Double Fold Frame

double folding tank frame, space saving portable water tank, firefighting water storage container

December 28, 2021  Double Fold Frame Tanks by Joel Wright



The original FOL-DA-TANK frame tank was designed in 1954 to open quickly like a child’s playpen – or in today’s terms Pack n Play.  Our founder elegantly transferred the playpen concept to make a durable portable water tank for firefighting.  It’s a story of American ingenuity at its finest. 


First responders train so they can open a FOL-DA-TANK and fill it with water fast because lives and property depend on their speed.  Parents who need a portable safe place for their infant to play depend on how easy it is to unfold the Pack n Play because they are simultaneously responsible for their child’s safety while creating a new safe space.  Both applications of the folding frame design make it easy and fast to convert from a portable system in storage to a water or child containment device. 


One issue is how to store and transport these devices.  If you are a parent with a Suburban you can transport your Pack n Play and half of your house.  If you have a smaller vehicle you can probably fit the collapsed Pack n Play into your trunk.   The original folding frame tanks are about the size of a ladder.  The bigger the tank the longer it is when collapsed.  The double fold frame folds to half the length of a regular tank.  For example, a standard 3,000 gallon tank is 13’3” long when folded and the double fold is only 6’9” long.  While the double fold will be 15” wide vs 8”, the shorter length allows it to fit into a pickup bed or most command vehicles.  Tankers or engines have a rack system or special compartment to hold a standard FOL-DA-TANK.  If you are firefighter with the need for another tank and you only have room in the command vehicle then a double fold frame tank may be an option.


We manufacture the double fold frames by cutting the straight side in half and installing a robust hinge with a detent pin and a reinforcing slide that acts like a heavy duty deadbolt lock.  The hinge and slide ensure the double fold is just as durable and strong as the regular tank.  Deploying a double fold frame tank takes a few more movements than the regular frame tank, but with training it can be done in seconds.  Keith’s short video shows what a double fold looks like.

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