Multifaceted new Air Valve combats water hammer in multi-storey buildings

To reduce water hammer in multi-storey buildings, Designed Network Solutions (DNS) has launched a new Special Execution Air Valve, DNS-3F-AS-HR.

Water hammer (transient pressure surges) caused by sudden changes in the velocity of the water moving through the pipeline, can now be eliminated by installing the new DNS-3F-AS-HR at the top of each riser. With its built-in anti-shock feature, this new Air Valve reduces the velocity of the approaching water column.

Transient pressure surges also occur when a riser is first primed or during maintenance – but the DNS-3F-AS-HR

benefits from exclusive, double anti-slam technology that removes unwanted surges and pulsations, offering perfect sealing in low pressure conditions.

In addition, a building power outage, which sees the main riser drain – due to usage within the building, will also create water hammer. When power is restored, pumps want to fill the raiser as quickly as possible. Typically, a standard air valve at the top of the riser will let it fill two quickly, resulting in the water column slamming into the top of the riser and causing a water hammer event. However, this can all prevented by the new DNS Air Valve, which allows the release of air pockets in a multi-storey building to prevent collapses in the water or fire-main system on pump start-up.

During normal system operation, air produced by the pipeline that accumulates at the top of the riser will be discharged by the DNS Air Valve whilst under pressure. This will prevent any air entrapment that can corrode metallic pipes.


‘New Critical Air Valve Monitoring System’

In response to an issue that causes unnecessary costs because the location of air valves is not known, Designed Network Solutions (DNS) have also introduced a new Critical Air Valve Monitoring System.

According to DNS, the ‘disappearance’ of air valves means that many companies in the manufacturing/industrial sector are often unaware if these valves are operational or fit for purpose – creating potential burst and leakage events. DNS also state that non-functional air valves cause a constant build-up of air within pipelines, forcing pumps to work much harder than they should. This results in a reduced flow capacity and inefficient pump operation.

Designed Network Solutions’ (DNS) Director, Craig Stanners said: “For far too long, engineers have been unable to properly maintain air valves or address serious issues such as contamination, water quality, transient and water hammer; simply because they don’t have access to the right information. Now, with a proper Air Valve Monitoring System, they can carry out their work far more efficiently, reducing surge and transient events – first because they’ll know what’s actually in the network – and secondly, because they’ll be notified by an alarm to advise when an air valve is not working as it should be”.

The new DNS Critical Air Valve Monitoring System can log (at least) two main parameters:

  • Pressure within the main – and then alarms if the pressure drops to below 0.2Bar because at this point the air valve is at risk of opening.
  • It also monitors the air valve environment and whether it is operating within atmospheric conditions, or if the air valve is submerged and therefore poses a significant contamination risk.


Craig Stanners added: “It is staggering to think just how many ‘lost’ air valves there are out there that could be sucking in all types of rubbish – causing contamination and costing businesses too much in the way of maintenance costs. But now at last, this new Critical Air Valve Monitoring System is a gamechanger”.

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