I remember reading something about this when the 3x rule first came out.
8.6.5.2.1.3* Unless the requirements of 8.6.5.2.1.4 through 8.6.5.2.1.9
are met, sprinklers shall be positioned away from obstructions a minimum
distance of three times the maximum dimension of the obstruction (e.g.,
structural members, pipe, columns, and fixtures). The maximum clear
distance required shall be 24 in. (609 mm) in accordance with Figure
8.6.5.2.1.3.
8.6.5.2.1.4* For light and ordinary hazard occupancies, structural
members only shall be considered when applying the requirements of
8.6.5.2.1.3.
8.6.5.2.1.8 The requirements of 8.6.5.2.1.3 shall not apply to sprinkler
system piping less than 3 in. (80 mm) in diameter.
To me, 8.6.5.2.1.8 says that you don't have to apply the 3x rule to less
than 3", but are required to apply the 3x rule for pipe 3" and larger.
Then, if you follow to 8.6.5.2.1.4, you only have to apply the 3x rule
for structural members in light/ordinary hazard areas. So, if that
reasoning is sound, then you could put an upright sprinkler directly on
the 4" pipe if you are in a light/ordinary hazard area. If it is
storage or EH areas, then you must do the 3x rule away from the edge of
the pipe to comply with the criteria.
On 11/24/2011 10:37 AM, Ron Greenman wrote:
It's a holiday and I'm not obliged to reference (my personal rule of the
day) but isn't there also a rule about not attaching a uprights directly to
pipe 3" nom and over? OK, broker my new rule since I'm just sitting around
waiting for orders from the Commander of Thanksgiving anyways. NFPA 13-2010
ed. 8.6.5.2.1.8 exempts piping less than 3" from the 3x rule, otherwise....
And that rule has always (always is at least 1999 edition if not older)
been there. (Big change editions to 13 I recall 1954, 1991, 1999, and
everything this century). Happy National Eating Day. Do take a moment to
reflect about those hat are going hungry in this country where we throw
more food away per capita than most of the world produces, and how you feel
about that. Are you an "every man for himself" type or a "we're all in this
boat together" person? Or somewhere in between? We show a collective
appearance to the world that is a composite of "me plus us" to one degree
or another. Like going to a date are you satisfied with the way we look, or
not, or don't care? Sorry to talk politics (but not partisan mind you) but
I'm feeling thankful and ashamed at the same time.
On Thu, Nov 24, 2011 at 8:21 AM, Travis Mack<[email protected]> wrote:
Assuming a SSU, you need to be 3x the diameter of the pipe away. So, your
deflector would need to be 13.5" away from the top of the pipe. That
measurement is on the diagonal, so you could arm out the side and up so the
distance hits 13.5". There is also an exception to the 3x rule, that in
light and ordinary hazard areas, only structural members shall be
considered for the 3x rule. So, using that allowance, the sprinkler could
be directly on the pipe if you have an SSU in a light or ordinary hazard
area.
Happy Thanksgiving!
Travis Mack
MFP Design, LLC
480-505-9271
Sent from my iPad
On Nov 24, 2011, at 8:34 AM, Cory Power<[email protected]>
wrote:
Does anyone know the minimum distance an upright can be above of a 4"
main. it will be coming off a 4 x 1 on a dry system. There isn't much room.
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