There may be cases where it is not possible in practice to immediately ensure certain reception guarantees in detention, for example due to the geographical location or the specific structure of the detention facility. Any derogation from those guarantees should be temporary and should only be applied under the circumstances set out in this Directive. Derogations should only be applied in exceptional circumstances and should be duly justified, taking into consideration the circumstances of each case, including the level of severity of the derogation applied, its duration and its impact on the applicant concerned.