benefits of looped FW vs. dead in run 2

[keybo]

I am new to FW design and am QC reviewing several commercial site plans. Our consulting engrg design company seems to always use looped systems for FW to commercial sites (the sites are warehouses, plane hangers, retail)rather than "dead in" runs. Other than the redundancy that a looped system provides, what are reasons for using one system over the other? These are typically small sites with one to 3 fire hydrants.

 

[cvg]

looping your fire control system is just good practice. All things being equal, it increases the pressure and flow at each fire hydrant. Dead end lines are often not allowed by agencies especially where the length exceeds 300 or 400 feet. Pipe size can also be decreased and still provide adequate flows.

 

[RWF7437]

Agreeing with CVG,
looping improves reliability by feeding water from two directions rather than one. This allows some service to continue even after a main break.
looping reduces head loss ( energy loss )by reducing velocity by about half.
looping may also reduce water quality problems by allowing circulation even at times of low flow and by not allowing solids to settle at low points in the pipeline.

These are some of the reasons it is considered good practice.

good luck

 

[keybo]

Thanks for the info.
As a follow up question, does anyone know if commercial insurance companies look at FW system type when setting rates? Do they give lower rates for looped systems? Is this even something they ask about when writing policies?