I am a fire protection and risk management engineer working at group level with fire safety issues for a world leading chemical products manufacturer.
I would like to ask the this forum’s members objective opinion about the potential risks related to the use of flexible plastic inner liners for metal 200 l (53 US gal) drums. The liquids dispensed in these drums have are of class IA or IIIA.
Background: There is a big push to use these liners in China (this is all about China) because the country currently has stringent restrictions regarding metal waste. Consequently other companies have started using these inner liners as a customer added value because these facilitate re-use of the drums and thereby the problem of generating metal waste is removed. Consequently we are also pushed to begin using these liners.
When I was faced with this problem and knowing the risks primarily associated with static electricity I immediately became an opponent against using these liners. My interpretation of the NFPA 30 section 9.4 is that these liners are not allowed to be used in connection to storage of the type of products we manufacture. However I perceive the information in the code slightly vague because there is no specific reference to flexible plastic inner liners. For making this more clear with regards to what I mean with an inner liner, imagine a plastic bag in the drum in the same way you would have at home in your waste bin. That bag I refer as the inner liner.
Even though I received an argument from the local colleagues that these liners are made of conductive plastic, I am still sceptical because I am not sure how one ensures that grounding and bonding is made total between the liner and the drum. Combining plastic and metal will definitely affect the conductive properties of the metal drum thus increasing the risk of charge generation and accumulation.
The three main risks with these liners as I see them:
- Increased risk of charge generation and accumulation when dispensing the product into the drums
- Added fire load in the production and warehouse facilities by having these liners as part of our packaging material
- I am not sure how the liner’s integrity when inside the drum plays a role from a spillage or a fire perspective, because the liner is in the drum, thus protected by it. However I am concerned for what it may happen at the customer site where they will handle the drums and the products within.
Having said the above I would like you to kindly share with me your objective opinion on the matter or if you have any experiences, bad or good, with this type of liners.
Thank you in advance for your responses
Daniel M. (MSc. Risk Management and Safety Eng.)