Venus and Mars. I raise hypothetical questions, you hunter-gatherers answer the question instead of pursuing the issue of statistics :) and how to find them. Quite a change from the suggester of a group hug:)
I agree on the BFP, MIC, and although we often have the ITC on a riser manifold, we generally have a way to bleed the air off the high point to avoid false signals. Good point on calculating the Expected Value, taking the frequency a step further and including impact. glc -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Chris Cahill Sent: Friday, February 27, 2009 11:02 AM To: [email protected] Subject: RE: statistics But if you are doing a risk analysis you are forgetting the outcome side. For example, failure of a BFP to protect the public in theory could be catastrophic to many if not all on the water supply. Failure of a BFP in a fire should only affect one building. On the theoretical side some may die from the fire and/or billions of $ lost but it ain't getting a whole city sick or contaminating an aquifer used by 10's of millions. So the rates alone are irrelevant. You need to take risk and multiply it by loss then you have the answer on which way to go. Don't get me wrong BFP's are a bunch of hooey. 1st question - about 0 for both, BFP's are a waste of money in the first place. 2nd - MIC is an issue we need to or will be dealing with more often. Remember ESF only seems at this point to be an Allied problem. I vote treat the MIC. 3rd - off the end gets some/most air out reducing false alarms and eliminating some air/water interface rusting. MIC coatings help with the added oxygen in the water. I vote end. Chris Cahill, P.E. Fire Protection Engineer Sentry Fire Protection, Inc. 763-658-4483 763-658-4921 fax Email: [email protected] Mail: P.O. Box 69 Waverly, MN 55390 Location: 4439 Hwy 12 SW Waverly, MN 55390 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of George Church Sent: Friday, February 27, 2009 9:15 AM To: [email protected] Subject: statistics Just as we recently discussed that we don't know how many heads a year are installed, or how many have been installed in the past 100+ years, when discussing unexpected activations, statistics of some order of magnitude would be helpful in numerous other things. Which occurs more frequently, failure of a backflow to protect the public supply, or failure of a backflow to allow full forward flow of water to a sprinkler system when needed? Is the possibility of MIC greater than the likelihood of ESF from MIC coatings? This would aid us in deciding, on systems comprised of combo steel and CPVC, if we want to use uncoated pipe (more susceptible to MIC) or risk Environmental Stress Fractures? Is it better to run the ITC off the riser and limit the new oxygen into the system, or run it off the tail end and check for blockage? There are countless other items we have no data upon which to base our decisions. Our best guesses may be completely wrong- guess our batting average would be no better than 50-50, and likely the answer may be based on something more important but not considered. glc -----Original Message----- From: George Church [mailto:[email protected]] Sent: Friday, February 27, 2009 10:07 AM To: '[email protected]' Subject: RE: Fire marshall Just as a plumber would assume testing a sprinkler backflow is limited to the backflow portion of the test, not aware of the forward flush we're more concerned about. glc _______________________________________________ Sprinklerforum mailing list http://lists.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) _______________________________________________ Sprinklerforum mailing list http://lists.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) _______________________________________________ Sprinklerforum mailing list http://lists.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)
