Daniel, Number one is that you will have to remove the insulation BELOW the wet piping that feeds the upper units. If batts you could simply re-install the same insulation over the pipes. You DO NOT want to encapsulate any piping between layers of insulation. Insulation is just that--insulation. It retards the heat transfer between the areas/objects it separates. If you sandwich the piping you not only retard the heat loss from the pipe but you also retard the heat gain from the room below. You must have heat input, which requires energy and is therefore an active process, to sustain temperatures above freezing when the ambient environment is below freezing. Insulation is a passive system that slows heat loss or gain depending on which side of the barrier your standing. Completely encapsulating will retard both with loss winning in the end unless your original mass is sufficient to retain the heat for the entire time you are experiencing freezing temperatures. Note that the water in the ice cube tray doesn't immediately turn to ice as soon as you put it in your freezer but will in a flash freezer. The object is to make the piping be part of the heated space (the R value of ceiling materials commonly used in apartments is too little to be of consequence) so that the heat gain from the room is greater than the heat loss to the attic. Number two is blown in insulation will likely fail some day no matter how you install it unless you build dams along the runs of piping so the insulation doesn't slide off your "tenting." The insulation is fluid and will, like water, seek it's own level so that the R-38 you applied throughout (which was probably more like R-32 over the piping because it sits higher than the top face of the ceiling material that the insulator will measure from, or maybe be full coverage since he'll hump it over the pipe but then it will settle out over time) will eventually fall to a lesser R value. And it you don't tent in some way the insulation will flow under the pipes thus creating problem one. "Developing a new antifreeze" would entail coming up with an additive that lowers the freezing point of water and is, cheap, environmentally friendly, not a health hazard, will stay in solution with the water without the need for constant stirring, is simple to transport and handle, and, of course, non-combustible. And there needs to be an incentive that makes it worthwhile. Consider that glycerin and propylene glycol have far greater use in the cosmetics, food, and automotive industries, as those chemicals now exist, than they will ever have in fire sprinklers. other chemicals in great abundance with anti-freeze properties that we don't use in our industry are ethylene glycol (highly poisonous) and alcohol (highly flammable). I'm no chemist but I'm sure that there are other things equally dangerous for our purposes out there already that lower the freezing point of water. There are other chemicals that put out fires but they are impractical for full buildings. There are design solutions for the problem in the not yet built buildings but the existing inventory will be a challenge. I'm confident (but can't be sure with my crystal ball in the shop and all) that the TIAs issued the other day will be modified and that some sort of pre-mix will be allowed. For instance in Western Washington where I've never seen temperatures below the high teens in the past 25 years a solution below the combustibility threshold will probably work whereas in Utah that probably wouldn't. In areas of Siberia the utility pipes are above ground and in steam jackets because that's the more effective way to lay pipe than burial.
On Fri, Aug 20, 2010 at 9:20 AM, Daniel Adams <[email protected]> wrote: > Are there any thoughts or ideas concerning development of a new antifreeze > which doesn't have the flammability issues of propylene glycol or glycerine > (and the possible timeframe of when it could be on the market) ? A local > fire authority I spoke with yesterday gave options of heat-tracing (or heat > taping), insulation or a dry system to protect an apartment building which > has a row of attic heads at the ridge and a layer of piping running on top > of the bottom chords of the roof trusses to supply the heads in the units > below. (The lower layer of pipe will be covered with R-38 loose fill > insulation). How can it be determined if the R-38 insulation will adequately > protect the piping below if it is revised into a wet-pipe system ? The > piping that is above the insulation will likely be revised into a dry > system. But this is only one job and thinking of all contractors and > projects out there, the scope of these TIA's is pretty significant. I would > imagine that somebody is working towards development of a new antifreeze > formulation and just wanted to check if anyone has heard of such. > > Thanks, > Daniel N. Adams > Designer > Interwest Fire Protection, Inc. > 404 Ironwood Drive > Salt Lake City, UT 84115 > [email protected] > _______________________________________________ > 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 1101 So. Yakima Ave. Tacoma, WA 253.680.7346 Member: AFSA, SFPE, ASCET, NFPA, NFSA, AFAA, ASEE, NIBS, WSAFM, WFC They are happy men whose natures sort with their vocations. -Francis Bacon, essayist, philosopher, and statesman (1561-1626) _______________________________________________ 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)
