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ITCO advises on tank entry
DOWN THE HATCH
SAFETY • ITCO IS CONTINUING ITS MISSION TO IMPROVE SAFETY IN THE USE OF TANK CONTAINERS WITH NEW GUIDANCE ON SAFE TANK ENTRY
THE INTERNATIONAL TANK Container Organisation (ITCO) has published a fifth document in its technical series, TG05, Safe Entry into a Tank Container. The document provides guidance for ITCO member companies – and others – that engage in activities that require personnel to enter the interior of a tank container for the purposes of inspection, maintenance or remedial cleaning.
The document focuses solely on the tank entry process, presenting the inherent risks that will be encountered and must be managed properly. ITCO says that, ideally, procedures should be reviewed to see if there are any ways to allow the relevant tasks to be carried out without the need to physically enter the tank, such as the use of CCTV. ITCO also notes that national legislation governing confined space entry should take precedence over its guidance and users should always comply with the appropriate legislation as a matter of course.
Those involved in tank entry, whether as personnel entering a tank or those responsible for managing the process, need to be aware of the potential for those inside a tank to be asphyxiated through a lack of oxygen or intoxicated by gases and vapours that are present in the tank. Those are two different things but have the same risk: that the person inside the tank may be overcome and, in the worst case, can die.
DEFINE THE SPACE Before considering the safety risks involved in tank entry, it is important to establish the precise conditions inside a tank. ITCO refers to definitions used by the US Occupational Safety and Health Administration (OSHA), which clarify a distinction between ‘confined space’ and ‘permit required confined space’.
A confined space is one that has adequate size and configuration for employee entry, has limited means of access and egress, and is not designed for continuous employee occupancy.
Permits are required when such a confined space contains or may contain a hazardous atmosphere. Operators need to be aware that tank configurations may result in gases being trapped or concentrated in particular parts of the tank, meaning that a single gas measurement may not give a complete picture of the risks inside. There is also a need to take account of baffles, pumps and other equipment that can present a trip hazard.
In any case, a Tank Entry Permit must be issued prior to any work inside a tank; this must be completed by a competent person who has assessed the risks and put procedures in place to mitigate those risks. The permit should assess the tank’s conditions, in particular the nature of the last cargo carried in the tank and whether it has been cleaned or contains residues. ITCO stresses that the Tank Entry Permit should not be confused with the Cleaning Receipt or Cleanliness Certificate, and provides examples of all three documents.
ITCO also stresses the importance of training, not just for those entering a tank but also for the person issuing the Tank Entry Permit and any personnel on hand to provide safety assistance. This applies equally to external contractors or inspectors. The nature of the required training is often
specified by local health and safety legislation but additional, function-specific training will be needed, appropriate to the service provider’s site and company policy.
PERMISSION TO ENTER ITCO is clear that the Tank Entry Permit is the key to safe operations, but notes that there are several factors that must be taken into account. The risks in any tank entry operation vary widely, depending on whether the tank contains residues or has been fully cleaned of its last cargo, hazardous or not. The permit should, for example, show the fullest information possible on the last cargo, including the UN number and proper shipping name, together with the technical name of the substance if is not included in the proper shipping name. For non-regulated substances, the technical name should also be shown. Abbreviations and proprietary names should not be used. Information on the last cargo should come from a traceable document. The safety data sheet (SDS) may provide information on the assessed hazards and required safeguards for that cargo.
“Last cargo is important and essential information,” the ITCO document notes. “In the event of an accident, precise and prompt information is required to be provided to emergency and medical responders.”
It is the nature of the last cargo that will determine the atmosphere inside the tank; the presence of vapours from cargo residue or from inert gas can create an oxygen-deficient atmosphere, and some vapours will have a toxic effect on anyone breathing them. It is vital, therefore, that the atmosphere inside the tank is measured using a calibrated gas and oxygen meter to ensure that the tank is safe to enter. This check should be part of the issuance of the Tank Entry Permit and must be undertaken immediately prior to entering the tank. ITCO notes that, before opening the tank to take this measurement, operators should check that the tank is not under pressure. FIT FOR PURPOSE The purpose of the tank entry process should also be considered, as it too has a bearing on the safety measures that may need to be taken. This is particularly important if any
repairs are to be carried out, regardless of whether or not they involve hot work.
A Tank Entry Permit should be time-limited and take account of the assessed risks. For example, a tank assessed as safe to enter for the purpose of remedial cleaning might subsequently contain vapours as a result of the cleaning process, whereas a cleaned tank being entered to undertake a visual inspection might be assessed as being safe to enter for a longer period.
The Tank Entry Permit should also list the required safety equipment, as appropriate for the work envisaged. This might include, for example, the gas and oxygen meter, ventilation and breathing equipment, lighting, protective clothing, harness, alarm and a safety watch attendant. ITCO advises that safety training exercises should be carried out periodically and that these should include training on the removal of an incapacitated person from the tank.
ITCO says that it may be possible to devise an alternative documentation process if, after a thorough evaluation, it is determined that the tank does not represent a ‘permit required confined space’. In such cases it may be enough simply to use an alternative procedure involving the marking of the existing cleanliness document, or to securely mark the tank with a tag. This should only be done following a systematic safe entry assessment. The ITCO document TG05, Safe Entry into a Tank Container, can be downloaded free of charge from the Organisation’s website, www.itco.org.
THERE ARE MANY REASONS FOR SOMEONE TO BE
INSIDE A TANK CONTAINER BUT THE SAFETY
