Water mist know-how continues to be a relatively new concept in phrases of fireplace suppression, but it’s proving to be an thrilling growth in the industry. As the trade evolves, so do the rules, legal guidelines and requirements to have the ability to improve safety and allow improvement. These can vary largely from country to nation, and even region to region.
The method during which a water mist system operates is an identical mechanism to the standard sprinkler system in that the nozzles are usually activated through a bulb which blows at a selected 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 installed – from arriving as a large ‘bar’ of metallic, to changing into the environment friendly water mist nozzles we see installed in lots of new projects/developments throughout a lot of the globe right now.
The steel arrives for slicing
Here at Dual Mist Ltd, Stainless Steel 304 is used for many parts as it is extremely sturdy and corrosion resistant in comparability to different related metals. The body is machined out of Brass CZ121, which arrives as massive bars of metal which would possibly be delivered to the warehouse in 3m lengths. This is then reduce into two smaller components able to insert into the machine. Not all water mist firms have the ability to machine the components they require in-house though it can prove very useful for value and production functions as we are about to see.
Machining
The metal is fed to a Nakamura WT150 CNC lathe. This high-performance Japanese machine tool is supplied with carbide tooling and high-pressure through 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 parts.
A Citizen L12 additionally makes the filters with a functionality of drilling 365 holes in fifty one seconds, utterly automated – this means it could turnover an incredible 4,000 filters in a weekend utterly 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 rather more durable. All components are then inspected for dimensional accuracy earlier than the assembly stage.
This Technifor Laser machine engraves every nozzle in preparation for the testing stages.
Assembly
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 total of 13 parts or ‘components’. These parts are then meticulously put together and assembled by the manufacturing group requiring a fair amount of labour before the ultimate product is achieved. Various phases include tightening with specially tailored instruments, urgent utilizing a hand-press and using a particular ‘Locktite’ formula at some stages which is a threadlock that stops fixings from coming loose 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 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 by way of the assorted stages of testing.
Testing
Cull Testing
Also generally recognized as bubble testing in layman’s phrases, this take a look at is to ensure no harm has occurred to the bulb throughout assembly and is a critical test for LPCB approval. The check involves using a high-powered microscope to measure the dimensions of the bubble in every bulb before putting in warm water to be able to shrink the size of the bubble to nothing. Once this is checked, the nozzles are then left to relaxation and return to room temperature earlier than the bubble is measured as quickly as once more so as to guarantee it has returned to the unique dimension within a small tolerance.
Leak Testing
Every nozzle is also stringently tested for leaks by making use of 24-bar pressure for 1 hour and making certain no water has escaped. It is rare for any leaks on the production line, however this is an extremely important stage of the testing as leaks may happen if filth is trapped throughout the seal face.
Activation Testing
On a monthly basis, random nozzles are additionally tested for activation by placing the nozzle on a pressure jig at various pressures and applying heat to the bulbs. The nozzles should all activate cleanly throughout the complete stress range specified to that nozzle.
A member of the production staff makes use of a microscope and software to find out the size of each bubble within the bulb.
Approvals
At Dual Mist Ltd, these tests usually are not just to assure the quality of the production line however are additionally an necessary a half of the LPCB Approval. These approvals enable clients to recognise that the products they’re buying are made to the very best possible quality commonplace in the region.
The drawback to this is that the Approval Testing system could be both costly and time-consuming – typically needing to be booked a number of months upfront and requiring years of exhausting work to attain.
The nozzles produced by Dual Mist have been put by way of their paces at BRE Global when it comes to each fire testing and component/type approval.
Tamper proofing
In order to guarantee that no person is tempted to interfere with the grub screw holding the bulb, a small plastic bung is pressed into the grub screw. xp2i on the bulb is then subsequently mounted.
The nozzles are then able to be packaged and despatched off for set up.
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.
Installation
Rather than having to use the heavy and labour-intensive steel pipes typically used in high-pressure techniques, low-pressure water systems can use CPVC piping. This is a particular kind of fire-resistant plastic enabling quick set up. Instead of threading each pipe, a heated glue can be utilized to rapidly build large pipe networks. These networks are accredited to handle up to 12 bar stress. The nozzles are screwed into a particular pipe adaptor using a half-inch gas 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 client.
The final product once installed. This shows how we anticipate to see the nozzles once a project has been completed.
Conclusion
As we can see there are many phases to go from metal to nozzle head with each nozzle taking a major effort by varied professionals to complete to the approved normal.
Not only do water mist nozzles require multiple stages of machining and assembling, they must also endure a string of checks so as to be accredited for installation. Once installed, there are even additional checks undergone, typically by third-party organisations in order for the entire hearth suppression system to finally be handed over to the shopper.
Water mist expertise assures safety, quality and assurance by way of the stringent testing that’s required.
With the recent publication of water mist standards, particularly in Britain over latest years, constructing developers can now be assured that the quality required for water mist techniques is now at an equal commonplace to other suppression methods.
For more info, go to www.dualmist.com
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