<azonenberg>
I will be getting a 4-foot ductless fume hood
<azonenberg>
to do more serious chem in
<rqou>
oh ninja'd
<azonenberg>
I've used them but dont own one atm
<azonenberg>
Your vacuum is limited to a bit above the vapor pressure of water, and you cant obviously get an anhydrous atmosphere
<azonenberg>
but they're nice for some stuff
<rqou>
yes of course
<azonenberg>
You know, now that i think about it
<azonenberg>
i think it's basically a diffusion pump
<azonenberg>
but using water as the working fluid
<rqou>
you can pump UHV oil if you want to deal with the mess :P
<rqou>
hmm idea
<rqou>
you should just store LN2 and then use it for both nitrogen supply and vacuum cold traps
<azonenberg>
I dont want cryogenics for several reasons
<azonenberg>
first, shelf life
<azonenberg>
i wont use that much N2 per day, boil-off would result in significant loss
<azonenberg>
vs a sealed pressure cylinder basically doesnt leak
<azonenberg>
second, a LN2 tank leaking/venting will result in significant hypoxia in the area
<rqou>
ah that makes sense
<azonenberg>
A single pressurized N2 cylinder slowly venting into a garage wont render the air unbreathable
<azonenberg>
not enough volume
<rqou>
i guess UCB is different in that we use a ton of nitrogen
<rqou>
and the tanks are outside
<azonenberg>
Yeah but there have still been accidents where LN2 tanks have suffocated people silently
<azonenberg>
If i keep the total volume of inert gas stored in the space to the point that all cylinders venting at once would still keep the air somewhat breathable
<azonenberg>
i dont have to worry about adding gas detectors etc
<rqou>
a number of years back some idiot undergrad here tried to push a 400L dewar down the stairs
<azonenberg>
i bet that ended real well
<rqou>
fortunately it didn't break
<rqou>
not texas A&M :P
<rqou>
lesson learned: just make _sure_ you don't go in the lab during dead week/finals week because that's when tampered LN2 tanks are most likely to explode :P
<rqou>
wait, that doesn't seem right :P :P
<azonenberg>
lolol
<azonenberg>
anyway, yeah
<rqou>
iirc that's actually what the investigation said
<azonenberg>
it's going to take me a year or two to build the lab of my dreams
<rqou>
the tank never exploded before because people were using up the LN2
<azonenberg>
but it should be pretty awesome when i'm done with it :)
<azonenberg>
400 SF of lab space to start, possibly more depending on how many rooms the wife lets me assimilate
<azonenberg>
plus the office area my desk will be at
<rqou>
can I just move into your new house? :P
<azonenberg>
Can you pay rent + lab fees? :p
<azonenberg>
in all seriousness one of the things i like about having my own lab is that nobody else is using it
<azonenberg>
so tools dont go missing etc
<rqou>
there's a lab fee too? :P
<azonenberg>
All these toys arent free...
<nmz787>
my lab fee tonight was I had to go pickup takeout food for my wife
* nmz787
sleeps
<azonenberg>
lol
<rqou>
pfft... wife problems
<rqou>
the solution is to set up the lab first before acquiring a wife :P
<azonenberg>
rqou: lol
<azonenberg>
But if you dont have a wife who signs for all the packages containing your lab equipment while you're out working to pay for the lab?
<rqou>
just don't get things delivered with signature required
<rqou>
or pick them up at the post office, which is fine unless the post office gets closed due to a "safety incident"
<azonenberg>
So don't buy anything interesting? :p
<rqou>
(yes this happened, I don't know what the incident was though)
<rqou>
hilariously, my signature required items are usually the most mundane
<rqou>
usually a piece of crap from eBay
<rqou>
I'm watching my housemates play BotW now, and this game has a ridiculous number of mechanics and distractions
<azonenberg>
Hmm
<azonenberg>
Continuing TRAGICLASER work
<azonenberg>
autonegotiation (in loopback) is successful, it negotiates 100/full
<azonenberg>
it brings up the link, the LFSR and symbol sync is successful
<azonenberg>
Then after about 5 us it drops
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<awygle>
azonenberg: should still get a nitrogen detector imo
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<azonenberg1>
(10:09:39) azonenberg: awygle: it wouldnt be a N2 detector
<azonenberg1>
(10:09:44) azonenberg: it'd be an oxygen detector
<azonenberg1>
(10:09:49) azonenberg: To detect a concentration below "sane"
<azonenberg1>
Also, i dont see the point
<azonenberg1>
If the whole tank leaked the concentration in the room would go from like 21% to 18% or something
<azonenberg1>
which is totally breathable
azonenberg1 is now known as azonenberg
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<pie_>
azonenberg, but what if you're allergic to nitrogen
<jn__>
pie_: in that case earth is a pretty bad planet
<awygle>
azonenberg: I'm just a belt and suspenders fan. Especially for stuff like "I will DEFINITELY NEVER bring more than X amount of this stuff into my garage"
<pie_>
jn__, ;D
<pie_>
*awygle proseeds to do the suspender snapping motion*
<pie_>
wait
<pie_>
belt *and* suspenders? wut
<awygle>
pie_: it means "more than one safety measure"
<pie_>
ahh
<awygle>
If your belt breaks your suspenders still hold up your pants
* pie_
completely misunderstood
<azonenberg>
awygle: well a cylinder has a fixed volume
<azonenberg>
You can do the math for how much the O2 concentration in the room will drop if it all vents at once
<azonenberg>
So for example: 20x20 foot garage, 8 foot ceilings is 400*8 = 3200 ft^3
<azonenberg>
Of which 21% is O2 so we have 672 ft^3 of O2 in there
<awygle>
azonenberg: sure but someday you're getting your cylinder delivery and the delivery guy knocks over his cart full of cylinders and then you die horribly
<azonenberg>
Continuing on, say a 350 ft^3 cylinder would replace 350 of the 3200 ft^3 of air with inert gas
<azonenberg>
So 2850 ft3 of 21% O2 (598 ft^3) then the rest is inert
<azonenberg>
assuming uniform mixing through the space (likely, since N2 is very soluble in air)
<azonenberg>
we have 3200 ft^3 of gas with 598 ft^3 of O2 or 18.6% O2
<azonenberg>
Or 88% of the normal ambient concentration
<azonenberg>
The ppO2 would be the same as moving from sea level to an altitude of ~1 km above sea level
<azonenberg>
Your body wouldnt even notice
<awygle>
It just seems like the risk reward doesn't balance, for me. I'd rather have a backstop to my "safe by design". *shrug*
<azonenberg>
I might put sensors in, but my rule of safety is
<azonenberg>
1) risk reduction / elimination
<azonenberg>
2) engineering controls
<azonenberg>
3) PPE
<azonenberg>
4) alarms
<azonenberg>
3/4 are kinda equal i guess
<azonenberg>
IOW, first priority is to make the system inherently incapable of producing a harmful state
<azonenberg>
Which can be done in this case by limiting total cylinder volume
<azonenberg>
If that fails, you'd have engineering controls like forced air ventilation to ensure some minimum number of air changes per hour
<azonenberg>
ensuring that if the cylinder did leak after X time the air would be breathable even if it wasnt initially
<azonenberg>
and that a slow leak would never reach dangerous levels
<azonenberg>
PPE would be something like a SCBA - totally impractical to wear all the time in the garage
<azonenberg>
and alarms are only there to tell you to GTFO if something goes wrong, they cant protect you at all
<azonenberg>
I just dont see the need for 3/4 if you've engineered the risk out of existence
<azonenberg>
it's like being worried about electrocution on a board powered by two AA batteries
<awygle>
An advantage of a sensor is that it can inform you of a problem that your engineering controls are protecting you from
<azonenberg>
sure you can use insulated tools and the one-hand rule
<azonenberg>
But if contact with the highest voltage on the board (assuming you dont have any step-up converters on it) is harmless
<azonenberg>
there's no point
<azonenberg>
And yes
<azonenberg>
I'd likely get an O2 sensor, but not for the N2 tank
<azonenberg>
it would be if i got a gas fire suppression system
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<azonenberg>
Which, upon discharge, drops the O2 concentration in the room down to about 11% or so which is barely breathable
<azonenberg>
(assuming inergen vs FM-200, Novec, or one of the fluorinated agents)
<azonenberg>
If you then had a N2 cylinder pop on top of THAT you'd have trouble
<azonenberg>
If i had inergen plus inert gas for process purposes, it would not be possible to use engineering design to eliminate the risk of leakage rendering the air unbreathable
<azonenberg>
So then 2-4 come in
<azonenberg>
I'm thinking i may go back to a fluorinated agent though, because inergen looks like it might be more expensive than i had initially budgeted
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<pie_>
>> <azonenberg> IOW, first priority is to make the system inherently incapable of producing a harmful state
* pie_
notes for later
<pie_>
azonenberg, do fire supressants generally mix with air?
<pie_>
im asking because suffocating due to a pool of denser gas is obviously not productive
<rqou>
just run and you probably won't suffocate immediately :P
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<rqou>
e.g. the voice trick with He/SF6 usually doesn't kill people :P :P
<pie_>
hehe
<pie_>
how do you know they arent forever dead inside
<rqou>
nah, i think that label only applies to cartoon characters that own nuclear power plants
<pie_>
:D
<azonenberg>
pie_: It depends on the agent in use
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<azonenberg>
Generally speaking gas suppression agents, other than CO2, are designed to be miscible with air
<rqou>
so, let's rank homelabs in the order of safety: 1) azonenberg 2) awygle 3) whitequark 4) rqou :P :P
<azonenberg>
There's three main types of suppression systems
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<azonenberg>
there's "total flooding" inert gases, like CO2, that basically displace all air in the place in a relatively uncontrolled fashion
<azonenberg>
This is obviously going to be fatal to personnel in the area, but its cheap and easy to set up as you dont need any real precision in cylinder volume etc
<azonenberg>
There's precisely mixed inert gases, like inergen, that are carefully tuned to reduce the O2 concentration in the space low enough that common materials wont burn (more precisely they will combust but the combustion wont produce enough heat to sustain a chain reaction, so it will self-extinguish)
<azonenberg>
but not so low as to be harmful to personnel during escape from the space
<azonenberg>
and then there's chemically active agents like halons, FM-200, Novec, etc
<azonenberg>
These usually are stored as a liquid so they take up less space than gases, cost less in plumbing and labor to install, but the agent itself costs more
<azonenberg>
They work by a mix of evaporative cooling chilling the fire and chemically interfering with the combustion through a variety of means
<rqou>
what happens if you have a thermite fire?
<azonenberg>
None of them will work and some might even make it worse
<azonenberg>
that said, they would probably all help to keep the thermite from igniting anything else
<azonenberg>
you'd get pyrolysis of whatever the thermite touched but if there was no oxygen it wouldn't burn and the fire wouldnt spread beyond the thermite itself
<rqou>
ah ok
<pie_>
self oxidized fun
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<rqou>
what about "highly nitrated yellow dyes?" "asking for a friend" :P
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<azonenberg>
lolol
<rqou>
i assume such chemicals are also banned in your lab? :P
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<rqou>
azonenberg: so in addition to drug precursors and nukes, what else is banned in your lab?
<azonenberg>
High explosives
<azonenberg>
Propellants are OK in moderate quantity if properly stored
<rqou>
so no nitrated yellow dyes
<azonenberg>
Let me put it this way
<azonenberg>
Nothing beyond 1.4S
<rqou>
so on sciencemadness somebody claimed that he actually was visited by LE and managed to get away with describing a compound as a historically used yellow dye
<azonenberg>
lolol
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<rqou>
so, what about using H2O2 to attempt to destroy unwanted side products and using color as the only determiner of when side products were gone? :P
<rqou>
oh yeah, the solvent was acetone
<azonenberg>
...
<rqou>
yes, this happened
<rqou>
apparently the grad student only noticed when he started doing the workup and noticed he had much more "product" than expected
<rqou>
fortunately he realized what he did and reported it
<azonenberg>
and what, then he realized he had a big pile of TATP crystals sitting on the bench?
<azonenberg>
:p
<rqou>
pretty much
<azonenberg>
or did he notice while it was still in solution
<rqou>
hmm i don't know
<rqou>
maybe it was still in solution
<azonenberg>
ah that's *relatively* safe then
<azonenberg>
:p
<rqou>
tatp is surprisingly easy to synthesize
<rqou>
no wonder ISIS seems to like it so much
<azonenberg>
It's so easy to synthesize half the time people make it they weren't trying to
<azonenberg>
And they only notice when they wonder "hey, why is my glassware in pieces and flying toward me at high velocity?"
<qu1j0t3>
i figured it wouldn't take long to reach you.
<pie_>
yeah i wasnt going to show him :P
<pie_>
im pretty sure it came from here
<qu1j0t3>
nah, i got it from elsewhere.
<pie_>
(eh, happens when the same people go go the same channels, also irc memes)
<qu1j0t3>
a PM, even.
<pie_>
hm.
<awygle>
Speaking of properly stored propellants, are there any surprising properties of nitrate salts that I should be aware of, other than "fun oxidizing agent for rocket fuels"?
<rqou>
i thought salts were quite safe?
<rqou>
are you also working on RFNA synthesis? :P
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<awygle>
I think that too, but I am not a chemist
<azonenberg>
awygle: Which salts?
<awygle>
Not just no but hell no
<azonenberg>
Ammonium nitrate? :p
<rqou>
just buy a farm and you will magically become not a terrorist for buying that :P