Path: utzoo!utgpu!watserv1!watmath!att!cbnews!military
From: cga66@ihlpy.att.com (Patrick V Kauffold)
Newsgroups: sci.military
Subject: Re: Ship survivability (USS Midway)
Message-ID: <1990Jul10.024805.10027@cbnews.att.com>
Date: 10 Jul 90 02:48:05 GMT
References: <1990Jul5.020444.14132@cbnews.att.com>
Sender: military@cbnews.att.com (William B. Thacker)
Organization: AT&T Bell Laboratories
Lines: 43
Approved: military@att.att.com



From: cga66@ihlpy.att.com (Patrick V Kauffold)
>From article <1990Jul5.020444.14132@cbnews.att.com>, by wrf@mab.ecse.rpi.edu (Wm Randolph Franklin):
> 
> 1. Standards  for  buildings on land  often  require a heat  detector in
> every storeroom.  Why don't ships do this?  Would the  extra wiring pose
> a greater threat than the earlier notice?  Would there be too many false
> alarms?
> 
Commercial passenger vessels are required to have smoke/heat detectors, plus
automatic doors. These work reasonably well, and have been around for at
least 30 years.

Warships, however, don't have to comply with these standards, and usually 
don't. The primary reason is that warships have a lot of people on board to
run around and check on each and every space. Common practice is to have a
"roving watch"; usually the Deck Dept. has one, and the Engineering Dept. has
one; together, they manage to cover each and every space on the ship. During
the day (when people are working in the spaces), the watches only go into the
uninhabited spaces (voids); at night, each space is supposed to be visited 
on every watch (4 hours), and some are visited hourly (for readings, like
reefer spaces, etc.). So you have (probably) more safety and reliability
with a "people" system.

Recent construction has included electronic smoke detection equipment, but
the traditional roving watch system remains.

> 2.  Why isn't Halon used?  It's used  in computer  rooms on land.   It's
> supposed  to  quench  most fires at  a  concentration not (immediately?)
> fatal  to people?   If it's  a  war,  the immediate danger  of  the ship
> sinking is greater than the danger  of future cancers (the  Agent Orange
> argument).  Note that I'm  not certain that Halon is  a long term hazard
> to people.
> 
Halon is in use on some of the newer ships. Older ships have CO2 flooding
systems, principally in machinery spaces where oil fires might be expected.
I have seen some salt-water sprinkler systems for store rooms which would
be subject to class I fire hazard, but they are not popular because they
require a lot of maintenance and they have a nasty habit of going off by
themselves due to shock, corrosion, etc.

Pat Kauffold AT&T Bell Labs Naperville, IL (708) 713-4726