Hmmm, 2006 IRC
R317.2 Townhouses. Each townhouse shall be considered a separate building and shall be separated by fire--resistance-rated wall assemblies meeting the requirements of Section R302 for exterior walls. R302.1 Exterior walls. Construction, projections, openings and penetrations of exterior walls of dwellings and accessory buildings shall comply with Table R302.1. TABLE R302.1 Exterior Walls - Walls (Fire-resistance rated) 1 hour with exposure from both sides 0 feet So that allows zero separation when the exterior walls of each townhouse have a one hour fire resistance rating. Essentially two independent buildings with one hour rated exterior walls pushed up against each other. Sounds to me like 2 hours of fire resistance. Also just what is an exterior wall ?. EXTERIOR WALL. An above-grade wall that defines the exterior boundaries of a building. Includes between-floor spandrels, peripheral edges of floors, roof and basement knee walls, dormer walls, gable end walls, walls enclosing a mansard roof and basement walls with an average below-grade wall area that is less than 50 percent of the total opaque and nonopaque area of that enclosing side. So an exterior wall defines the exterior boundaries of a building, emphasis on building. I'll take that, if one collapses the other remains standing since they are independent of each other. Ok so lets look at the exception; Exception: A common 2-hour fire-resistance-rated wall is permitted for townhouses if such walls do not contain plumbing or mechanical equipment, ducts or vents in the cavity of the common wall. Electrical installations shall be installed in accordance with Chapters 33 through 42.Penetrations of electrical outlet boxes shall be in accordance with Section R317.3. R317.2.1 Continuity. The fire-resistance-rated wall or assembly separating townhouses shall be continuous from the foundation to the underside of the roof sheathing, deck or slab. The fire-resistance rating shall extend the full length of the wall or assembly, including wall extensions through and separating attached enclosed accessory structures. So just how do we build a common 2 hour fire resistance rated wall, remember it has to be common and not part of one building or the other. The H-Stud Area Separation Wall (ASW) system offers the advantages of constructing common walls with fire resistive protection and noise reduction between neighboring housing units. This lightweight, non-load bearing 2-hour fire rated drywall assembly was developed as a vertical fire protection that provides STC sound ratings up to 60-64 between common wall units in wood framed townhouses and apartment complexes up to four stories (44') in height with the assumption all floor heights are of normal elevation. This system was designed as a fire barrier between adjacent dwelling units allowing for the falling away of construction on the fireexposed side without collapse of the entire wall. This is accomplished with the aluminum breakaway clips that attach the ASW to adjacent wood framing. When one side of the system is exposed to fire, the clips soften, break away and allow the wall on the fire side to give way. The aluminum breakaway clips on the non-fire side will remain intact, holding the ASW in place as a barrier to protect neighboring spaces. While the term "firewall" isnt used it sure looks, walks and quacks like one. If anyone wants the assembly detail; http://www.nationalgypsum.com/submittal/09%2021%2016.33-23.pdf http://www.americangypsum.com/pdfs/AreaSeparationWallSystem.pdf PS, No endorsement of any kind is made or intended, used for demonstration purposes only. Hope that helps, John Drucker Jr CET Fire Protection Subcode Official Fire/Building/Electrical Inspector New Jersey -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Roland Huggins Sent: Thursday, November 05, 2009 3:39 PM To: [email protected] Subject: Re: Townhouse or Apartment Building There you go - just a rated partition and not a fire wall. I'll either have to call Ken - John Jr or just reference having the code boys to get'er done Roland On Nov 5, 2009, at 12:25 PM, Ken Holsopple (forum) wrote: > Roland - > >> From the IRC 2006 > > Under Section R317 Dwelling Unit Seperation > > R317.2 Townhouses. > Each townhouse shall be considered a separate building and shall be > separated by fire--resistance-rated wall assemblies meeting the > requirements of Section R302 for exterior walls. > > Exception: A common 2-hour fire-resistance-rated wall is permitted for > townhouses if such walls do not contain plumbing or mechanical > equipment, ducts or vents in the cavity of the common wall. Electrical > installations shall be installed in accordance with Chapters 33 > through 42. > Penetrations > of electrical outlet boxes shall be in accordance with Section R317.3. > > R317.2.1 Continuity. > The fire-resistance-rated wall or assembly separating townhouses shall > be continuous from the foundation to the underside of the roof > sheathing, deck or slab. The fire-resistance rating shall extend the > full length of the wall or assembly, including wall extensions through > and separating attached enclosed accessory structures. > > Ken Holsopple _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) CONFIDENTIAL AND PROPRIETARY: This email message is intended only for the use of the individual or entity to which it is addressed and may contain information that is privileged and confidential, nor is it, unless specifically stated, intended to be relied upon by any person or persons other than the individual or entity named above and no warranties or representations are made or intended to persons or entities not named above. 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