What is a Fixed Flow Firefighting Nozzle?

A fixed flow nozzle gives you a single flow capacity on the fire ground. These nozzles can be combination, giving you a straight stream and fog pattern option, or not. Smooth bores are one type of fixed flow nozzle, but not every fixed flow nozzle is a smooth bore.

We talk about Smooth Bore nozzles here. For this article, we will focus on combination nozzles.

What is a Fixed Flow Nozzle? 

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A fixed flow firefighting nozzle is a nozzle with a single flow capacity. Your nozzle operator cannot choose another flow rate if the current flow is not enough for your needs.

While you cannot choose another flow rate, your crew could choose to over pump the nozzle to achieve a higher flow rate based on your nozzle’s K-factor. This will increase the nozzle reaction your crew must manage.

Read more about your nozzles K-factor here. 

How Does a Fixed Flow Nozzle Work? 

A fixed flow nozzle operates like other nozzles you are accustomed to. You can control water flow using the bail handle. On combination nozzles you can also choose your pattern by adjusting the bumper at the front of the nozzle.

Learn more about fixed flow nozzles here! 

What are the Pros and Cons of Using a Fixed Flow Nozzle? 

Every nozzle has positives and negatives associated with it. Here are a few pros and cons related to fixed flow combination nozzles:


  • Nozzle operation is simple and straightforward.
  • Nozzle operators can choose between a straight stream or fog pattern based on their needs.
  • Single flow eliminates the possibility of accidentally selecting a different flow rate and minimizes communication needed between nozzle operator and pump operator.


  • It is possible to accidentally move the bumper and shift your flow pattern.
  • If you need additional flow, you cannot choose another flow rate. You must either shut the line down and switch nozzles or over pump and manage additional nozzle reaction.

Is a Fixed Flow Combination Nozzle Right for You? 

The decision to use a fixed flow nozzle is up to you and your crew! Each firefighter has their preferences in nozzles and the best way to find yours is to try them, train with them, and stay informed of the latest research and innovations. It’s also important to consider the needs of the fire ground you typically experience. You may end up preferring a fixed flow nozzle for one type of fire and favoring another style in a different scenario.

Your available water supply may also impact your nozzle decision. Fire departments that have consistent and predictable water supplies may be well suited to a fixed gallonage nozzle. Ultimately, nozzle choice can be complicated and knowing which nozzle is right for your crew depends on a variety of factors.