It is common to protect chemical warehouse doors with removable door barriers. These barriers are not in use during the day and allow traffic in and out of the warehouse. At night the barriers are put in place to ensure the warehouse is properly bunded.
These barriers usually consist of a lightweight steel barrier pivoted at one end. The barrier when closed will drop in between two plates faced with a pair of hard rubber seals. The seals are important for maintaining water tightness. One particular facility being inspected had a number of such door barriers in place. On inspection it was found that the rubber faces had become very worn with cuts and missing pieces in the rubber seal.. A cable tie could easily be poked between the steel barrier and the rubber seal indicating a lack of integrity. The bunded warehouse failed the visual inspection.
Spare seals took a number of months to obtain from the manufacturer and thus there was the potential for an environmental incident whilst waiting for the spares to be fitted.
The take away from this cautionary tale is to ensure a stock of spares are kept on site and the barriers inspected as part of the routine preventative maintenance programme. A monthly or quarterly inspection interval is recommended depending on the frequency of use.