Low-Level Strainers / Jet Siphon

Recently Got Big Water had a discussion on double diamond placement of portable tanks which evolved into a low level strainers/jet siphon discussion.

Member Roger Sill was unfamiliar with a low level strainer manufactured by Firovac.  This strainer was not included in a test result done by Got Big Water.  However, Charles Clark from Colerain Township responded to Mr. Sill concerning the experience they have had with this Firovac strainer with jet siphon.  Following is the response from Charles Clark:

"The TFT low level strainer/jet siphon using a one inch orifice consumes 364 GPM from a fire pump when transferring water from one dump tank to another @ 150 psi.  This can be confirmed by consulting published charts of flows from various orifice sizes at various pressures.  The Belmont Tanker Task Force in eastern Ohio did a study (spring 2016) of jet siphon efficiency.  They tested the TFT jet siphon.  along with several others.  They used a truck scales to very precisely measure the net water transferred by each jet siphon.  Most jet siphons use a one inch orifice.  A few jet siphons use 3/4 inch orifices.  Only one low level strainer/jet siphon in the study used a 1/2 inch orifice.  That unit is produced by Firovac (manufacturer of vacuum tankers).  It transferred a net flow of 807 GPM from dump tank to dump tank while consuming only 91 GPM from the fire pump @ 150 psi.

This stingy use of water from the fire pump is as revolutionary as the advent of dump tanks years ago. It is said that the use of a dump tank is equal to adding another tanker to the rotation.  I think switching to jet siphons that only use 91 GPM each from a pumper makes it possible to eliminate a pumper ofter set up to run jet siphons.

This fall we conducted a tanker shuttle drill in which a 1250 GPM pumper was able to push 1,060 GPM back a lane to a mock fire scene.  No jet siphon pumper was needed because only 192 GPM was needed to run two Firovac jet siphons.  Transferring with two TFT jet siphons would have consumed (recirculated) 724 GPM leaving only 526 GPM available to pump to the fire scene.  Eliminating the need for a jet siphon pumper is critical for water supply operations in a single traffic lane."

Any discussion on this topic is encouraged.


That was the question I was asked, by a group of Volunteer Firefighters a few years ago, when they were trying to decide how to replace their old, worn out (well used) tanker. Being a small, rural station, they didn't have a lot of money to spend. I was stumped! I had never been asked that question in the 20 years since I first saw a vac tanker operate.
We were doing a rural water movement class, and this tanker was spending a lot of time waiting to fill or dump. We had an engine set up at the fill site, and a dump tank set, 2 miles away at the dump site. There was a problem! This ONE tanker was always waiting, to fill or dump. I finally found the problem. We were trying to use a NEW piece of equipment, in a shuttle designed for an OLD type of water movement.
Vacuum Tankers are STAND ALONE. One firefighter sets up and fills (usually at a site closer to the fire), same firefighter drives and dumps, WITHOUT GETTING OUT OF THE TRUCK! No engine needed to fill, no extra help, no 1,000 feet of 5" hose. With the system being used, "WE WERE IN HIS WAY"
I have complete confidence in our firefighters. They aren't stupid, but maybe a little hardheaded. Sometimes, "that's the way we have always done it", gets in our way. Even if you are not completely convinced that the vacuum tanker system works best, try and find a used FIROVAC! I COULD NOT. Seems there are very few, if any. Good Luck!

The more years we are in business, there have been a couple USED FIROVAC Units that have popped up for sale and typically we try to work with the selling department to find it a great new home!

  • In 2017, Wooster Twp. decided to upgrade their first Firovac. As a result, Rocky Mount Fire Protection Fire District in Rocky Mount, Missouri purchased Wooster Twp's First Firovac!
  • Winter 2017/2018 Owego - Southside Department in New York upgraded to a brand new 4 Man Cab Eagle QP and decided to sell their Refurbished Firovac Unit. It is now part of the Newald, WI Fire Department!
  • Another Department, West Hurley also rehomed their 2002 Firovac this spring, to a small department down in Bremen, KY recently!

Firovac's are built to last many years and we are excited to see some of these Departments with smaller budgets benefit from other departments that are beginning to upgrade their  Firovac Units!

If your department is ever in the market for a NEW or USED Firovac, please, do not hesitate to contact us! We will do our best to build what your department needs or to help locate a used Firovac to meet your departments needs!