svs3
Contributor
Try the NOAA Diving Manual 4th edition pp. 15-18 and 15-19
Peace,
Sam
Peace,
Sam
O2 Cleaning of Tanks
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blacknet
Contributor
Hello,
Warhammer, again see mil-std-1330 for exact procedures involved in o2 cleaning. There's more involved steps than using 'simple green'.
Ed
Warhammer, again see mil-std-1330 for exact procedures involved in o2 cleaning. There's more involved steps than using 'simple green'.
Ed
rainreg
Garlic Breath
Hey guys and gals well I am back after extensive researching the post from Svs3 (great job on the research Svs3, but you need to go that one step further to get the latest and greatest info).
I am forwarding KN the two (2) Abstract papers that were completed after the document you posted. Elliot Forsyth also completed these Abstracts. (One of the Abstracts is 10 pages long the other is 14 pages long) They also have several References you may find interesting.
KN will post the Abstracts on the board for all to view. This is the latest and greatest information and also explains in-depth the previous document you posted. I hope you will all read the information and put it to good use.
Rainreg
"Back to my research"
I am forwarding KN the two (2) Abstract papers that were completed after the document you posted. Elliot Forsyth also completed these Abstracts. (One of the Abstracts is 10 pages long the other is 14 pages long) They also have several References you may find interesting.
KN will post the Abstracts on the board for all to view. This is the latest and greatest information and also explains in-depth the previous document you posted. I hope you will all read the information and put it to good use.
Rainreg
"Back to my research"
King_Neptune
Founder
Here there are in Adobe PDF format as either an actual PDF file or as a PDF file inside a self extracting EXE file (SFX) for better download. Chose your desired format ...
1) Scuba Paper .pdf ...
2) Cleaning .pdf ...
3) Cleaning .exe ...
4) Scuba Paper .exe ...
5) Both PDFs in a .exe ...
Any problems just let me know.
=-)
1) Scuba Paper .pdf ...
2) Cleaning .pdf ...
3) Cleaning .exe ...
4) Scuba Paper .exe ...
5) Both PDFs in a .exe ...
Any problems just let me know.
=-)
100days-a-year
Contributor
Gotta love that.10 pages of just about 0 semantic content.Everyone was right.Yippee.Interesting fact #1 Viton o-rings are only 2 1/2 times less likely to burn?I remember in my o2 cleaning class my instructor used a match,a glass jar ,pliers and a viton o-ring to show me the importance of removing all traces of contaminants.How about a discussion of abdiatic generation of ignition sources?
In case anyone's not interested in reading the scuba paper above, let me summarize:
If you coat the inside of your cylinder with Mobil DTE 24 "which has been shown to ignite readily in oxygen systems" and then fill it to 1000psi in 20 milliseconds, you may get an explosion.
And just how much did the taxpayers pay for that little gem of a data point?
Talk about a worthless study! It would have been far more informative if they had introduced a worst-case substance, like Mobil DTE 24, and then filled at an acceptable rate and seen if they could induce combustion.
I can't wait to read the next study.
Roak
If you coat the inside of your cylinder with Mobil DTE 24 "which has been shown to ignite readily in oxygen systems" and then fill it to 1000psi in 20 milliseconds, you may get an explosion.
And just how much did the taxpayers pay for that little gem of a data point?
Talk about a worthless study! It would have been far more informative if they had introduced a worst-case substance, like Mobil DTE 24, and then filled at an acceptable rate and seen if they could induce combustion.
I can't wait to read the next study.
Roak
rainreg
Garlic Breath
Sorry you had difficulties understanding the content of those documents, you probably need to go back and really read the documents completely. The summary you posted is not a summary at all,There is alot of important information within those pages. It seems to me that you are jumping to conclusions and doing your best to support the very old and outdated 40% rule. If you read the documents fully you would have also noted that there are many agencies that support better cleaning methods for <23.5% and the like.
The process to achieve proper cleanliness is very cost effective and relatively easy to comply with, if you are willing to learn. The old washdown with simple green and charge the customer for a nitrox cleaning is an unforgivable deception of the client.
1. You cannot o2 clean or even Nitrox clean a 2nd stage regulator. Period. so those of you who have paid for this wonderful service get a refund. want more info I have plenty to offer. (850) 913-0888 to anyone who honestly wants to learn feel free to give me a call. I am available After 930PM Central Time until 1am M - Sat.
The fact is there are so many others out there that just don't get it, the facts are there and so is the testing. you can go on thinking whatever you want but don't spread your unprofessional opinion to others that want to learn the correct way to take care of their equipment and themselves. Which is based on facts and a proven process.
Rainreg
The process to achieve proper cleanliness is very cost effective and relatively easy to comply with, if you are willing to learn. The old washdown with simple green and charge the customer for a nitrox cleaning is an unforgivable deception of the client.
1. You cannot o2 clean or even Nitrox clean a 2nd stage regulator. Period. so those of you who have paid for this wonderful service get a refund. want more info I have plenty to offer. (850) 913-0888 to anyone who honestly wants to learn feel free to give me a call. I am available After 930PM Central Time until 1am M - Sat.
The fact is there are so many others out there that just don't get it, the facts are there and so is the testing. you can go on thinking whatever you want but don't spread your unprofessional opinion to others that want to learn the correct way to take care of their equipment and themselves. Which is based on facts and a proven process.
Rainreg
In order to have a fire you need 3 elements.. the first being oxygen and a fuel source and lastly a ignition source. If you remove any of the 3 you dont have a fire. Planly, a Nitrox tank is handicapped from the start since you cant remove the oxygen to prevent or stop a fire because thats what the tank is used for in the first place!
Fuel Sources: What qualifies as a "fuel" depends partly upon the oxygen concentration, because as oxygen concentration rises, so does the ability of many substances to burn. To quote ASTM (American Society of Testing and Materials) publication G88 (5.2.3) "As oxygen concentration decreases from 100 percent with the balance being inert gases, there are progressive decreases in the likelihood an intensity of potential reaction. Greater latitude may therefore be exercised in the design of a system for dilute oxygen service" This is why much of the dive community, to date, believes that oxygen service standards are unnecessary with 40 percent or less oxygen, but are with more then 40 percent.
As the oxygen concentration rises, the ability for many substances to burn also rises, and the temperature at which they'll ignite falls. This means that many substances that we think of as nonflammable or inconsequential in air systems may be fuel sources when exposed to high oxygen concentrations, depending upon the temperature which may include: silicone and silicone greases which is applied to all air o-rings, neoprene, trace compressor lubricants that may get into a air tank, organic material, plastic shavings, human skin oils, dust from various sources. Which is why we use special cleaning procedures to remove contaminants that may burn.
Igition Sources: Even the most rigorously cleaned tank may have some trace contaminants which is why we must minimize the sources of ignition. An ignition source is anything that can raise the temperature - even momentarily. This can be as low as 235c / 450f.
The most common source of ignition are compression and friction within the system itself, both as a result of the speed of the gas flowing through it.
You're probably quite familiar with heat of compression, such as the way scuba tanks heat up when filled. What may not be obvious is that compression can occur momentarily as a gas flow through pipes and valves, or into closed space (such as a line that will be opened later) especially if released at a high rate. When the flow meets a restrictive bend or other blockage, it backs up and, thanks to inertia, piles up against itself, resulting in adiabatic compression. If the gas is flowing fast enough - and it can be flowing faster than the speed of sound - it's possible for this compression to raise temperatures momentarily to more than 900c / 1600f. In the presence of high oxygen, this may be more than enough to ignite any contaminants present.
Friction can generate comparable heat, either through high speed contact of the gas itself within the piping and through some types of valves, or through friction from contaminant particles being swept at high speed in contact with the system.
Explosion: Remember that when working with pure oxygen that a common result of a internal fire will be explosion.
So what needs to be oxygen cleaned? The entire dive community, Compressed Gas Association (CGA), National Fire Protection Association (NFPA), The American Society of Testing and Materials (ASTM), The US Navy (USN), and NOAA guidelines indicate that it's necessary to oxygen clean and otherwise prepare for oxygen service anything that will come in contact with more than 40% oxygen, or that may reasonably be expected to accidentally come in contact with more than 40% oxygen due to equipment failure or improper procedures, however some groups inside and outside the dive community advocate oxygen cleaning for anything with more than approx. 21% to 25% oxygen.
The CGA lists 6 differnt ways to oxygen clean in its publication "Cleaning Equipment for Oxygen Service" G-4.1. These include using steam/hot water with detergents, caustics, acid, solvent, vapor and mechanical methods for cleaning. Of these, most dive operations find steam/hot water with detergents the most useful, sometimes accompanied by mechanical methods (scrubbing). Some use solvents for items that cannot be exposed to heat.
Step 1: The equipment is disassembled and cleaned of dirt, debris, and other contaminants
Step 2: Metal items are cleaned in a weak acid solution and an ultrasonic cleaner.
Step 3: The item is bathed in steam or hot water with a suitable detergent.
Step 4: The cleaned item is rinsed
Step 5: Item is air dried. Contamination should be avoided.
Step 6: The item is inspected for contamination.
Simple green is a common cleaning solution. The US Naval facilities Engineering Command evaluated Simple Green for use as a cleaner and degresser for in place hyperbaric piping systems and found it acceptable. According to their reports, Simple Green doesn't react with oxygen or water, and isn't toxic.
Also any components that are not oxygen compatible must be replaced with oxygen clean, oxygen compatible compnents. Neoprene o-rings may be acceptable in low pressure, lower temperature oxygen applications, but viton-a resist heat better, and is the best material in high pressure applications. The most common lubricants used in oxygen cleaning include Kryton and Christo-Lube MCG-111. According to virtually all organizations that deal with gas handling, silicone grease is considered incompatible and SHOULDNT be used in oxygen service.
As for Scuba Equipment... The guideline has been that with enriched air with up to 40% oxygen, standard scuba equipment may be used together without modification. This conforms with the policies and field experience of NOAA, the US Navy, and US Coast Guard, OSHA commerical diving regulations, plus the field experience of numerious underwater research institutions and recreational enriched air diving operations. However, there are some mfg that stipulate that any of their equipment must meet oxygen service standards if used with more then approx 23-25% oxygen, or that their equipment shouldnt be used with enriched air at all. In the event of an incident.. its your butt on the line.. In either case its a good idea to use oxygen compatible lubricants when servicing equipment for use with enriched air up to 40%. While its questionable to do so, aside from the additional cost, there's little drawback to doing so.
KEEP THESE POINTS IN MIND!:
Local laws may dictate having more then 21% oxygen must be oxygen cleaned and oxygen compatible.
Since the mfg is the expert on there materials and design of its product, its best to adhere to such recommendations.
Oxygen cleaning should only be carried out by professionals certified to do so!.
Fuel Sources: What qualifies as a "fuel" depends partly upon the oxygen concentration, because as oxygen concentration rises, so does the ability of many substances to burn. To quote ASTM (American Society of Testing and Materials) publication G88 (5.2.3) "As oxygen concentration decreases from 100 percent with the balance being inert gases, there are progressive decreases in the likelihood an intensity of potential reaction. Greater latitude may therefore be exercised in the design of a system for dilute oxygen service" This is why much of the dive community, to date, believes that oxygen service standards are unnecessary with 40 percent or less oxygen, but are with more then 40 percent.
As the oxygen concentration rises, the ability for many substances to burn also rises, and the temperature at which they'll ignite falls. This means that many substances that we think of as nonflammable or inconsequential in air systems may be fuel sources when exposed to high oxygen concentrations, depending upon the temperature which may include: silicone and silicone greases which is applied to all air o-rings, neoprene, trace compressor lubricants that may get into a air tank, organic material, plastic shavings, human skin oils, dust from various sources. Which is why we use special cleaning procedures to remove contaminants that may burn.
Igition Sources: Even the most rigorously cleaned tank may have some trace contaminants which is why we must minimize the sources of ignition. An ignition source is anything that can raise the temperature - even momentarily. This can be as low as 235c / 450f.
The most common source of ignition are compression and friction within the system itself, both as a result of the speed of the gas flowing through it.
You're probably quite familiar with heat of compression, such as the way scuba tanks heat up when filled. What may not be obvious is that compression can occur momentarily as a gas flow through pipes and valves, or into closed space (such as a line that will be opened later) especially if released at a high rate. When the flow meets a restrictive bend or other blockage, it backs up and, thanks to inertia, piles up against itself, resulting in adiabatic compression. If the gas is flowing fast enough - and it can be flowing faster than the speed of sound - it's possible for this compression to raise temperatures momentarily to more than 900c / 1600f. In the presence of high oxygen, this may be more than enough to ignite any contaminants present.
Friction can generate comparable heat, either through high speed contact of the gas itself within the piping and through some types of valves, or through friction from contaminant particles being swept at high speed in contact with the system.
Explosion: Remember that when working with pure oxygen that a common result of a internal fire will be explosion.
So what needs to be oxygen cleaned? The entire dive community, Compressed Gas Association (CGA), National Fire Protection Association (NFPA), The American Society of Testing and Materials (ASTM), The US Navy (USN), and NOAA guidelines indicate that it's necessary to oxygen clean and otherwise prepare for oxygen service anything that will come in contact with more than 40% oxygen, or that may reasonably be expected to accidentally come in contact with more than 40% oxygen due to equipment failure or improper procedures, however some groups inside and outside the dive community advocate oxygen cleaning for anything with more than approx. 21% to 25% oxygen.
The CGA lists 6 differnt ways to oxygen clean in its publication "Cleaning Equipment for Oxygen Service" G-4.1. These include using steam/hot water with detergents, caustics, acid, solvent, vapor and mechanical methods for cleaning. Of these, most dive operations find steam/hot water with detergents the most useful, sometimes accompanied by mechanical methods (scrubbing). Some use solvents for items that cannot be exposed to heat.
Step 1: The equipment is disassembled and cleaned of dirt, debris, and other contaminants
Step 2: Metal items are cleaned in a weak acid solution and an ultrasonic cleaner.
Step 3: The item is bathed in steam or hot water with a suitable detergent.
Step 4: The cleaned item is rinsed
Step 5: Item is air dried. Contamination should be avoided.
Step 6: The item is inspected for contamination.
Simple green is a common cleaning solution. The US Naval facilities Engineering Command evaluated Simple Green for use as a cleaner and degresser for in place hyperbaric piping systems and found it acceptable. According to their reports, Simple Green doesn't react with oxygen or water, and isn't toxic.
Also any components that are not oxygen compatible must be replaced with oxygen clean, oxygen compatible compnents. Neoprene o-rings may be acceptable in low pressure, lower temperature oxygen applications, but viton-a resist heat better, and is the best material in high pressure applications. The most common lubricants used in oxygen cleaning include Kryton and Christo-Lube MCG-111. According to virtually all organizations that deal with gas handling, silicone grease is considered incompatible and SHOULDNT be used in oxygen service.
As for Scuba Equipment... The guideline has been that with enriched air with up to 40% oxygen, standard scuba equipment may be used together without modification. This conforms with the policies and field experience of NOAA, the US Navy, and US Coast Guard, OSHA commerical diving regulations, plus the field experience of numerious underwater research institutions and recreational enriched air diving operations. However, there are some mfg that stipulate that any of their equipment must meet oxygen service standards if used with more then approx 23-25% oxygen, or that their equipment shouldnt be used with enriched air at all. In the event of an incident.. its your butt on the line.. In either case its a good idea to use oxygen compatible lubricants when servicing equipment for use with enriched air up to 40%. While its questionable to do so, aside from the additional cost, there's little drawback to doing so.
KEEP THESE POINTS IN MIND!:
Local laws may dictate having more then 21% oxygen must be oxygen cleaned and oxygen compatible.
Since the mfg is the expert on there materials and design of its product, its best to adhere to such recommendations.
Oxygen cleaning should only be carried out by professionals certified to do so!.
blacknet
Contributor
Hello,
rstone, congrats on the homework you have spent time and energy in finding on this matter. I must also ask if you know of any lab testing that states 40% is the rule and where the 40% figure came from. FYI noaa, usn and cgi (among others) now states 23.5% or 25% is the standard and they are stating that the 40% is a arbitrary figure that was used untill further testing was conducted.
As for the fire portion this is true, however you still have the issue of sparks, combustion and the like to worry with. As for materials goes you will ALWAYS have a source i.e. titanium regulators and AL tanks (check the fire department class ratings) So by this you have a) o2 in the tank (any percentage) a material (particulate matter in the tank or the tank material itself) and heat/combustion/etc (compression of gasses, opening the valve fast, improper storage in your trunk durring a trip/dive/vacation.
I must say that was some enlightening info you posted but I thought i'd add this part to the equasion.
Ed
rstone, congrats on the homework you have spent time and energy in finding on this matter. I must also ask if you know of any lab testing that states 40% is the rule and where the 40% figure came from. FYI noaa, usn and cgi (among others) now states 23.5% or 25% is the standard and they are stating that the 40% is a arbitrary figure that was used untill further testing was conducted.
As for the fire portion this is true, however you still have the issue of sparks, combustion and the like to worry with. As for materials goes you will ALWAYS have a source i.e. titanium regulators and AL tanks (check the fire department class ratings) So by this you have a) o2 in the tank (any percentage) a material (particulate matter in the tank or the tank material itself) and heat/combustion/etc (compression of gasses, opening the valve fast, improper storage in your trunk durring a trip/dive/vacation.
I must say that was some enlightening info you posted but I thought i'd add this part to the equasion.
Ed
You must remember that anyone involved with enriched air blending must recognize that as oxygen percentage rises, all things being equal, so does the rick of an oxygen-related fire/explosion. This isn't in question (it's basic physics), but what's debated is whther this risk is significant or not.
The 40% rule in the dive community came about because of the references sited below:
Federation Regulations, commercial diving operations, Part 1910.430
NOAA Oxygen specifications
OSHA Oxygen Specifications 1910.320
US Coast Guard Oxygen Specifications
Title 46, 197.452 Oxygen Cleaning & 46 CFG 197.451
US Navy Oxygen Specifications: US MIL-STD-777E (SH) Note K-6-4, Cat. K.6
I also have a list of references if interested in them, although as you stated newer references have stated 23-25%.
Therefore while some in the dive industry support the "up to 40% guideline" other gas-using entities such as NASA, advocate 23-25% range, as has some mfg's.
Muddying the controversy is that the limit at which you become concerned with oxygen service standards varies depending upon the application. For example, hyperbaric chambers with human occupants are maintained at oxygen service standards if oxygen content will exceed 25%. This is because a chamber typically has more sources of combustible material, and a humber wouldnt be able to escape the chamber if a fire occurred. The guideline that less-than-40 percent does not require oxygen service standards has a good track record, however being that his is being debated be conservative with respect to oxygen service standards.
Well its not just AL tanks that react unfavorably with oxygen compatible lubricants, however remember that oxygen compatible lubricants dont have the same viscosity as silicone grease, and break down more quickly, however they generally hold up for a year... as for steel.. for example.. Normally we dont think of steel as something that burns, and in air, you can heat steel until it melts with it catching fire. Yet, steel burns readily when exposed to pure oxygen. A torch cuts steel with fire and a stream of pure oxygen; once the steel begins burning, the flame from the torch is shut off, and the torch simply streams pure oxygen to guide the cut. The steel actually burns. As an example of how oxygen concentration affect flammability, consider this: Some of the halon compounds used in fire extinguishers actually BURN in pure oxygen.
As for filling tanks.. scuba tanks filled from conventional air stations can accumulate trace oils with each fill. This is one reason why the PADI enriched air diver course emphasizes using a dedicated cylinder for enriched air.
The 40% rule in the dive community came about because of the references sited below:
Federation Regulations, commercial diving operations, Part 1910.430
NOAA Oxygen specifications
OSHA Oxygen Specifications 1910.320
US Coast Guard Oxygen Specifications
Title 46, 197.452 Oxygen Cleaning & 46 CFG 197.451
US Navy Oxygen Specifications: US MIL-STD-777E (SH) Note K-6-4, Cat. K.6
I also have a list of references if interested in them, although as you stated newer references have stated 23-25%.
Therefore while some in the dive industry support the "up to 40% guideline" other gas-using entities such as NASA, advocate 23-25% range, as has some mfg's.
Muddying the controversy is that the limit at which you become concerned with oxygen service standards varies depending upon the application. For example, hyperbaric chambers with human occupants are maintained at oxygen service standards if oxygen content will exceed 25%. This is because a chamber typically has more sources of combustible material, and a humber wouldnt be able to escape the chamber if a fire occurred. The guideline that less-than-40 percent does not require oxygen service standards has a good track record, however being that his is being debated be conservative with respect to oxygen service standards.
Well its not just AL tanks that react unfavorably with oxygen compatible lubricants, however remember that oxygen compatible lubricants dont have the same viscosity as silicone grease, and break down more quickly, however they generally hold up for a year... as for steel.. for example.. Normally we dont think of steel as something that burns, and in air, you can heat steel until it melts with it catching fire. Yet, steel burns readily when exposed to pure oxygen. A torch cuts steel with fire and a stream of pure oxygen; once the steel begins burning, the flame from the torch is shut off, and the torch simply streams pure oxygen to guide the cut. The steel actually burns. As an example of how oxygen concentration affect flammability, consider this: Some of the halon compounds used in fire extinguishers actually BURN in pure oxygen.
As for filling tanks.. scuba tanks filled from conventional air stations can accumulate trace oils with each fill. This is one reason why the PADI enriched air diver course emphasizes using a dedicated cylinder for enriched air.
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