This is one of a series of very similar trailers we have built for the construction industry.

It is used to test large buildings for their heat conservation properties. An enormous,

petrol-drive fan is installed in the trailer, drawing in air through the front hatch and

the two side roller shutters and blowing out, through a massive flexible tube, into an office,

warehouse or the like, building up great pressure. You then switch it off and wait to see

how long it takes for the pressure to drop. This tells the people who know how to work

these things out just how much money is being wasted through precious heat leaking

through badly fitting doors and windows. We believe it's an EC rule that this has to be done.