API 521 FIRE RELIEF

[Chem2020]

In PSV calculation for fire case we may take credit for the insulation only if the insulation meets the fire proof definition per PI 521. Often equipment insulation are intended for weather insulation and not fire. If I want to take credit, I need to confirm that the insulation meets the fire proof definition which includes materials requirement and installation requirement. I would like to know if the mineral fiber insulation with aluminium jacketing is normally taken credit per API 521 requirements for new installed equipment. I have attached the pages from API 521. Any guidance? Thank you

 

[don1980]

The mineral fiber material is acceptable, but you should use a SS jacketing material. The instillation must resist being disloged by the impact of fire fighting water. Aluminum jackets will melt very quickly. Once that's gone, the insualtion material is at risk of falling off or being blown off by the fire water.

The insulation heat reduction credit is high, so you want to be sure that you have a good installation (material & jacketing) before using that credit.

There's a lot of insulation materials on the market, and these materials typically come in different types/grades - some are OK and some are not. You need to check with the vendor to be sure you're selecting a material that meets the conditions cited in API 521.