rjbrown2
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Everything posted by rjbrown2
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A sticker don't make it so. I worked for the Bell System (Western Electric and Bell Labs and successors) from 1970 till 2002. The standard land line ran on -48 VDC (stemming from the days of local battery) with AC ringing voltage being impressed on it (ended being over 100 V) I won't claim absolute knowledge, but I never ran across 110 V phones as in the usual utility supplied juice
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The Goodson - Hergenrether paper "Investigating the Causal Link Between Lightning Strikes, CSST, and Fire" lays it on coronal type discharge due to enhanced electric fields at the corrugation peaks/valleys. I think I copied the paper from this site a few years ago.
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Not even sure what to say!
rjbrown2 replied to Robert Jones's topic in Fireplaces, Chimneys & Wood Burning Appliances
And I quote from the late 'Uncle' Ben Ellis, a great Bell Labs, Western Electric, AT&T Senior Staff Engineer: "One measurement is worth a 1000 expert opinions." RIP Ben ! and good luck Chad -
What are we trying to accomplish with this material ? What would be the economic justification of several $K for this install ? Any guess on payback period ?
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I think one of the grand arbiters of questions like 'Is this material easily ignitable?' in the US is the UL testing protocols and listings. ASTM too... They put numbers to the flame spread and smoke generation characteristics (optical density) for various products and materials that are presented to them for their published testing procedures. When I used to work for Ma Bell and her children we would submit cable designs for the infamous Steiner Tunnel Test (UL 723 I think)
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My small sample experience with electric water heaters is that 9 years is just a fraction of their useful life. Depending on water chemistry, the biggest problem I have found with electrics is the cal-rod burnout due to 'mineral' deposits. I had one unit where I had to replace the lower rod on an 18 month cycle. I wedged a stainless steel 'fin' against the base between the rod loop and extended the life to over three years.
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You could check the latest edition of the International Residential Code (IRC) for the allowed places and dimensions when drilling and notching floor joists. In the old copy I have it is Section R502
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Spelling in a non-phonetic, poly sourced language like American English is not correlated with the intelligence of the writer. There are some fanciful quotes variously attributed to Jefferson, Mark Twain, et al about the narrowness of people who can only think of one way to spell a word. I liken spelling to good table manners, like not belching loudly after the meal, or wiping your mouth on your sleeve...
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I have two 50 gallon electric water heaters installed in 2007. Both have plug disconnects mounted near each tank.
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That dial-cable driven device is just asking for someone to strip the gears on the dial end or shear a set screw or torsion fail the shaft on the dial end when that someone in the tub sees/hears the tub leaking their (or their child's) nice, hot water down the drain. At least when the old lever type is in the down position, the worst the Gorilla arm is likely to do is to snap off the lever.
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I thought attic access was a fire fighting issue. Behind the fridge presents some issues: First, how the heck are the FFs gonna know its there if no body is home. And, it is a slow down to move it when seconds count.
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Maybe you can have it both ways. To keep the firearms analogy going...You can store the ammo in an ammo cans on the shelf instead of leaving it scattered around on the kitchen table by using footnotes/endnotes or appendices.
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Maybe this is Captain Obvious stuff...048 is 4 tons as short hand for 48,000 BTU/hr or 024 for two tons = 24,000 BTU/hr etc.
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That's where I started, but a gave just a little more than that in words, because the question revolved around the relative importance of pressure vs. flow. It only got mathematical when I was questioned on it. ?It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience.? Albert Einstein Happy T Day!
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Marc: Poiseuille conducted his original experiments in the 1840s using distilled water and eventually extended his work to other fluids. The H-P equation is very much applicable to water. I think I know the root of our difference here (as if anyone cares now except you and me) The form of H-P changes when Velocity is included in the Delta P equation instead of Q Delta P = (32*Mu*L*V)/D^2 The reason I discussed the form that I did was because the variables that were relevant in the discussion were: pressure and flow rate
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Marc: I was putting into words the classic Hagen-Poiseuille (perhaps one of your relates?) equation for laminar flow of an incompressible Newtonian fluid in a long constant cross section pipe. To wit, the pressure drop is expressed as: Delta P = (128*Mu*L*Q)/(Pi* D^4) or in terms of R Delta P = (8*Mu*L*Q)/(Pi*R^4) Where Delta P = pressure loss, L = pipe length, Q = volume flow rate, Mu = dynamic viscosity, D = diameter, R = radius, and Pi is our constant 3.14159...etc
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When you do the math for pressure drop in a circular pipe in the kind of situation you find in residential plumbing, you note that the drop is directly proportional to the volume flow rate (gallons/minute) but inversely proportional to the fourth power of the diameter of the pipe. This is so overwhelming that whenever there is the slightest question about sufficient supply based on pressure, go bigger even if costs a little more. Saying it in other words, for the same pressure drop you will be able to deliver a lot more water to the point that something else will be the limiting factor.
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I don't know about propane, but natural gas is only combustible between about 5 and 15% fuel/air. Given that natural gas is CH4 (molecular weight about 16) and air is 28.something, the gas will be moving smartly towards the heavens. Propane, OTOH is more dense than air, but I don't know how concentrated it could get in this situation and what the numbers are.
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Depending on local environmental conditions in said basement, the concrete might be warmer than the surrounding air (in places like BC) and the conduction heat transfer coefficient is much greater than the free convection heat transfer coefficient of the air - so much engineer BS for it might be a good thing to be on the floor for the battery assuming no flooding conditions
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General Question: Problem area noted and the decision to write it up may be a forthcoming. How comfortable are y'all in general about supplying suggestions or solutions (in writing) to problems that you find (to your clients) given the litigious nature of our society? Especially when, in the process, you might be practicing engineering depending on the subject area which as my Momma used to say might get somebody's "dandruff up."
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Nah..that's too much work. Get one of those heavy gauge 2 or 3 ft extensions with a triple head on it and plug it in, thread it through the verticals and lay it on the deck. Mount a pointy wooden dowel on the inside of the weather cover with the point in contact with the reset button. Viola! or something like that...GFCI pops...deflect the cover with a stick to reset the breaker. Done.
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You see this all the time in industrial settings, but they are controlled environments. One immediate thought is little kids. Although we are dealing with gray water here a high percentage of the time, you wouldn't want your grandbabies playing near the spout where the nasty comes out. I know, I know..they shouldn't be there unsupervised, but it can happen.
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NIST studied the ignition and flame spread characteristics of latex paint versus oil based paint back in 2002 and surprise, surprise. Latex painted surfaces (CMUs) were about 2 times more difficult to ignite than oil based. I wonder how similar the residue of diesel fuel is to oil based paint. After the VOCs evolve from your diesel paint/stain job, wonder whats left? It might not be as scary as it first sounds.
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Maybe belt and suspenders, but how about test the panel to ground for ~V and wear heavy rubber gloves while removing and replacing the panel cover?
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My late in-laws had a home in Scottsboro, AL that was built in about 1968. The electric water heater was replaced in 2000 or 2001. I don't remember the brand.