[SML] Room limits

[Bill Conner]

The 18" is often questioned.  I question it when an architect or other
assumes that is the basis for the number of "seats".  I know with
undivided seats - benches and pews for instance - that people will
rarely sit closer than 24" - maybe 23".  It is why contemporary
churches go to theatre style seats with arm rests - people will sit
closer together - 21 to 22" - or roughly 10%.  On the  other hand,
using 18" for bleachers for thousands starts to be a burden for width
of egress.  But there is also the bleachers in schools - sometimes
with grade school kids - and they might take as little as 15-16" - so
it can get crowded - not to mention managing an emergency egress of
mostly 12s and under is no small task.  Lots to consider.



On Mon, Jun 3, 2019 at 1:51 PM Jerry Durand via Stagecraft
<stagecraft at theatrical.net> wrote:
>
> 18 inches of width per seat including arms?  I've flown on that airline!
>
> On 6/3/19 9:40 AM, Bill Conner via Stagecraft wrote:
> > Here are some values and text from 2015 IBC.  Life Safety Code is
> > pretty similar:  (note that "net" menas net sq ft per occupant)
> >
> > "Assembly with fixed seats See Section 1004.4
> >
> > Assembly without fixed seats:
> >   Concentrated (chairs only—not fixed)  7 net
> >   Standing space 5 net
> >   Unconcentrated (tables and chairs)  15 net
> >
> > Stages and platforms 15 net"
> >
> > And here is text from 1004.4:
> >
> > "1004.4 Fixed seating. For areas having fixed seats and aisles, the
> > occupant load shall be determined by the number of fixed seats
> > installed therein. The occupant load for areas in which fixed seating
> > is not installed, such as waiting spaces, shall be determined in
> > accordance with Section 1004.1.2 and added to the number of fixed
> > seats. The occupant load of wheelchair spaces and the associated
> > companion seat shall be based on one occupant for each wheelchair
> > space and one occupant for the associated companion seat provided in
> > accordance with Section 1108.2.3. For areas having fixed seating
> > without dividing arms, the occupant load shall be not less than the
> > number of seats based on one person for each 18 inches (457 mm) of
> > seating length. The occupant load of seating booths shall be based on
> > one person for each 24 inches (610 mm) of booth seat length measured
> > at the backrest of the seating booth."
> >
> > Lastly:
> >
> > "1004.2 Increased occupant load. The occupant load permitted in any
> > building, or portion thereof, is permitted to be increased from that
> > number established for the occupancies in Table 1004.1.2, provided
> > that all other requirements of the code are met based on such modified
> > number and the occupant load does not exceed one occupant per 7 square
> > feet (0.65 m2) of occupiable floor space. Where required by the
> > building official, an approved aisle, seating or fixed equipment
> > diagram substantiating any increase in occupant load shall be
> > submitted. Where required by the building official, such diagram shall
> > be posted."
> >
> > The code does require you add the occupant loads of each space.  Also
> > keep in mind this is all primarily to determine the minimum number of
> > and aggregate clear width of means of egress.  Its assumed that if the
> > plan and building was approved that a 1500 sq ft stage has adequate
> > egress for 100 people.  Most codes only assembly areas are required to
> > be posted.  But I can also tell you that having heard this issue
> > discussed by building and fire service officials, designers, and
> > owners, the interpretations vary.  And fatalities in assembly spaces
> > are often due to  overcrowding.  So as Steve says, ultimately up to
> > the local authorities, but at least you have some of the numbers.
> >
> > Standing room was mentioned.  On my seating drawings I show potential
> > standing room "spaces" on my plans when called for so that it can be
> > approved in plan review and included on the posting.  It the best way
> > to document it I know of.
> >
> >
> >
>
> --
> Jerry Durand, Durand Interstellar, Inc.
> www.DurandInterstellar.com
> tel: +1 408 356-3886
> @DurandInterstel
>
>
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-- 
Bill Conner Fellow of the ASTC