Introducing water mist technology – Part 2

Water mist expertise remains to be a comparatively new concept by method of fireplace suppression, but it is proving to be an thrilling growth in the industry. As the trade evolves, so do the regulations, laws and requirements in order to improve safety and enable improvement. These can vary largely from country to country, and even area to region.
The means by which a water mist system operates is an identical mechanism to the standard sprinkler system in that the nozzles are often activated through a bulb which blows at a particular temperature permitting for the activation of the mist by way of a low-pressure water piping system.
Here we have a look at how some water mist nozzles are produced and installed – from arriving as a large ‘bar’ of metallic, to becoming the environment friendly water mist nozzles we see put in in plenty of new projects/developments across much of the globe today.
The steel arrives for cutting

Here at Dual Mist Ltd, Stainless Steel 304 is used for so much of parts as this can be very sturdy and corrosion resistant compared to different comparable metals. The physique is machined out of Brass CZ121, which arrives as large bars of metallic which might be delivered to the warehouse in 3m lengths. This is then minimize into two smaller components able to insert into the machine. Not all water mist corporations have the power to machine the elements they require in-house although it can show very beneficial for value and production purposes as we are about to see.
Machining

The metal is fed to a Nakamura WT150 CNC lathe. This high-performance Japanese machine tool is supplied with carbide tooling and high-pressure by way of coolant methods, with the twin-spindle and twin-turret making haste of the otherwise sophisticated components. A Citizen M532 Sliding Head Lathe is used for the smaller elements.
A Citizen L12 also makes the filters with a functionality of drilling 365 holes in 51 seconds, fully automated – this means it might possibly turnover an unbelievable 4,000 filters in a weekend utterly unmanned.
The brass heads are additionally de-burred on the machine, removing all sharp edges earlier than being polished and despatched for Electroless Nickel Plating. This provides a corrosion-proof coating to the brass, enabling it to turn into much more durable. All components are then inspected for dimensional accuracy earlier than the assembly stage.
This Technifor Laser machine engraves each nozzle in preparation for the testing levels.
Assembly

There are many small components of assorted shapes and sizes that make up the nozzle – In the DM4R nozzle, (as seen on the leak-testing pic) there are a complete of thirteen parts or ‘components’. These components are then meticulously put together and assembled by the manufacturing group requiring a fair amount of labour earlier than the ultimate product is achieved. Various levels include tightening with specifically adapted tools, urgent utilizing a hand-press and using a selected ‘Locktite’ method at some phases which is a threadlock that prevents fixings from coming free through the operational lifetime of the product. The ultimate stage of assembly is rigorously loading the bulb and making use of the correct load to it utilizing a torque wrench.
The assembled nozzles are then placed on one other machine in order to be labelled and uniquely identified using a serial quantity. At Dual Mist Ltd this is accomplished on a Technifor Laser Engraver fitted with a 4th axis unit earlier than they’re able to be positioned by way of the varied levels of testing.
Testing

Cull Testing

Also often known as bubble testing in layman’s terms, this check is to ensure no harm has occurred to the bulb throughout meeting and is a critical take a look at for LPCB approval. The test involves using a high-powered microscope to measure the dimensions of the bubble in every bulb earlier than inserting in heat water in order to shrink the scale of the bubble to nothing. Once this is checked, the nozzles are then left to rest and return to room temperature earlier than the bubble is measured as soon as once more in order to ensure it has returned to the original dimension within a small tolerance.
Leak Testing

Every nozzle can additionally be stringently tested for leaks by making use of 24-bar pressure for 1 hour and guaranteeing no water has escaped. It is uncommon for any leaks on the manufacturing line, however this is an extremely vital stage of the testing as leaks may occur if dirt is trapped inside the seal face.
Activation Testing

On a monthly foundation, random nozzles are also examined for activation by placing the nozzle on a strain jig at varied pressures and applying heat to the bulbs. The nozzles should all activate cleanly across the entire stress vary specified to that nozzle.
A member of the manufacturing group makes use of a microscope and software to find out the scale of every bubble in the bulb.
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At Dual Mist Ltd, these tests aren’t simply to guarantee the standard of the production line but are also an necessary a part of the LPCB Approval. These approvals allow prospects to recognise that the merchandise they are buying are made to the highest possible quality commonplace in the region.
The drawback to that is that the Approval Testing system could be each expensive and time-consuming – generally needing to be booked a quantity of months prematurely and requiring years of hard work to achieve.
The nozzles produced by Dual Mist have been put by way of their paces at BRE Global by way of each fire testing and component/type approval.
Tamper proofing

In order to guarantee that no person is tempted to intrude with the grub screw holding the bulb, a small plastic bung is pressed into the grub screw. The pressure load setting on the bulb is then subsequently mounted.
The nozzles are then ready to be packaged and despatched off for installation.
Here is an instance of a control panel having been put in in The Claridges Hotel, London, UK. This is where the system is operated.
Installation

Rather than having to use the heavy and labour-intensive steel pipes usually utilized in high-pressure methods, low-pressure water systems can use CPVC piping. This is a special sort of fire-resistant plastic enabling quick set up. Instead of threading each pipe, a heated glue can be used to rapidly build large pipe networks. These networks are permitted to deal with up to 12 bar strain. The nozzles are screwed into a special pipe adaptor using a half-inch fuel fitting.
An electrical control panel is fitted for the system management together with pumps and a water tank, often with a mains feed.
The system is examined, signed off and handed over to the shopper.
The last product as soon as put in. This exhibits how we expect to see the nozzles once a challenge has been accomplished.
Conclusion

As we can see there are lots of levels to go from steel to nozzle head with every nozzle taking a major effort by various professionals to finish to the permitted normal.
Not solely do water mist nozzles require a quantity of stages of machining and assembling, they must additionally endure a string of tests so as to be accredited for installation. Once put in, there are even additional checks undergone, generally by third-party organisations to ensure that the entire fireplace suppression system to finally be handed over to the client.
Water mist expertise assures security, high quality and assurance by way of the stringent testing that’s required.
With the recent publication of water mist standards, particularly in Britain over current years, constructing developers can now be assured that the standard required for water mist systems is now at an equivalent standard to other suppression systems.
For extra info, go to www.dualmist.com

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