Hello!
I think first you need to split it up into:
損失の危険 risk of (exposure to) loss
and 相当額 = sum equal to

So (I think) it's just referring to the amount that would be at risk in the event of a loss - a fire, or theft, etc etc.

So, literally: a/the sum equal/equivalent to the loss exposure (hereinafter, "risk")

Or, perhaps, more simply: loss exposure amount/total (as prescribed in the internal "risk management code"...etc etc)

Although perhaps somebody knows a nicer way of putting it....!!