Sphere Deluge Nozzle / Sprinkler Design 1

[az5333]

Hi Fellow Fire Professionals,

I am working on designing a deluge spray nozzle for a sphere holding hydrocarbons (BLEVE risk). The client has their own design of installing an umbrella type upright spray nozzle at the top center of the sphere. Once the deluge valve is activated, the water will flow out of this nozzle and spread outwards along with sphere walls to cool the vessel in case of adjacent tanks fire scenario. However, one of the spheres has nozzle at the top of the tank's center and therefore this installation would not work. I am proposing using several sprinklers (some facing inwards and some facing outwards) installed in a ring pattern around the top nozzle of the tank (please see attached sketch for reference). Considering that the sprinkler nozzle is sized sufficiently for the required flow (total of 900 gpm with each sprinkler spraying 112.5 gpm), would this arrangement work in successfully spraying water on the sphere so the water will slide down the sides and completely cover the sphere (just as their existing nozzle would do)? I would like to understand from your past experiences. Appreciate the feedback.

 

[skdesigner]

NFPA 15-2022 7.4.2.4 indicates that the surface area below the vessel's equator can't be considered wettable from 'rundown' from nozzles at the top of the vessel. Additional rings of nozzles would need to be installed below the vessel's equator, arranged to spray upwards.

 

[az5333]

Thank you so much @skdesigner for your response and very helpful feedback.