Introducing water mist know-how – Part 2

Water mist know-how is still a comparatively new concept in terms of fire suppression, but it is proving to be an thrilling improvement within the trade. As the business evolves, so do the laws, laws and necessities so as to improve security and allow improvement. These can vary largely from country to country, and even area to area.
The method by which a water mist system operates is a similar mechanism to the traditional sprinkler system in that the nozzles are often activated by way of a bulb which blows at a selected temperature allowing for the activation of the mist through 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 turning into the efficient water mist nozzles we see installed in many new projects/developments throughout much of the globe right now.
The metallic arrives for slicing
Here at Dual Mist Ltd, Stainless Steel 304 is used for lots of components as this could be very durable and corrosion resistant in comparison to other similar metals. The body is machined out of Brass CZ121, which arrives as giant bars of steel that are delivered to the warehouse in 3m lengths. This is then reduce into two smaller elements able to insert into the machine. Not all water mist firms have the ability to machine the elements they require in-house although it could prove very useful for price and production functions as we’re about to see.
The steel 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 difficult components. A Citizen M532 Sliding Head Lathe is used for the smaller parts.
A Citizen L12 additionally makes the filters with a functionality of drilling 365 holes in fifty one seconds, utterly automated – this implies it may possibly turnover an incredible four,000 filters in a weekend fully unmanned.
The brass heads are also 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 become far more sturdy. All parts are then inspected for dimensional accuracy earlier than the meeting stage.
This Technifor Laser machine engraves each nozzle in preparation for the testing phases.
There are many small parts of various sizes and shapes that make up the nozzle – In the DM4R nozzle, (as seen on the leak-testing pic) there are a complete of 13 elements or ‘components’. These elements are then meticulously put collectively and assembled by the manufacturing staff requiring a good amount of labour before the ultimate product is achieved. Various levels embrace tightening with specially tailored tools, pressing utilizing a hand-press and using a particular ‘Locktite’ formula at some phases which is a threadlock that prevents fixings from coming unfastened in the course of the operational lifetime of the product. The last stage of assembly is carefully loading the bulb and applying the proper load to it using a torque wrench.
The assembled nozzles are then positioned on another machine so as to be labelled and uniquely recognized utilizing a serial number. At Dual Mist Ltd that is carried out on a Technifor Laser Engraver fitted with a 4th axis unit earlier than they’re able to be placed by way of the various phases of testing.
Cull Testing
Also often identified as bubble testing in layman’s terms, this check is to make sure no damage has occurred to the bulb throughout assembly and is a critical check for LPCB approval. The take a look at involves using a high-powered microscope to measure the scale of the bubble in each bulb earlier than placing in warm water in order to shrink the dimensions of the bubble to nothing. Once that is checked, the nozzles are then left to rest and return to room temperature before the bubble is measured once once more so as to guarantee it has returned to the unique dimension within a small tolerance.
Leak Testing
Every nozzle can be stringently tested for leaks by applying 24-bar strain for 1 hour and making certain no water has escaped. It is rare for any leaks on the manufacturing line, however that is an especially vital stage of the testing as leaks may occur if dust is trapped throughout the seal face.
Activation Testing
On a month-to-month foundation, random nozzles are also examined for activation by placing the nozzle on a strain jig at varied pressures and making use of heat to the bulbs. The nozzles ought to all activate cleanly across the whole pressure vary specified to that nozzle.
A member of the manufacturing group uses a microscope and software program to determine the scale of every bubble in the bulb.
At Dual Mist Ltd, these tests aren’t simply to assure the standard of the manufacturing line but are also an essential part of the LPCB Approval. These approvals allow clients to recognise that the products they’re buying are made to the very best attainable high quality normal in the area.
The disadvantage to that is that the Approval Testing system may be each pricey and time-consuming – generally needing to be booked several months prematurely and requiring years of onerous work to attain.
The nozzles produced by Dual Mist have been put through their paces at BRE Global in phrases of each fireplace testing and component/type approval.
Tamper proofing
In order to ensure that no person is tempted to intervene 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 fixed.
The nozzles are then able to be packaged and despatched off for installation.
Here is an example of a management panel having been installed in The Claridges Hotel, London, UK. This is the place the system is operated.
Rather than having to make use of the heavy and labour-intensive metal pipes typically utilized in high-pressure techniques, low-pressure water techniques 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 as much as 12 bar pressure. The nozzles are screwed into a special pipe adaptor utilizing a half-inch gas fitting.
An electric management panel is fitted for the system management together with pumps and a water tank, often with a mains feed.
The system is tested, signed off and handed over to the client.
The last product as quickly as put in. This reveals how we expect to see the nozzles as quickly as a challenge has been completed.
As we are in a position to see there are numerous levels to go from steel to nozzle head with each nozzle taking a significant effort by various professionals to complete to the accredited normal.
Not solely do water mist nozzles require multiple stages of machining and assembling, they want to also bear a string of tests to have the ability to be approved for set up. Once installed, there are even additional tests undergone, sometimes by third-party organisations to guarantee that the complete fire suppression system to finally be handed over to the client.
Water mist expertise assures security, quality and assurance by way of the stringent testing that’s required.
With the latest publication of water mist requirements, significantly in Britain over current years, constructing builders can now be assured that the quality required for water mist systems is now at an equivalent commonplace to different suppression techniques.
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