03-08-2019, 04:25 PM
RE: EVIDENCE OF AIRFIT P10 VENT OBSTRUCTION CAUSING HYPERCAPNIA
MORE THAN YOU EVER WANTED TO KNOW ABOUT DAWN:
SnoringInOregon suggested using Dawn for cleaning P10:
I was interested in looking more closely at the ingredients in Dawn when I noted that at least two alcohol type-agents were included.
We have probably all encountered labels or user manuals exhorting us to never use alcohol containing products when cleaning a display panel.
Never use alcohol or ammonia-based cleaning fluid on your screen. We understand why many people use window cleaner on their monitors, many high-end flat screen computer monitors and HDTV sets have a nice glossy glass screen. The problem, however, is that both ammonia-based cleaners (e.g. window cleaners like Windex) and alcohol-based cleaners (diluted rubbing alcohol or specialty alcohol cleaners sold in electronics stores) can strip anti-reflective coatings off screens, cause clouding, or otherwise damage the screen. Even if you have a glossy glass screen, that screen is most likely coated with things that aren’t as durable and chemically resistant as glass. Don’t risk using using alcohol or ammonia-based cleaning fluids.
I am an outboard motor user, and many of us know that ethanol containing gasoline is probably damaging for our smaller gas engines. The first time I got servicing when my outboard started to run poorly, the service rep said the most likely culprit is ethanol. He said the ethanal causes the plastics in gaskets, fuel lines, etc. to deteriorate and often flaky, crumblies from the inner surface of the fuel line are found clogging the fuel system. In fact, he told me that Yamaha and Honda have said the use of ethanol containing gas will negate the warrantees on their outboards.
"Ethanol has inherent properties that can cause corrosion of metal parts, including carburetors, degradation of plastic and rubber components, harder starting, and reduced engine life," says Marv Klowak, global vice president of research and development for Briggs & Stratton, the largest manufacturer of small engines. "The higher the ethanol content, the more acute the effects."
So, I suspect that the most likely “harsh” component of Dawn is the “denatured alcohol”. This term usually refers to ethanol (as in alcoholic beverages) that is cut with an ingredient that makes it taste bad, gives severe symptoms, makes you blind or to die.
Of course we have no idea the percentage of these various ingredients and we aren’t material chemists, so this is just my hunch from what little I know. I did find a site that detailed the effect of denatured alcohol on various plastics: Crazing or stiffening seems to be the operative term. Also, we don’t know what kind of plastic is used in the vents.
However, assuming that by alcohol you either mean ethanol, which is the drinking kind of alcohol, or isopropanol, which is the alcohol in many cleaning products, then I can give you some advice based on common plastic types. Both are similar enough in their solvent properties that we can generalize.
Alcohol will damage some plastics, but not all. I will list my answers by the resin code, or "recycling symbol", found on most plastic items:
Poly(ethylene terephthalate), PET or PETE - PET is not very soluble in ethanol or isopropanol, but prolonged exposure may cause crazing or stiffening due to the dissolution of plasticizers.
High-Density polyethylene, HDPE - HDPE is resistant to most things.
Poly(vinyl chloride), PVC - PVC is not very soluble in ethanol or isopropanol, but prolonged exposure may cause crazing or stiffening.
Low-Density polyethylene, LDPE - LDPE is resistant to most things.
Polypropylene, PP - PP is resistant to most things.
Polystyrene PS - PS is not very soluble in ethanol or isopropanol, but prolonged exposure may cause crazing or stiffening.
This stands for "other", but the most common is polycarbonate, which is not very soluble in ethanol or isopropanol, but prolonged exposure may cause crazing or stiffening.
Rubber - most rubbers are probably resistant to alcohols, but prolonged exposure will cause loss of elasticity
I suspect that most of us replace cpap components before this ethanol related deterioration becomes clinically relevant.
As an aside, it is interesting that silicone is such a resilient material.
(https://www.shinetsusilicone-global.com/...bber_e.pdf)
Resistance to Oils, Solvents and Other Chemicals:
With regards to the effects of solvents and industrial chemicals on silicone rubber, the following data has been complied: Silicones are chemically inert and are attacked by very few common materials. Among them are concentrated sulphuric acid, hydrofluoric acid and, after long term exposure, high pressure steam. Like any elastomer, silicone has a tendency to physically absorb those materials with a solubility parameter near its own. This absorption may cause the rubber to swell and to soften slightly. In a few applications, this volume increase is advantageous. For example, a silicone rubber gasket exposed to certain solvents will swell to form a tighter seal. The change undergone by silicone rubber in contact with an absorbed solvent is primarily physical. After the solvent has completely evaporated, the silicone rubber will return to its original physical properties.
Heat and cold resistance:
Silicone rubber withstands high and low temperatures far better than organic rubbers. Silicone rubber can be used indefinitely at 1500C with almost no change in its properties. It withstands use even at 2000C for 10,000 hours or more, and some products can withstand heat of 3500C for short periods. Silicone rubbers are thus suitable as a material for rubber components used in high temperature environments. Silicone rubber also has excellent resistance to cold temperatures. The embrittlement point of typical organic rubbers is between -200 and -300Ct compared to -600 to -700C for silicone rubbers. Even at temperatures at which organic rubbers turn brittle, silicone rubber remains elastic. Some products withstand extremely low temperatures of -1000C and below.
Resistance to oils, solvents and other chemicals:
Silicone rubber has outstanding resistance to oil at high temperatures. Among common organic rubbers, nitrile rubber and chloroprene rubber have somewhat higher oil resistance at temperatures below 10000. but at higher temperatures silicone rubber is superior, Silicone rubber also has excellent resistance to solvents and other chemicals. It is essentially unaffected by polar organic compounds (aniline. alcohol, etc.) or dilute acids or bases, with the increase in volume due to swelling in the range of only silicone rubber does swell in non-polar organic compounds like benzene, toluene and gasoline but unlike most organic rubbers, jt does not decompose or dissolve, and will return to its former state when the solvent is removed.
Weatherability
Silicone rubbers have exceptional weatherability. Ozone created by corona discharge rapidly deteriorates most organic rubbers, but has almost no effect on silicone rubber. In addition, silicone rubber can be exposed to wind, rain and UV rays for long periods with virtually no change in its physical properties. contact with such chemicals.
Moisture and steam resistance
Silicone rubber can be immersed in water (cold water, warm water, boiling water) for long periods with water absorption of about 1%, and with virtually no effect on mechanical strength or electrical properties. Typically, under ordinary pressure, contact with steam causes almost no deterioration of silicone rubbers.
Physiologically inert
Living tissues are affected by contact with silicone rubber to a lesser degree than by exposure to other organic polymers. Silicone rubber is physiologically inert, and is thus used for baby bottle nipples and stoppers in medical applications
I actually suspect that if someone scientifically tested the silicone pillows for resilience and durability and other relevant physical characteristics, they could safely be used for much longer than the replacement schedule of 3 months would suggest (In fact, Resmed actually recommends 2 pillows/month).
The physical characteristics of silicone would seem to make it ideal to resist deformation, deterioration from heat, cold, moisture. Nor should it be susceptible to transmission of bacteria and grunge when kept reasonably clean. And being a medical application, I would expect the silicone Resmed uses is of very high quality.
Makes me wonder if these replacement recommendations are more based on economics than medical necessity. I have used my pillows for extended periods and suffered no apparent ill effects or increased leakage from deformation. Of course, this does not apply to other components such as tubing and frame which are made from plastics that probably deteriorate at a more rapid rate, or are not so easily cleaned or disinfected.
I wonder if these high replacement rates are accepted by the insurance carriers because they can convince people that the parts that contact the face, especially the nostrils and mouth must easily become irreversibly contaminated in a short period of times. (I also could understand it if the hard plastic rim of the P10 pillow began to deform and no longer stay in the frame, but I have not had a problem with it leaking or popping out.)
An example of short shelf life would be pharmaceuticals. While there are a few common meds like tetracycline, that deteriorate and even become toxic with time, many meds probably have a useful and safe shelf life far beyond the expiration date. For ten years I worked in refugee camps on the Thai Cambodian border. At one time we gathered expired medication sample packs to use in areas where there were no alternatives. I recall asking a pharmaceutical representative, if he thought the use of these out of date meds would be safe. He said that truthfully, many drugs are fine well beyond the expiration date as long as they aren’t exposed to higher temperatures which hastens chemical breakdown. Imagine how much is spent on refilling medications that probably are still good.
I AM NOT RECOMMENDING YOU EXCEDE THE EXPIRATION DATE OF YOUR MEDICATION!
I am merely pointing out that factors other than medical necessity may influence expiration dates and, in our case, replacement schedules.
Finally, looking at the other less probable culprits in Dawn:
Sodium Lauryl Sulfate Cleaning Agent Sodium Laureth Sulfate: SLS and SLES are surfactants which are the actual soaping ingredients found in all personal cleansing products including shampoos. Sulfates are the most common surfactant and offer a great balance of excellent cleaning properties without being harsh. All shampoos use some form of surfactant to capture oil and dirt and clean it off your hair.
Lauramine Oxide: is an amine oxide based nonionic surfactant. It is one of the most frequently-used surfactants of this type. Like other amine oxide based surfactants it isantimicrobisl, being effective against common bacteria such as S. aureus and E. coli.
Methylisothiazolinone, is a powerful synthetic biocide and preservative within the group of isothiazolinones, which is used in numerous personal care products and a wide range of industrial applications. It is a cytotoxin that may affect different types of cells
Phenoxyethanol: is used as a perfume fixative; an insect repellent; an antiseptic; a solvent for cellulose acetate, dyes, inks, and resins; a preservative for pharmaceuticals, cosmetics and lubricants; an anesthetic in fish aquaculture; and in organic synthesis.
Phenoxyethanol is a type of alcohol but from what I could find, I suspect it is likely used in a small amount and if so, making it less likely to significantly attack the integrety of the plastic in the frame.
SnoringInOregon suggested using Dawn for cleaning P10:
I was interested in looking more closely at the ingredients in Dawn when I noted that at least two alcohol type-agents were included.
We have probably all encountered labels or user manuals exhorting us to never use alcohol containing products when cleaning a display panel.
Never use alcohol or ammonia-based cleaning fluid on your screen. We understand why many people use window cleaner on their monitors, many high-end flat screen computer monitors and HDTV sets have a nice glossy glass screen. The problem, however, is that both ammonia-based cleaners (e.g. window cleaners like Windex) and alcohol-based cleaners (diluted rubbing alcohol or specialty alcohol cleaners sold in electronics stores) can strip anti-reflective coatings off screens, cause clouding, or otherwise damage the screen. Even if you have a glossy glass screen, that screen is most likely coated with things that aren’t as durable and chemically resistant as glass. Don’t risk using using alcohol or ammonia-based cleaning fluids.
I am an outboard motor user, and many of us know that ethanol containing gasoline is probably damaging for our smaller gas engines. The first time I got servicing when my outboard started to run poorly, the service rep said the most likely culprit is ethanol. He said the ethanal causes the plastics in gaskets, fuel lines, etc. to deteriorate and often flaky, crumblies from the inner surface of the fuel line are found clogging the fuel system. In fact, he told me that Yamaha and Honda have said the use of ethanol containing gas will negate the warrantees on their outboards.
"Ethanol has inherent properties that can cause corrosion of metal parts, including carburetors, degradation of plastic and rubber components, harder starting, and reduced engine life," says Marv Klowak, global vice president of research and development for Briggs & Stratton, the largest manufacturer of small engines. "The higher the ethanol content, the more acute the effects."
So, I suspect that the most likely “harsh” component of Dawn is the “denatured alcohol”. This term usually refers to ethanol (as in alcoholic beverages) that is cut with an ingredient that makes it taste bad, gives severe symptoms, makes you blind or to die.
Of course we have no idea the percentage of these various ingredients and we aren’t material chemists, so this is just my hunch from what little I know. I did find a site that detailed the effect of denatured alcohol on various plastics: Crazing or stiffening seems to be the operative term. Also, we don’t know what kind of plastic is used in the vents.
However, assuming that by alcohol you either mean ethanol, which is the drinking kind of alcohol, or isopropanol, which is the alcohol in many cleaning products, then I can give you some advice based on common plastic types. Both are similar enough in their solvent properties that we can generalize.
Alcohol will damage some plastics, but not all. I will list my answers by the resin code, or "recycling symbol", found on most plastic items:
Poly(ethylene terephthalate), PET or PETE - PET is not very soluble in ethanol or isopropanol, but prolonged exposure may cause crazing or stiffening due to the dissolution of plasticizers.
High-Density polyethylene, HDPE - HDPE is resistant to most things.
Poly(vinyl chloride), PVC - PVC is not very soluble in ethanol or isopropanol, but prolonged exposure may cause crazing or stiffening.
Low-Density polyethylene, LDPE - LDPE is resistant to most things.
Polypropylene, PP - PP is resistant to most things.
Polystyrene PS - PS is not very soluble in ethanol or isopropanol, but prolonged exposure may cause crazing or stiffening.
This stands for "other", but the most common is polycarbonate, which is not very soluble in ethanol or isopropanol, but prolonged exposure may cause crazing or stiffening.
Rubber - most rubbers are probably resistant to alcohols, but prolonged exposure will cause loss of elasticity
I suspect that most of us replace cpap components before this ethanol related deterioration becomes clinically relevant.
As an aside, it is interesting that silicone is such a resilient material.
(https://www.shinetsusilicone-global.com/...bber_e.pdf)
Resistance to Oils, Solvents and Other Chemicals:
With regards to the effects of solvents and industrial chemicals on silicone rubber, the following data has been complied: Silicones are chemically inert and are attacked by very few common materials. Among them are concentrated sulphuric acid, hydrofluoric acid and, after long term exposure, high pressure steam. Like any elastomer, silicone has a tendency to physically absorb those materials with a solubility parameter near its own. This absorption may cause the rubber to swell and to soften slightly. In a few applications, this volume increase is advantageous. For example, a silicone rubber gasket exposed to certain solvents will swell to form a tighter seal. The change undergone by silicone rubber in contact with an absorbed solvent is primarily physical. After the solvent has completely evaporated, the silicone rubber will return to its original physical properties.
Heat and cold resistance:
Silicone rubber withstands high and low temperatures far better than organic rubbers. Silicone rubber can be used indefinitely at 1500C with almost no change in its properties. It withstands use even at 2000C for 10,000 hours or more, and some products can withstand heat of 3500C for short periods. Silicone rubbers are thus suitable as a material for rubber components used in high temperature environments. Silicone rubber also has excellent resistance to cold temperatures. The embrittlement point of typical organic rubbers is between -200 and -300Ct compared to -600 to -700C for silicone rubbers. Even at temperatures at which organic rubbers turn brittle, silicone rubber remains elastic. Some products withstand extremely low temperatures of -1000C and below.
Resistance to oils, solvents and other chemicals:
Silicone rubber has outstanding resistance to oil at high temperatures. Among common organic rubbers, nitrile rubber and chloroprene rubber have somewhat higher oil resistance at temperatures below 10000. but at higher temperatures silicone rubber is superior, Silicone rubber also has excellent resistance to solvents and other chemicals. It is essentially unaffected by polar organic compounds (aniline. alcohol, etc.) or dilute acids or bases, with the increase in volume due to swelling in the range of only silicone rubber does swell in non-polar organic compounds like benzene, toluene and gasoline but unlike most organic rubbers, jt does not decompose or dissolve, and will return to its former state when the solvent is removed.
Weatherability
Silicone rubbers have exceptional weatherability. Ozone created by corona discharge rapidly deteriorates most organic rubbers, but has almost no effect on silicone rubber. In addition, silicone rubber can be exposed to wind, rain and UV rays for long periods with virtually no change in its physical properties. contact with such chemicals.
Moisture and steam resistance
Silicone rubber can be immersed in water (cold water, warm water, boiling water) for long periods with water absorption of about 1%, and with virtually no effect on mechanical strength or electrical properties. Typically, under ordinary pressure, contact with steam causes almost no deterioration of silicone rubbers.
Physiologically inert
Living tissues are affected by contact with silicone rubber to a lesser degree than by exposure to other organic polymers. Silicone rubber is physiologically inert, and is thus used for baby bottle nipples and stoppers in medical applications
I actually suspect that if someone scientifically tested the silicone pillows for resilience and durability and other relevant physical characteristics, they could safely be used for much longer than the replacement schedule of 3 months would suggest (In fact, Resmed actually recommends 2 pillows/month).
The physical characteristics of silicone would seem to make it ideal to resist deformation, deterioration from heat, cold, moisture. Nor should it be susceptible to transmission of bacteria and grunge when kept reasonably clean. And being a medical application, I would expect the silicone Resmed uses is of very high quality.
Makes me wonder if these replacement recommendations are more based on economics than medical necessity. I have used my pillows for extended periods and suffered no apparent ill effects or increased leakage from deformation. Of course, this does not apply to other components such as tubing and frame which are made from plastics that probably deteriorate at a more rapid rate, or are not so easily cleaned or disinfected.
I wonder if these high replacement rates are accepted by the insurance carriers because they can convince people that the parts that contact the face, especially the nostrils and mouth must easily become irreversibly contaminated in a short period of times. (I also could understand it if the hard plastic rim of the P10 pillow began to deform and no longer stay in the frame, but I have not had a problem with it leaking or popping out.)
An example of short shelf life would be pharmaceuticals. While there are a few common meds like tetracycline, that deteriorate and even become toxic with time, many meds probably have a useful and safe shelf life far beyond the expiration date. For ten years I worked in refugee camps on the Thai Cambodian border. At one time we gathered expired medication sample packs to use in areas where there were no alternatives. I recall asking a pharmaceutical representative, if he thought the use of these out of date meds would be safe. He said that truthfully, many drugs are fine well beyond the expiration date as long as they aren’t exposed to higher temperatures which hastens chemical breakdown. Imagine how much is spent on refilling medications that probably are still good.
I AM NOT RECOMMENDING YOU EXCEDE THE EXPIRATION DATE OF YOUR MEDICATION!
I am merely pointing out that factors other than medical necessity may influence expiration dates and, in our case, replacement schedules.
Finally, looking at the other less probable culprits in Dawn:
Sodium Lauryl Sulfate Cleaning Agent Sodium Laureth Sulfate: SLS and SLES are surfactants which are the actual soaping ingredients found in all personal cleansing products including shampoos. Sulfates are the most common surfactant and offer a great balance of excellent cleaning properties without being harsh. All shampoos use some form of surfactant to capture oil and dirt and clean it off your hair.
Lauramine Oxide: is an amine oxide based nonionic surfactant. It is one of the most frequently-used surfactants of this type. Like other amine oxide based surfactants it isantimicrobisl, being effective against common bacteria such as S. aureus and E. coli.
Methylisothiazolinone, is a powerful synthetic biocide and preservative within the group of isothiazolinones, which is used in numerous personal care products and a wide range of industrial applications. It is a cytotoxin that may affect different types of cells
Phenoxyethanol: is used as a perfume fixative; an insect repellent; an antiseptic; a solvent for cellulose acetate, dyes, inks, and resins; a preservative for pharmaceuticals, cosmetics and lubricants; an anesthetic in fish aquaculture; and in organic synthesis.
Phenoxyethanol is a type of alcohol but from what I could find, I suspect it is likely used in a small amount and if so, making it less likely to significantly attack the integrety of the plastic in the frame.
