Sprinkler for airport terminal building

[HVAC68]

We are designing an airport project. The terminal building has a height of around 20metres (65 feet). Should we install sprinklers ? I am applying more of logic than a code issue here and hence my question - With a height of 20metres, by the time the fire reaches the top and operates the sprinkler, it may be too late. Alternatively, even if we were to locate a sensor at a lower level and get the sprinkler to activate much earlier, will the sprinkler be effective with water coming from such a height ?

Would appreciate inputs from the experts.

Thanks in advance

HVAC68

 

[TravisMack]

I have read where sprinklers can be effectively used up to heights of 100' above the fire. However, if you are concerned about droplets not getting to the fire, you can use large drop sprinklers as long as it is not an FM installation.

The other alternative that you suggested is to make it a deluge system and activate it with a detector. That could help, but if the system is large, you are talking a very large amount of water.

Granted, I am a fire sprinkler guy, but I think the answer to the question you asked above is YES. It is better to have them there than not.

 

[stookeyfpe]

What is the applicable Building Code - or - if no Building Code is adopted, what applicable NFPA standard are you designing the building to? This will govern the requirement for fire protection.

NFPA 415, Standard on Airport Terminal Buildings, states that a terminal building with an area greater than 12,000 square feet requires automatic sprinkler protection. See section 4.5.1.1.

Lowering the sprinklers won't work. This is a violation of the standard governing the installation of sprinklers (NFPA 13) because the link must be heated to operate - this heating occurs when the ceiling gas layer reaches a temperature that is equal or greater than the fusible link or frangible bulb after the thermal lag time has been overcome.

Concerning the ability of the ceiling sprinkler to operate, this is a function of sprinkler's detection link sensitivity to a given fire producing an estimated heat release and burning rate. In your case, it may be appropriate to mathematically model the conditions. Software such as DETACT is available to determine if the sprinklers will work. I caution you to not go down the road of finding and downloading the software and populating it with ill conceived values for the variables. Other variables like building geometry and ventilation will influence the outcome. Seek professional assistance in this case unless you are qualified to perform such an analysis.

If a performance design is chosen which will be used an equivalency to a requirement in a standard or code, documentation of the design fire conditions is crucial. An example is a design fire based on wood and cloth furniture. After the building is opened, all of the furnishings are replaced with furniture formulated with plastics. This produces a fire with a higher heat release rate and faster burning rate.

 

[HVAC68]

Yes, we may have to meet the relevant NFPA codes.

I read an article about fire sprinklers in Hongkong airport sometime back which appeared in NFPA Journal. I am trying to locate that document in which they have indicated that fire sprinklers were not provided.

I am not a fire specialist - as I said in my first point, apart from the code issue, am trying to apply logic.

Sometimes, the codes may not cover all eventualities (like higher ceiling heights in this case) - hence blindly following a code may not be the right thing. Having said that, we also want to be sure that we do the right thing. Maybe precedence in similar airport designs may be of help.

HVAC68

 

[AdamMurray]

I think the only way you could possibly eliminate the sprinklers is to model the building and prove they would be ineffective....even then the AHJ may require them.