fire flow vs. fire hydrant
fire flow vs. fire hydrant
(OP)
Good day!
Iam a rookie and having difficulties on determining the location of the fire hydrant and deciding the fire flow for the building area.
I am using nfpa 1 for my reference of the needed fire flow. The scenario is that there are multiple buildings with a separation of 6m on each side for the vehicle road. all the building are dormitory building (as per nfpa 101) with 3 floors, 950sq.m each.Type II (111) construction and as per local code it doesn't require automatic sprinkler.
When computing for fire flow needed I add all the floor area (950*3) and use the table on nfpa 1 to determine the fire flow which is 2500 gpm (I used the full flow and not deducted the 75% max. as per the code because the building is not sprinklered) and equivalent to minimum of 3 hydrant with the max. spacing of 122 meters (also from table of nfpa 1).
does it means that every building i will put 3 hydrant each? or i could do space the hydrant that the 3 hydrant would cover 2 or more building?
because putting up the 3 hydrant each building is not economical.. please find attache file proposal. the max. radius per hydrant is 50m as per the local code.
also make a comment on my computation if it is valid.
**note. Is anyone has an experience using the ISO method when determining such case?
Thanks and more power
Iam a rookie and having difficulties on determining the location of the fire hydrant and deciding the fire flow for the building area.
I am using nfpa 1 for my reference of the needed fire flow. The scenario is that there are multiple buildings with a separation of 6m on each side for the vehicle road. all the building are dormitory building (as per nfpa 101) with 3 floors, 950sq.m each.Type II (111) construction and as per local code it doesn't require automatic sprinkler.
When computing for fire flow needed I add all the floor area (950*3) and use the table on nfpa 1 to determine the fire flow which is 2500 gpm (I used the full flow and not deducted the 75% max. as per the code because the building is not sprinklered) and equivalent to minimum of 3 hydrant with the max. spacing of 122 meters (also from table of nfpa 1).
does it means that every building i will put 3 hydrant each? or i could do space the hydrant that the 3 hydrant would cover 2 or more building?
because putting up the 3 hydrant each building is not economical.. please find attache file proposal. the max. radius per hydrant is 50m as per the local code.
also make a comment on my computation if it is valid.
**note. Is anyone has an experience using the ISO method when determining such case?
Thanks and more power





RE: fire flow vs. fire hydrant
RE: fire flow vs. fire hydrant
but as per the nfpa 1, that is the required fire flow needed. the fire flow is required flow rate at 20 psi used for fire fighting.
does it means it will be the capacity for my water tank and water supply? or it will be only an indication if the fire hydrant is sufficient within the building and hydraulic calculation would be the basis for the required pump capacity and water tank?
tnx again man.
RE: fire flow vs. fire hydrant
Travis Mack
MFP Design, LLC
www.mfpdesign.com
RE: fire flow vs. fire hydrant
Usually in a case like this you would take your drawings to the local fire brigade (who will be the users of this system) and ask how much water they think the system should have. They might ask for 1000 gpm (which is about 4 hose streams).
RE: fire flow vs. fire hydrant
I disagree. The fire flow values in the IFC and NFPA 1 are commonly applied on a daily basis as these codes are adopted in about 98% of the governmental jurisdictions in the U.S. I know for a fact that questions regarding the proper application of the fire flow are answered on a weekly basis.
RE: fire flow vs. fire hydrant
What do you mean by governmental jurisdiction? Is that a development funded by the federal government? Presumably every public utility is under some kind of government juristiction, probably the city or the county.
When I was working in the US as a sprinkler designer, most flow tests I saw tended to indicate water suppy typically around 1000-2000 gpm in the street. It could be less in a remote area with sparse development.
RE: fire flow vs. fire hydrant
Our local authority (Costa Rica) would require in a case like this:
- One hydrant 2.5NH (most hyd. remote) of 500 gpm @ 85-100psi, or two remote close to each other hydrants 2.5NH 250 gpm @ 85-100psi.
And.
- Exterior and/or interior hose stations 1.5NH 100gpm @ 65-85 psi, with flow removable restrictors or pressure reduction valves.
RE: fire flow vs. fire hydrant
RE: fire flow vs. fire hydrant