Debasish Routine monthly visual inspection by a plant operator or from owner is just to get preliminary information on abnormalities in the tank. There is a vast qualitative difference in both these inspections - although one may supplement the other to a large extent. AI inspection once in 5 years calls for : Visual check for external corrosion (uniform or other types of corrosion from carry over dust or other contaminants from atmosphere), check on foundation condition, check on foundation bolts if any any uneven lifting is seen, condition of piling if accessible for tanks, check on structural support condition, paint condition of tank, tank roof, tank structual support, stair cases etc, roof plate, nozzles connected to the tank, insulation condition if tank is insulated, safety valve or breather valve condition, seal condition if the tank is floating roof type, earthing condition check, flame arrestor condition (if installed), piping associated with the tanks including the auxiliary equipment connected to the t ank, tank drain conditions, application of other N.D.T examination - where possible - like UT Thickness, paint thickness evaluation for degradation etc. There is a vast qualitiative difference in this examination or inspection dibe by AI and from that of routine inspection done by plant operator once in a month. AI is a trained and qualified inspector authorized to do this job - not only of AST but all presssue vessels / piping, heat exchanvers, towers, furnaces, safety systems, compressors, turbines etc in a process plant. Indian Factories Rules - if applied properly and done properly to above storage tanks (AST) - (atmospheric condition tanks) - calls for maintenacne of record of the above external visual check and N.DT supplementary check test conditions (indirectly implying that the job is done by AI) - all the above once in six months. Factory Rules in India do not stipulate or do not specify who should do the inspection. It has not specified whether it should be done by AI or plant operator or plant maintenance personnel. It indirectly implies that external inspection forms as much a part for record and future maintenance and operation care by careful inspection once in six months . Trust this is of help to you C.V.Srinivasan Nishi Engineers Pvt Ltd. Chennai India June 13 E-mail: nishi@vsnl.com >API 653 para 6.3.1 (Routine In-Service) calls for >"walk-around" inspection within every 1 month by >owner/operator personnel or by an AI which includes Visual & >other checks. Para 6.3.2 (External Inspection) also calls >for Visual Inspection but every 5 years but specifically by >AI. >Now if the former includes Visual what is the special need >for Visual as per para 6.3.2. >Kindly discuss. >regards

Chakra OISD was essentially set up for PSU oil companies as private sector oil companies were not there at that time. Not sure, currently, if private sector oil companies in India also form a part of OISD and OISD's mandatory / regulatory guidelines. C.V.Srinivasan Nishii Engineers Pvt Ltd Chennai India June 14 E-mail: nishi@vsnl.com >Dear Srinivasan, > >Thanks for letting know that Factories Rule has something to >say for AST. In PSU refineries in India, now-a-days, >inspection of AST is done as per OISD (Oil Industries Safety >Directorate) Std. 129. It stipulates many things and with >our established procedures, the inspection frequency becomes >like this -- > >a) Pre-monsoon (along with revisioning & testing of F/A & >BV) & post monsoon inspection - basically a six-month >frequency inspection. No NDT is generally done, unless >requirement is felt by Inspection Engr. >b) For Fl. roof tanks, quarterly inspection of roof, seal >system, etc. >c) Stipulated detailed external inspection of tank. >Frequency differs from 2 to 3 years depending on the >service. >d) Stipulated internal inspection of tank. Frequency 5-10 >years depending on service. > >I am not very clear whether OISD does not cover other >refineries as well. > >Regards > >Chakra