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Does Automist comply to the requirements of BS 8458?

Automist Smartscan Hydra has been independently, third party, tested by Exova Warrington Fire to confirm that it meets the performance requirements of BS 8458 2015, as validated by BSI Verification Certificate VC 71258.

Automist Smartscan Hydra is fundamentally different from a traditional watermist system (BS 8458). It is a dry pipe system triggered by a wall mounted, electronic nozzle, as opposed to a ceiling-mounted, wet pipe, glass bulb system. It is often the case that new or innovative products fall outside the scope of existing product standards, as new technology differs in some way from the standardised product. Standards are meant to be expressed in terms of performance rather than design or descriptive characteristics so they do not limit anticompetitive effects or impede innovation. Unfortunately this was not considered when BS 8458 was first created.

We are working hard to expand the scope of the standard to include electronic nozzles, but this does not stop Plumis from demonstrating it is fit for purpose. Below we list all the requirements in BS 8458, explain which are prescriptive and which are performance-based, and evidence how we comply with the applicable clauses.


BS 8458 Requirement

Prescriptive or Performance?

Automist Smartscan Provision

Comment on Compliance

1. Scope 

"watermist systems with automatic nozzles" 

 Prescriptive Does not use automatic nozzles as described in the definitions "an integral quick-response thermal release element" but system still functions automatically Uses an electronically controlled nozzle configuration + multicriteria smoke & heat detector.  Out of scope of standard but complies with performance intent of operating automatically, as opposed to manually. 
5. System actuation should be automatic by glass bulb or fusible link, initiated by heat.  Prescriptive System is actuated automatically by a multicriteria smoke & heat detector.  Actuation is not by glass bulb or fusible link, but it is automatic and by heat as well as smoke. Out of scope of standard but complies with performance intent of initiation by heat. 

6.1 Fire Tests 

When tested, nozzle should suppress fires for 10 minutes for domestic or 30 minutes for residential. 

Performance System runs automatically for 30 minutes until the stop button on the pump is pressed.  Complies with domestic and residential performance. Run time programmed to default at 30 mins given there is no need for a tank 

6.1 Fire Tests 

Defines tests and performance criteria. 

Performance The system meets the criteria of the applicable clauses a) and b). Clause c) is not applicable as Automist is not a mechanical, automatic ceiling mounted nozzle. The electronic nozzle will not activate involuntarily due to heat leak from the room.  Electronic nozzles comply with the fire performance requirement. 

6.2 Limits of Application 

Defines limits of applicability. 

3.5m or 5.5m high 

32m2 or 80m2 

Performance Tests a,b,c,d and e have met the pass criteria so 3.5m high and 80m2 are acceptable limits. Any room heights beyond 3.5m require a fire engineering assessment. Plumis to be consulted in case of doubt.  Fire tests demonstrate that system meets requirements to be used on heights up to 3.5m and areas of up to 80m2. 

6.3 System Design 

b) Should be a wet pipe system. 

Prescriptive System is a dry, unpressurised, pipe system. Delay in activation considered in the fire testing which assumes the worst case scenario.  Fire tests have demonstrated that being a dry, unpressurised, pipe does not negatively impact performance (despite worst case 19 seconds hose filling time tested) and avoids risk of Legionella. 

6.3 System Design 

c) Thermally actuated nozzles should meet requirements for quick response in accordance with BS EN 12259-1. 

Performance System is actuated by a third party certified EN 54 detector or BS EN 14604:2005 alarm. These carry out the same function of the fusible link but have less thermal inertia than a fusible link so reaction times are faster.   This performance requirement applies to systems which utilise a quick response nozzle. Given Automist does not use this device, this requirement does not apply to it. EN 54 and BS EN 14604:2005 do instead. 

6.4 Extent of Protection

all parts of the dwelling 

Performance System can be installed in as many rooms as necessary depending on objective. Partial protection is acceptable as a compensatory measure, elective safety enhancement or as part of a fire engineered solution.  Extent of coverage varies for any suppression system. Full coverage is common and best practice, but not mandated when fire engineering principles are followed.  See 6.4 Extent of Protection  
6.5 Hydraulic calculations  Performance Automist is a pre-engineered system so hydraulic calculations are not required.  No requirement to comply. Pre-engineered design precludes the requirement. 

6.6 Discharge Performance

Flow for 64sqm Area of Maximum Operation 

Performance This is a pre-engineered, electronically controlled system, so only one spray head activates, so no additional flow needs to be designed as no other spray heads will activate. 

No requirement to comply. 

See 6.6 Discharge Performance  

6.7 Discharge duration should be 30 minutes for residential. Performance Discharge duration is 30 minutes or until stop button on pump is pressed.  Complies with requirement. 

6.8.1 Water Supplies 

Design should identify water supply requirements 

Performance Automist requires 1bar and 5.6lpm for 30 minutes. Dry pipe avoids Legionella risk.  Complies with requirement. 

6.8.2 Water Supplies 

Water can be from mains supply boosted by a pump. 

Prescriptive Automist is always supplied from a mains supply and boosted by its own pump.  No need for water tank due to low pump flow.  Complies with requirement. 

6.8.4 Mains Water Supplies

Flow requirement of 64m2 plus 25lpm (domestic) or 50lpm (residential) 

Performance Priority valve not expected to be required in Automist installation due to its very low flow requirement. 6lpm install flow requirement to be validated as part of commissioning procedure.  Complies with requirement. A 8lpm flow test is performed 
6.9 Backflow Prevention  Performance WRAS approved backflow check valve included in every install  Complies with the performance requirement of avoiding backflow contamination. 

6.10 Nozzle coverage and location 

Spacing, positioning, height 

Prescriptive Automist's different principle of operation requires different locations as per Design, Installation and Operation Manual (DIOM) which must be followed (always the case for pre-engineered systems, typical for watermist systems).  Coverage and positioning defined in the Design, Installation and Operation Manual (DIOM), as per clause 6.10, but not on the ceiling, permits proven fire suppression performance validated by third party testing. 
6.11 Components testing and certification  Performance Automist has been internally tested against relevant UL 2167 requirements to ensure component robustness. Third party certification testing in progress.   Meets performance intent through in-house testing but not yet compliant. Pipes and Fittings  Prescriptive Automist accepts the use of stainless steel piping, as per standard or flexible, corrosion proof, hoses, protection from fire by fire resisting barriers as per Plumis spec.  Complies with requirement intent of using piping which is unaffected by corrosion or by fire. Alarm devices  Performance If a building or dwelling has comprehensive automatic fire detection and alarm provision that provides adequate fire alarm and warning arrangements to initiate evacuation, additional watermist alarms to initiate evacuation might be unnecessary. Grade A and C alarms can be inputs to Automist and vice-versa Automist can be input to alarm panels  Automist can be integrated to the fire detection as a slave or master setup to comply to the requirement. Valves  Prescriptive

a) labelled stop valve is present upstream of pump 

b) system test valve not required as open nozzle (system flow and integrity tested at nozzle) 

c) drain valve not required as open nozzle (quick disconnect used for water purge) 

d) alarm valve not required (alarm triggered electronically) 

Complies with the requirements which are relevant and applicable. 

6.11.4 Electrically operated devices 

Fire pump power supply 

Performance Fused, fire resisting cable, from supply side of consumer unit used   Complies with requirement. 
6.11.5 System strainers  Prescriptive Strainer present upstream of pump  Complies with requirement. 

6.11.6 Fire Pumps 

Location, protection and automatic test 

Performance Location and protection requirements in the DIOM. Automatic churn of the pump is not possible on a non pressurised system.  Cannot comply with requirement because not a wet pipe system. Automist pump does not need to be churned to maintain reliability. It is a positive displacement pump and locked motor rotors is addressed under the EN60335 standard part 19 'Abnormal Operation'. See 6.11.6 Fire Pumps Location, Protection and Automatic test  
6.13 Additives  Prescriptive No additives used  Not applicable. 
7. Installation, commissioning and documentation  Prescriptive Frost protection only if water supply pipes to pump can freeze, remaining system is dry. System commissioning allows for full discharge, fire simulation test. Higher reliability than 7.2. Plumis warranty only provided when Commissioning Certificate sent to Plumis by authorised installer.  Complies and supersedes requirements. 
8. Maintenance   Descriptive An Automist annual service consists of a full recommissioning of the system (alarm & discharge) as detailed in the DIOM.    
Annex C. Room fire tests  Performance System has been tested in accordance with requirements of Annex C and meets all performance criteria. Clause a) and b) passes applicable criteria. Clause c) not applicable as Automist is not a mechanical, automatic ceiling mounted nozzle. The electronic nozzle will not activate involuntarily due to heat leak from the room.  Complies with performance. The improved control of an electronic nozzle system ensures that no more than one nozzle activates, ensuring consistency in the system water demand. 


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