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Thickness of compress air tanks, and max pressure of brass fittings? Answered

Who here knows about compress air?

Regarding about the tanks in standard air compressors if i'm ryt (70 to 90psi) how thick is the tank and is it stainless?

also, standard brass fittings? wat r der maximum presure??

i need to know these for safety before i can proceed with my proj, if im correct presure tanks have d tendency tio explode. and metals shatter.
so... i dont want to die yet...

can anyone help?


If you are dealing with home made or modified high pressure systems, you should fill it with water and slowly increase the pressure using a regulator up to a level above the maximum working pressure, from a safe distance, in order to ensure that it can safely withstand the pressure.

As for fittings, it is probably best to get them form a source that shows what standard they are made to, or the max. pressure.

its the maxiimum working pressure i'm having problem knowing, i understand dat St2=pd den just diide by factor of safety... but its because i'm not expose to dis practice as much..

is submerging it in water a safety precaution? again speaking on stock knowlege, i understand dey do dat in hydrolic testing for leakage, and to lower temp like wat they do in scuba tanks...

since the only compressor i have is the standard compressors, so i'm ptting my limits to say 70 to 80 psi...

i wana know how thick should my cylinder must be...
like , those any one know if theres like a rule of thumb in pessure vessels...

.  You don't submerge the tank, you fill it with an incompressible fluid (very often water is the best choice) and then pressurize to approx 2.5 times (depends on use, but 2.5 is a good figure for stuff that will be around ppl) the working pressure. Make sure there is no air or other compressibles in the testing fluid. Pressurize the vessel and block it in. If the pressure doesn't drop after 4-24 hours, you are good to go. Keep temperature constant.
.  Why an incompressible fluid? It doesn't "explode" like a compressed fluid. Once the pipe is breached, pressure drops to zero - there should be very little collateral damage.

HEY!!! i like the idea!!! and yeah much safer!!!... but does this mean that the"sorry for the term" presurizer of the test vessel is str8 up to a compressor???like a piston pushing tru the liquid....?

Around 3mm thick is common in that pressure range. Usually they are made of mild steel. Standard brass airline fittings can handle over 100 PSI.

3mm? not to re ask or doubut, but aint that to thin? again just asking... mild steel? is that CRS (cold roll stell?) i have access in stainless, brass, crs, and aluminum( but the aluminum i have access is the lowest grade, usualy use in decoratives) how would i know if its mild steel?

No, that's pretty well standard for small air tanks. Yes, CRS.


.  +1 ... assuming a small tank. To get a proper number for the thickness you need to know the load on the tank, geometry of the tank (round? cylinder? dished heads?), type of metal (as per Steve, mild steel/CRS should work well at the relatively low pressure you are using), &c. As a rough rule-of-thumb, the bigger the tank, the thicker the metal required.
.  In real units, that's ~1/8 inch. ;)

i'm sorry, wats dished head? dats the 1st tym i heard of it.

well ok, i was gonna ask dat if 70 psi falls in the category of small air tanks, red ur info, so i guess u know wat ur saying.. cool, corses on mach shop, sadly im on phil...

any ways... so 3mm is ok crs.. so is dat like with factor of safety, or i'll go say 5mm to be safe? and... is this how to put it, should be a solid? like.. a pipe/tube, or a solid bored? or can i roll a sheet? and weld? but it could be weak.. (although good failsafe..) but i guess u its har to roll a 3mm sheet... to about 2 - 4 in diam..

Use a piece of mild steel pipe - weld 6mm ends on it, but you need to get it pressure tested before you use it. That must be done hydraulically - surprisingly, you may find the local fire station can do it for you.


aww.. sadly... fire station in our country maye aint like urs in the uk, ours are all just trucks, dey dont even have scba... plus its not really a station, more like the fire trucks are just parked in d streets. hahaha,

any ways... i still dont get d part of pressure testing. uhm... cant i like just... make d pipe, it wnt be spherical at the end... but i'll make it thicker i guess... but ... again... wats the testing for? and wat do u mean by hydraulicaly done? are u refering to bigger compressors?

A gas filled pressure vessel is a bomb, just not exploded yet. Hydraulic testing makes sure that the thing is safe by testing at 150% overload, in a way that, even if the tank bursts, leaves you only with wet feet and in possession of all your limbs.


u mean like, we will test it for 150, if it held, meaning i have assurance it will be ok for 100% sumthing like dat?

150% is nearer 200PSI, but yes, and also MAKE SURE YOU HAVE AN OVERPRESSURE VALVE.


relief valve... or safty valve, got it, tnx... 17 days, den i can give my focus to this proj. in 17 days i'll be taking my bored exam. but tnx bro! still have to find d facilities to test it thogh... but tnx! i'llrepost maybe if i have other probs that occur.. hehehe!