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

An alternative may be  to have an explosion release membrane to the outside of the house, rather like the 'tear here' deliberately weakened walls and roof designs one sees on larger substation buildings and ammunition dumps and so forth. ;-)

Joking aside,one has to be clear as to the purpose of the ventilation,  the removal of heat can safely be into the house, but the removal of Hydrogen or worse a hydrogen oxygen mix rapidly becomes a serious matter requiring dilution to outside.

Equally for a well functioning lithium battery there is no gas production that vents most of the time, and if it ever it does, you may well have another problem as well namely a serious fire...

This (US) video compares shooting a rifle slug at a primary cell, a modest Lithium Ion battery (2590 prismatic size) and a zinc air cell. https://www.youtube.com/watch?v=PO8Nu3F8mkA

The 2590s are used a lot in the manpack radios, which is sobering,

Mike

pww235 said:

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

Those recommendations would generally be for "normal use" condition and foreseeable fault, and possibly not consider the battery as a victim of fire itself?

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.

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.