Revision to testing rules in UK

[tenor]

We (our club) have just been advised that full visual & ultrasonics with lagging off will now be required at 7 year intervals (was 10).  That is quite a change and can mean a lot of work, but I have no idea why the rules are to change.
Even worse for traction engines where access to the firebox sides for U/S would require almost total dismantling.  It also means the chances of completing such a test in a club testing day is a non starter, so much more work for the testers.
I don't hear of any serious boiler shell failures, so why the change?
Does anybody know the reasons?

Martin

[Neale]

Is that for steel boilers? Not heard anything like that for copper boilers.

[GeorgeRay]

The 2018 edition of the test code advised that the lagging should be removed at 7 year intervals for steel boilers which may be extended to 10 years at the discretion of the boiler inspectors. It sounds like your club has only just realised this.