Introducing water mist expertise – Part 2

Water mist expertise continues to be a relatively new idea by way of fireplace suppression, yet it is proving to be an thrilling growth in the trade. As the trade evolves, so do the regulations, laws and necessities so as to improve safety and allow growth. These can differ largely from country to country, and even area to area.
The method by which a water mist system operates is an analogous mechanism to the normal sprinkler system in that the nozzles are usually activated by way of a bulb which blows at a specific temperature allowing for the activation of the mist through a low-pressure water piping system.
Here we take a look at how some water mist nozzles are produced and installed – from arriving as a big ‘bar’ of steel, to becoming the environment friendly water mist nozzles we see installed in many new projects/developments across much of the globe right now.
The metallic arrives for cutting

Here at Dual Mist Ltd, Stainless Steel 304 is used for so much of elements as this can be very sturdy and corrosion resistant compared to different related metals. The body is machined out of Brass CZ121, which arrives as massive bars of metallic which would possibly be delivered to the warehouse in 3m lengths. This is then minimize into two smaller elements ready to insert into the machine. Not all water mist firms have the ability to machine the parts they require in-house though it could show very beneficial for cost and manufacturing purposes as we’re about to see.

The metal is fed to a Nakamura WT150 CNC lathe. This high-performance Japanese machine software is supplied with carbide tooling and high-pressure through coolant systems, with the twin-spindle and twin-turret making haste of the otherwise complicated parts. A Citizen M532 Sliding Head Lathe is used for the smaller components.
A Citizen L12 additionally makes the filters with a capability of drilling 365 holes in fifty one seconds, utterly automated – this means it could turnover an unimaginable four,000 filters in a weekend completely unmanned.
The brass heads are also de-burred on the machine, eradicating all sharp edges earlier than being polished and despatched for Electroless Nickel Plating. This supplies a corrosion-proof coating to the brass, enabling it to turn into rather more sturdy. All parts are then inspected for dimensional accuracy before the assembly stage.
This Technifor Laser machine engraves every nozzle in preparation for the testing stages.

There are many small parts of various styles and sizes that make up the nozzle – In the DM4R nozzle, (as seen on the leak-testing pic) there are a total of 13 parts or ‘components’. These components are then meticulously put together and assembled by the production staff requiring a fair amount of labour before the final product is achieved. Various phases include tightening with specifically adapted instruments, urgent utilizing a hand-press and utilizing a selected ‘Locktite’ method at some phases which is a threadlock that stops fixings from coming unfastened during the operational lifetime of the product. The final stage of assembly is fastidiously loading the bulb and making use of the proper load to it using a torque wrench.
The assembled nozzles are then placed on another machine in order to be labelled and uniquely recognized utilizing a serial number. At Dual Mist Ltd that is done on a Technifor Laser Engraver fitted with a 4th axis unit earlier than they’re able to be placed by way of the varied phases of testing.

Cull Testing

Also generally known as bubble testing in layman’s phrases, this take a look at is to ensure no harm has occurred to the bulb during meeting and is a critical test for LPCB approval. The check includes using a high-powered microscope to measure the size of the bubble in every bulb earlier than inserting in warm water in order to shrink the scale of the bubble to nothing. Once this is checked, the nozzles are then left to relaxation and return to room temperature before the bubble is measured as quickly as again to be able to ensure it has returned to the original measurement within a small tolerance.
Leak Testing

Every nozzle can also be stringently tested for leaks by applying 24-bar pressure for 1 hour and ensuring no water has escaped. It is rare for any leaks on the manufacturing line, but this is a particularly important stage of the testing as leaks could occur if dirt is trapped within the seal face.
Activation Testing

On a month-to-month foundation, random nozzles are additionally tested for activation by placing the nozzle on a stress jig at numerous pressures and making use of heat to the bulbs. The nozzles should all activate cleanly throughout the entire stress vary specified to that nozzle.
A member of the manufacturing team makes use of a microscope and software to determine the size of every bubble within the bulb.

At Dual Mist Ltd, these exams usually are not simply to assure the quality of the production line however are additionally an important part of the LPCB Approval. These approvals allow clients to recognise that the merchandise they are buying are made to the highest potential quality standard within the region.
The drawback to this is that the Approval Testing system may be both pricey and time-consuming – typically needing to be booked a quantity of months in advance and requiring years of exhausting work to realize.
The nozzles produced by Dual Mist have been put by way of their paces at BRE Global when it comes to both hearth testing and component/type approval.
Tamper proofing

In order to guarantee that nobody is tempted to intervene 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 able 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 the place the system is operated.

Rather than having to use the heavy and labour-intensive steel pipes often utilized in high-pressure techniques, low-pressure water methods can use CPVC piping. This is a special kind of fire-resistant plastic enabling quick installation. Instead of threading diaphragm seal , a heated glue can be utilized to rapidly construct large pipe networks. These networks are permitted to handle up to 12 bar strain. The nozzles are screwed right into a special pipe adaptor using a half-inch fuel becoming.
An electrical management panel is fitted for the system control together with pumps and a water tank, normally with a mains feed.
The system is tested, signed off and handed over to the client.
The final product as quickly as installed. This exhibits how we expect to see the nozzles once a challenge has been completed.

As we are in a position to see there are many levels to go from metallic to nozzle head with every nozzle taking a big effort by varied professionals to complete to the accredited standard.
Not only do water mist nozzles require multiple levels of machining and assembling, they have to also bear a string of tests to have the ability to be permitted for set up. Once put in, there are even additional tests undergone, sometimes by third-party organisations to guarantee that the whole fireplace suppression system to lastly be handed over to the shopper.
Water mist expertise assures safety, high quality and assurance via the stringent testing that is required.
With the recent publication of water mist standards, notably in Britain over recent years, constructing builders can now be assured that the quality required for water mist systems is now at an equivalent normal to different suppression systems.
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