Dustydog said:
That explains why caravans still leak
I'm sorry Dusty,
I don't understand your comment.
Perhaps I should explain I did not work for a caravan manufacture, though some of the the products we produced were sold to caravan manufacturers.
We employed and exceeded some of the industry's most stringent quality assurance procedures, conforming to BS EN ISO 9001 QS9001 (Automotive) & elements of TS9001(Aerospace) which set target performances for our suppliers for consistency or product, and delivery schedules. Any supplier whose products fell outside of our parts per million permitted failure rates had increased goods inwards surveillance so we were confident that parts reaching our production lines were of the correct specification.
By employing good product design techniques, the opportunities for incorrect assembly were minimised, resulting with a less than 1:1000 reject on test at any stage in production, and by analysing the failures that did arise, the information was used to to influence production engineering control and or design revisions to further drive down the reject rates and raise get it right first time.
In the gas of gas and electrical products, the production lines were obliged by legislation to carry out certain testing, which we did at sub assembly stages, and as a final full product test . Only after all the tests were successful was a a product serial number produced and given to the appliance. As a further quality and reliability test. at least 2% of all finished products were withdrawn from finished stock and given a laboratory inspection.
Periodically about 1:1000 items was put on an extended test for reliability.
What we could not control were other organisations (for example domestic gas fitters , Some large construction companies and caravan manufacturers) miss -storing, -handling or damaging our products before they were installed.
Just as an example back in 1990 we had about 10 pallets of product returned to us by one caravan manufacture with a note claiming they were all faulty,
We found two complete pallets where a fork lift truck had driven its forks through the appliances.
There were pallets that were full but had been left out in the rain ( all at least 18 months old)
There were pallets where all the cartons had exactly the same external damage and the packs of fittings had been removed. Each pallet was worth about £2500.
With carelessness like that its hardly surprising that caravans have such a poor reliability record.