Introducing water mist technology – Part 2

Water mist expertise remains to be a relatively new concept by means of hearth suppression, but it is proving to be an exciting development within the trade. As the industry evolves, so do the laws, laws and necessities in order to improve security and enable development. These can vary largely from nation to country, and even area to region.
The method in which a water mist system operates is an identical mechanism to the traditional sprinkler system in that the nozzles are often activated through 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 put in – from arriving as a big ‘bar’ of steel, to changing into the environment friendly water mist nozzles we see put in in lots of new projects/developments throughout much of the globe at present.
The steel arrives for cutting
Here at Dual Mist Ltd, Stainless Steel 304 is used for many parts as this could be very durable and corrosion resistant in comparability to different related 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 minimize into two smaller elements able to insert into the machine. Not all water mist companies have the ability to machine the elements they require in-house though it may possibly prove very helpful for cost and production functions as we are 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 sophisticated parts. A Citizen M532 Sliding Head Lathe is used for the smaller components.
A Citizen L12 additionally makes the filters with a capability of drilling 365 holes in 51 seconds, completely automated – this implies it could turnover an incredible four,000 filters in a weekend utterly unmanned.
The brass heads are additionally de-burred on the machine, removing all sharp edges before being polished and despatched for Electroless Nickel Plating. This offers a corrosion-proof coating to the brass, enabling it to become far more sturdy. All components are then inspected for dimensional accuracy earlier than the assembly stage.
This Technifor Laser machine engraves each nozzle in preparation for the testing levels.
There are many small components of varied 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 good quantity of labour before the final product is achieved. Various phases embody tightening with specifically adapted tools, urgent utilizing a hand-press and using a selected ‘Locktite’ method at some stages which is a threadlock that stops fixings from coming free through the operational lifetime of the product. The ultimate stage of assembly is fastidiously loading the bulb and making use of the correct load to it using a torque wrench.
The assembled nozzles are then positioned on one other machine to find a way to be labelled and uniquely identified utilizing a serial number. 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 through the various phases of testing.
Cull Testing
Also known as bubble testing in layman’s terms, this check is to ensure no injury has occurred to the bulb during assembly and is a critical check for LPCB approval. Cancel anytime includes using a high-powered microscope to measure the scale of the bubble in each bulb before inserting in heat water in order to shrink the dimensions of the bubble to nothing. Once this is checked, the nozzles are then left to relaxation and return to room temperature before the bubble is measured as soon as again so as to ensure it has returned to the unique dimension within a small tolerance.
Leak Testing
Every nozzle is also stringently tested for leaks by applying 24-bar stress for 1 hour and ensuring no water has escaped. It is uncommon for any leaks on the production line, but that is an especially vital stage of the testing as leaks might occur if filth is trapped within the seal face.
Activation Testing
On a monthly basis, random nozzles are also examined for activation by putting the nozzle on a pressure jig at various pressures and applying warmth to the bulbs. The nozzles should all activate cleanly across the entire stress range specified to that nozzle.
A member of the production team uses a microscope and software program to find out the size of every bubble within the bulb.
At Dual Mist Ltd, these exams are not simply to assure the standard of the manufacturing line however are also an important a part of the LPCB Approval. These approvals allow customers to recognise that the products they’re shopping for are made to the best potential high quality normal in the area.
The drawback to this is that the Approval Testing system can be each costly and time-consuming – typically needing to be booked several months in advance and requiring years of exhausting work to achieve.
The nozzles produced by Dual Mist have been put through their paces at BRE Global in phrases of each hearth 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 fixed.
The nozzles are then able to be packaged and sent off for set up.
Here is an instance 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 metal pipes typically used in high-pressure methods, low-pressure water methods can use CPVC piping. This is a special sort 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 approved to deal with as a lot as 12 bar pressure. The nozzles are screwed into a particular pipe adaptor utilizing a half-inch fuel becoming.
An electrical 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 as soon as put in. This reveals how we expect to see the nozzles once a project has been completed.
As we will see there are many phases to go from metal to nozzle head with every nozzle taking a major effort by numerous professionals to finish to the permitted commonplace.
Not only do water mist nozzles require multiple levels of machining and assembling, they have to also bear a string of exams so as to be approved for set up. Once put in, there are even further exams undergone, sometimes by third-party organisations in order for the complete fire suppression system to lastly be handed over to the consumer.
Water mist technology assures safety, quality and assurance by way of the stringent testing that is required.
With the latest publication of water mist requirements, particularly 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 methods.
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