Introducing water mist technology – Part 2

Water mist technology is still a relatively new idea by method of hearth suppression, but it is proving to be an exciting improvement within the industry. As the business evolves, so do the regulations, legal guidelines and requirements so as to enhance safety and allow development. These can differ largely from country to nation, and even area to area.
The way by which a water mist system operates is a similar mechanism to the normal 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 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 metal, to changing into the efficient water mist nozzles we see put in in many new projects/developments throughout a lot of the globe at present.
The steel arrives for cutting
Here at Dual Mist Ltd, Stainless Steel 304 is used for so much of components as it is extremely sturdy and corrosion resistant in comparison to different similar metals. The body is machined out of Brass CZ121, which arrives as large bars of metal which are delivered to the warehouse in 3m lengths. This is then minimize into two smaller elements able to insert into the machine. Not all water mist corporations have the flexibility to machine the components they require in-house though it could show very beneficial for value and production purposes 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 by way of coolant methods, with the twin-spindle and twin-turret making haste of the otherwise sophisticated elements. A Citizen M532 Sliding Head Lathe is used for the smaller parts.
A Citizen L12 also makes the filters with a capability of drilling 365 holes in 51 seconds, completely automated – this implies it may possibly turnover an unbelievable four,000 filters in a weekend utterly unmanned.
The brass heads are also de-burred on the machine, eradicating all sharp edges earlier than being polished and sent for Electroless Nickel Plating. This supplies a corrosion-proof coating to the brass, enabling it to become rather more durable. All parts are then inspected for dimensional accuracy earlier than the assembly stage.
This Technifor Laser machine engraves each nozzle in preparation for the testing stages.
There are many small elements of various shapes and sizes that make up the nozzle – In the DM4R nozzle, (as seen on the leak-testing pic) there are a total of thirteen elements or ‘components’. These parts are then meticulously put collectively and assembled by the production group requiring a good amount of labour earlier than the ultimate product is achieved. Various phases embody tightening with specifically adapted tools, pressing utilizing a hand-press and using a particular ‘Locktite’ formula at some levels which is a threadlock that prevents fixings from coming loose through the operational lifetime of the product. The ultimate stage of meeting is fastidiously loading the bulb and applying the correct load to it using a torque wrench.
The assembled nozzles are then positioned on one other machine so as to be labelled and uniquely recognized utilizing a serial quantity. At Dual Mist Ltd that is done on a Technifor Laser Engraver fitted with a 4th axis unit earlier than they’re able to be placed by way of the varied stages of testing.
Cull Testing
Also generally recognized 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 critical test for LPCB approval. The check includes using a high-powered microscope to measure the dimensions of the bubble in every bulb earlier than inserting in heat water so as 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 once again in order to ensure it has returned to the original dimension inside a small tolerance.
Leak Testing
Every nozzle is also 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 production line, however that is a particularly vital stage of the testing as leaks could occur if dirt is trapped throughout the seal face.
Activation Testing
On a monthly basis, random nozzles are also examined for activation by placing the nozzle on a pressure jig at various pressures and applying warmth to the bulbs. The nozzles should all activate cleanly throughout the whole stress vary specified to that nozzle.
A member of the production team uses a microscope and software program to discover out the size of each bubble within the bulb.
At Dual Mist Ltd, these tests usually are not simply to guarantee the standard of the production line however are additionally an necessary part of the LPCB Approval. These approvals allow clients to recognise that the merchandise they are shopping for are made to the highest potential high quality commonplace in the region.
The disadvantage to that is that the Approval Testing system can be both costly and time-consuming – typically needing to be booked several months in advance and requiring years of onerous work to realize.
The nozzles produced by Dual Mist have been put via their paces at BRE Global in phrases of both fire testing and component/type approval.
In order to ensure that no one is tempted to interfere 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 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 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 techniques, low-pressure water techniques can use CPVC piping. This is a particular sort of fire-resistant plastic enabling fast installation. Instead of threading each pipe, a heated glue can be used to quickly construct giant pipe networks. These networks are permitted to deal with up to 12 bar strain. The nozzles are screwed into a particular pipe adaptor utilizing a half-inch gasoline fitting.
An electrical control panel is fitted for the system management together with pumps and a water tank, often with a mains feed.
The system is examined, signed off and handed over to the shopper.
The final product as quickly as put in. This exhibits how we expect to see the nozzles as soon as a venture has been accomplished.
As we can see there are heaps of phases to go from steel to nozzle head with each nozzle taking a big effort by numerous professionals to complete to the approved commonplace.
Not only do water mist nozzles require a quantity of stages of machining and assembling, they want to additionally undergo a string of tests in order to be approved for set up. Once put in, there are even further checks undergone, typically by third-party organisations to guarantee that the whole hearth suppression system to finally be handed over to the consumer.
Water mist expertise assures security, high quality and assurance by way of the stringent testing that is required.
With the recent publication of water mist standards, significantly in Britain over current years, building builders can now be assured that the quality required for water mist methods is now at an equal standard to different suppression techniques.
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