What To Do After Failing Your Fire Hydrant Flow Test: Part 1 – Investigating For Faulty Components

Oct 11, 2021

If you’ve recently failed a fire hydrant flow test, you may be concerned about what happens next. Cost, timing and even your ability to continue business in the interim may all be points of concern.

Luckily, failing your fire hydrant flow test does not mean all hope is lost. When you fail your hydrant flow test, some fire maintenance companies may recommend the installation of a fire pump (or tank), however, these can prove to be problematic over time, as they require space, are costly, and also introduce the need for monthly inspections. So, before going to the trouble of installing a pump, there are several checks that an HTC Group engineer can conduct that may result in a simple solution.

Read on to learn more about the inspections that can be conducted if you fail a hydrant flow test.

#1: Check There Is Not A Partially Closed Valve

More often than not, a failed hydrant flow test can be the result of a hydrant valve that is simply closed, when it should be open. Some valves have a ‘reverse thread’, meaning that the operator can leave it in the closed position by mistake. You’d be surprised how often this is the cause of a failed hydrant flow test.

#2: Measure The “Friction Loss” Across The Fire Hydrant System To Identify Blockages

‘Friction loss’ can affect a number of components of your fire hydrant, such as the reticulation main tapping, isolation valves and check valves can deteriorate and increase the systems ‘friction loss’. The images below show some examples of components that have deteriorated over time. This decreases the pressure available at the hydrant outlet and may cause the hydrant system to fail.

Traditionally, friction loss is measured by looking for visual indicators with an in-pipe camera. Hydraulic Testing & Certification use a comprehensive method that consists of measuring the pressure, pipe size, pipe length and elevation at a range of locations to accurately and directly measure the friction loss at several points in the system. Any mismatch between the expected friction loss and the actual friction loss indicates a faulty component that can be replaced to improve the hydrant performance. This technique offers advantages to traditional in-pipe camera inspections as it does not rely on visual indicators of high friction loss, it measures the friction loss directly without having to isolate or drain the system.

Image 1: A corroded unlined Cast Iron pipe with significant internal corrosion
Image 2: A corroded wafer check. Despite the relatively light corrosion, replacing this wafer check valve increased the available pressure by 135kPa at 20L/s and caused the system to go from a fail to a pass. 

#3: Log The Static Pressure Available From The Town Main

The water utility main supply pressure can be influenced by many external, short-term factors such as utility operations (reservoir filling), background use from neighbouring sites or high volume use on-site. To investigate this, pressure loggers are installed at key locations to monitor the supply pressure.

At HTC Group, we aim to set our own customer service standard by striking the balance between assured compliance, and minimising defect rectification expenses. We provide a range of options to put the power back into your hands to keep your hydrant system compliant. If you need professional hydrant testing you can trust, be sure to contact our helpful team today.

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