Flammable and or Combustible

Flammable and or Combustible

I received a couple of e-mails about flammability and combustibility issues. Without getting too drawn out I will try to condense my research without leaving out important points.

The flammability and combustibility (explosiveness) of the paint and solvent products we use is characterized by a FLASHPOINT, which is the lowest temperature at which a liquid will produce enough vapors to combine with air and become ignitable if some source of ignition is present, such as a spark, or open flame. The National Fire Prevention Association (NFPA) has a high and low flashpoint that it uses to classify liquids as flammable and/or combustible. Considered flammable if the flash point is below 100° F, and combustible if the flash point is at or above 100° F. The NFPA has gone a step further and classified flammable liquids into three separate classifications and combustibles into three separate classifications as well. These listings, while too extensive for this article can be obtained by contacting the NFPA. Your MSDS sheets will give you this information as well. Keep in mind that if you combine various solvents and paints, the mixture will be as flammable as the lowest flashpoint of its individual ingredients. There is another classification system, as set forth by the Consumer Product Safety Commission (CPSC), which uses three levels: Extremely Flammable (below 20° F), Flammable (between 20° F and 80° F), and Combustible (80° F to 150° F). I think you will find the NFPA classification more favorable to our safety needs because the flammable classification of 80° F to 100° F makes us think about those storage areas that we use which are susceptible to high heat, like a hot garage, especially in the summer months! I know I’ve mentioned this in an early article but its worth mentioning again; be careful when rubbing things down with certain solvents. Friction generates heat and static electricity. Remember sliding around on the carpet then zapping one of your family members or friends with the static discharge from your finger, it works the same way with certain cleaning processes, only with more explosive consequences!

Another flammable and combustible area that we don’t often think about is that which is produced when sanding wood, rosin, and certain metals. If the air becomes to saturated with just the right amount of these dust particles, the same spark, or open flame that sets off vapor and air mixtures can set off the dust and air mixture with the same violent results. This is why good ventilation is a necessity, and it’s important to wet down certain working areas when heavy sanding work will be done.

Finally, Spontaneous Combustion usually results when organic oil soaked paper and rags are put into containers or even storage rooms that do not provide a good air flow. Organic oils slowly oxidize in air and release heat as a bi-product. It is this heat that cannot dissipate which causes the spontaneous combustion.

Most local codes require flammables to be stored in metal cabinets, this is intended to keep fire away from them for at least 10 minutes to allow the occupants time to escape a burning building. You should store flammables and/or combustibles outside of your workspace and only keep those items that you will be using for that day within your workspace. In reality many of us store all our paints and solvents within our shop, that is until we get a visit from the Fire Chief! No matter what you decide to do, think about your safety as well as the safety of the folks around you that may be affected by the choices you make.

I do hope you find these little articles useful and I do appreciate the occasional e-mail, even the bad ones! They let me know if I’m on the right track and in some cases give me inspiration for the next article…Thanks! Robin