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Re: [Seaint-SEAOSC] Nfpa

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I do not have a current copy of the NFPA Life Safety Code, but I recall 
that it references the ASCE 7.

Per ASCE 7
Dead loads consist of the weight of all materials
of construction incorporated into the building including,
but not limited to, walls, floors, roofs, ceilings,
stairways, built-in partitions, finishes, cladding, and
other similarly incorporated architectural and structural
items, and fixed service equipment including the
weight of cranes.

ROOF LIVE LOAD: A load on a roof produced
(1) during maintenance by workers, equipment, and
materials and (2) during the life of the structure by
movable objects, such as planters or other similar
small decorative appurtenances that are not occupancy

If it is "fixed" it is a dead load and should not be counted as live load. 
As an extreme example, if the solar panels weighed 20 psf, and your roof LL 
 is 20 psf, you have zero capacity for the maintenance workers.

A similar issue was posed some years ago with ballasted satalite dishes on 
roof tops.  They were categorized as dead load.  The "fixing" was the 
ballast to keep it in place.  We located them in places (over columns and 
girders) where we had sufficient margin.

Regards, Harold Sprague

> From: MStuart(--nospam--at)
> Date: Fri, 1 Feb 2013 15:19:38 +0000
> To: seaint-seaosc(--nospam--at)
> Is anyone aware of a provision of the NFPA Life safety Code that mandates
> that the minimum Roof Live Load required by the regular building code
> cannot be compromised as a part of any superimposed loads (such as solar
> panels) placed on top of a roof such that the full minimum building code
> roof live load is held in reserve/available for first responders to 
> safety access a roof during an emergency/fire?
> D. Matthew Stuart, P.E., S.E., F.ASCE, SECB, MgtEng
> Structural Division Manager
> Pennoni Associates Inc.
> One Drexel Plaza
> 3001 Market Street, 2nd Floor
> Philadelphia, PA 19104
> Office 215-222-3000 x7895 | Direct 215-254-7895
> Fax 215-222-0789 | Mobile 908-309-8657

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