Two waterlines serving one sprinkler system

[cda]

If hydraulicly it can be proven it will work you can do it as per NFPA 24 and 13. BUT most likely not, the flow will be about 150 GPM .10/1500 or less if they use quick response sprinkler. What is the static and residual city water pressure, how many feet of 2" main do we have from the building to the city street, do we have any elevation change between the two points. Is it a straight run or do we have many elbows. How old is the pipe if old most likely not 2" anymore because of interior corrosion, what type of pipe copper, steel, cast iron. As you can see many factors to be considered. Make sure you get a sprinkler contractor involved and review the hydraulics calculations line by line that will be the only way to know for sure. If it works you are good, if not we'll nice try, now put in a new properly sized main.

Do you agree it has to be listed for fire protection use??

If so have you seen two inch listed for fire protection use?

 

[fireguy]

. Make sure you get a sprinkler contractor involved and review the hydraulics calculations line by line that will be the only way to know for sure. If it works you are good, if not we'll nice try, now put in a new properly sized main.

What happens when the first annual sprinkler IT&M is done and the servicing sprinkler contractor does a forward flow and there is not adequate flow?

 

[cda]

What happens when the first annual sprinkler IT&M is done and the servicing sprinkler contractor does a forward flow and there is not adequate flow?

Require a test as part of the acceptance test.

How are they going to merge two lines to one riser ??

Sounds like the water utlity may need to come of age

Either not require a meter or use a different type that can go inside the building

 

[cda]

My guess there is a monthly minimum charge for each meter.

So over the long run how much will two meters cost???

 

[Insurance Engineer]

What happens when the first annual sprinkler IT&M is done and the servicing sprinkler contractor does a forward flow and there is not adequate flow?

As long as the city water pressure is the same as when the hydraulic calculations are completed this should not occur. Providing the calculations have the backflow devices in the calculations. As I said make sure you check the calculations so they match what is on the plans AND when the site visit is made to confirm they match the approved plans.

How would this be any differnt then any other sprinkler design. You can always mandate a 10 psi safety cushion in the hydraulic calculations that would most likely kill the 2" pipe configuration. As an insurance AHJ we mandate the safety cushion on all sprinkler system all the time. Some states such as GA also require a safety cushion.

 

[cda]

does whatever set up they want to do comply with NFPA 13? Chapter 23 of the 2010 edtion

Chapter 23 Water Supplies

 

[SCBO1]

Good discussion fellas! Here is some additional info:

Static: 54 psi

Residual: 40 psi

Flow: 1060 gpm

pc1

 

[cda]

Good discussion fellas! Here is some additional info:Static: 54 psi

Residual: 40 psi

Flow: 1060 gpm

pc1

Does not matter

Underground piping shall meet nfpa 13

Talk to a trusted fire sprinkler company and see what their take is.