Window drencher - what if the window is open? 2

[AusLee]

Hi,

I'm Electrical so forgive the question if too dumb.

I'm working on a residential project where some apartment windows need to be drenched to avoid the risk of fire coming inside the unit from a source adjacent to the unit (the building has a funny architecture).

Now a question is coming up: what if the windows are open in case of fire?

The windows are motorized and there is a provision for a relay connected to the fire panel to trigger the window close mechanism. But the concern is that power to the apartment is not a Safety service and the apartment may lose power in case of fire (the incoming cables not being fire rated).

So there is talk that these windows be supplied from a safety service using fire rated cables and with back-up power source.

But the problem is, not all windows in all buildings are motorized as we all know.

Q1: So what happens in the case of buildings that have manual operated windows? surely no one expects that all windows will be closed in case of a fire in such buildings: what if someone was away from home and had left the window open?

Q2: Has motorization been specifically requested in this project for the purpose of making sure the windows will close, but the original design has fallen short from specifying the back-up power supply? Note for example that not all buildings have back-up generators so buildings with lifts required to operate in emergency mode might still find it that in case power is lost to the building, these emergency lifts will also be out of service? Emergency lighting and sprinkler pumps do have prescribed back-up power requirements in residential buildings but not the lifts, so what about these windows, any code requirement for their power supply?

In my mind I think there is no issue in the windows being open, the worst case is that water will come inside the apartment and wet everything; the flow of water calculated as per the standard will also be sufficient to fight the incoming flame (so many liters per square meter).

If you could please shed some light on this issue, all my searches led to see how the sprinkler is installed but nothing about the status of the window.

Thanks

 

[cdafd]

So by chance is this job/ question not in the US??


I have not seen glass protection/ sprinkler, used on glass that is not fixed/ non openable.


Does the inside of the building have fire sprinkler protection??

 

[AusLee]

Hi cdafd,

1. No this is in Australia, the codes are, among others:
[ul]
[li]Building Code Australia (BCA) is the regulation that requires the 2hr protection[/li]
[li]AS 2118.2 is the code that applies to the drenchers[/li]
[/ul]

2. The building does have inside a sprinkler system only for the car park because it has more than 40 cars; the residential floors are not sprinklered, except for the drenchers, because the building is not high rise and there is a smoke detection and alarm system installed. In a high rise building we would have sprinkler heads everywhere in the common areas and inside the bedrooms but in this project it is only the drenchers. In Australia, the purpose is to evacuate the people. With regards to the fire itself, there is interest in limiting the spread and intensity of the fire but I don't know how far that goes from a legislative perspective. I would say it goes as far as limiting the fire into the compartment where it started but I can't hold my hand to my heart.

From the attachment, it is clear that at lease the balcony doors are operable and as per the original post some windows are operable. For the windows, we can get specified a certain type of screen like a "fly screen"; in that case, even if the window is open, the screen gets drenched and still serves the purpose.

The symbol of "+" and semi circle at each corner is just an elbow, it is not a sprinkler head.

What do you think we should do about the doors please?

 

[cdafd]

Does the building code or sprinkler design say anything about an operable opening??

Is there online access to::
AS 2118.2-2010 Automatic fire sprinkler

 

[cdafd]

Cannot see the entire document, •AS 2118.2 but it looks like it is set up for openings. With out seeing the entire document, not sure if the openings have to be automtic closing or anything else::

This Standard sets out requirements for the design, installation and commissioning of drencher systems intended to provide automatic external protection to windows, doors and
other openings from exposure to fire.

http://www.essentialpropertyservices.com.au/articles/wall-wetting-sprinklers.aspx

if you have a link to AS 2118.2 , it


would be interesting to read thorugh it.

 

[TravisMack]

If you are using Tyco WS sprinklers, then they are for non-operable windows only.

I can't say that I have ever seen exposure protection for operable windows.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

"Follow" us at

https://www.facebook.com/pages/MFP-Design-LLC/92218417692

 

[cdafd]

Auslee

I take these are closed head sprinklers and not open??

If you have a link to AS 2118.2 , it would be interesting to read thorugh it

 

[AusLee]

Hello,

Ok there are 3 things it seems: 1) the code, 2) the type of system and 3) what to do with the doors.

1) For the code:
AS 2118.2 says it is there for protection of openings in walls but the openings have to be in-filled by a glazing or similar. Clarification C2.2 on page 8 (sorry the copy is locally branded I cannot send) it says: drenchers are not considered suitable for providing water spray to an unfilled opening. So with regards to the BCA illustration showing the sprinkler over a vent opening, that does not preclude what the same article says that the building surveyor will refer to AS 2118.2 which clearly states that that opening will have to be louvered somehow.

2) For the type of system
I can't get hold of the specs but the code and some (electrical) logic:
1. If it is a dry system (open head?) then I need to activate it either from a smoke detection and alarm system or from a closed head nearby. As per the floor plan there doesn't seem to be any other heads adjacent so i am guessing this is a wet system.
2. Whether dry or wet: i don't think that in case of fire and water flowing I can pinpoint Exactly where the water is going so that i can closed automatically the door of that balcony affected by fire.

3) What to do with the doors
This remains the question.
I do not want to close the doors on people who might get trapped on the balconies. This just doesn't sound right.
I can safely assume that the balcony subject to fire will not have anyone on it as there will be flames sufficient to melt the sprinkler head, so that particular balcony door can be made to close automatically, but what if someone re-opens the door manually: i will need a microprocessor and software to setup logic:
IF FIRE
AND DOOR OPEN
THEN CLOSE
REPEAT
Not only so, but that microprocessor has to be in your speak UL-listed

So I think that I will need to rely on AS 2118.2 Clarification C1.1 (i think you can get that with the free preview) where it says that if a building is internally sprinklered to AS 2118.1, then a sprinkler on the balcony would suffice. As I don't have a sprinkler system inside the building, I will need to get an alternative solution to: replace the drencher on the balcony with a sprinkler + supplement ama necessary inside the unit by doing the fire simulation.

What do you think?

 

[cdafd]

with out seeing the entire standard still hard to comment

As for the doors, put automatic closing arm on them?? Closes every time some one opens it, like on a rated door. As long as not blocked open.

As you say can't tell where the fire is, in order to set up something to close the windows.

 

[AusLee]

Thanks, the closing arm idea is nice. I will have to convince the Architect cz atm the doors are sliding.

 

[cdafd]

auslee

Sorry cannot figure out how to download the standard

1. sounds like someone need to decide if this can even be used, when there are acutal openings that open, and might stay open.

2. If it can be used, does anything need to be done with the openings.

 

[racookpe1978]

Now, think about the impact.

If the fire starts, it MUST be drenched (stopped) before more damage occurs, right?
if the fire "enters" an open (dry) window, the room contacts will likely catch fire, and be destroyed .. BUT .. the other rooms on either side or above the now-burning room will also catch fire, be destroyed, and inflame the entire building on the "other side" of the "open" firewall.

if the open window is drenched from a sprayer or nozzle outside, and the water goes into the room , the carpet gets wet - but does not burn, and the open contents not in a closed dresser or table or filing cabinet "might" get wet, right? So the contents of one room might get destroyed, but they will not catch fire, not spread the fire to other rooms, and not burn the contents within the room - whether covered or not.

So, you have made efforts to get the windows on a safety-circuit so they can close when the power is out - a circuit not likely to fail in an ordinary fire, though they may on an electric circuit board or transformer/breaker panel fire. That may be as good as you can prudently get.

 

[MatthewJWillis]

Please keep in mind.., generally there are sprinklers on the other side.
They don't pack the ummph the others do, but they will surprise you with how effective they can be.

R/
Matt

 

[AusLee]

@sdafd: there is no way to Download the standard, it has to be purchased from SAI global unfortunately, unless your work has access... the standard says it does not apply if the infill is open.

@racookpe1978:
1) i agree with you and this is what i think happened in the Dubai fire on New Year's eve (this year and last year as well) if you youtube the videos, you see what you said exactly happening and I agree on the principle of drenching the interior and this is what we proposed. But in Australia how it works is if you will not comply with the code then we can't just agree on it there is a Fire Engineer who will demonstrate that the alternative solution meets the performance requirement of the code, otherwise the Certifying Authority will not issue an Occupancy Certificate at the end of the job.

2) i have raised a concern that "as good as we can get" is not good enough. We should follow a So Far As Is Reasonably Practical approach. In a court case after the event, the first question a Judge would ask will be Why have you opted for an alternative solution, demonstrate that a compliant solution under SFAIRP could not be achieved. Like i said: the door closing mechanism itself should be fire rated. Not only so, but as it is made-to-become-part of the Safety systems, then the periodic building fire safety inspections should include survey of these door closers. I have never seen this happen in a residential apartments building and this tells me that this solution as currently proposed does not meet SFAIRP.

@MatthewJWillis: yes i did consider fire fighting measures in the source but this is immediately voided by the fact that sprinklers are not mandatory in all buildings so a fire in a fire compartment might as well be allowed to keep burning for 2 hours. That is the time it takes for the Fire & Rescue team to come and start using the hydrants. So we can't rely on the fire being extinguished at the source.

 

[cdafd]

Auslee

""""""""""the standard says it does not apply if the infill is open"""""""

Sounds like the architect needs to go back to the drawing board, and figure a different approach, that meets code, for the openings.

Does not sound like drenchers are going to be the way to go.

 

[AusLee]

Yeah for the moment they're hiding behind the motorization to close the infills so the standard would continue to apply.

 

[cdafd]

Yeah right

First problem is getting the Windows to work correctly

Than long term maintenance of the system

Plus once again, does it even meet the standard