"防火百叶窗" can be translated into English as "fire-resistant shutter" or "fireproof shutter".
"Fire-resistant" emphasizes the material's ability to withstand fire to a certain extent, while "fireproof" implies a higher level of fire resistance, often indicating that the material will not catch fire or support combustion.
In this context, both terms can be used, but "fire-resistant shutter" might be slightly more common in technical or engineering contexts, as it accurately describes the shutter's ability to resist fire without making an absolute claim of being completely fireproof. However, "fireproof shutter" is also widely understood and used.
Choose the term that best fits your specific context or intended level of fire resistance.