HI Guys, We are planning to open and inspect a 4500m3 Methanol tank in the next few months, i was hoping someone out there might have some experience on the procedures taken to do this kind of work. It is the first time this will be done, the tank is in operation 15 years and i just want to make sure that we have everything covered before opening and anybody enters. Was looking for some advice on how long the tank should be left to naturally vent, how much washing down if any.We have been told that we only have 5 days to do this (production needs) Thanks in advance, Torres

There is some good information above, but please note that the LEL is 6% not 10%, I suspect this is a typo. I make typos but thought this one important enough to be clarified. Additionally you should also ensure that :- - there is a detailed RA and written procedure for the job - the above RA & Procedure needs to developed by someone Competent that understands the risks and how to control them - Competent Supervision - Competent staff to the work in this confined space This is a very large vessel and a high risk task, it is essential that it is managed and controlled Competently. I would also open access points top and bottom where present to aid natural ventilation and where possible access the empty, clean, vapour free tank at ground level. Steve

Torres, Whilst there is excellent information given so far, I cannot enter the discussion on % levels dont have access to the right information at the moment. But I personally would err on the save side. Additionally I would add that whilst you will run it very strictly within a PTW system this should require ALL possible openings being locked open or covers removed, and a lock out tag out ( loto) system being in strict operation. Blowers or exhuast devices will also be of assistance to ventilate and assist during entry. Again strict entry control should be applied. Regular measurements of the atmosphere should be conducted together with restrictions on any work being done on the tank. Regards Wizard

Thanks guys, all of this is of a great help to me. Extraction was talked about but for reasons steve mentioned we decided to go with blowing the air through with the correct blower type. The other thing is that this tank has a floating roof with a nitrogen blanket above so this should be a help in the venting (in a sense that the whole tank should not have methanol vapour).We are hoping that an initial flush with 300/400M3 of water will be enough?? It will be strict PTW, constant monitoring, and all equipment Ex rated. The guys coming to inspect have entered methanol tanks before and are fully aware of the dangers involved. Thanks, Torres

Hi Thought I would chip in on this topic and probably add the obvious. Anyone entering tank should be confined space trained. By the nature of the task and Environment I would suggest to HIGH RISK level. An emergency plan should be in place emergency services should be notified of the nature of the task with correct times of when the task is to take place (not so much to put them on stand by but to give them a heads up what and when you will be doing things.) Designated rescue teams should be on stand by and with in easy reach of where the task is to take place. any staff entering tank should rehearse emergency drills. after venting etc gas monitor readings should be taken prior to entry, and every 5-10 minutes there after. Designated top man records readings. A bottom man should also be positioned at bottom of ladder and is always to remain in contact with top man. a top man / winch operator should always be at top of tank during any time anyone is in the tank and not have or be responsible for any other duties or allow himself to become distracted whilst task is taking place. clear method/means of communication , between all involved in the task ,should be established prior to entry. an agreed means of raising alarm in case of any emergency situation. all equipment used, winches harnesses escape sets etc should be inspected and where applicable tested prior to task. PLAN PLAN PLAN. and i would make sure that the confined space entry RA and Emergency plans and procedures are signed off before the task takes place.