Is it that time of year ... AGAIN? 4th of July, the humidity hits hard, temperatures soar, the All-Star Game is just around the corner. I guess we need to roll out heat collectors again.
Upturned, downturned, it doesn't matter. Heat collectors not only don't work, the worst-case scenario is that they encumber or interrupt operation of the sprinkler. In a nutshell, a sprinkler is set below the maximum deflector distance to the deck with a metal pan above the deflector. A fire starts at the floor below and, presuming the plume isn't centered on the sprinkler, it rises up past the sprinkler to the deck above and jets out horizontally. The layer of combustion byproduct will eventually log down to the elevation of the sprinkler, but now the deflector is in between the thermal element and the hot layer. The whole thing is a disaster, predicated on the false premise that a 12" square pan will provide any entrapment of heat, which it surely won't. Just say NO to heat collectors and watch out for falling concrete chunks at Yankee Stadium. Steve Leyton Protection Design & Consulting -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Thom McMahon Sent: Wednesday, July 09, 2008 2:24 PM To: [email protected] Subject: RE: Treatment of pipe racks as obstructions Since "Heat Collectors" are not a recognized method of forcing a sprinkler head in an exposed location to operate, a better approach might be "Obstruction Enhancement". So you think your pipe rack will obstruct the flow of water from fire sprinklers mounted above that rack. Don't look for none compliant "Heat Collectors" create an obstruction by enhancing the bottom of the pipe rack, say with a 48" wide sheet of 26ga metal. Now you have a true obstruction and rules to deal with it. Thom McMahon, SET Firetech, Inc. 2560 Copper Ridge Dr P.O. Box 882136 Steamboat Springs, CO 80488 Tel: 970-879-7952 Fax: 970-879-7926 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Wednesday, July 09, 2008 8:24 AM To: [email protected] Subject: Treatment of pipe racks as obstructions All, Maybe I am not looking in the right sections, but I have not found 13, 8.5 and 8.6 to be particularly useful in addressing pipes on pipe racks. For example, you have a situation where a pipe rack 5 ft. below sprinklers that is 6 ft. wide with pipe diameters up to 8" (including insulation" with varying spaces between pipes. What is the consensus on pipe size and spacing of pipes in a rack before it is considered a true obstruction? I realize the conservative approach would be to provide sprinklers under the pipe rack, but that is not always feasible. This seems to be a gray area. What about 2 tier pipe racks? If sprinklers are installed beneath racks, what is the consensus on heat collection methods. There are differing opinions and studies on this. Some say 12" x 12" collectors with downturned edges are good or not good. Some say flat 12" squares are better. Others say no to both or state that collectors need to be much larger. Similar questions relating to cable trays. What say you guys and gals? Thanks, James L.(Jim) Roberts, PE/SET Fluor Corporation 100 Fluor Daniel Drive - C104F Greenville, SC 29607 864.281.5149 864.281.4916(Fax) ------------------------------------------------------------ The information transmitted is intended only for the person or entity to which it is addressed and may contain proprietary, business-confidential and/or privileged material. If you are not the intended recipient of this message you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any action taken in reliance upon this message is prohibited. 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