Single Building - Multiple Services and FDCs

[gouveia]

I am looking for another opinion on whether the Fire Department Connections need to be "interconnected" when a large building is supplied by more than one underground service/riser. The case I have in mind is a large warehouse (200,000 sq ft) with risers at opposite ends as was commonly done in the past. Is there a code requirement or good practice recommendation?

NFPA 13-2010 paragraph 8.17.2.4.5 states "Where a fire department connection services only a portion of a building, a sign shall be attached indicating the portions of the building served."

Is section intended to apply to a partially sprinklered buildings to advise that the entire building is not protected? Or is it intended to permit multiple FDCs as long as you clearly indicated which portion of the building it protects?

I am aware that NFPA 14 paragraph 7.5.1 states "Where two or more standpipes are installed in the same building or section of building, they shall be interconnected." But for this specific case there would be no standpipes.

 

[stookeyfpe]

Technically, your design using two separate FDCs with the appropriate signs would be compliant with NFPA 13.

With that said, remember that the purpose of the FDC is to supplement the automatic sprinkler system. As someone who spent a few years fighting structure fires while getting my degree, such a FDC arrangement is putting a lot of faith on the back of the firefighters assuming they will connect to the correct FDC. The cost of the added pipe is incidental in my mind versus the potential loss if an Engine company doesn't selecting the correct FDC.

The proposed design in your post meets the minimum NFPA 13 requirements. However, the owner should understand the ramifications of assuming that the firefighters on Engine Company XX will select the correct FDC, especially if the fire occurs at the boundary of the 2 sprinkler systems at 3:30 AM.

 

[PEDARRIN2]

We always design the system so there is an alarm/strobe by the fire department connection that is connected to the sprinkler zone which has sprinklers flowing. That way the fire department knows which FDC to connect their hoses.

Also, you can bring all the FDC's back to a locations and put the alarms/strobes there as well. that way if the FD wants to hook up to more than one FDC - they are able to do so without having to travel the distance of the building.

 

[LCREP]

"FDC is to supplement the automatic sprinkler system"

Yea BUT when the pump operator puts more pressure into the FDC then what he/she has coming into the pump they are in fact supplying ALL the water to the sprinkler system. By increasing the pressure they are shutting off the supply of water from the underground water main via the backflow preventor and or check valve that will close. Until the pressure is lower on the sprinkler/standpipe side of the check valve it will not open. I never understood the position of NFPA 13 on this.

****************************************
Fire Sprinklers Save Firefighters’ Lives Too!

 

[pipesnpumps]

The purpose of the FDC is to supplement the pressure, as stookey mentioned. By supplementing the pressure it also increases the flow through the open (popped) sprinkler heads, and can increase the density on the fire to where the fire is perhaps suppressed (heat release rate decreased) instead of just controlled (kept constant).. Why go in with SCBA and risk lives if you can dump copious amounts of water right over the fire by hooking up hoses? Then if the pumper truck is shutoff or fails the check valves operate (ug opens, FDC closes) and it goes back to the lower flowrate supplied by the city water pressure. Then go in with an attack hose (250 gpm) and hopefully put it out.

That is my take on the intent as an engineer, not a firefighter, and based on input from fellow FPEs and AHJs. Stookey can provide better insight than me to that end.

Real world knowledge doesn't fall out of the sky on a parachute, but rather is gained in small increments during moments of panic or curiosity.

 

[stookeyfpe]

The original person posed a question. He didn't return for an answer.

Good luck gouveia. We answered your question.

 

[gouveia]

Thank you for the answers. I am in agreement that it is permitted to have multiple undergrounds and FDCs. But generally should not be done since it makes things more complicated.