I bought a BX700UI APC UPS for my linux arm server setup (40 watts) to protect it from power cut. - I have the server in the bedroom is it dangerous to have such an Ups in a small bedroom? - Thinking of gases?
Valve regulated lead acid (VRLA) batteries and modular battery cartridges (MBC) do not require special battery rooms and are suitable for use in an office environment. Air changes designed for human occupancy normally exceed the requirements for VRLA and MBC ventilation.
Also there is a little known fact that Hydrogen will not explode with O2 unless it exceeds the lower explosive level, LEL concentration of 4%, then the probability rise above 0% at this threshold with a spark.
Compare generation of volume of gas from a faulty battery and faulty OVP and failed charger safety ( triple-mode failure).
background and my logic
How much gas volume can an SLA battery generate compared to humans breathing out toxic carbon monoxide (CO)? not much.
Yet a vented lead acid battery, which can generate 60x more than a SLA is unsafe, if overcharged .
For a small bedroom, this would need a lot of batteries to generate 4% H2 from overcharge failures and H2 generation, given convection flow of air needed for humans to not asphyxiate from CO breathing. An SLA battery is unlikely to create this amount of H2 with a battery fault compared to the flow of CO from breathing out. It may also trigger UPS battery fail alarm if this condition were detected.
In normal operation it should not emit any gasses, the sealed lead acid batteries may occasionally vent a very small quantity of hydrogen during charging, but so does your digestive tract.