Nurse Tendering and Why Drop Tanks Are the Way to Go

Got Big Water has been posting some formerly published articles. One was from the "FireRescue" publication by Wayne Eder on 04/01/2011 entitled "Basic Rural Water Shuttle Ops".

Although it is an older article, it still holds up today. He addresses "The Nurse Tender" stating: Many progressive and well-trained fire departments still rely on the antiquated "Nurse tender" concept, in which a water tender pulls in and pumps directly to an engine company, providing a continuous supply of water until the tender runs dry and must go refill.

There's a basic formula for water shuttle that must be addressed to help us understand the weakness of the "nurse tender" concept.

Unload or dump time (UT) = Travel Time to Fill Site (TTF) + Fill Time (FT) + Return Time (RT) = Total Fill/Dump Cycle

Using this equation, with a fill site two miles away, and basing the travel time on a conservative 35 mph, the total time to shuttle on a 2,000-gallon tender would work out as follows:

UT (pumped off in 22 minutes) + TTF (6 minutes) + FT (5 minutes) + RT (6 minutes) = 39 minutes.

If the pumping engine is using a 500-gallon tank and flowing 100 GPM, it will be empty long before the "nurse tender" returns, thus allowing the fire to spread and placing the lives of both firefighters and victims in jeopardy. THIS IS AN EXTREMELY INEFFICIENT AND DANGEROUS PROCESS THAT CAN BE CORRECTED THROUGH THE USE OF PORTABLE TANKS." For example, with Firovac's portable tanks.

"Many firefighters avoid the use of portable tanks for a variety of reasons (weight, deployment, fear of drafting, etc.) but in the rural environment, the portable tank is your best friend. In the aforementioned scenario, we can improve operations dramatically by deploying a 2,000-gallon portable tank alongside the attack engine. Our new formula would look something like this:

UT (through the dump valve in 2 minutes) + TTF (6 minutes) + FT (4.5 minutes) + RT (6 minutes) = 18.5 minutes."

THAT IS BETTER THAN HALF THE ORIGINAL SCENARIO, PLUS the pumping engine then has a reserve of water, not just the 500-gallon in the tank on the unit, which may sustain flow until the tender returns. 

How many rural departments have fill sites within two minutes of a fire? Vacuum units have a greater chance of accessing nearby static water. Many non-vacuum units drive further distances to hydrants but we will not change that time in this calculation. 

A drop tank can usually be deployed proficiently in the same amount of time it takes to pull a hose and hook to the pumping engine.

This is a no-brainer. Why are we regressing to "antiquated" technology, just so everyone "fits in"? Why should we "fit into" a cumbersome system? Are we not there to put the fire out as quickly and efficiently as possible?

Not a lot of change is needed to accomplish this.