remember reading of a similar incident before ... and with google to the rescue found it
How one sunbeam turned a tycoon's mansion to ashes
A BLAZE that caused millions of pounds damage to a tycoon's mansion was started by a freak accident involving a towel and a shaving mirror. The unique chain of events that devastated the eight-bedroom home of Sir Peter Michael, chairman of Classic FM radio, was explained by an expert.
The concave mirror acted as a magnifying glass, concentrating the sun's rays into a single point, said Berkshire's fire brigade safety officer Greg Boys. At that point, the temperature rose to 200C, causing the towel to burst into flames. Mr Boys said four factors had to combine to start the fire at the Grade 11 listed building near Hungerford.
Firstly, the sun would have to be low enough to shine directly on the bathroom mirror. Then the mirror would have to be in exactly the right position to direct the magnified rays on to the towel. Also, the towel would have to he at the precise spot where the rays converged. Finally, there would have to be material nearby for the fire to take hold. "A centimetre out in any of the first three factors could well have prevented the fire from ever taking place," said Mr Boys. "It was a chance in a million."
Firemen hit on the mirror theory while investigating the blaze. Mr Boys added: "We had to wait for ideal conditions so we could test that theory out. "Eventually, they all came together and we dashed over to the house, set up the mirror and towel and waited to see what happened. "What we saw confirmed the theory. The sun hit the mirror, converging on the towel, which was ablaze within minutes."
Sir Peter, 58, said: "It just makes you think how unfair life can be."