Introducing water mist expertise – Part 2

Water mist expertise continues to be a comparatively new concept in terms of fire suppression, yet it is proving to be an exciting development within the trade. As the business evolves, so do the rules, legal guidelines and requirements to be able to improve safety and allow improvement. These can vary largely from nation to country, and even region to area.
The means in which a water mist system operates is a similar mechanism to the normal sprinkler system in that the nozzles are often activated via a bulb which blows at a particular temperature permitting for the activation of the mist via a low-pressure water piping system.
Here we have 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 environment friendly water mist nozzles we see put in in many new projects/developments across much of the globe right now.
The metal arrives for slicing

Here at Dual Mist Ltd, Stainless Steel 304 is used for so much of components as it is extremely sturdy and corrosion resistant compared to other similar metals. The physique is machined out of Brass CZ121, which arrives as massive bars of steel that are delivered to the warehouse in 3m lengths. This is then cut into two smaller parts ready to insert into the machine. Not all water mist companies have the ability to machine the components they require in-house though it could show very beneficial for cost and production functions as we’re about to see.

The steel is fed to a Nakamura WT150 CNC lathe. This high-performance Japanese machine device is equipped with carbide tooling and high-pressure via coolant techniques, with the twin-spindle and twin-turret making haste of the otherwise difficult elements. 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 unbelievable four,000 filters in a weekend completely unmanned.
The brass heads are also de-burred on the machine, removing all sharp edges earlier than being polished and sent for Electroless Nickel Plating. This provides a corrosion-proof coating to the brass, enabling it to become far more durable. All components are then inspected for dimensional accuracy before the meeting stage.
This Technifor Laser machine engraves each nozzle in preparation for the testing phases.

There are many small components of varied sizes and shapes that make up the nozzle – In the DM4R nozzle, (as seen on the leak-testing pic) there are a complete of thirteen elements or ‘components’. These elements are then meticulously put collectively and assembled by the manufacturing staff requiring a good quantity of labour earlier than the ultimate product is achieved. Various stages embrace tightening with specially tailored tools, pressing using a hand-press and using a specific ‘Locktite’ formulation at some levels which is a threadlock that forestalls fixings from coming free during the operational lifetime of the product. The final stage of meeting is rigorously loading the bulb and applying the right 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 this is accomplished on a Technifor Laser Engraver fitted with a 4th axis unit earlier than they’re able to be positioned via the varied phases of testing.

Cull Testing

Also known as bubble testing in layman’s phrases, this take a look at is to ensure no injury has occurred to the bulb throughout assembly and is a crucial test for LPCB approval. The check involves using a high-powered microscope to measure the size of the bubble in each bulb earlier than inserting in warm water to be able to shrink the scale of the bubble to nothing. Once that is checked, the nozzles are then left to relaxation and return to room temperature before the bubble is measured as quickly as once more so as to guarantee it has returned to the unique dimension inside a small tolerance.
Leak Testing

Every nozzle can additionally be stringently examined for leaks by applying 24-bar stress for 1 hour and making certain no water has escaped. It is uncommon for any leaks on the manufacturing line, but this is a particularly important stage of the testing as leaks may occur if dirt is trapped throughout the seal face.
Activation Testing

On a month-to-month foundation, random nozzles are additionally tested for activation by inserting the nozzle on a pressure jig at various pressures and applying heat to the bulbs. The nozzles ought to all activate cleanly throughout the whole strain range specified to that nozzle.
A member of the manufacturing group makes use of a microscope and software program to determine the dimensions of each bubble within the bulb.

At Dual Mist Ltd, these checks aren’t simply to assure the standard of the manufacturing line but are additionally an necessary a part of the LPCB Approval. These approvals allow customers to recognise that the merchandise they are shopping for are made to the very best possible quality normal in the area.
The disadvantage to that is that the Approval Testing system could be each pricey and time-consuming – typically needing to be booked several months in advance and requiring years of onerous work to attain.
The nozzles produced by Dual Mist have been put via their paces at BRE Global in phrases of both hearth testing and component/type approval.
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In order to make sure 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 fixed.
The nozzles are then able to be packaged and despatched off for set up.
Here is an example of a management panel having been put in in The Claridges Hotel, London, UK. This is where the system is operated.

Rather than having to make use of the heavy and labour-intensive metal pipes usually utilized in high-pressure methods, low-pressure water systems can use CPVC piping. This is a special kind of fire-resistant plastic enabling quick installation. Instead of threading every pipe, a heated glue can be utilized to quickly build giant pipe networks. These networks are accredited to deal with up to 12 bar stress. The nozzles are screwed into a special pipe adaptor using a half-inch gasoline fitting.
An electric control panel is fitted for the system control together with pumps and a water tank, normally with a mains feed.
The system is examined, signed off and handed over to the shopper.
The final product once put in. This exhibits how we anticipate to see the nozzles as soon as a project has been completed.

As we can see there are heaps of stages to go from steel to nozzle head with every nozzle taking a significant effort by numerous professionals to finish to the permitted normal.
Not only do water mist nozzles require multiple levels of machining and assembling, they must additionally endure a string of exams so as to be accredited for set up. Once installed, there are even further exams undergone, sometimes by third-party organisations to guarantee that the whole fire suppression system to lastly be handed over to the consumer.
Water mist know-how assures safety, quality and assurance through the stringent testing that is required.
With the recent publication of water mist standards, notably in Britain over latest years, building builders can now be assured that the quality required for water mist methods is now at an equal normal to different suppression techniques.
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