Black iron pipe working pressure?

[RickP]

Hello all, this is my first new thread. Does anyone know the max working pressure of schedule 40 black iron pipe for compressed air? (welded, not seamless)

This came up in another thread and I'm confused about whether it's 150 psi or 200+ psi.
I just bought a bunch of 1/2 inch black iron pipe and I'd like to have the pipe at full tank pressure, which is above 150 psi for me.

 

[RickP]

Here's what I found:

ASTM A53 B Carbon Steel Pipes - Max Working Pressure of 214 psi.

ASTM A53 Specification
This specification covers seamless and welded black and hot-dipped galvanized steel pipe in NPS 1/8 to NPS 26. . . The tubing shall undergo a seamless or welding process.

I'm not sure why Lowes rates this pipe as 150 psi max,
but Home Depot rates the same size pipe as 300 psi max working pressure (different manufacturer).

The fittings were different too: Lowes and Home Depot.

This specification might have caused some of the confusion:

ASME B31.9 Building Services Piping - lists the pressure limit as 150 psi.

ASME B31.9 Specification
ASME B31.9 has rules for piping in industrial, institutional, commercial and public buildings, and multi-unit residences

 

[RickP]

So for compressed air piping in a regular home garage, wouldn't the limit be 200+ psi?
(from ASTM A53) Has anyone worked with these specifications enough to know for sure?

 

[Bobdog]

Looks like 214, according to the chart below.

Most shop air is under 150psi, so I'd say you're fine unless you want to run over 200psi, then I'd go to sch 80 pipe.


http://www.engineeringtoolbox.com/astm-steel-pipes-working-pressure-d_775.html

 

[Sureshot]

Hello all, this is my first new thread. Does anyone know the max working pressure of schedule 40 black iron pipe for compressed air? (welded, not seamless)

This came up in another thread and I'm confused about whether it's 150 psi or 200+ psi.
I just bought a bunch of 1/2 inch black iron pipe and I'd like to have the pipe at full tank pressure, which is above 150 psi for me.

It is good to go. Remember it has a safety factor as well. I have seen sched 40 taken to 2000 psi.

 

[LG63]

Is the Lowe's pipe actually marked A53? If not, perhaps it's made to their own commercial spec. Either way I don't think you have anything to be concerned about, there is a HUGE safety factor in these numbers. I would be much more concerned about the tank rusting over time.

 

[RickP]

Is the Lowe's pipe actually marked A53? If not, perhaps it's made to their own commercial spec.

Good call.

Lowes lists code approvals as "N/A"

Home Depot says: "Standard pipe complies with ANSI/ASTM A733, A53"

 

[CNGsaves]

ANSWER . . . .
. . .
. . . . . All the pressure you will ever need in your lifetime !!!

STEPS: . . buy black pipe steel, cut black pipe steel, thread black pipe steel, assemble black pipe steel with pipe dope and/or teflon tape.

 

[crewchief888]

i plumbed our shop with almost 400 feet of black pipe from HD in 2001

no leaks so far.

our compressor kicks off at 175psi.

 

[ddawg16]

Or use PVC......................





after you bang his wife.....



hey...it's Saturday....and beer 30 somewhere.....

 

[koditten]

I've seen countless applications where black pipe was used in hydralic systems.

In any case, the joints will fail long before the pipe does, usually the results of water freezing in a low spot.

I'm in charge of my plants plant air system, so I see alot of what you are asking.

KO

 

[STClurker]

10, the number of posts before PVC was mentioned

 

[some zilch]

my woodsplitter has lots of black iron pipe fittings on it, and it runs at 2750psi

 

[DekeT]

my woodsplitter has lots of black iron pipe fittings on it, and it runs at 2750psi

Serious difference between the effect of liquid and gas on the pressure containment.

 

[CNGsaves]

10, the number of posts before PVC was mentioned

That's old STINKING DDawg . . . 117 posts has Rotted His Brain !!!

He should have just stayed at the ********** since 9,999 posts !!

 

[G_P]

Seen a few log splitters with black iron pipe and fittings in use. No way your compressor will burst the pipe.

Sent via carrier pigeon.

 

[Gas Ax]

So for compressed air piping in a regular home garage, wouldn't the limit be 200+ psi?
(from ASTM A53) Has anyone worked with these specifications enough to know for sure?

I believe the numbers from Engineering toolbox are pretty good I don't have the ASME code in front of me to double check but it passes the sniff test.

Is the Lowe's pipe actually marked A53? If not, perhaps it's made to their own commercial spec. Either way I don't think you have anything to be concerned about, there is a HUGE safety factor in these numbers. I would be much more concerned about the tank rusting over time.

The key item the Lowes pipe doesn't call out is "Sch 40" it likely has a thinner wall thickness which directly impacts the pressure rating.

my woodsplitter has lots of black iron pipe fittings on it, and it runs at 2750psi

Yes but without knowing the diameter and wall thickness of the pipe on there this is meaningless and can lead to dangerous assumptions.

Serious difference between the effect of liquid and gas on the pressure containment.

No pressure is pressure. The pipe will fail at the same point without regard to what is in it. The difference is how much energy will be released when the pipe fails. While most people make the false assumption that if something fails under a hydrolic load it is safe there can still be quite a lot of energy stored if the system is large enough and under enough pressure.

 

[RickP]

ANSWER . . . .
. . .
. . . . . All the pressure you will ever need in your lifetime !!!

STEPS: . . buy black pipe steel, cut black pipe steel, thread black pipe steel, assemble black pipe steel with pipe dope and/or teflon tape.

That's my plan!!

I was just wondering which end of the pipe to install the regulator.

 

[RickP]

No pressure is pressure. The pipe will fail at the same point without regard to what is in it. The difference is how much energy will be released when the pipe fails. While most people make the false assumption that if something fails under a hydrolic load it is safe there can still be quite a lot of energy stored if the system is large enough and under enough pressure.

Thanks guys. I saw so much conflicting information out there buried in other threads, I wanted to settle it once and for all . . . . . .


. . . . . before someone asks how much air pressure PVC can handle!

 

[rockwithjason]

Or use PVC......................





after you bang his wife.....



hey...it's Saturday....and beer 30 somewhere.....

HAHA! well played sir!

 

[jerryd68]

Thanks guys. I saw so much conflicting information out there buried in other threads, I wanted to settle it once and for all . . . . . .


. . . . . before someone asks how much air pressure PVC can handle!

I agree that pressure is pressure, most of the piping systems that I have seen failed are becuase of system upsets, i.e. something happened in the system to cause a slug of water in a steam line or hydrostatic pressure because liquid refrigerant is trapped, or corrosion in condensate lines pitting the pipe or corroding the threaded fittings. Liquid hammer is a very dangerous thing, once that force it moving it doesnt like to stop or change direction. I have seen steam mains blown apart and it is not a pretty sight especially when people are hurt as a result.

 

[DekeT]

No pressure is pressure. The pipe will fail at the same point without regard to what is in it. The difference is how much energy will be released when the pipe fails. While most people make the false assumption that if something fails under a hydrolic load it is safe there can still be quite a lot of energy stored if the system is large enough and under enough pressure.

Yes I know that and did not make any false assumptions. Had I meant what you inferred I would have said "affect" and not "effect". btw, welcome to the forum.

 

[nehog]

That's my plan!!

I was just wondering which end of the pipe to install the regulator.

The end with the hole in it works best.

 

[Bob C]

I have run 245 PSI in schedule 40 Black Iron Pipe.

 

[RickP]

The end with the hole in it works best.

I will definitely make it a point to remember that, Mr. nehog sir!

But I'm confused, did you mean the pointy end or the other end?

 

[Matthew3901]

So the question I have about black iron pipe for air lines is this: What about corrosion from moisture in the air over time? Or is the inside of the pipe treated/coated?

thanks
Matt

 

[Matt Matt]

I have had schedule 40 to 400 psi with proper dope and fittings. Over 100 joints, no leaks. The pipe has no problem holding it, the threads do. Most schedule 40 will hold 10,000 PSI. But, the fittings are not rated for that, neither are the threads.

For most black pipe and fittings and threads, I would suggest keeping it under 200 psi, Unless you’re using a Loctite thread sealant.

 

[kbs2244]

I belive the pipe spec have both a pressure and a burst strength.
Pressure is a constant and burst an "impact" resistance.
(Burst is for a water hammer concern.)
That is the cause of the confusion about PVC drain (non-pressure) pipe
What is printed on the pipe id the burst pressure.
It doesn't stand up to the constant pressure.

They do make plastic pipe for pressure use.
It is not very popular in construction use.

 

[Firebrick43]

Seen a few log splitters with black iron pipe and fittings in use. No way your compressor will burst the pipe.

Sent via carrier pigeon.

You do know they make schedule 80 and schedule 160 pipe? Don't equate black pipe in a log splitter to schedule 40.

 

[Lelandwelds]

So the question I have about black iron pipe for air lines is this: What about corrosion from moisture in the air over time? Or is the inside of the pipe treated/coated?

thanks
Matt

It gets really nasty if you dont get rid of the water. That why the pipe slopes, has drip legs,exits the top of loop before station drop, and has filters in place. As long as the **** doesnt make it out to where the air is used, it doesnt really hurt anything. Imported SS pipe and fittings sometimes aren't much more expensive.

Try to find good pipe and fittings. Use one of the good thread sealers ( there are 4 or 5 good ones. I like the oxygen safe ones.) If you use teflon, spend $6/ roll not $1/roll. Loops and surge tanks help with air hogs. Pipe unions are your friend. A pipe threader makes the job manageable. Leaks are expensive. Fix them.

Oxygen, fuel gases, and shielding gases can all be piped. Dont use copper for acetylene. All this stuff was pretty much perfected in the 1950s.

 

[firebirdparts]

Serious difference between the effect of liquid and gas on the pressure containment.

Yeah, liquid is a lot worse for shock loads. Are you just making stuff up?

 

[Lelandwelds]

Lets go fail some and get our own numbers.

 

[lakeroadster]

Here's what I found:

ASTM A53 B Carbon Steel Pipes - Max Working Pressure of 214 psi.

ASTM A53 Specification
This specification covers seamless and welded black and hot-dipped galvanized steel pipe in NPS 1/8 to NPS 26. . . The tubing shall undergo a seamless or welding process.

I'm not sure why Lowes rates this pipe as 150 psi max,
but Home Depot rates the same size pipe as 300 psi max working pressure (different manufacturer).

The fittings were different too: Lowes and Home Depot.

This specification might have caused some of the confusion:

ASME B31.9 Building Services Piping - lists the pressure limit as 150 psi.

ASME B31.9 Specification
ASME B31.9 has rules for piping in industrial, institutional, commercial and public buildings, and multi-unit residences

Home Depot lists the pipe as ASTM A53 Grade A.... not grade B
Lowes doesn't list the grade... unless I missed it.

 

[rburke65]

You guys realize this thread is 4 1/2 years old, right?

 

[speed bump]

Why not just walk in and read what is printed on the pipe?

 

[RickP]

So the question I have about black iron pipe for air lines is this: What about corrosion from moisture in the air over time? Or is the inside of the pipe treated/coated?

thanks
Matt

Holy thread resurrection Batman! I'd forgotten all about this thread.

Black pipe is not coated inside -- you could use galvanized pipe if you're worried about that. But I don't like the galv pipe because the coating might flake off the inside of the pipe (and it's more expensive). I'd prefer to use copper over galv pipe.

 

[Matthew3901]

Holy thread resurrection Batman! I'd forgotten all about this thread.

Black pipe is not coated inside -- you could use galvanized pipe if you're worried about that. But I don't like the galv pipe because the coating might flake off the inside of the pipe (and it's more expensive). I'd prefer to use copper over galv pipe.

So in essences you need a trap and dryer in line to prevent corrosion.

Sent from my SPH-L710 using Tapatalk

 

[RickP]

So in essences you need a trap and dryer in line to prevent corrosion.

I wouldn't worry about black pipe corrosion for a residential system -- you're already getting corrosion in the tank, which is going to be a lot worse than in the pipe. A trap at the end of the pipe run will take care of any rust flakes that make it that far, and taking the drops off the top of the mains will also help.

A dryer is needed for removing the entrapped moisture to protect painting or sandblasting from being contaminated with water. A dryer would be complete overkill for preventing corrosion inside the pipes. A Franzinator or other simple method of removing water would be fine for that.

But if you're really worried about corrosion, there are lots of better options out there - copper pipe is one choice, or else aluminum/plastic pipe kits would be quick and easy to install. My design uses black pipe because it stores a lot of extra compressed air in the 3/4-inch mains and it's thermal mass keeps it from heating up too much with my limited use. Plus, it was cheaper than copper.

 

[Lelandwelds]

Black pipe pipe systems had all the bugs worked out 50 years ago. If you have a compressor that can exceed black pipe's numbers, you already know the correct material to use for piping.

I dont think anyone has mentioned the pipe is a decent qualitySTEEL and the fittings are MALLEABLE IRON .

Get your own numbers. Vacant lot. Sand bags. Vertical opening short pipe blast shield. Co2 tank for 700 to 1000 psi. Hydraulic lines. (Just kidding. Destructive testing isnt for amateurs)

Somebody start a pex for airline thread.

 

[toysareforboys]

I dont think anyone has mentioned the pipe is a decent qualitySTEEL and the fittings are MALLEABLE IRON .

The pipe I'm not super worried about but what PSI can you run the fittings at?!

I'm building a liquid propane flame projector for a pyro music firework show. They want a 100ft+ height flame for at least 11 seconds, pretty tricky. They tried a bunch of commercial flame projectors but none of them could go that big.

I found a 33LB forklift propane tank dirt cheap. The stock liquid propane output valve has SUPER slow flow. So instead of using the stock valve I took out the pressure relief valve and put a tee where it screwed into the tank (3/4" NPT), screwed the pressure relief into the tee and put a 500psi rated stainless steel full port ball valve on the other tee port. All the flow you could ever want (run the tank upside down for liquid, right side up for vapor).

The scary part is liquid hammer There's a digitally controlled solenoid flow valve (on/off only, and it's pretty much instant) and with the ball valve fully open (running at full anger) I'd imagine there's going to be big liquid hammer when it closes!

They make a soft close solenoid valve but I wouldn't be able to use ONLY that valve as the flames dance to music for a bit before the big flame and need instant on/off for little fireball puffs. I think I could install BOTH valves (in series even) so during the music I can use my existing quick open/close valve, then during the full anger run I can lock the quick valve open and use the slow close valve to send up the big flame.

Another issue is the fittings get really cold when I run it at full anger. Does temperature effect how much pressure the fittings can take? I'm talking super cold like as in -44c/-47f. After the ice fell off the fittings the first time I used it they rusted almost instantly.

Where can you get beefier fittings? I found a shop selling stainless steel fittings and pipe but they said they are only rated to 150psi!?? They could special order me some 200psi rated ones but they wanted crazy cash for them.

The first time I ran it at full anger the ball valve cracked where the input threads are (on the high pressure/tank side). Luckily it wasn't a large leak and I was able to turn off the pilot light before it ignited. I had to vent all the gas out of the tank to replace the ball valve. I believe it cracked due to the huge amount of thrust from the liquid leaving the solenoid flow valve. It put angled pressure on the pipe and the ball valve is closest to where a pivot point would be so experienced a ton of bending force. I'll have to make sure I super support the solenoid flow valve and piping so no physical pressure is applied to the pipe/fittings.

Let me know where I can get beefier fittings if anywhere. Brass or stainless would be nice (to stop them from rusting instantly). Would like to avoid galvanized so no flakes make it into my control valves.

Get your own numbers. Vacant lot. Sand bags. Vertical opening short pipe blast shield. Co2 tank for 700 to 1000 psi. Hydraulic lines. (Just kidding. Destructive testing isnt for amateurs)

If my regulator ever fails we'll find out real quick! Nitrogen (3000psi) fed directly into the propane tank at 175psi (3/4" port from the nitrogen tank, 3/4" in/out port on the regulator, 3/4" jackhammer hose, 3/4" inch port directly into the forklift propane tank). Common practice in hot air ballooning (nitrogen injection).

And yeah yeah, I know, it violates the cert of the tank and probably a ton of other rules too.

LETS COOK!

-Jamie M.