Fire risks of intermediate bulk containers (IBCs)

Members’ attention is drawn to a recent communication from the UK Health & Safety Executive (HSE) regarding the fire performance of composite or plastic IBCs. These are widely used for storage and transportation of combustible liquids.

There have been a number of serious recent fires in the UK that started or spread as the direct result of the use of plastic IBCs for combustible liquids. Following investigations at the scenes of these fires, a research project was undertaken by the HSE to provide data to allow more reliable risk assessments for premises using IBCs for liquid storage and to provide a stimulus and direction for change in IBC selection and design.

A short and very informative video of an IBC fire test, which provides a graphic summary of the findings, can be viewed at hse.gov.uk/research/rrhtm/rr564/

A comprehensive report on this matter was prepared by HSE. Some of the main findings of the report are summarised below.

Main findings:

• In an IBC fire, all (combustible) liquid in a stock of unclad IBCs on level ground is likely to be released in a period of the order of five to ten minutes;
• IBCs containing liquids with a hydrocarbon character, e.g. fuel oils, edible oils and lubricants, fail very much more quickly in fires than those containing water. The leakage rate on failure is also very much higher;
• Plastic components of IBCs, i.e. valves, corner protection, plastic pallets etc., are easily ignited, e.g. by a match;
• Even IBCs containing high flashpoint liquids (up to at least FP 200°C) give severe pool fires involving all of the contents;
• Metal cladding, of the sort currently used for static protection of some IBCs, can reduce drainage rates. However, very rapid leakage of liquid may still occur following explosions in the ullage;
• Unless composite IBC design can be improved to reduce the rate of liquid drainage in fires, the potential consequences of fires will continue to be very serious.

Main recommendations:

• Risk assessments for IBC storage areas or buildings should be based on the premise that liquid loss will be rapid and complete;
• The risk assessment should cover the interaction between IBCs and steel drums. It is good practice to segregate IBCs and drums to avoid rapid onset of catastrophic failure of drums and associated fireballs and projectiles;
• A risk assessment is required for areas or buildings that contain any combustible liquids in IBCs or plastic drums with flashpoints up to at least 200°C;
• Manufacturers and suppliers of IBCs should provide clear information on the potential behaviour of IBCs in fire when the containers are supplied;
• Kerbs and partitions in storage areas may be useful in checking the flow of liquid and spread of fire. For partitions to be effective, the drainage of storage areas should be carefully controlled;
• Manufacturers should explore the potential for improvements in design;
• Operators of sites with large stocks of IBCs should consider the pattern of drainage in the event of fire.

The full report – Fire performance of composite IBCs – can be downloaded from hse.gov.uk/research/rrpdf/rr564.pdf