[dd251] Re: Water Mist Systems
- From: "brian blessed" <resisprinklers@xxxxxxxxxxx>
- To: dd251@xxxxxxxxxxxxx
- Date: Wed, 22 Jan 2003 00:36:49 +0000
To all members,
I have just read the email from William and as someone who is independant
and has nothing to gain from criticising sprinkler or water mist systems I
would comment as follows:
Firstly we need to establish the difference between a 'life safety sprinkler
system' and a 'life safety' sprinkler system. BS5306 has a clear set of
guidelines as to what needs to be carried out to ensure that a sprinkler
system complies with 'life safetey'. If the system is fed from the towns
main then the system should be fed from superior mains with two separate
connections to seperate mains. If the system is fed from pumps and tanks
then the tank needs to be split into two seperate sections with seperate
ball valves and suction lines. The main valve set needs to have a bypass
fitted. All floors need to be split into zones and no zone shall have more
than 200 sprinkler heads fed from it. All valves need to be monitored and
the signals should go to a panel which gives clear indication of the valve
status. All sprinkler heads should be quick response. If two ecectric pumps
are installed (one duty & one standby) then there should be an auto
changeover panel installed so that should mains electricity fail then the
pumps will run off stanby generaor. Mains electricity needs to be brought in
from an uninterupted supply.
All of these reccomendations are there with the intention of reducing risk.
It would be wrong to confuse 'life safety' and these sort of precautions
when talking about domestic or residential systems as if the above actions
were implemented when protecting someones home then they would almost
certainly push the cost of the system way beyond the budget of the house
holder, builder, local authority etc.
With regard to the other questions I would comment as follows:
1) Pressure ratings of systems are normally linked with the nozzle design.
As William will no doubt be aware different nozzles work with different
pressures. A long throw sidewall head will need a different pressure to a
ESFR head. Asking for the pressure requirement is a neither here nor there
question, what will be deduced from this?
2) Why ask if pipework complies with DD252 or UL listings? Why do you leave
out FM, CEN, BS, NFPA? If pipework delivers water to a fire then is it not
doing what its meant to be doing? What if you fitted 65mm fire hoses
throughout the premises, these are used by fire fighters every day and are
strung across roads, pulled up the sides of buildings, dragged through
builders yards to get to skip fires but still deliver water to a fire. Are
these not acceptable? What exactly is your point?
3) Apparently there are no residential sprinkler or water mist heads listed
in Barbados! What happens if someone wants to protect themselves against
fire in the home there? Come on, technology needs to move on, if systems can
be installed that reduce fatalities and reduce fire damage then we should
all be embracing them.
4) What blockages would you invisage in a water mist system that are
different to a sprinkler system. Sprinkler systems are fantastic but I have
come across sprinkler systems with lumps of wood holding the clack open,
birds nests in alarm gongs, metal discs from mechanical tee installs left in
the pipework, I could go on but what is your thinking behind asking this
question?
5) Why do you think that leaking through diaphram seals in the states is due
to maintenance issues? I can only think that by diaphram seals you mean the
seals on the nozzles themselves. How many sprinkler systems have the heads
removed on every service visit and the seal inspected? If the heads were
removed then they would in accordance with BS5306 need to be replaced with
new heads. Are you suggesting that every sprinkler and water mist nozzle in
the world should be replaced every service visit? Or do you think they may
need replacing more frequently due to this 'diaphram seal' problem? I would
welcome your advice on this.
6)Sprinkler systems do not have a blanket 'approval' complying with water
authority regulations, the design has to take in to account these
regulations. Systems cannot be boosted directly from the town main, a double
check valve needs to be installed and if a tank is used on the system then
it should have a type 'A' air gap. These water authority regulations can be
designed into a sprinkler or water mist system quite easily. What are your
reccomendations on this subject?
7) If the water authority regulations mentioned above are complied with then
there should not be a problem as these are written up specifically to
prevent cross contamination. The same obviously goes for sprinkler and water
mist systems. I do know that US, fire departments have been using these type
of wetting agents for a number of years with amazing results. Do some
research and check it out.
8) With regard to full capacity operating for ten minutes then this would
need to be answered by a water mist company. A thought however: Should the
water board shut the main for repairs then could a sprinkler system operate
for the full time? Fire needs to be dealt with as quickly as possible as the
longer it burns the quicker it will spread. The first few seconds/minutes of
the fire are the most critical, controlling it at this stage are paramount.
I could not make sense of the paragraph about retro-fit systems.
To finish I would say to you all sprinkler systems have a huge role to play
in this world, so do water mist systems. Do not be inclined to fight each
other because you think that one system is a threat to the other in terms of
market share. There is plenty of work out there, lets all pull together and
make this a safer place.
PS: Who is Simon Quillish?
Best regards
Billy B.
>From: "William" <william@xxxxxxxxxxxxxxxxxxx>
>Reply-To: dd251@xxxxxxxxxxxxx
>To: <dd251@xxxxxxxxxxxxx>
>Subject: [dd251] Water Mist Systems
>Date: Tue, 21 Jan 2003 17:36:57 -0000
>
>To all members
>
>I have read the recent e-mail on water mist sytems and have a few questions
>that many people have asked.I am also astounded that the word guarantee for
>any sprinkler system is used. The principals of a life safety system is
>based on risk as there will never be a guarantee of electric or water.
>
>QUESTIONS
>
>1) What pressure rating does the system work at
>
>2) Does all the pipework comply with DD252 or UL listing and also comply
>with the manufactures requirements.
>
>3) Are mist sprinkler heads listed for residential use any where in the
>world.
>
>4) Are there blockages within the system over a period of time /or is it
>dry
>
>5) Systems like these used in the states have failed through leakage of
>diaphram seals this is probably because of maintenance issues
>
>6) Cross contamination with water ( has the system got the relevant
>approvals from the relevant authorites) This is a legal requirement
>
>7) Are the fire retardent agents used within the system ok for the water
>authorites and manufacturers of products used
>
>8) Can the system operate at full capacity for 10 minutes as in the NFPA
>13D or DD251 standard.
>
>To my knowledge water mist systems are currently being fitted to domestic
>properties where a standard is not applicable (retro-fit) as these are
>deemed to be above and beyond whats required for regulations?
>
>In my opinion no system not stated or complying with the relevant standards
>can be considered for any form of relaxations either building or fire.
>
>I trust I will receive comments back on this issue
>
>William Butler
>
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