Riser that goes down question?

[DavidCR]

Hi you all and thanks for all the good work in this forum.

I´m designing a sprinkler system for an hydropower plant, with several floors underground, it is not fully sprinklered, there are sprinklers only in the lube oil main equipment area.

The water comes from above and goes down in a combined system as described in the attached drawing.

Due to space limitations I´m planing to locate the sprinkler control valve in the upper level. Then it goes down to the protected lower floor.

My questions are:
1. Does the arrangement complies with NFPA?. Any comment?

2. Does a typical vane type flow detector (like a Potter VSR)can be installed vertically with flow going downwards?

3. And a old doubt that I want to solve. The control OS&Y valve and pipe is 2.5" but by the hydraulic calculations a 2" pipe would be enough. So what is the required size of the drain and valve per NFPA 13, 3/4" or 1-1/4"?

Blessings and thanks in advance.

 

[stookeyfpe]

David,

I'll offer my comments.

1) NFPA 13 is based on protection throughout the building. However, a hydro power plant is not a building that the NFPA 13 technical committee has any experience with. I would at a minimum document the hazards in those areas where automatic sprinkler protection is not required. One issue you may have is if this plant is in the US. The International Fire Code requires automatic sprinklers in all basements > 1,500 square feet area because of the complications of manual firefighting in basements. It's analagous to climbing down a chimney while the fire is burning.

2) I reviewed the Potter VSR data sheet it has no specific limitations based on the direction of water flow. I saw nothing that indicated the flow direction influences its installation.

3) The purpose of a drain is to remove the water. The smaller the pipe diameter, the longer the drain time and the longer the fire protection system is out of service. Whenever possible I would ask for or require a larger diameter drain pipe.

 

[KDLLC]

David, the way section 8.16.2.4.3 and table 8.16.2.4.2 are written, I think you have to provide the larger size (1 1/4").

 

[cdafd]

Not sure how accurarte the picture you supplied is, BUT

1. you could do a floor control valve in the lower floor

2. not sure how much more system there is above the lower floor, BUT would require a flow switch prior to the standppe connection

3. I would want a flow control above as high in the supply pipe in the building incase there is some type of break, to indicate a flow of water before I see it coming under the door.

 

[EEJaime]

Also you need to beware of the building designation. Some AHJ's will deem an "underground structure" must be sprinklered. Case in point. We are involved with an underground baggage and utility tunnel at an airport, the entire tunnel must be sprinklered. Not only that, but we must have pumping provisions for the forced main drainage system. I would definitely get a read from your Fire Official before proceeding. There are strict exiting requirements as well, but that is someone else's baileywick.