What's the difference btw Flashpoint (COC) and Flashpoint (PMCC)?

[Ken4]

Example here: http://www.bplubricants.co.uk/bpglis/lubtds.nsf/technicaldata/405343*English*UK?OpenDocument

 

[John K]

It has been too long and my memory isn't working right. I went to ASTM and tried a search....but no luck. They are just different methods, one is Open Cup, the other is PM Closed Cup. I'm not much help, I used to know what they stood for! It is hell to get old! John

 

[John K]

I did another search in Google and came up with this instrument... http://www.sartec.co.uk/grabner.htm and on a search of 'comparison of flashpoint analysis' came up with this link... http://neptune.spacebears.com/cars/stories/labtest.html Cleveland Open Cup - found what the other C stood for. PMCT - Pensky-Martens Closed Tester found these in table of contents from ASTM but did not access the actual methods. John

 

[TallPaul]

quote:

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Originally posted by labman: I doubt flash point tells us much about an oil. An oil could have a low flash point due to a small amount of low boiling solvent used to carry in an additive. It would quickly, and harmlessly flash off into the crankcase ventilation. The volume lost would be negligible.

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Good point and it may explain why, for instance, Royal Purple 10w40 lists such a poor flash point. I always equated a high flash point with a robust base oil and maybe so, but if your point is the case, then a low flash point is not necessarly an indicator that the oil is not robust.

 

[TC]

From my NFPA Fire Protection Handbook: 1. Tagliabue "Tag" Closed Tester for liquids with FPs at or below 200F (ASTM D56). 2. Pensky-Martens Closed Tester for liquids with FPs over 200F (ASTM D93). 3. ASTM D3278 (apparently a closed test) is for finishes (paints, enamels, laquers, etc.) with FPs from 32F-230F . 4. Open cup tests (Tag Open Cup - ASTM D1310, and Cleveland Open Cup - ASTM D92) are sometimes used for flammable liquids "in transportation." Open cup flashpoints represent conditions with the liquid in the open and are generally higher than closed cup flashpoint figures for the same substances. 5. For motor oils, the standard consistently used (at least in the U.S.) appears to be COC/ASTM D92.

 

[labman]

If you find TOC or TCC that is Taglibue? or some such. It seems nobody can use the same test method as anyone else. I doubt flash point tells us much about an oil. An oil could have a low flash point due to a small amount of low boiling solvent used to carry in an additive. It would quickly, and harmlessly flash off into the crankcase ventilation. The volume lost would be negligible. Flash point is more for shipping. You must know it to assure proper handling. Methane, octane, dino oil, and polyethylene differ chemically only by molecular weight, and all burn readily once started. They have vastly different shipping requirements.

 

[Dustman]

For info, flashpoint is not a physical property of a liquid that can be measured in the same way as boiling point or freezing point. Flashpoint is the result of a flashpoint test; the equipment and manner in which the test is undertaken will all affect the result, hence the same oil tested in different flashpoint apparatus will give different answers! That there are so many different test apparatus is the result of different industries, in different countries, over a long period of time, all attempting to answer the simple question "what is the safety hazard of this liquid"? Abel closed cup and Pensky-Martens closed cup date from late 1800s, Tag close cup and Cleveland open cup date from the early 1900s, to which we can add the more modern equilibrium and rapid equilibrium test methods. Flashpoint is essentially the lowest temperature of a liquid at which vapours from a test sample combine with air to give a flammable mixture that will 'flash' (i.e. explode) when an ignition source is applied. Firepoint is the lowest temperature of a liquid at which vapour combustion and burning commences when an ignition source is applied and thereafter is continuous even after the removal of the ignition source. There are two general classes of flashpoint test: open cup and closed cup, and as the name implies the vessel containing the test sample is either open or closed prior to the ignition source being applied. The open cup was initially developed to assess the potential hazards of liquid spillage. In this test, a sample is introduced into a cup that is open at the top. As the cup and liquid are being heated, an ignition source is passed horizontally over the surface of the liquid to test if the vapours 'flash'. If the test is repeated at increased temperature, a point may be reached when the sample continues to burn without further application of the ignition source - the firepoint. A closed cup test contains any vapours produced and essentially simulates the situation where a potential course of ignition is accidentally introduced into a container, such as a fuel tank or oil sump. The test cup has a close fitting lid that can be opened to allow air in at the same time as the ignition source is applied. Note that firepoint testing is not undertaken in closed cup apparatus. It is no surprise, of course, that open cup tests usually give higher flashpoints than closed cup tests. Quite often, the choice of which test method or test standard to use is set out in the product specification or detailed in the regulation you are trying to meet. For example, UN Recommendations on the Transport of Dangerous Goods specifies the following standards as being acceptable for non-viscous liquids; 4 US standards, 2 British standards, 1 Russian standard, 6 Dutch standards, 3 German standards and 3 French standards. To quote Mark Twain from Huckleberry Finn "you pays your money and you takes your choice!" Here's a list of the common tests from a commercial flash point testing site.

 

[Dustman]

That website link for the different flash point tests is broken - try this one flash point testing