From owner-freebsd-isp Tue Feb 20 14:47:52 2001 Delivered-To: freebsd-isp@freebsd.org Received: from bsdie.rwsystems.net (bsdie.rwsystems.net [209.197.223.2]) by hub.freebsd.org (Postfix) with ESMTP id B480437B401 for ; Tue, 20 Feb 2001 14:47:49 -0800 (PST) (envelope-from jwyatt@rwsystems.net) Received: from bsdie.rwsystems.net([209.197.223.2]) (2350 bytes) by bsdie.rwsystems.net via sendmail with P:esmtp/R:bind_hosts/T:inet_zone_bind_smtp (sender: ) id for ; Tue, 20 Feb 2001 16:44:46 -0600 (CST) (Smail-3.2.0.111 2000-Feb-17 #1 built 2000-Jun-25) Date: Tue, 20 Feb 2001 16:44:46 -0600 (CST) From: James Wyatt To: David Drum Cc: freebsd-isp@FreeBSD.ORG Subject: Re: Redundancy... In-Reply-To: <20010220153328.A76130@elvis.mu.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-isp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Tue, 20 Feb 2001, David Drum wrote: > Quoth Jim Sander: > > Some areas will prohibit you from storing liquid fuel on premisis. > > Storing a couple 20lb H2 tanks (or CNG/LPG/propane if the cell can do a > > clean conversion for you) is much more acceptable (if no less dangerous > > under proper conditions) than a having a big jug of diesel around. > > I would like to second Jim's comment about the danger of compressed > gas tanks. Storing compressed, flammable gas cylinders indoors is > equally dangerous/illegal to liquid fuels. While hydrogen will disperse > if not enclosed, other gases (propane) will pool at the point of lowest > elevation, guaranteeing an eventual concentration sufficient to sustain > combustion if ignited (boom). As if we haven't moved far enough off-topic here... Most liquid fuels are toxic and head for the water table when leaked. Most gasses disperse, though they can pool if leaked indoors. Few gassious fuels have the energy/weight or energy/volume ratios that liquid fuels do. It is also easier to double-wall liquid storage tanks and use water-based leak detectors in the interstial cavity thus created. btw: We had a snake that "found" the primary power feeds to a large machine room for one of our customers. No problem, just have all the hosts and Lieberts on a huge UPS long enough to start the very large generator, right? Well, the transfer switch between the generator, UPS, and utility mains died - a critical single point of failure. 25 minutes later we had a dark, warm machine room with dozens of RS/6000s and Compaq servers getting a *very* involuntary shutdown. Cooked a few drives when the A/C stopped. You can't avoid all risk, but you can manage most of it and plan for worst-case. Generators do not remove all UPS and utility power risk. - Jy@ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message