From: peterwieck33@gmail.com   
      
    Charles, you need to remember that this venue exists to provide overly   
   complex solutions to simple problems after extensive discussions of picayune   
   and irrelevant issues.   
      
   The OP wanted a device to shut off a whole-house exhaust fan if a fire (or   
   smoke) is detected.  Depending on what is already there, he has various   
   options. They are not complicated, do not require specialized skills and are   
   not overly costly.    
   The OP is not discussing an ANSUL system. And, given what I do for a living, I   
   would _NEVER_ even suggest or refer to an ANSUL system in a normal family   
   residence. I would suggest a good Class K fire extinguisher if one is that   
   heavily into it that a    
   standard ABC device would not be appropriate.    
      
   Sprinklers? That is an issue in itself. New-Code around here does require   
   residential sprinkler systems under some circumstances. In new construction,   
   they are merely costly. For existing construction, they can be extremely   
   costly. Doing the math on our    
   house as an example, it would take roughly forty (40) heads to include   
   closets, turns, hallways and such. More if I could not use side-spray heads.   
   Would "city pressure" be enough, or would I have to boost? 80 psi is required   
   at full-flow, so no, city    
   pressure (60 psi on the third floor - I know) would not be adequate. And,   
   should there be an associated power-failure to the fire - Oops - now I need a   
   fuel-fired pump. Note that we live in a center-hall colonial built in 1890.   
   Not an easy finagle to get    
   piping anywhere not already established. Even using a flex material (PEX or   
   Vic-Flex).    
      
   So, the best advice under other-than-extreme conditions is to keep the   
   smoke-detectors up-to-date, test them regularly, and RESPOND to them when they   
   go off. Have the appropriate fire extinguishers in the appropriate locations,   
   and even fire one off    
   every so often to be familiar with their use.  CO Detectors if one burns fuel   
   in unvented or conventionally vented devices, and so forth.  KISS   
      
   Common sense isn't.    
      
   Now, you want some irony?  About 30 years ago, I was involved in a forensic   
   investigation of a residential fire in a house built in 1795, but fully   
   upgraded over the years. The owner had just upgraded his 100A service to a   
   200A service so as to install    
   central AC, and also a brand new whole-house fire alarm, with all the bells,   
   whistles, devices and so forth that were current in the 1990s. Local code then   
   required that said fire alarm be powered directly from the mains, without a   
   fuse or breaker. So,    
   what did our clever electrician do? He connected the feed to the alarm   
   (Copper) into the mains at the lugs (Aluminum). This being a fairly standard   
   house in Chestnut Hill, PA, the basement was typically damp. Well, the   
   aluminum started to talk hard to    
   the copper, and between the two of them, sparks started to fly. *POOF*. Took a   
   mere 45 days from installation. The 200A Panel was a puddle of steel on the   
   floor. The fire got hot enough to ignite 200-year-old rough-sawn SLYP joists.   
   Not easy. And, once    
   they get started, they go.    
      
   Peter Wieck   
   Melrose Park, PA    
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)