Introducing water mist technology – Part 2

Water mist know-how is still a relatively new concept in terms of hearth suppression, yet it is proving to be an exciting development within the business. As the trade evolves, so do the rules, laws and requirements to be able to enhance safety and allow improvement. These can vary largely from nation to country, and even region to area.
The way in which a water mist system operates is a similar mechanism to the normal sprinkler system in that the nozzles are normally activated through a bulb which blows at a selected 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 large ‘bar’ of metal, to changing into the environment friendly water mist nozzles we see installed in many new projects/developments across much of the globe today.
The steel arrives for slicing
Here at Dual Mist Ltd, Stainless Steel 304 is used for many elements as this can be very sturdy and corrosion resistant in comparison to other similar metals. The body is machined out of Brass CZ121, which arrives as giant bars of metal that are delivered to the warehouse in 3m lengths. This is then minimize into two smaller components ready to insert into the machine. Not all water mist companies have the power to machine the elements they require in-house though it can prove very useful 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 device is supplied with carbide tooling and high-pressure through coolant systems, with the twin-spindle and twin-turret making haste of the in any other case complicated components. A Citizen M532 Sliding Head Lathe is used for the smaller components.
A Citizen L12 additionally makes the filters with a functionality of drilling 365 holes in 51 seconds, utterly automated – this implies it could turnover an incredible four,000 filters in a weekend completely 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 supplies a corrosion-proof coating to the brass, enabling it to turn out to be much 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 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 parts are then meticulously put collectively and assembled by the production group requiring a fair quantity of labour before the final product is achieved. Various stages include tightening with specifically adapted tools, urgent utilizing a hand-press and using a selected ‘Locktite’ formula at some phases which is a threadlock that prevents fixings from coming loose during the operational lifetime of the product. The final stage of assembly is carefully loading the bulb and applying the correct load to it using a torque wrench.
The assembled nozzles are then positioned on another machine in order to be labelled and uniquely recognized utilizing a serial number. At Dual Mist Ltd this is done on a Technifor Laser Engraver fitted with a 4th axis unit earlier than they are able to be positioned by way of the varied phases of testing.
Cull Testing
Also known as bubble testing in layman’s terms, this check is to make sure no damage has occurred to the bulb during assembly and is a crucial test 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 inserting in heat water to be able to shrink the size 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 to have the ability to ensure it has returned to the original dimension within a small tolerance.
Leak Testing
Every nozzle can also be stringently tested for leaks by making use of 24-bar strain for 1 hour and ensuring no water has escaped. It is rare for any leaks on the manufacturing line, however this is an especially very important stage of the testing as leaks might occur if dirt is trapped throughout the seal face.
Activation Testing
On a monthly foundation, random nozzles are also examined for activation by inserting the nozzle on a stress jig at various pressures and making use of heat to the bulbs. The nozzles should all activate cleanly across the entire stress range specified to that nozzle.
A member of the manufacturing team makes use of a microscope and software to find out the scale of every bubble within the bulb.
At Dual Mist Ltd, these checks usually are not just to guarantee the standard of the production line but are additionally an essential part of the LPCB Approval. These approvals allow prospects to recognise that the merchandise they’re buying are made to the best potential high quality standard in the region.
The disadvantage to this is that the Approval Testing system can be both costly and time-consuming – generally needing to be booked a quantity of months upfront and requiring years of hard work to realize.
The nozzles produced by Dual Mist have been put via their paces at BRE Global by means of both fireplace 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 stress load setting on the bulb is then subsequently fastened.
The nozzles are then able to be packaged and despatched 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 often used in high-pressure systems, low-pressure water systems can use CPVC piping. This is a special sort of fire-resistant plastic enabling fast installation. Instead of threading every pipe, a heated glue can be utilized to shortly construct large pipe networks. These networks are accredited to handle as a lot as 12 bar stress. The nozzles are screwed right into a special pipe adaptor using a half-inch gasoline becoming.
An electrical control panel is fitted for the system control together with pumps and a water tank, often with a mains feed.
The system is tested, signed off and handed over to the shopper.
The ultimate product once put in. This reveals how we expect to see the nozzles once a challenge has been completed.
As we will see there are numerous levels to go from metallic to nozzle head with each nozzle taking a significant effort by various professionals to complete to the approved standard.
Not only do water mist nozzles require multiple levels of machining and assembling, they must also undergo a string of tests to be able to be approved for set up. Once put in, there are even additional exams undergone, sometimes by third-party organisations to ensure that the complete fireplace suppression system to lastly be handed over to the shopper.
Water mist know-how assures security, high quality and assurance through the stringent testing that is required.
With the recent publication of water mist standards, notably in Britain over current years, constructing developers can now be assured that the quality required for water mist systems is now at an equivalent standard to different suppression techniques.
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