When in the blast radius of a grenade, regardless of a successful reflex save or not, does the damage apply to the gear being worn by the character as well as to their stamina/health?
1 Answer
From Starfinder Player's Guide p. 183:
Grenades are thrown weapons that detonate in an explosive radius when they reach the target. A grenade's listing on Table 7-7: Grenades shows its explosion radius. Some grenades have additional effects, such as blinded or entangled, that apply only to creatures in the explosion radius that fail a Reflex save against the grenade. The DC of the save is equal to 10 + half the grenade's item level + your Dexterity modifier. Any penalty you take to your attack roll also applies to this save DC.
Information about Grenades are (per the Index) on p. 170 (a reference to them as ammunition), 178-179 (the actual grenades purchasable table), and 183-184 (the grenade description subsection).
None of these pages reference grenades inherently causing equipment damage, so they do not automatically Sunder.
Furthermore, the Breaking Objects section on p. 409 does not include any reference to area attacks automatically damaging objects or equipment.