Yes LR does mention evaporation as “alternative method”, but DNVGL doesn’t want to do it, saying you can evaporate from tanks which are listed under 3.1..
Your Question:
Good day,
We had been requested to by the owner’s representative to mention the evaporation in sludge tank, bilge holding tank & Incinerator waste oil service/settling tanks in IOPP certificate Supplement B.
As far as I remember; evaporation by means of heating coils is not regarded as other acceptable means and should not be mentioned in IOPP Supplement B Item 3.2.3?
Or if any other option to officially record this for the owners for future ?
Appreciate for your kind advises.
Thank you for contacting DNV GL Technical Helpdesk.
Please note the following approach by DNV GL in IOPP Certificate Supplement “sludge tank water evaporation” - cases:
1. Natural water evaporation of sludge tanks:
DNV GL does not use item 3.2.3 in IOPP Supplement for description of natural water evaporation of sludge tanks, as heating of such tanks is mandatory for vessels operated on HFO, and thus NOT considered “Other acceptable means”. Internal Air pipe agitation/bubbling system or internal mill/circulation pump (as original delivered from tank manufacturer) is also not considered as “Other acceptable means”.
2. Forced water evaporation of sludge tank:
If a sludge tank is fitted with EXTRA ARRANGEMENT for forced water evaporation, other than the mandatory requirements; example: Extra Set of Heating Coils, Extra Insulation, Evaporation Fan, Evaporation Ejector etc. (all mentioned alternatives are subject to formal approval by DNV GL), then DNV GL considers this as “Other acceptable means” and we describe the system under item 3.2.3 in the IOPP Supplement.
DNV GL is of the opinion that the view above is also founded in the IMO guidelines.
As per IMO guidelines in MEPC.1/Circ.736/Rev.2, there is no requirement that sludge tank water evaporation should be mentioned in IOPP Certificate Supplement. Please see the attached example #8 in MEPC.1/Circ.736/Rev.2 for evaporation of water from a sludge tank. In this example there is only requirement that tank should be listed under item 3.1 of IOPP supplement. Disposal of oil residue / sludge through evaporation can be mentioned in “Oil Record Book” under code C 12.4 as long as the tank is recorded in table 3.1 of IOPP supplement.
To conclude: Please do not enter 'Other acceptable means' in the IOPP Supplement item 3.2.3 for natural evaporation of sludge tanks as described above.
Hope the above explains.
Best Regards,