black and galvanized pipe for air lines - 150psi max?

[CNGsaves]

Let's help the OP finish what he started . . . installing a black pipe steel air line system. It excellent for moisture disipating, strong, affordable, and easily built.

OP states multiple times that PVC idea is dead . . . he's fully aware of danger.

Finally, OP never asked a thing about copper.

Let the guy install his black pipe steel air line system and be done with it. I'd even say go ahead and put in 1" black pipe (even SCH 80 or higher) if it makes him happy (it's his money)!! It will be a beast and last air line system he'll ever need.

I'm with you OP . . . let the black pipe build begin!

 

[tk06]

Let's help the OP finish what he started . . . installing a black pipe steel air line system. It excellent for moisture disipating, strong, affordable, and easily built.

OP states multiple times that PVC idea is dead . . . he's fully aware of danger.

Finally, OP never asked a thing about copper.

Let the guy install his black pipe steel air line system and be done with it. I'd even say go ahead and put in 1" black pipe (even SCH 80 or higher) if it makes him happy (it's his money)!! It will be a beast and last air line system he'll ever need.

I'm with you OP . . . let the black pipe build begin!

your replies are really helpful, why thank you.....

 

[tk06]

good little calculators to determine pipe size psi drops, thought it might help someone else sometime

http://www.kaeser.com/Online_Services/Toolbox/Pressure_drop/default.asp

http://www.about-air-compressors.com/estimating-pressure-drop.html

 

[tk06]

Where are you guys getting your numbers?

Try this one.....

http://www.kalhour.com/downloads/psi_chart_as_per_pipe_wt.pdf

Schedule 40 3/4" pipe should be good for about 2000 PSI.

Don't even bring up the PVC for airline issue.....it's been beat up too many times on this site....

Another option is copper pipe......

To be honest, I had not thought about copper pipe at all, but copper would be much easier to install, especially if one can get it in 21' lengths as well, im not sure what CNGsaves meant with " installing a black pipe steel air line system. It excellent for moisture disipating, " anyhow im going to ask about copper price and see just how much more it might be. thanks for the help!

 

[Alchymist]

T... anyhow im going to ask about copper price and see just how much more it might be. thanks for the help!

You are probably not going to like the answer - copper is quite expensive.

 

[tk06]

You are probably not going to like the answer - copper is quite expensive.

I have to look at the difference in type l or type M copper not sure why M would not handle 200 psi for future growth if needed

I'll be calling them this morning some time

 

[djjsr]

Type M will work just fine. Even the annealed specs far exceed anything you'll get from the normal garage compressor.

Refer to table 3C.


http://www.copper.org/applications/plumbing/techref/cth/tables/cthindex_table.html

 

[CNGsaves]

I have to look at the difference in type L or type M copper not sure why M would not handle 200 psi for future growth if needed

I'll be calling them this morning some time

Copper is going to be more expensive!! PLUS, more importantly with copper you will be losing the moisture disipating benefits of black pipe. With copper, you'd at minimum need a Franzinator first, then moisture separators/filters at each drop. With black pipe (especially oversized 3/4" or 1" as OP intends), may be little need for Franzinator and minimal moisture at each drop.

I'm sticking with recommendation of 3/4" black pipe if OP wants all one size, and then spend to heart's content on "higher psi" levels of pipe depending on his budget. Good luck!

 

[djjsr]

Current prices at Menards ........

10' black steel
1/2" $7.96
3/4" $9.96
1" $13.96

10' M copper
1/2" $8.48
3/4" $13.98
1" $23.98

 

[BD1]

If you want a slick clean copper install ,go with PROPRESS.
http://www.bing.com/images/search?q=propress&qpvt=propress&FORM=IGRE

It will be a few bucks more but nice and clean. Most suppliers will rent you the tool too.

 

[rburke65]

What kind of compressor do you have that you are concerned with psi values of this degree?

 

[rlitman]

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

ASTM specs

Great link. Look down the ratings column, and you'll notice a huge jump in pressure rating when you go from 2" to 2 1/2" pipe. Clearly, the point of failure is in the threaded fittings. When you go to welded connections, the strength nearly triples.

Read the mfg specs - the rating is for water, not air. Big difference and the mfg will not recommend using PVC for air.

And that's the big point about steel pipe. Black pipe's working pressure is rated for saturated steam. This is calculated based on a formula that gives sufficient derating (a service factor that could be 10x) from a yield pressure (which is still well below the burst pressure).

PVC is rated for liquid pressure, which does not have any safety derating from the yield pressure. I recall a thread somewhere where somebody applied proper derating to PVC for service with a compressible gas (not even steam, which is just impossible), and 7PSI was the number they came up with that would give you a comparably safe limit for PVC use.

 

[Air_Cooled_Nut]

If you want a slick clean copper install ,go with PROPRESS.
http://www.bing.com/images/search?q=propress&qpvt=propress&FORM=IGRE

It will be a few bucks more but nice and clean. Most suppliers will rent you the tool too.

I read a PDF document on that and it looks nice. I wonder how much more (percentage-wise) it would cost over black pipe.

 

[Clik]

I've got a left over 200 roll of pressure washer hose I plan to use. It's rated for 3000 PSI.

If I didn't I'd look into HDPE. Some shop air line kits use it with a liner to keep it rigid. That defeats the purpose to me but I guess looks sell. I'd prefer to bend around corners and over the garage doors. You need drip legs to drain moisture anyway, so, just put them in the low spots which is the only way they'd work optimally anyway.

 

[Clik]

If you use copper keep it off of concrete walls with plastic hangers as electrolisis will eat it up after a while. If you run it through a wall, sleeve it with PVC or wrap it in insulation.

 

[CNGsaves]

I've got a left over 200 roll of pressure washer hose I plan to use. It's rated for 3000 PSI.

If I didn't I'd look into HDPE. Some shop air line kits use it with a liner to keep it rigid. That defeats the purpose to me but I guess looks sell. I'd prefer to bend around corners and over the garage doors. You need drip legs to drain moisture anyway, so, just put them in the low spots which is the only way they'd work optimally anyway.

Take a look at OP Title of thread . . . it clearly says OP was considering black pipe or galvanized pipe (ie Steel). Now he knows that black pipe steel is best overall material for the purpose of low moisture air line system. Only decision left was size of pipe and whether higher quality pipe was necessary (not so, IMHO).

Your hodge-podge idea of leftover **** (pressure washer hose or HDPE) is NOT something anywhere as safe and functional as black pipe steel. Go ahead and loosen up lug nuts on your car wheels and drive all you want on abandoned highway . . . . but don't suggest that rest of us do the same!!

 

[FunkyfullWidth]

I don't see why pressure washer hose wouldn't be safe??? I'd be more concerned about the connectors and adapters. Not to mention the id of the hose itself restricting air flow... I don't think pressure washer hose would be very efficient, but unsafe? Why are you saying it's unsafe?

I've used Regular rubber air line run along walls for years with out any problem, and those don't have the pressure raiting of pressure washer hose.

Here's a thread on pressure washer hose...
http://www.garagejournal.com/forum/showthread.php?t=119092

 

[rlitman]

As I said, pressure ratings are not what people read into them.

Air hose is rated for air pressure. Pressure washer hose is rated for hydraulic pressure.
The air pressure rating in pressure washer hose is much lower, but yeah, it would still be fine for air. Just very expensive.

 

[CNGsaves]

I don't see why pressure washer hose wouldn't be safe??? I'd be more concerned about the connectors and adapters. Not to mention the id of the hose itself restricting air flow... I don't think pressure washer hose would be very efficient, but unsafe? Why are you saying it's unsafe?

I've used Regular rubber air line run along walls for years with out any problem, and those don't have the pressure raiting of pressure washer hose.

. . . . can you say Jerry Rig . . . . LOL.

Why build ****, when OP wants to build best LIFETIME air system he can?

 

[FunkyfullWidth]

. . . . can you say Jerry Rig . . . . LOL.

Why build ****, when OP wants to build best LIFETIME air system he can?

I'm not sure what was jerry rigged? I had an air line out of site out of mine that delivered air effectively for what it was needed for. Jerry rigged would be hose clamps and barbed fittings. I wasn't pushing the pressure washer hose, it just doesn't seem practical, especially at 200 feet. Just stating that I can't see why it would be unsafe..

 

[tk06]

Current prices at Menards ........

10' black steel
1/2" $7.96
3/4" $9.96
1" $13.96

10' M copper
1/2" $8.48
3/4" $13.98
1" $23.98

that is much cheaper there than here, Black pipe through industrial supply 1.56 ft home depot in 10ft was 19 bucks

copper 3/4 type m at home depot was 17 for 10 ft, 1" was over 30.00

have not heard from the industrial supply place on copper

I

 

[tk06]

Take a look at OP Title of thread . . . it clearly says OP was considering black pipe or galvanized pipe (ie Steel). Now he knows that black pipe steel is best overall material for the purpose of low moisture air line system. Only decision left was size of pipe and whether higher quality pipe was necessary (not so, IMHO).

your right about not needing schedule 80, I was confusing the pipe rating with fitting ratings, heck I nver knew they were different, I just assumed (shows you never assume) that the 150 meant it was only good for 150 psi, which is the pressure of the fitting not the pipe,

schedule 40 steel pipe will be fine for 150 psi system,

but im still not sure what you meant on the low moisture, are you saying the black pipe is better than galvanized? or better than copper?

hopefully I will have all the prices today and can get this ordered and picked up in the next couple days , and get this done this weekend (crossing fingers)

Again, thanks for _everyone's_ help, I hate doing things twice, and i'm on number two now with this (only have myself to blame there)

Tom

 

[CNGsaves]

but im still not sure what you meant on the low moisture, are you saying the black pipe is better than galvanized? or better than copper?

Yes, by it's very construction a black pipe steel air line system will be better at disipating moisture than copper. You're not going to be able to afford the proper pipe for galvanized, so throw out galvanized altogether. Black pipe is heavy and cold which will take away the heat from compressed air.

Good luck on your black pipe air line system. Only minor details to implement in design is slight slope so any moisture will actually run down main line to drip leg of last drop. Also, I'd recommend that main line of air line system is up high near ceiling, then initially the drops go UP (thus put the open hole of T upwards) so that air has to travel UP to get through the elbows that direct the air back down the drop.

 

[Pcoghlan]

CNG, when you say the proper pipe for galvanized what do you mean?

This for example? I spoke to a local shop here in town and they said their air system was installed using galvanized from the local HD, this one below:

http://www.homedepot.com/h_d1/N-5yc...vanized+pipe+3/4&storeId=10051#specifications

 

[CNGsaves]

CNG, when you say the proper pipe for galvanized what do you mean?

This for example? I spoke to a local shop here in town and they said their air system was installed using galvanized from the local HD, this one below:

http://www.homedepot.com/h_d1/N-5yc...vanized+pipe+3/4&storeId=10051#specifications

Big box store galvanized is not appropriate for air line system as moisture can flake off the galvanized finish. Black pipe is the way to go for air line system.

Yesterday I dropped by my local Lowes and 10 ft stick of 1/2" black pipe steel is $8.99 and 3/4" black pipe in 10 ft stick is $10.82 which is pretty good price.

Likely could beat that price at wholesale plumbers supply like Winnelson or Locke Supply, both would also have contractor length sticks of 21 ft black pipe.

 

[Torque1st]

I have a reference manual I have used for many years. It closely agrees with other references manuals I have acquired also. It gives pressure rating tables for both threaded and welded seamless pipe of various sizes. The threads are the weak points. For 1/2" schedule 40 seamless pipe with welded fittings it lists a working pressure rating of 2,900PSIG, with threaded fittings that drops to 660PSIG. The corresponding safety factors are 5:1 for seamless with welded connections and 10:1 for seamless with threaded. The threading process introduces more variables so the safety factor is increased. Using welded seam pipe depends on many quality factors but it can generally drop the working pressure rating by ~1/2 again or clear down to ~330PSIG for that seam welded 1/2" sched 40 pipe at HD or the supply co.

3/4" sched 40 type pipe has slightly lower pressure ratings of:
seamless welded, 2,398PSIG;
seamless threaded, 631PSIG;
& welded seam threaded ~315PSIG.

YMMV- Don't take my word for it, if you have a critical application have a PE run the calculations required.

Using fittings at slightly higher working pressures than they are rated for reduces the safety margins. Those margins vary among manufacturers and application but generally run at least 4:1 but I have seen much higher.

PVC is not legal or recommended for compressed air or gases. The pressure ratings are for liquid only. The PVC material shatters like glass when placed under stress. Impact, mechanical movement, bending, vibration, thermal, or chemical stress can cause a rupture.

Copper is not allowed in some jurisdictions.

Black steel pipe is specified in most mechanical codes for compressed air systems.

Galvanized is OK but it is not specified in mechanical codes. Use at your own risk. I personally use it.

Nominal (**) size copper pipe has a smaller interior cross section than the same nominal size steel pipe which results in a higher flow velocity, more friction, and a higher pressure drop per foot of line.

Copper pipe fittings and connections have a smoother profile than steel fittings which reduces pressure loss.

In my experience the above two items approximately cancel each other out.

Copper has a higher thermal conductivity than steel pipe. Moisture removal efficiency is basically a wash between similar nominal size copper and steel. Plastic airline materials do not condense the moisture in home air systems properly but they work in industrial settings with refrigerated dryers etc.

Buying an assortment of ******* and fittings can reduce threading and assembly time. Take back any excess you don't need.

Splicing in a new connection is fairly easy. Cut a section of the pipe run at the appropriate point. Remove the two adjoining pipe sections. Shorten and thread the ends of the adjoining sections. Take the pipe with you when you go to the store for fittings and they may thread them for you. Install a Tee fitting and a Union with appropriate sized *******.

Keeping a pipe tap and die around for your air system is not a bad policy.

 

[tk06]

Big box store galvanized is not appropriate for air line system as moisture can flake off the galvanized finish. Black pipe is the way to go for air line system.

Yesterday I dropped by my local Lowes and 10 ft stick of 1/2" black pipe steel is $8.99 and 3/4" black pipe in 10 ft stick is $10.82 which is pretty good price.

Likely could beat that price at wholesale plumbers supply like Winnelson or Locke Supply, both would also have contractor length sticks of 21 ft black pipe.

man where you do you guys live, your pipe prices are far better there than here, black pipe was 1.56 ft for 1" from industrial supply 3/4 was 13.** per 10 at home depot and lowes, copper 3/4 type m was 17+ per 10 ft, and over 2.00 per ft at industrial supply place. I figured lowes and home depots would be about the same price all over,

Maybe I will call further towards atlanta, I did draw out a bit easier route, but I still have to have 160 ft of pipe. then again with only 160 ft of pipe, I really wont save too much,

I'm going to try and get the pipe today, again thanks for all the help, I have learned a lot about the whole air pipe deal, and one thing you guys have done was given me the tools to learn more about it, which may definitely help in the future, when you search the right terms in google there are some nice articles on the subject, heck of the write ups was on this board I did not see, before I started this long thread

 

[Mr onetwo]

Back in my pipefitter days we installed many compressed air systems in factory/warehouse type situations.Almost always used seamless sch40 pipe with 300lb mallable fittings.These industrial type systems generally run 200 to 250 PSI.I would imagine this was the standard engineered formula.In your case I would use 3/4" sch40 A53 ERW pipe(american or canadian) with good american "WARD" brand 150lb mallable fittings for your main and 1/2" drops.Stay away from foreign pipe and fittings if you can...I think the ratings and quality are BS! Make sure you pitch your main and take off your drops from the top.Cold working pressure is well above anything you will need.Also, I have never seen galvanized pipe used in a commercial/industrial air system.The "galvanization" on modern pipe is a far cry from what it used to be IMHO!

 

[DekeT]

I have to question this conventional wisdom about sloping pipe toward your last drip leg. Sure you would have a drip leg at the end but i find consider inducing water in the direction of your output to be counter productive. I think it more useful to slope back to the tank to collect moisture and use either the tank or a drip leg just outside the tank to collect moisture. That way you may conveniently relieve the tank and the air lines within easy reach. If use a shutoff between the tank and lines you can empty the lines by simply releasing the stored air in the line.
More moisture is condensed near the tank with less farther downstream. If you have a long lines it just seems more efficient to drain closer to the condensation.

 

[Torque1st]

I have to question this conventional wisdom about sloping pipe toward your last drip leg. Sure you would have a drip leg at the end but i find consider inducing water in the direction of your output to be counter productive. I think it more useful to slope back to the tank to collect moisture and use either the tank or a drip leg just outside the tank to collect moisture. That way you may conveniently relieve the tank and the air lines within easy reach. If use a shutoff between the tank and lines you can empty the lines by simply releasing the stored air in the line.
More moisture is condensed near the tank with less farther downstream. If you have a long lines it just seems more efficient to drain closer to the condensation.

Keep the moisture moving in the direction of the airflow. If you slope your lines like you suggest the water will pile up due to airflow and re-enter the airstream as droplets.

SEE:
http://www.tptools.com/StaticText/airline-piping-diagram.pdf

 

[kwb]

How the hell are you guys saying moisture goes away? It might condense out but it has to go somewhere and it will either be through the tool or caught in a watertrap.

Secondly - the only part of my (or any system I have been around) air piping is discharge of compressor to the tank. The lines from tank to the shop have never felt anything different than the ambient. Maybe if you have a really big compressor on a small tank would this become an issue but it just isn't anything I have seen in practical application.

 

[Clik]

Quote:
Originally Posted by Clik
I've got a left over 200 roll of pressure washer hose I plan to use. It's rated for 3000 PSI.

If I didn't I'd look into HDPE. Some shop air line kits use it with a liner to keep it rigid. That defeats the purpose to me but I guess looks sell. I'd prefer to bend around corners and over the garage doors. You need drip legs to drain moisture anyway, so, just put them in the low spots which is the only way they'd work optimally anyway. Take a look at OP Title of thread . . . it clearly says OP was considering black pipe or galvanized pipe (ie Steel). Now he knows that black pipe steel is best overall material for the purpose of low moisture air line system. Only decision left was size of pipe and whether higher quality pipe was necessary (not so, IMHO).

Your hodge-podge idea of leftover **** (pressure washer hose or HDPE) is NOT something anywhere as safe and functional as black pipe steel. Go ahead and loosen up lug nuts on your car wheels and drive all you want on abandoned highway . . . . but don't suggest that rest of us do the same!! --------------------------------------------------------------------------------
3000 PSI Pressure Washer hose is rated for what 15 TIMES what a shop air compressor puts out? How would that be "unsafe"? I have used Pressure Washer and Sewer Cleaning Pressure Hose up to 1.5" for 40 years. The idea that it's rated for hydraulic not air would only give it a higher safety factor. Air doesn't have near the kinetic energy of water. Water hammer creates much higher pressure spikes than air ever wouthey wouldnld. The idea that there's something wrong with HDPE is BS too. There are many companies selling HDPE kits to pro shops and have been for years. Pipe material is irrelevant to water removal. You need drains and seperator/filters regardless of pipe material.

 

[Alchymist]

--------
3000 PSI Pressure Washer hose is rated for what 15 TIMES what a shop air compressor puts out? How would that be "unsafe"? I have used Pressure Washer and Sewer Cleaning Pressure Hose up to 1.5" for 40 years. The idea that it's rated for hydraulic not air would only give it a higher safety factor. Air doesn't have near the kinetic energy of water. Water hammer creates much higher pressure spikes than air ever wouthey wouldnld. The idea that there's something wrong with HDPE is BS too. There are many companies selling HDPE kits to pro shops and have been for years. Pipe material is irrelevant to water removal. You need drains and seperator/filters regardless of pipe material.

The potential energy stored in an air line is what causes the damage when one ruptures. Note that hydro testing is done with water, not air.

And pipe material is relevant to water removal. Very little water will condense out in a plastic pipe compared to a metal one.

 

[CNGsaves]

I've got a left over 200 roll of pressure washer hose I plan to use for air line system . . . . . (clip) . . .
If I didn't I'd look into HDPE. Some shop air line kits use it with a liner to keep it rigid. . . . .(clip) . . . . The idea that there's something wrong with HDPE is BS too. There are many companies selling HDPE kits to pro shops and have been for years. Pipe material is irrelevant to water removal. You need drains and seperator/filters regardless of pipe material.

Oh my, oh my. Start your own thread if you want to cobble together left over scraps of **** to build air line system. The OP was asking what he thought was legitimate question of PSI limits of black pipe steel for his planned air line system. He got plenty of scientific data to convince him black pipe steel is more than plenty strong for 150psi or 175 psi that he might put into system.

OP wanted straight answers on budget black pipe steel for his air line system. Looks to me, he's got it! When he's done building it (regardless of pipe size) it will be awesome lifetime air system.

Above Clik comment "Pipe material is irrelevant to water removal" really takes the cake. Looks like your "Google" has not been busy enough. Good luck with making that one work!

 

[djjsr]

Yes, by it's very construction a black pipe steel air line system will be better at disipating moisture than copper.

I don't understand this. What does this mean?

 

[tk06]

well now that I have done Black pipe install, I thought I would give a update

Black pipe is a lot of work, particularly when you do 1", 3/4" is MUCH easier to work with, and by that I mean it is much easier to cut, thread, handle and tighten.

that said, even at the price of copper being right at 4 bucks a ft for 1" copper and just over 2 dollars a ft for 3/4" copper around here, (home depot had some 10 ft sticks in 3/4 1.79 ft) but did not carry the higher grade in 3/4,

I think there was very little money saved going to steel. even though the steel prices where just over a buck a ft! that is unless you have plenty of time and do not pay anyone to help do the install, and also just straight runs with little turns,

anyhow you have a choice, black pipe or copper, black pipe is cheaper even same sizes, black pipe is much cheaper when you go to 1" diameter sizes and that was my deciding factor.,,,,, but the time involved is far greater than I would have thought, and if your paying someone about 10 bucks a hour for labor help, your not saving anything. even if you payed someone the same to help install the 1" copper, I thought the time difference would had payed for itself

would I do steel again? it all depends on the layout, if in a empty building, to run all the way around a perimeter, I would say I might, only if I did not have to pay for help. and would definitely if doing over 1" pipe, but if it came to the point of having to do a lot of cuts and threading, (plus remember using a pipe wrench on every drop is a lot when you make the t's go up to draw air from the top of the pipe) I would say not no, but HECK no! .... that is if you think you can braze/sweat the joints! plus the copper will look nicer over time I think.

again thanks for everyone's help, I learned more than I thought I ever wanted to know about pipe, (be it copper or steel) . air flow, the benefits of larger diameter pipe and moisture. my install was not the typical shop install as I have a CNC plasma table at the furthest point, when you are running constant air (think holding a blow gun wide open ) all the basic pipe requirements are thrown out the window with larger diameter pipe the air will move slower, less moisture in the line,, less psi drop at end run. at a given cfm ,

did I go over kill with the 1" for my needs? perhaps, but not by much, where I used the 3/4 to run the last 60ft or so and for the drops

and my tidbit on the pvc users such as I was, while taking my down, I held a t in one hand while unthreading a bushing (where a hose quck disconnect was) and the T split , it would have been a very short time before the air pressure blew that T apart, in fact might have the first time I put 150 psi to it, that t was head level , I'm glad I did not pressurize my pvc with the new higher pressure

 

[Torque1st]

Thanks for the feedback!!!

 

[CNGsaves]

Congrats TK06 on completing your black pipe steel air line system!!

With lifetime build you've made with 1" and 3/4" black pipe, you'll have reliable and safe dry air for many years to come.

When you get shop fixed up to point to take pictures, be sure to post your layout for all your hard work. Best of luck to you!

 

[tk06]

Update!! black and galvanized pipe for air lines - 150psi max?

Well, things happen, and it seems now, im going to be doing another pipe install, we bought a piece of property with a decent size shop, ill be adding on too the shop, but not right now,

we are 60 x 30 in size , I sure wish it was 35 deep though, the real issue is, it is only 12ft tall (darn it) makes it hard for a lift, so the part we ad on to will be 16ft

anyhow air lines here we come again......... im going to loop the entire shop with 1" to date I have not had a drop of water come out of my water separators at my plasma table that you could visually see, so tapping the drops from the top of the pipe with a T and having my pipe run slightly but pretty noticeable downhill to dedicated drain lines seems to have worked perfectly since my install years ago now

 

[DekeT]

Re: Update!! black and galvanized pipe for air lines - 150psi max?

Well, things happen, and it seems now, im going to be doing another pipe install, we bought a piece of property with a decent size shop, ill be adding on too the shop, but not right now,

we are 60 x 30 in size , I sure wish it was 35 deep though, the real issue is, it is only 12ft tall (darn it) makes it hard for a lift, so the part we ad on to will be 16ft

anyhow air lines here we come again......... im going to loop the entire shop with 1" to date I have not had a drop of water come out of my water separators at my plasma table that you could visually see, so tapping the drops from the top of the pipe with a T and having my pipe run slightly but pretty noticeable downhill to dedicated drain lines seems to have worked perfectly since my install years ago now

I agree that 1 inch is the way to go. Looping is an added bonus too. The larger pipe size will reduce the velocity of the airflow allowing further cooling. Providing two paths will also reduce velocity and promote cooling.