2 replies to this topic

[Sumair0994]

Hi everyone!
In accordance with NFPA 15, fir a vertical above ground tank, the fire water spray rings should be installed with a maximum spacing of 3.7 m vertically, and nozzle spacing should not be greater than 10 ft in any case. What I would like to ask is information on criteria for horizontal spacing between nozzles. The text above specifies only the max limit but on what basis should the optimum basis be selected? Should I refer to NFPA 13 in thos case?

[spchauhan12]

Hi per my understanding for spacing you may follow NFPA 13. Consider Max.- 10ft. as above & Minimum 6 ft (1.8 m) as per NFPA 13 Section 8.7.3.4. You have to accomodate all sprinklers so that total fire water demand covers Area under fire by all sprinklers.

 

Regards,

SP

[ankur2061]

Hi,

 

7.4.2.2 of NFPA 15 states that:

 

"The horizontal distance between nozzles shall be such that spray patterns meet or overlap at the protected surface".

 

Also 7.4.2.5 of NFPA 15 states that:

 

"Where projections (manhole flanges, pipe flanges, support brackets, relief valves, etc.) will obstruct water spray coverage, including rundown on vertical surfaces, additional nozzles shall be installed around the projections to maintain the wetting pattern that otherwise would be seriously interrupted."

 

If you know the degree coverage of your nozzle, then you can provide a horizontal spacing to meet the requirement as per 7.4.2.2.

 

Hope this helps.

 

Regards,

Ankur.