Distant Voice,
if it is not ALARP it is not safe
That is a slightly erroneous statement – though I think I understand what you are trying to say. However, your use of the word “safe” as an absolute term is incorrect. “Safety”, however quantified (HRI for example) is a range. Absolute safety is simply not possible – hence someone defining ALARP which is deemed as safe as "reasonably practicable" – i.e. the best we can do given funding, value of life etc, etc. In simple terms, you get
100% Unsafe
Watch out!
V
V
V
V
ALARP
Best we can do.
V
100% Safe
The Holy Grail!
where the ALARP position is shifted as far down as we can get it given funding, blah, blah, blah! Therefore, if something is not ALARP, it is just not as safe is it could be; it is slightly above the old ALARP position. It’s not a question that it is now magically “unsafe”, it is just less safe, or, rather, in this case, probably a greater risk of ocurrance than the previous ALARP position.
Just because something is deemed to be at ALARP does not make it 100% safe. You just will be less likely to be sued in Court because you can demonstrate that you have done as much as you could practicably be expected to do! By how much less safe it is (i.e. how far up has the point moved) requires a futher Risk review - possibly using existing data - reposition the ALARP point - and justify that.
I am not surprised that IPT do not want to go beyond the TL's stated point because they would then have to justify why they moved what they effectively defined as part of the ALARP criteria in the first case; in other words they would need to justify the shift in what was considered ALARP. Or, perhaps, "politically" the TL made a statement which they feel they are honour-bound to adhere to without any recourse to "scientific consideration"! I don’t know the details so I won’t comment further.
Anyway, hope that has helped vis-a-vie the
if it is not ALARP it is not safe
statement!
Cheers,
H ‘n’ H