The In-Line Pressure Gauge – By: Chris Collier

The in-line pressure gauge is an essential and often overlooked piece of equipment when operating off of a standpipe.  From the earliest days of our pump operator training we are taught to start at the nozzle and work back to the pump to calculate the discharge pressure for a given line.  Lets look at a simple example:

  • Smooth bore nozzle with a 1 1/8" tip = 50 pounds per square inch (psi) nozzle pressure
  • 200' of 2 1/2" hose @ 5 psi friction loss per length = 20 psi to compensate for friction loss
  • Line operating on the 2nd floor = 5 psi for grade change
  • Discharge pressure = 75 psi

This is very easy to calculate quickly in your head because all of the factors in the equation are known.  How do you know how many psi to add for the piping between the fire department connection (FDC) and the standpipe outlet on the 4th floor?  The short answer to this question: you don't know.  It is impossible to know the piping configuration of every standpipe and you are crazy to think that if you knew it you could calculate it quickly at the time of a fire. 

The quickest, easiest, and most accurate way to provide the proper pressure at the standpipe outlet is through the use of an in-line pressure gauge.  This appliance, when connected directly to the standpipe outlet, allows us to calculate discharge pressure as if the pump panel of the engine was in the stairwell.  The example above with the smooth bore nozzle and 200' of 2 1/2" hose can be calculated exactly the same way, ensuring 75 psi at the standpipe outlet to provide 50 psi at the nozzle. 

The in-line pressure gauge becomes even more important when we have multiple lines operating off of the same standpipe.  If the fire is on the 4th floor, the first line should be connected on the 3rd. floor.  The second line which will either back up the first line or proceed to the floor above (5th floor) will be connected to the standpipe outlet on the 2nd floor.  If the first line was 200' the second will have to be at least 300'.  The second line will also be going up three floors – from the 2nd to the 5th so we will have to add 5 psi per floor to compensate for head pressure.  Smooth bore nozzle (50 psi) + 300' of 2 1/2" line (30 psi) + 3 floors elevation (15 psi) = 95 psi.  The only way to be sure that each line is pumped at the proper pressure is to place the in-line pressure gauge on the standpipe outlet. 

There are a few steps we need to take before attaching the in-line pressure gauge to the standpipe outlet.  First open the standpipe outlet and let it run for a few seconds… yes, the floor is going to get wet and so are the stairs, its okay.  This serves two purposes: first, it tells us that we have a functional standpipe that has water and second, it will hopefully flush any obstructions from the outlet.  Once the outlet is flushed, turn it off and look inside.  If there are any obstructions still in there remove them with the channel locks that you carry in your standpipe kit.  Now, connect your in-line pressure gauge to the outlet and your hose to the gauge. 

Once all of the sections of hose are connected and the line is flaked out, open the standpipe outlet valve ALL THE WAY!  At this point you will get a static pressure reading since there is no water moving through the line.  Once the line is opened adjust the standpipe outlet valve until you get the desired residual pressure on the in-line pressure gauge.  It is extremely important to set the pressure while the line is flowing water.  If necessary, the nozzle team can open the nozzle in the stairwell or the public hallway to set the pressure before moving into the fire area. 

Thanks for reading and be safe!  As always, feel free to add your questions, comments, or suggestions.



  • Tim Gaffney says:

    What type of in-line pressure gauge is used for this article? Looking to up-grade equipment in our standpipe pack.

  • J. Sezack says:

    While channel locks are ok, I prefer a decent sized pipe wrench for standpipe operations. The added weight is more than made up for by the increased torque and larger capacity. A stuck pressure reducing device, cross threaded pipe adapters, or a stripped operating stem are all better handled with a pipe wrench. Keep the channel locks in your pocket and put a wrench in the standpipe kit.

1 Trackback

Leave a Reply

Your email address will not be published. Required fields are marked *

background image Blogger Img

Brotherhood Instructors Blog

We specialize in the basic fundamentals of firefighting. While we believe that hazardous materials, terrorism, emergency medical and the various rescue disciplines are essential parts of the Fire Service, we also think that the basic fundamentals of firefighting have been overlooked in recent years. We are here to help turn that trend in the other direction.

FE Talk: Humpday Hangout

Firefighters and the Risk of Asbestos Exposure – Mark Hall, Guest Blogger
Being a firefighter must be real tough job, thanks for giving us an insight about the many risks in that field.
2014-01-16 09:04:59
carroll price
Power Saw Decompression Valves – By: Andrew Brassard
Some smaller chainsaws like the Stihl 025 are very hard to start because they are not equipped with a compression relief valve. Anyone who owns one of these saws will probably tell you that it was not as hard to start when new as it became later on. My theory, as to why this happens,…
2013-12-23 18:04:43
Chris Cahoon
Another Rex Tool Modification – By: Andrew Brassard
Andrew, I am looking to have this mod done. The first thing I need to do is purchase a Rex Tool. Do you recommend getting the original Rex and cut the handle of as you have done here or buy the Lil Rex and try to modify that version? Thanks bro, Chris
2013-02-03 15:34:13
History of Lock Pulling Tools
I cant believe how quickly things have moved on. Imagine how things will have moved in the next 100 years. wow. Remember cassette tapes... people will be saying.. remember ipads hahaha
2012-09-03 06:12:14
Asbestos and Mesothelioma Lawsuits The Best Asbestos Lawyer
Firefighters and the Risk of Asbestos Exposure – Mark Hall, Guest Blogger
[...] exposure, ask your doctor about asbestos, cancer and other health complications.Create a video blog Bruce Peters asked: Exposure to asbestos can lead to the development of serious health problems late...s, were exposed to asbestos at some point during their occupational history. A number of occupations [...]
2012-08-15 12:36:40
Blood On Our Hands
Blood On Our Hands
Lights and Sirens
Lights and Sirens
Goodreads Book Giveaway
Goodreads Book Giveaway
Emergency Feeding
Emergency Feeding
Easy-Button Firefighting
Easy-Button Firefighting

Photos from Past Classes

Visit Our Youtube Channel

Sign up for our Email Newsletters

* indicates required

FireEMS Blogs eNews

Sign-up to receive our free monthly eNewsletter