"Filter cleaning method, fitted with reverse jet, frequency of visual inspection, at least once a month."
"Reduced inspection frequency of bag filter may be appropriate as follows; (c) for filters fitted with reverse jets or the mechanical shakers where operating experience has demonstrated satisfactory operation of the arrestment plant (d) where process operation is infrequent."
"Seating of pressure relief devices on silos should be checked at least once a week or before a delivery takes place, whichever is the longer interval."
"I see no need to prescribe the form of log books and find no reason to relax the normal requirement for weekly silo top inspections as set out in PG3104 and as reflected in other permits. I recognise that safety is an important consideration for work at height but the weekly checks need not involve dismantling and the work is required to minimise the risk of potentially polluting dust emissions. It is for the operator to ensure that the conditions are safe on top of the silo and in the actions to it."