Hi Graham,

Without wanting to interrogate the author...

The PAS document requires all indoor locations which contain storage batteries to be ventilated to outdoors (6.5.4) and refers to BS EN IEC 62485 for further information. This does not account for various battery compositions - particularly lithium iron phosphate. There is no direct reference to a baseline ventilation rate (62485 has a calc but it's based on older battery chemestry).

Presumably we can take a sensible approach here and follow battery manufacturer's guidance/recommendations with regard to the provision and rate of ventilation?

Regards,

Peter

pww235 said:

This does not account for various battery compositions - particularly lithium iron phosphate. 

Are they not covered in BS EN IEC 62485-5 ?

Clause 7.3 of that standard clearly says that harmful gases can be produced and contains requirements to help stop the production of those from the BMS - but that doesn't take into account that the battery might itself be a victim of fire, even though the Scope of the standard says it covers private residences.

Having said that, there's a whole list of stuff in Clause 9.1 of BS EN IEC 62485-5 that needs to be taken into account, and ventilation is needed (if a battery is installed at home) to help address BS EN IEC 62485-5:2021 Clause 9.1 b).

Have people seen the post on linkedin by GivEnergy?  Titled

 Industry update 

Stating things like

Away from the PAS and in terms of safety, you can absolutely install GivEnergy LiFePO4 batteries in lofts where appropriate siting, lifting, access and regulations are considered and historic installations are not affected.

This COULD confuse people like when people were advised to fit a Zappi with only an MCB

I saw that too. Crazy to dismiss safety based guidance because it doesn't suit. 

I noticed they claim to be getting BSI to rework their regs too

to balance things out they should also llink to this presentation. The adverts are a pest, but the talk, and some of the images, should be sobering stuff for the 'have a go'  merchants.

Mike

Not contesting the battery should be in a 30 min enclosure, all for that.

The BMMS can do it's thing and cut off the supply. I'm failing to see why the battery being a victim of fire is a pre-requisite for dedicated ventilation to the outside - we normally want to close off such ventilation systems under fire conditions to avoid fuelling said fire.

If vent is required, the required flow rate should be readily available (by calculation or a minimum standard, etc) IMO. 

Wow, really interesting video. Ive never installed a Lithium ion battery in a dwelling.

Im shocked that we allow the sale of electric light vehicles using batteries based on Lithium ion chemistry. 

For some balance you should watch the following video which includes tests on LifePO4 batteries. The battery chemistry of most leading domestic ESS providers.

https://youtu.be/Qzt9RZ0FQyM?si=4qcPtXdFwJIazArL

Im shocked that we allow the sale of electric light vehicles using batteries based on Lithium ion chemistry. 

New things don't necessarily have to be totally safe - no worse than what they replace will often do.

Given the risks of carrying tens of litres of petrol around (and many instances of ICE engine fires from just driving along the motorway - no need for any impact damage) and the likes of the Liverpool multi-storey car park fire (started by an ICE Landrover apparently), in a way society could "afford" quite a few serious incidents and sill be in a better position.

  - Andy.

pww235 said:

pre-requisite for dedicated ventilation to the outside

Toxic chemical production. It's not Lithium chemistries either ... many battery chemistries have the problem.

Agreed, this could be cables too ... although in most homes people will be out before cables start burning, the Data guys already have made some decisions on ICT cabling in BS 6701 that haven't happened in BS 7671 (at least as yet).

pww235 said:

we normally want to close off such ventilation systems under fire conditions to avoid fuelling said fire

Hence distance from windows, doors etc. ... the building still needs to comply with other fire regs after changes are made to the electrical installation.

pww235 said:

the required flow rate should be readily available (by calculation or a minimum standard, etc) IM

OK, possibly something to ask the manufacturer.

All good questions ... but the Public Consultation period is the time to make suggestions and provide reasons why provisions in a standard ought to change or be more permissive.

Just to note that, with BS 7671, the relevant Public Consultation period that matters isn't necessarily the one just before the next Edition is published, but the ones on standards that start IEC 60364-xxx and BS HD 60364-xxx, because with the UK being a member of CENELEC, we have to adopt the technical intent of the EU-wide agreed standard. We can make things more onerous, or make minor changes to wording to make things easier to interpret, but if we want to drop or relax a provision, this usually needs to be done before the CENELEC standard is published (that then makes its way into BS 7671 at the next Edition). See pages 15 and 16 of BS 7671:2018+A2:2022 for a list of the standards we (have to) adopt from CELENEC.

pww235 said:

we normally want to close off such ventilation systems under fire conditions to avoid fuelling said fire.

I guess it’s to vent the toxic gases like Hydrogen Flouride that are emitted if cells are punctured or in TR. Though ironically in an “cold roof” attic space a LifePO4 battery would be well ventilated by natural airflow. Also ironically, the battery is less likely to suffer impact damage in this less frequented space.

Also i was under the impression that the recommendation was to stop incoming air and cooking canopy extracts under fire alarm conditions, but to maintain top of stairwell ventilation to aid smoke clearance.

pww235 said:

we normally want to close off such ventilation systems under fire conditions to avoid fuelling said fire.

I guess it’s to vent the toxic gases like Hydrogen Flouride that are emitted if cells are punctured or in TR. Though ironically in an “cold roof” attic space a LifePO4 battery would be well ventilated by natural airflow. Also ironically, the battery is less likely to suffer impact damage in this less frequented space.

Also i was under the impression that the recommendation was to stop incoming air and cooking canopy extracts under fire alarm conditions, but to maintain top of stairwell ventilation to aid smoke clearance.