Boiler manhole is a small maintenance opening on a coal-fired boiler, also known as a header manhole assembly, which includes the header itself. Its feature is the manhole.Pipe couplingMounted on the outer end of the container body or end cover, the handhole tube fitting φd hole connects with the container body or end cover φd hole. The end of the handhole tube fitting is equipped with a spherical end cap or a flat end cap.