A pipe through a fire-separating wall or floor is a hole in the fire rating unless it is sealed properly. This guide explains fire stopping pipe penetrations in HMOs and hotels using Approved Document B: the three routes, the pipe size limits in the tables, and when a collar, wrap or sleeve is needed. It includes a worked four-flat example, what the Astroflame product pages say, and current prices checked on 24 October 2026.