7.2.4 in entirety is as follows:
*7.2.4* When system pressure-regulating devices are used in lieuof providing separate pumps, multiple zones shall be permittedto be supplied by a single pump and pressure-regulating device(s) under the following conditions:(1) Pressure-regulating device(s) shall be permitted to controlpressure in the lower zone(s).(2) A method to isolate the pressure-regulating device(s)shall be provided for maintenance and repair.(3) Regulating devices shall be arranged so that the failure ofany single device does not allow pressure in excess of175 psi (12.1 bar) to more than two hose connections.(4) An equally sized bypass around the pressure-regulatingdevice(s), with a normally closed control valve, shall beinstalled.(5) Pressure-regulating device(s) shall be installed not morethan 7 ft 6 in. (2.31 m) above the floor.(6) The pressure-regulating device shall be provided with inletand outlet pressure gauges.(7) The fire department connection(s) shall be connected tothe system side of the outlet isolation valve.(8) The pressure-regulating device shall be provided with apressure relief valve in accordance with the manufacturer’srecommendations.(9) Remote monitoring and supervision for detecting highpressure failure of the pressure-regulating device shall beprovided in accordance with NFPA 72, National Fire Alarmand Signaling Code.* I may be reading it wrong, but I don't see this section as being applicable only when two hose connections are used. Tony On Wed, Sep 6, 2017 at 12:34 PM, Steve Leyton <[email protected]> wrote: > Read 7.2.4 closely: “Where more than two hose connections are used > downstream of a pressure-regulating device …” > > > > A floor control assembly or a single hose connection with integral PR > device does not require redundancy or a bypass because that section of the > standard only applies to multiple hose connections influenced by a single > PR device. > > > > My opinion only, but the standard clearly says what is says … > > > > SL > > > > *From:* Sprinklerforum [mailto:[email protected]. > org] *On Behalf Of *Tony Silva > *Sent:* Wednesday, September 06, 2017 11:27 AM > *To:* [email protected] > *Subject:* PRV By-pass > > > > NFPA 14, 2010, 7.2.4 (4) requires a bypass across a prv. Is it only when > multiple smaller prv's are used instead of a larger prv, or whenever any > prv is used? > > My application is there is a prv at the floor control stations supplying > combined sprinkler/standpipe. Would this prv need a by-pass? > > The other question is will every prv need control valves upstream and > downstream? > > I know it is good engineering practice to have the valves and by-pass, but > very often there is not much space inside the stairs. What is the general > industry practice? > > Thanks, > > Tony > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler. > org > >
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