Double entry for recording impairment loss?

Impairment loss is recognized immediately in P&L  (unless the asset is carried at revalued amount) Thus, entries would be:

Dr  Impairment losses a/c (P&L account)

Cr  Asset account a/c (Balance sheet account)

If the asset is carried at revalued amount, impairment loss is treated as a reduction in revaluation gain.

Dr Revaluation surplus (B/S account)

Cr  Asset account a/c (B/S account)