There always seems to be confusion surrounding fusible vents on stainless steel IBCs. What are they? Do we need to have them? Fusible vents are required by UN/DOT on all intermediate bulk containers (IBCs). It's a necessary feature for the safe use of stainless steel tote tanks.

The Department of Transportation regulations state in section DOT CFR 178.705 (2)(i) that "IBCs must be capable of releasing a sufficient amount of vapor in the event of fire engulfment to ensure that no rupture of the body will occur due to pressure build-up.  This can be achieved by spring-loaded or non-reclosing pressure relief devices or by other means of construction."

Manufacturers of IBCs have determined that using a fusible link is the best method available for safely releasing excess vapor in emergency situations.  There are a few options for fusible vent caps.  The most common fusible vent is the 3” Threaded Fusible Vent/Cap.  Also simply known as a fusible cap, this device offers the protection of a fusible vent combined with the convenience of a 3” threaded removable cap that is commonly used as a fill port.  Cable lanyard and hardware for attachment to tank are included. 

When the intermediate bulk container is exposed to excessive heat, the fusible link is designed to melt away to allow the inner core to fall into the tank thereby releasing the vapor.  This alleviates the intense pressure build up inside the stainless steel IBC to significantly reduce the likelihood of explosion. 

Below are fusible cap installation guidelines for stainless steel IBCs:

1. Check the nipple that the cap is to be installed on to make sure it is round and has a smooth edge.
2. Always use a new gasket.
3. Hand tighten until gasket meets the nipple's edge, then use a spanner wrench to snug.  (Caution: Using a hammer to tighten the cap will cause damage to fusible material.)
4. Tighten to a torque of 30 Ft-Lbs.

A 'Five-in-One' is a good option for those who want to combine the fusible vent/cap with a pressure and vacuum relief device. Gits Manufacturing describes how this aptly named cap combines five features into one compact device, "It is a 3" threaded removable fill cap, high temperature fusible device, pressure relief vent, and vacuum relief vent with integral vent guard."  The vent guard also offers roll over protection in accordance with DOT regulations.  Cable lanyard and hardware for attachment to tank are included. 

The use of fusible vents on stainless steel intermediate bulk containers are a necessary safety feature required by UN/DOT.  Click here to see more on intermediate bulk container regulations.

To get all your intermediate bulk container questions answered, send us an email, or give us a call at 1-800-634-4128 .