Attempting Spontaneous Combustion

6 months ago, I was talking about the dangers of oil-soaked rags, and bought some linseed oil (raw) to see if I could duplicate some of the ship fires I experienced, where incorrect disposal of linseed oil rags resulted in a spontaneous combustion.

It has taken from until now to actually carry out the first test, so into a wheelbarrow I placed a clean (new) rag, which had been significantly doused in raw linseed oil.  I used a wheelbarrow because it is obviously fire resistant, and means if I needed to, I could wheel it away, or flood it with water (or hit it with the fire extinguisher).

I ran the actual experiment outside for safety reasons again, and it’d be interesting to know if that had an impact on the initial results.

linseed experiment-3

Spontaneous Combustion Experiment

Inside the shed I set up a laptop with some data logging software on it, and had a USB-powered thermocouple inserted into the centre of the rags to monitor the temperature.

linseed experiment-2

Oiled Rags

The rags were quite soaked in the linseed oil, and screwed up like they were carelessly being thrown away.

The Results:

linseed experiment-1

Temperature Range

I set the experiment to run for 10 hours (didn’t think it would need all that, but there you go), and sampling every 30 seconds.  1200 data points in all.  To explain some features of the graph – the first tiny spike was where I tested the ambient temperature.  The test started in the shade around 10:30 am, went through the heat of the day (ambient temperature was around 31 degrees C), and approx 3 hours in, the sun began directly impacting on the experiment (as you can see with the sudden temperature rise).

The temp started around 21 C, and peaked at 61 C, 6 hours into the experiment.  Didn’t think that was too bad a result, but certainly wasn’t the smoldering wreck I was expecting.  I could still pick up a bit of a skin reaction and that fuzzy feeling in the back of the sinuses, so there was some reaction going on, just not as much as I was expecting.

However, there are a number of variables that quite conceivably had an impact on the result.  The linseed oil was raw, and not boiled, the rag was quite thick, and not worn down at all.  The rag was screwed up, but not particularly tightly, and was out in the open rather than in a bin under other objects pushing down on it (increasing the compactness).  It was outside, in direct sunlight (which may have caused some evaporation of the oil, rather than having it remain to slowly combust).

I guess a second test is in order to eliminate some of these variables, and see if we can’t score a result (aka burn baby!)

%d bloggers like this: