I'm worried about the interaction with reflect shields. It's been established previously that damage from Unstable Gas, which is probably the best comparison to this, gets reflected by such a shield, so you could use it to send back the 30 damage that would be dealt to yourself.
Speaking of UG, it costs 6|5
![Air :air](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/air18x18.png)
and 1
![Fire :fire](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/fire18x18.png)
to deal 20 damage after a turn (and takes a turn to set up). I'd say Sacrificial Fire should be balanced with respect to that. On the other hand, if it's a spell card it's going to be really easy to set up an OTK (Fire Bolt+3xSacrificial Fire, using a SoSac chain started a few turns ago to survive the damage? It'd have to be a few turns ago or you won't have enough time to generate enough quanta to pay for everything. Alternatively, Fire/Light stall, playing a Miracle to survive the damage. Light also has aforementioned reflective shield.)
On the shield bypass card, Fire already has several great ways to mitigate the effects of shields (growing damage, spell damage, Deflagration) so that might fit into a different element better.