Motorsport Composite Fundamentals: Fire Risk
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Fire Risk
03.16
| 00:00 | As we discussed in the resin fundamental knowledge module, the chemical reaction that cures resin is exothermic, meaning that heat is produced and released. |
| 00:09 | The exact amount of heat is going to depend on the type of resin and catalyst, the amount of each present, as well as the ambient conditions. |
| 00:17 | But generally speaking, a larger amount of resin or a higher percentage of catalyst or hardener will result in a higher exothermic peak. |
| 00:25 | If left to cure in our container, a mixture can generate enough heat to melt the plastic mixing pot, burn skin or ignite nearby combustible materials. |
| 00:35 | To the uninformed, the workshop bin would seem like a logical place to dispose of excess resin. |
| 00:40 | However, workshop rubbish bins often contain rag soaked in flammable liquids or other easily combustible materials like paper or cardboard from packaging. |
| 00:50 | Unfortunately this has resulted in the loss of many workshops and project cars over the years, not to mention the safety risk to anyone still in the building. |
| 00:59 | So what can we do to prevent this? The first step is to lower the risk in the first place. |
| 01:05 | This could mean mixing multiple smaller quantities rather than one larger mixture. |
| 01:10 | We should always use containers rated for the appropriate temperatures as well. |
| 01:14 | Typical polypropylene cups have melting points over 150 degrees celsius, which is usually sufficient, although large mixtures of epoxy resins can push these limits. |
| 01:25 | Past this, good ventilation not only reduces the respiratory risk discussed in the previous module, but also allows for safe heat exchange from the mixture. |
| 01:35 | After we've finished using the resin, we'll most likely have some remaining, so how do we deal with it? One approach is to empty it into a heat resistant container that's large and wide to disperse the resin over a larger area. |
| 01:48 | The more surface area, the more heat is transferred from the mixture, keeping the temperature lower. |
| 01:53 | Another approach is to allow the resin to fully cure in an open area away from anything flammable or combustible. |
| 02:00 | In the middle of a concrete workshop floor or outside on a concrete driveway are good options. |
| 02:05 | Just keep any pets or animals in the area in mind. |
| 02:08 | Professional composite workshops often have a large metal bin in an open area dedicated to this. |
| 02:14 | When cured, the resin is no longer dangerous. |
| 02:16 | At this point it's just a thermoset plastic, so can be disposed of with regular trash. |
| 02:22 | Disposing of liquid resin is a bit trickier and should be done as per the local chemical waste guidelines. |
| 02:27 | There are a few key things to remember from this module. |
| 02:31 | Heat released from the resin mixtures during the exothermic curing processes poses a serious fire risk. |
| 02:37 | If we're aware of this, we can lower the risk in the first place by mixing smaller batches and allowing for sufficient ventilation. |
| 02:45 | Excess curing resin should never be disposed of in a workshop bin unless it's specifically intended for that use in an open, well ventilated area with no other combustible materials. |
| 02:56 | Dispersing the mixture in a wider container to increase the surface area will also go a long way in lowering the temperature by promoting heat transfer. |
| 03:04 | Once cured, the solid plastic can be disposed of like regular trash, however when the chemical is liquid, be sure to follow your local regulations. |
