4.4　Manholes，Observation Holes and Boiler Setting Parts

4.4.1　There shall be no defects like scar，crack and sand inclusion and others on the inside and outside surfaces of manholes and observation holes，which shall be opened and closed flexibly.The joining surfaces shall be air-tight.

4.4.2　The sealing material shall be filled in the joining surface between the manholes or observation holes connected by bolts and the wall so that the joining surface shall be tight without leakage.The fixing bolts of the door frame shall be fully welded at the wall inside.The bolts shall be exposed by 2 threads-3 threads out of the nuts after tightening.

4.4.3　The interlock devices between the observation holes for the positive or negative pressure boiler and air access shall be adjusted well.The clearance between the nozzles and the shell shall be 0.5mm-0.55mm，and there shall be no plugging in air access.

4.4.4　There shall be no defects like scar or crack on the surface of boiler setting parts.The overall dimensions and materials of boiler setting parts shall meet the requirements of the manufacturer's drawings.When installing boiler setting parts，the expansion clearance shall be reserved according to the drawing requirements.

4.4.5　The materials of anchor parts，hooks and installation brackets made of abrasion resistant thermalinsulation materials shall be checked to confirm whether they meet the manufacturer's drawing requirements，and the overall dimensions of each component shall be checked to ensure that they meet the design requirements.

4.4.6　The welded parts between the anchor and the metal shell shall be ground to remove the rust and painting and other residues，and the coated electrode shall be removed completely after welding.