Hello Bill,
Most of us in this group would agree with you that this person is
using the sprinkler system as an excuse to not change their
traditional venue of activities. Proving to him that "we" know more
about his sprinkler system than he does is not the way to get him or
his supervisors to allow indoor free flight model in their facility.
A better way might be to bring him a HLG, LPP or any type of sport
rubber powered model and get him excited about flying it himself.
Then he could see there little danger to his sprinkler system from
these models.
That said, I worked for a fire sprinkler manufacturer for more than 16
years and can give you a basic understanding of sprinkler systems and
fire sprinklers.
First there are no mercury switches in fire sprinklers. Mercury
switches are an electrical device and automatic sprinkler systems are
required to operate with no external power.
There are two types of fuses that set sprinklers off. One is a solder
element, either under tension or compression. The other is called a
glass bulb sprinkler that uses a fluid filled glass ampule. It is
always under a compressive load. The fluid in it is mostly glycerin
and some dye. Both types must operate, without external power, when
the temperature at the fusible element reaches a specific set point.
Contrary to Hollywood depiction, each sprinkler head operates
independent of all other heads. Building owners and insurance
companies fear water damage as much as fire damage.
All sprinkler heads installed in any U.S. facility are either Factory
Mutual or Underwriters Laboratories approved. Probably both for a
governmental facility. Some of the tests FM and UL put sprinklers
through include tumbling the sprinkler head in a drum with short
lengths of cut 2x4's. After this test they must maintain their
structural integrity and operate properly. Some test involve dropping
steel balls on the glass bulbs from specific heights and testing them
for proper operation. The testing done by these laboratories
generally cost a manufacturer $750,000 to $1,000,000 to put a new
sprinkler head on the market.
If you are interested in finding out if rubber powered model airplanes
have caused premature sprinkler head operation contact one of the
following three groups or all three. Be very specific with your
questions. General answers may not help you.
National Fire Protection Association (NFPA)
http://www.nfpa.org
Factory Mutual Global (FM)
http://www.fmglobal.com/
Underwriters Laboratories (UL)
http://www.ul.com/
Go to their contact us section and email their customer service or
technical people and ask them the question. I am sure that most of
the U.S. facilities that allow indoor free flight have sprinkler
systems. Most local building codes require them, particularly in
schools, gyms and other governmental recreation facilities.
Use the information you get wisely. As I said you are not going to
get the powers to be to allow indoor free flight because "we" know
more about their sprinkler system than they do. If the sprinkler
system is really a major concern with them the information from NFPA,
FM or UL could set their mind at ease. But, I doubt that the
sprinkler system is the problem.
Regards,
Tom Juell
--- In Indoor_Construction_at_yahoogroups.com, "blogue36" <blogue36@...>
wrote:
>
> I checked out a fairly new county recreation center (built 2005) as a
> possible indoor flying site. See
>
> http://www.co.worcester.md.us/recreation/rec.htm
>
> I was told by the person in charge that flying airplanes,
> in this case just free flight, could possibly set off the sprinkler
> system if a plane struck one of the mercury switches. I didn't press
> the issue because of my ignorance of the subject and also it does pay
> to be nice! (The individual was exceedingly quick with the reply!)
>
> Can anyone provide information on the sensitivity of these
> mercury switches to impact by a rubber power airplane.?
>
> This site is located in the low population density center of the
> county, but to the north there is a large population of retirees and
> to the south Pocomoke City which is not too far from the NASA facility
> at Wallops Island.
>
>
> Bill Logue
> AMA 523248
>
Received on Sun Apr 27 2008 - 12:11:54 CEST