CR4 - The Engineer's Place for News and Discussion ®


Previous in Forum: Heat Treatment of Metal   Next in Forum: What Is It?
Close
Close
Close
26 comments
Commentator

Join Date: Nov 2006
Location: Roscoe IL
Posts: 70

Process Piping Question

11/27/2016 8:40 AM

not sure if this is the right forum, but here is my question... putting in a chiller system to handle inhibited glycol fluid through heat exchangers to cool 6 EDM machines. I didnt order/spec the system originally but I am performing the install. Piping is all in sched 80 pvc inside bldg but I must breach precast concrete wall to go outdoors to the chiller unit. My question is when I breach the wall and exit the bldg should I switch to brass for external connections? Unit is located outside of Chicago so temp swings are my main concern. Thoughts?

__________________
God's greatest gift is the ability to learn.... and the worst curse is the ability to rationalize our behaviour
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
2
Guru

Join Date: Oct 2008
Posts: 39041
Good Answers: 1533
#1

Re: Process Piping Question

11/27/2016 10:15 AM

Dow Chemical says,

Standard system materials can be used with DOWFROST heat transfer fluids. Steel, cast iron, copper, brass, bronze, solder and most plastic piping materials are all generally acceptable. DOWFROST fluids can also be used with aluminum at temperatures below 150°F (66°C). At temperatures above 150°F (66°C), use of aluminum is not recommended because the inhibitors will not fully protect aluminum components in the system. Galvanized steel is not recommended because the zinc will react with the inhibitor in the fluids, causing precipitate formation, depletion of the inhibitor package, and removal of the protective zinc coating, particularly above 100°F (38°C). Precipitation can also lead to localized corrosion.

When I worked with wet process equipment, for plain water and some chemical solenoids we either went with brass, unless we were using DI water, then 316L. Otherwise we used fittings of the same material as the piping.

You don't say if your plastic fittings will be threaded or socket and how you plan to make the transitions to metal.

I'd say look at your local piping codes then carry on.

Register to Reply Good Answer (Score 2)
Commentator

Join Date: Nov 2006
Location: Roscoe IL
Posts: 70
#2
In reply to #1

Re: Process Piping Question

11/27/2016 11:20 AM

my thought is to transition inside the bldg when I as I make the 90 from slip fit to NPT and then Brass pipe out... I plan to then use a hose to transition to the side of the unit to account for weather related movement and in case some clown smacks into the unit... I also plan on installing a 4ft high gaurdrail completely around the unit for added protection

__________________
God's greatest gift is the ability to learn.... and the worst curse is the ability to rationalize our behaviour
Register to Reply
3
Guru

Join Date: Oct 2008
Posts: 39041
Good Answers: 1533
#3
In reply to #2

Re: Process Piping Question

11/27/2016 11:45 AM

Fine. Use braided SS flex hose.

One other piece of advice, from experience.

Our equipment was unique, expensive, and highly specialized. Yours seems to be very straight forward and the process fluid is benign.

But, build it like it had to be taken apart once a month. In the long run it will save both time and money. Unions are your friend. Tru-union valves, and other replacement parts will save both down time and repair costs over the long haul.

Good luck.

Register to Reply Good Answer (Score 3)
Commentator

Join Date: Nov 2006
Location: Roscoe IL
Posts: 70
#4
In reply to #3

Re: Process Piping Question

11/27/2016 8:24 PM

I have already made all those things...lol including sys drains and ability to isolate any machine for repairs.... the transition section was a coin toss... Thanks for the extra info,I appreciate it!

__________________
God's greatest gift is the ability to learn.... and the worst curse is the ability to rationalize our behaviour
Register to Reply Score 1 for Good Answer
Guru

Join Date: Oct 2008
Posts: 39041
Good Answers: 1533
#5
In reply to #4

Re: Process Piping Question

11/27/2016 8:35 PM

Good for you! Somewhere down the road, some tech will appreciate you.

Register to Reply
Commentator

Join Date: Nov 2006
Location: Roscoe IL
Posts: 70
#6
In reply to #5

Re: Process Piping Question

11/27/2016 8:41 PM

That tech will be me....lol

__________________
God's greatest gift is the ability to learn.... and the worst curse is the ability to rationalize our behaviour
Register to Reply
Guru

Join Date: Mar 2011
Location: Sebastopol, California
Posts: 799
Good Answers: 33
#7
In reply to #6

Re: Process Piping Question

11/28/2016 2:01 AM

Waxing the bishop.

__________________
Most people are mostly good most of the time.
Register to Reply Off Topic (Score 6)
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 25917
Good Answers: 683
#8

Re: Process Piping Question

11/28/2016 4:37 AM
  • There is no technical need to change piping specification once outside the building beyond what is in the end Client's piping specifications, which need to be to hand as a first point of reference.
  • Ambient and process fluid temperatures will determine whether there is any need to lag the pipework. Again, the Client's piping insulation standards will be the first point of reference.

Reinvention of the proverbial wheel is an unnecessary activity when these documents are to hand. These documents will therefore take precedence over any advice received from this forum.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply Score 1 for Good Answer
Commentator

Join Date: Nov 2006
Location: Roscoe IL
Posts: 70
#10
In reply to #8

Re: Process Piping Question

11/28/2016 7:34 AM

Thats been the base of this... they were sold the chiller and heat exchangers some hose and the fluid and essentially told have a nice day..... I have come up with/spec and order the whole system on site had to strip/relocate 70 ft of wall behind /under running machines (visualize fat raccoon in a garbage can) install all the rack and piping design controls install all elec and today I'm starting on the installation in the parking lot for the chiller..... pad for chiller and anchor concrete for guardrails..... has been a very fun time!

__________________
God's greatest gift is the ability to learn.... and the worst curse is the ability to rationalize our behaviour
Register to Reply
Commentator

Join Date: Nov 2015
Location: England
Posts: 83
Good Answers: 1
#9

Re: Process Piping Question

11/28/2016 7:33 AM

Having one of the largest installed shed 80 process cooling systems in the UK, and all the problems of using imperial components shipped from the USA when the rest of the country is metric, I agree transitioning to metallic outside the building is a good idea. We've had a failure due to UV embrittlement, but a lot more down to people climbing/standing on inadequately supported pipework both inside and more over outside the building. Though a lot of pipework is overly restrained by rubber lined pipe clamps, it needs expansion loops and free sliding supports with appropriate anchoring support at valves, which has led to other failures due to expansion/contraction forces. Although your intending to use a glycol coolant don't forget to fit protective filtration to each machines feed, it may do little for years, but it will pay off...

Register to Reply Score 1 for Good Answer
Commentator

Join Date: Nov 2006
Location: Roscoe IL
Posts: 70
#11
In reply to #9

Re: Process Piping Question

11/28/2016 7:53 AM

Thats has been my thought process.... My main concerns going outside w/PVC was 1) temp/enviromental (Chicago are temp and weather swings) 2) maintenance.... my system high spot is the transistion from outside w/drains on both sides so I can isolate the system in case any failure. Each machine is individ valved both electrically and manually for the same reason. The heat exchangers are on custom pvc racks( pretty slick ones ) in the Clean water tank w/ stainless hard piping to elim any leakage into water being chilled. All machines have individ temp controls to maintain temps. The extra info from this thread has been great!! Nice to know I was on the right path all along lol

__________________
God's greatest gift is the ability to learn.... and the worst curse is the ability to rationalize our behaviour
Register to Reply
Anonymous Poster #1
#12
In reply to #11

Re: Process Piping Question

11/28/2016 8:21 AM
Register to Reply Score 2 for Off Topic
Power-User

Join Date: Jul 2016
Posts: 268
Good Answers: 9
#13
In reply to #11

Re: Process Piping Question

11/28/2016 9:45 AM

Some interesting points on how to make your CPVC piping system fail, or keep it intact, most due to installation failures...

http://www.californiasprinklerfitters.org/files/WhyCPVC-OccasFail.pdf

I would worry more about water hammer & accommodating expansion (inside & out) than the impact resistance of PVC or CPVC at low temperatures. Setting up galvanic cells with heat exchanger metal, coolant as the electrolyte? Brass piping is threaded fittings? Assume this is small bore piping?

Industrials often apply (threaded small bore<3"/>=3"welded large bore) stainless steel or black iron depending on corrosion requirements, some PVC, not so much brass...(?)

http://www.vinidex.com.au/technote-parent-page/pvc-pipes-in-low-temperature-applications/

Register to Reply
Guru

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 10004
Good Answers: 122
#14

Re: Process Piping Question

11/28/2016 4:24 PM

I would think South of Chicago, stray bullets would actually be your major concern with respect to leaks. Copper, brass, PVC, even stainless steel leak after a 9 mm bullet strikes them. I suppose you could go for heavy concrete encasement around the piping.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply Score 1 for Off Topic
Guru

Join Date: Oct 2008
Posts: 39041
Good Answers: 1533
#15
In reply to #14

Re: Process Piping Question

11/29/2016 12:11 PM

You might be able to say that about outside Lubbock too, what with all the Jackrabbit shootings going on.

Register to Reply
Guru

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 10004
Good Answers: 122
#16
In reply to #15

Re: Process Piping Question

11/29/2016 12:29 PM

I can't speak about what happens in "country" now, but back in the day, what happened in "country" stayed in "country". We were supposedly smart enough not to aim a weapon at:

1) natural gas pipelines or oil lines (over 95% of these were all buried underground except near well-heads, compressor stations, or refineries or CO2 plants).

2) engine or compressor engine radiators

3) tractor engines

4) irrigation pipe whether active or just stacked up waiting for next deployment

5) horses, cows, chickens, geese, ducks, hogs, or farmers, farmers wives, farmers daughters (especially the ones you might want to date later), farmers sons, or their field hands.

6) never, ever aim a weapon at a farmer's dog.

7) each other - unless it is a BB gun war in a caliche' pit.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Commentator

Join Date: Nov 2006
Location: Roscoe IL
Posts: 70
#17
In reply to #14

Re: Process Piping Question

11/30/2016 7:43 AM

this is far west of Chicago....more worried about some knothead loosing control of vehicle after too many doubleventi latte frappe somethings...lol

__________________
God's greatest gift is the ability to learn.... and the worst curse is the ability to rationalize our behaviour
Register to Reply
Power-User

Join Date: Feb 2007
Location: Aberdeen, Scotland
Posts: 322
Good Answers: 14
#18

Re: Process Piping Question

11/30/2016 9:41 AM

Back in my days working in aquaculture we used polyethylene piping (although this was for sea water). I just checked chemical compatibility and PE is suitable for prolonged contact with Ethelyne glycol.

It has the advantage that it is less brittle than PVC piping.

Register to Reply
Guru

Join Date: Oct 2008
Posts: 39041
Good Answers: 1533
#19
In reply to #18

Re: Process Piping Question

11/30/2016 9:54 AM

And the disadvantage that it needs more support, and may also be more sensitive to Uv degradation outdoors.

Register to Reply
Guru

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 10004
Good Answers: 122
#20
In reply to #19

Re: Process Piping Question

11/30/2016 5:21 PM

Black polypropylene piping comes to mind...

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru

Join Date: Oct 2008
Posts: 39041
Good Answers: 1533
#21
In reply to #20

Re: Process Piping Question

12/01/2016 5:35 PM

Polypropylene and polyethylene are both polyolefins. They are a lot alike, but PP is probably a little better choice.

I'm wondering what is wrong with brass if that's what to OP wants to use.

Register to Reply
Guru

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 10004
Good Answers: 122
#22
In reply to #21

Re: Process Piping Question

12/02/2016 4:15 PM

brass works just fine for that application, as long as the pipe is protected with suitable containment basin, there will be no environmental issue arising for any reason.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Power-User

Join Date: Jul 2016
Posts: 268
Good Answers: 9
#23
In reply to #22

Re: Process Piping Question

12/02/2016 8:49 PM

and maybe check for galvanic corrosion with ss heat exchangers. I haven't seen brass in (larger) industrial plants ever (medical/pharma, chemical, steel/metals, paper etc.(in US, Canada, China), steel, iron, ss, galv steel, even old timey sweated copper from the '50s or earlier copper.

Tho if brass small bore threaded, I imagine no problem getting people who know how to put it together with no leaks, or few leaks. Marine use, I guess fire house?

Register to Reply
Guru

Join Date: Oct 2008
Posts: 39041
Good Answers: 1533
#24
In reply to #23

Re: Process Piping Question

12/02/2016 9:13 PM

It's " inhibited glycol fluid" not salt water.

Register to Reply
Power-User

Join Date: Jul 2016
Posts: 268
Good Answers: 9
#25
In reply to #24

Re: Process Piping Question

12/02/2016 9:47 PM

the inhibited part selected to reduce the cell potential between brass & stainless, any conducting fluid makes an electrolyte...

Register to Reply
Guru

Join Date: Oct 2008
Posts: 39041
Good Answers: 1533
#26
In reply to #24

Re: Process Piping Question

12/03/2016 3:45 PM

The OP can sort that out.

Register to Reply
Register to Reply 26 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Anonymous Poster (1); Deefburger (1); duffdr (6); James Stewart (4); lyn (8); MACA (1); Neiljohn (1); PWSlack (1); rwilliams (3)

Previous in Forum: Heat Treatment of Metal   Next in Forum: What Is It?

Advertisement