CO2 fire suppression system

Hello, I am designing a lab (only 230V max 10A and 24V high current equipment (max 80A), no chemicals except lead acid batteries) that I would like to protect from fire risk.

I own the house and live in it. Not for commercial use. If I screw up, the only one impacted would be me or worst case scenario, firefighters/responders.

I understand the basic tenets of fire suppression. (the fire triangle). I would work on the oxygen part.

The CO2 system would need to displace most of the oxygen in the room, which happens to be 15m^3.

Things in my checklist :

-I would need a one-way passive valve to avoid room overpressure and allow oxygen displacement.

-A failsafe fire hazard detection, multiple sensors on the central ceiling point with a quorum (gas discharge only if 2 of 3 sensors agree that there is a fire situation).

-A safeguard system to disarm discharge if someone is in (manual with timed re-arm). A presence detection could be done but I think it could interfere with fire detection and would not be failsafe.

-An imminent discharge aural and audible alarm and an external panel that would light on and stay lit "CO2 discharge. do not enter"

-A robust, failsafe solenoid/valve that would open only if powered on and if a voltage is applied for a sufficient amount of time (to prevent a transient voltage to trigger a discharge)

-An exhaust and gas distribution nozzle on the ceiling.

-A C02 gas cylinder with sufficient size/pressure.

-Arduino logic to manage all this stuff

Big project, probably overkill and with hazard to personnel possible if not done properly (ear damage, cold burns, or even asphyxiation). I think I covered the most obvious requirements, But a fully tested project would be probably beyond reach.

A passive C02 extinguisher that floods the room in case of overheat would be probably sufficient, it's cheap, available to buy on the net but is it failsafe and without risk of false positives?

What do you think?

Aside from the fact that Arduino is not to be used for life-safety critical applications, the amount of oxygen needed to be displaced is not measured in square meters.

Agree don’t do this ! Why can’t you work safely and eliminate fire risk rather than putting out some fire as though it’s inevitable.

Checked and corrected thank you.

I will probably settle for a passive system.

Would probably be quite challenging and interesting such a system. the Arduino would probably have to be clustered to avoid a single point of failure.

I expect you will get a lot of warnings that you should not use an Arduino for life safety.

all you ask is available with existing over the counter products. adding anything that might defeat those is, shall we say, un-advisable ?

the blow-out panel is simple a hinged panel, sealed with with weather stripping, maybe refrigerator door style magnets seal only at the bottom ? pressure will allow it to move.

it sounds as though high levels of hydrogen are your main concern ? since they make LEL lower explosive level sensors, you can use one and ventilate the room accordingly.

Prevent the circumstances related to the 'event'
if a fire of gaseous hydrogen were to occur, it would be over well in advance of any fire suppression system activation. My thoughts run from 'fire' to 'detonation'

and that blow-out panel should be with a cage to protect any possible delay of operation.
we used to use entire walls of buildings that would have an acre of grass in which to land.
roof mounted panels were hinged with supports to prevent over swing

if you have temperature sensors on the batteries, you can stop charging when out of range

what you are really talking about is a Class1 Divsion 1 intrinsically safe environment.
ALL electricl devices should be outside of the environment. think using outside air to pressurised yoru electrioncs. and hoods over the batteries to allow that air to be introduced into the space, then exhaused.

an LEL sensor could detect adverse conditions at very low levels and shut down things in a effort to prevent getting into areas of concern.

those things are well within the realm of an Arduino .

Class I, Division 1: There are three different situations that could exist to classify an area as a Class I, Division 1 location:

  • Ignitable concentrations of flammable gases or vapors may exist under normal operating conditions.
  • Ignitable concentrations of such gases or vapors may exist frequently because of repair or maintenance operations or because of leakage.
  • Breakdown or faulty operation of equipment or processes might release ignitable concentrations of flammable gases or vapors, and might also cause simultaneous failure of electric equipment.

Not to be done in the place you live in anyhow !!!! - I’d expect your insurance to be invalid and your neighbours not happy either .