Introducing water mist know-how – Part 2

Water mist know-how is still a relatively new idea in phrases of fireplace suppression, yet it’s proving to be an thrilling improvement in the business. As the trade evolves, so do the rules, laws and requirements so as to improve safety and allow improvement. These can differ largely from nation to nation, and even area to region.
The means during which a water mist system operates is an identical mechanism to the standard sprinkler system in that the nozzles are usually activated by way of a bulb which blows at a specific temperature permitting 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 installed – from arriving as a large ‘bar’ of steel, to becoming the environment friendly water mist nozzles we see installed in plenty of new projects/developments throughout much of the globe right now.
The steel arrives for slicing
Here at Dual Mist Ltd, Stainless Steel 304 is used for so much of components as this may be very sturdy and corrosion resistant in comparison to different related metals. The physique is machined out of Brass CZ121, which arrives as giant bars of metallic which are delivered to the warehouse in 3m lengths. This is then reduce into two smaller parts able to insert into the machine. Not all water mist companies have the power to machine the parts they require in-house though it may possibly show very useful for price and production functions as we are about to see.
The metal is fed to a Nakamura WT150 CNC lathe. This high-performance Japanese machine tool is supplied with carbide tooling and high-pressure by way of coolant systems, 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 also makes the filters with a capability of drilling 365 holes in fifty one seconds, utterly automated – this means it might possibly turnover an unbelievable four,000 filters in a weekend fully unmanned.
The brass heads are additionally de-burred on the machine, eradicating all sharp edges before 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 components are then inspected for dimensional accuracy before the meeting stage.
This Technifor Laser machine engraves every nozzle in preparation for the testing levels.
There are many small parts of assorted styles and sizes that make up the nozzle – In the DM4R nozzle, (as seen on the leak-testing pic) there are a complete of thirteen components or ‘components’. These elements are then meticulously put collectively and assembled by the manufacturing group requiring a good quantity of labour earlier than the ultimate product is achieved. Various phases embrace tightening with specially adapted instruments, pressing utilizing a hand-press and using a selected ‘Locktite’ method at some phases which is a threadlock that prevents fixings from coming unfastened through the operational lifetime of the product. The final stage of assembly is rigorously loading the bulb and applying the right load to it using a torque wrench.
The assembled nozzles are then placed on another machine so as to be labelled and uniquely identified utilizing a serial quantity. At Dual Mist Ltd that is accomplished on a Technifor Laser Engraver fitted with a 4th axis unit earlier than they’re ready to be placed by way of the various stages of testing.
Cull Testing
Also known as bubble testing in layman’s terms, this take a look at is to make sure no damage has occurred to the bulb throughout meeting and is a important take a look at for LPCB approval. The test involves using a high-powered microscope to measure the size of the bubble in each bulb before placing in heat 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 as soon as once more so as to guarantee it has returned to the original size inside 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 production line, however that is an extremely very important stage of the testing as leaks may occur if dirt is trapped inside the seal face.
Activation Testing
On a monthly foundation, random nozzles are additionally tested for activation by placing the nozzle on a pressure jig at varied pressures and making use of warmth to the bulbs. The nozzles should all activate cleanly across the whole stress vary specified to that nozzle.
A member of the manufacturing team makes use of a microscope and software program to discover out the scale of each bubble in the bulb.
At Dual Mist Ltd, these exams aren’t just to assure the quality of the manufacturing line however are additionally an essential a part of the LPCB Approval. These approvals enable prospects to recognise that the merchandise they are buying are made to the best attainable high quality commonplace in the area.
The drawback to that is that the Approval Testing system can be each costly and time-consuming – generally needing to be booked several months in advance and requiring years of exhausting work to attain.
The nozzles produced by Dual Mist have been put through their paces at BRE Global when it comes to each fireplace testing and component/type approval.
Tamper proofing
In order to ensure 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 strain load setting on the bulb is then subsequently fastened.
The nozzles are then able to be packaged and sent off for installation.
Here is Basic 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 often utilized in high-pressure techniques, low-pressure water techniques can use CPVC piping. This is a particular type of fire-resistant plastic enabling fast set up. Instead of threading each pipe, a heated glue can be utilized to shortly construct massive pipe networks. These networks are permitted to handle up to 12 bar pressure. The nozzles are screwed into a special pipe adaptor utilizing a half-inch gasoline fitting.
An electrical management panel is fitted for the system management along with pumps and a water tank, normally with a mains feed.
The system is tested, signed off and handed over to the client.
The ultimate product as soon as installed. This exhibits how we expect to see the nozzles as soon as a project has been completed.
As we will see there are many stages to go from metal to nozzle head with every nozzle taking a major effort by various professionals to complete to the accredited standard.
Not solely do water mist nozzles require a quantity of levels of machining and assembling, they have to additionally endure a string of tests in order to be approved for set up. Once put in, there are even further exams undergone, typically by third-party organisations to guarantee that the entire hearth suppression system to lastly be handed over to the shopper.
Water mist technology assures safety, high quality and assurance through the stringent testing that is required.
With the recent publication of water mist standards, significantly in Britain over latest years, building developers can now be assured that the standard required for water mist methods is now at an equivalent commonplace to other suppression methods.
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