NFPA 211 (188.8.131.52) has long required the clean-out door to be permanently marked with verbiage that says "Warning: Do not obstruct. Keep combustible materials at least 18" away from this door", or something to similar effect. Has anyone seen this actually done or better yet a door that has this manufactured on it? Seems crazy to me that nearly 20 years since I started looking at 211 no one still offers a clean-out door with this on it? Can't find one anywhere on the web?