Introducing water mist expertise – Part 2

Water mist know-how is still a relatively new concept by method of hearth suppression, yet it’s proving to be an thrilling development in the trade. As the industry evolves, so do the rules, legal guidelines and requirements to find a way to enhance security and enable development. These can vary largely from country to country, and even region to region.
The means during which a water mist system operates is a similar mechanism to the traditional sprinkler system in that the nozzles are normally activated through a bulb which blows at a specific temperature allowing for the activation of the mist by way of a low-pressure water piping system.
Here we take a look at how some water mist nozzles are produced and put in – from arriving as a big ‘bar’ of steel, to turning into the efficient water mist nozzles we see put in in many new projects/developments throughout a lot of the globe at present.
The metallic arrives for chopping

Here at Dual Mist Ltd, Stainless Steel 304 is used for many parts as this can be very sturdy and corrosion resistant compared to other similar metals. The body is machined out of Brass CZ121, which arrives as large bars of metal which are delivered to the warehouse in 3m lengths. This is then minimize into two smaller parts able to insert into the machine. Not all water mist companies have the power to machine the components they require in-house although it may possibly prove very helpful for price and manufacturing purposes as we are about to see.

The metal is fed to a Nakamura WT150 CNC lathe. This high-performance Japanese machine software is equipped with carbide tooling and high-pressure by way of coolant techniques, 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 elements.
A Citizen L12 additionally makes the filters with a functionality of drilling 365 holes in fifty one seconds, fully automated – this means it could turnover an unimaginable 4,000 filters in a weekend completely unmanned.
The brass heads are additionally de-burred on the machine, removing all sharp edges before being polished and sent for Electroless Nickel Plating. This provides a corrosion-proof coating to the brass, enabling it to turn out to be rather more durable. All parts are then inspected for dimensional accuracy before the assembly stage.
This Technifor Laser machine engraves every nozzle in preparation for the testing levels.

There are many small elements of varied shapes and sizes that make up the nozzle – In the DM4R nozzle, (as seen on the leak-testing pic) there are a total of thirteen parts or ‘components’. These parts are then meticulously put together and assembled by the production staff requiring a good quantity of labour earlier than the final product is achieved. Various levels embody tightening with specifically tailored instruments, pressing using a hand-press and utilizing a particular ‘Locktite’ method at some levels which is a threadlock that stops fixings from coming free through the operational lifetime of the product. The ultimate stage of meeting is rigorously loading the bulb and making use of the proper load to it utilizing a torque wrench.
The assembled nozzles are then positioned on one other machine so as to be labelled and uniquely identified utilizing a serial quantity. At Dual Mist Ltd that is carried out on a Technifor Laser Engraver fitted with a 4th axis unit before they’re able to be positioned by way of the assorted phases of testing.

Cull Testing

Also often known as bubble testing in layman’s terms, this take a look at is to ensure no injury has occurred to the bulb throughout meeting and is a important take a look at for LPCB approval. The take a look at involves utilizing a high-powered microscope to measure the size of the bubble in each bulb earlier than placing in warm water so as 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 once once more in order to guarantee it has returned to the unique measurement within a small tolerance.
Leak Testing

Every nozzle can additionally be stringently examined for leaks by applying 24-bar strain for 1 hour and guaranteeing no water has escaped. It is rare for any leaks on the production line, but this is an especially important stage of the testing as leaks could occur if filth is trapped throughout the seal face.
Activation Testing

On a monthly basis, random nozzles are also examined for activation by inserting the nozzle on a strain jig at varied pressures and making use of warmth to the bulbs. The nozzles should all activate cleanly throughout the entire pressure range specified to that nozzle.
A member of the manufacturing group uses a microscope and software program to determine the dimensions of every bubble in the bulb.

At Dual Mist Ltd, these exams aren’t just to guarantee the quality of the production line however are also an essential part of the LPCB Approval. These approvals allow clients to recognise that the merchandise they are shopping for are made to the highest potential high quality normal in the area.
The disadvantage to this is that the Approval Testing system may be each expensive and time-consuming – generally needing to be booked a number of months prematurely and requiring years of exhausting work to achieve.
The nozzles produced by Dual Mist have been put by way of their paces at BRE Global by method of each hearth testing and component/type approval.
Tamper proofing

In order to ensure that nobody is tempted to intrude with the grub screw holding the bulb, a small plastic bung is pressed into the grub screw. The strain load setting on the bulb is then subsequently mounted.
The nozzles are then ready to be packaged and sent off for installation.
Here is an example of a control panel having been installed in The Claridges Hotel, London, UK. This is the place the system is operated.

Rather than having to use the heavy and labour-intensive metallic pipes usually utilized in high-pressure systems, low-pressure water techniques can use CPVC piping. This is a special kind of fire-resistant plastic enabling quick installation. Instead of threading pressure gauge , a heated glue can be used to rapidly build massive pipe networks. These networks are approved to deal with as much as 12 bar pressure. The nozzles are screwed into a special pipe adaptor utilizing a half-inch gasoline fitting.
An electric management panel is fitted for the system control together with pumps and a water tank, usually with a mains feed.
The system is examined, signed off and handed over to the consumer.
The last product once installed. This exhibits how we expect to see the nozzles as soon as a venture has been completed.

As we are ready to see there are numerous stages to go from metal to nozzle head with each nozzle taking a significant effort by numerous professionals to finish to the accredited commonplace.
Not only do water mist nozzles require multiple phases of machining and assembling, they must additionally endure a string of exams to be able to be accredited for set up. Once installed, there are even additional tests undergone, generally by third-party organisations to ensure that the whole fireplace suppression system to lastly be handed over to the consumer.
Water mist know-how assures security, high quality and assurance via the stringent testing that’s required.
With the latest publication of water mist requirements, 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 other suppression systems.
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