Frans, You've done it again: started a really good debate and ran it to all the way to the heart of the matter. I wonder who profited the most from that decision. On the other hand Isman's comment about using PRVs on the sprinkler and standpipes being OK has me pondering an arrangement where the PRV can be defined as being on the intake side of the standpipe rather than the discharge side of the pump.
On Wed, Apr 7, 2010 at 8:27 PM, Ed Vining <[email protected]> wrote: > Frans, you were too kind to the Technical Committee. The substantiation > should have been rejected. Except for Isman and the other Wisemen, the > Committee should be ashamed of its actions. > > Ed Vining > > > On Wed, Apr 7, 2010 at 3:33 PM, Frans Stoop <[email protected]> wrote: > >> Forumites, >> >> At last I found sort of a "why not" in the May 2003 ROP. >> In my opinion the substantiation is poor. >> Interesting: the committee was not unanimous. >> There are other references in the May 2003 ROP, but it basicly >> comes down to the same. Also interesting: some committee >> members recognize that there will be situations where it is >> unavoidable to apply some form of output regulation, either be it >> by relief valves, pressure reducing valves or variable speed diesels. >> See below what it reads. >> >> Frans Stoop >> TOS architecture & fire protection >> Netherlands <[email protected]> >> Tel. +31-24-324 0112 >> >> >> 20-23-(2-2-4 and 2-2.4.1) : Accept >> SUBMITTER: Technical Committee on Fire Pumps, >> RECOMMENDATION: Revise text to read as follows: >> 2-2.4* The net pump shutoff (churn) pressure plus the maximum static >> suction pressure, adjusted for elevation, shall not exceed the pressure for >> which the system components are rated. >> 2-2.4.1 Pressure relief valves and pressure control valves shall not be >> used >> as a means to meet this requirement >> SUBSTANTIATION: Pressure relief valves are currently being used for >> this purpose in some cases. >> COMMITTEE MEETING ACTION:Accept >> NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE:29 >> VOTE ON COMMITTEE ACTION: >> AFFIRMATIVE: 25 >> NEGATIVE: 2 >> ABSTENTION: 1 >> NOT RETURNED: 1 Vance >> EXPLANATION OF NEGATIVE: >> ISMAN: Our concern is the increase in system cost and corresponding >> decrease in reliability being mandated by the actions of the committee. >> Adequate documentation of a serious problem has been presented to >> the committee regarding the inability to size fire pumps for sprinkler >> systems with high flow and pressure demands such as ESFR systems. An >> inexpensive and technically sound solution was presented to the committee >> consistent with previous editions of NFPA 20. The committee has chosen >> to reject that solution without adequate substantiation and instead wants >> to mandate break tanks. Such a mandate will increase the cost of fire >> protection systems while decreasing the reliability. >> PUCHOVSKY: Sufficient justification has not been provided indicating >> why pressure relief valves cannot be used to regulate high pressures. >> NFPA 13 & 14 currently allow for the usp of such devices in sprinkler and >> standpipe systems where pressures exceed the pressure rating for which the >> system components have been listed. >> COMMENT ON AFFIRMATIVE: >> RESER: I have voted affirmative for this proposal but want the committee >> to be aware that their actions on this log will be difficult to comply with >> in >> some cases. Namely by not allowing the use of pressure control valves or >> pressure relief valves to control pump discharge pressure, some other means >> must be available. It is common to have wide fluctuations of pump inlet >> pressures. Consequently the designer and pump manufacturer must select >> a pump to supply the flow rate at the lowest inlet pressure to be expected. >> This has the potential for discharge over pressurization and the resulting >> safety and performance problems. Some other means such as variable speed >> drivers for fire pumps must be allowed or used. (See 20-113.) >> EXPLANATION OF ABSTENTION: >> DELERNO: There is no valid substantiation for 2-2.4.1. >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> For Technical Assistance, send an email to: [email protected] >> >> To Unsubscribe, send an email >> to:[email protected]<to%[email protected]> >> (Put the word unsubscribe in the subject field) >> > > > > -- > Ed Vining > 4819 John Muir Rd > Martinez CA 94553 > 925-228-8792 > Cell 787-0465 > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email to:[email protected] > (Put the word unsubscribe in the subject field) > -- Ron Greenman Instructor Fire Protection Engineering Bates Technical College Tacoma, WA Member: SFPE, ASCET, NFPA, AFSA, NFSA AFAA, NIBS, WSAFM, WFC _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
