safety of your nuclear plant (***ushima) or hospital patients (New Orleans)

Interesting it censors the name of the nuke plant.


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