Requirement Design of Tubes

Requirement design of tubes is made to make sure design tube can be used in certain temperature and pressure in steam boiler. Tubes are one pressure parts. These provisions should apply to any tubular pressure part that is either exposed over much of its length to hot gases for purposes of heat transfer or is directly butt welded to such a tubular pressure part.

Requirement design of tubes should comply with the requirements of the ASME Boiler and Pressure Vessel Code, Section I, Power Boilers. The calculation of tube thickness should be based on ASME BPV Section I.

The requirement design of tubes should describe the design basis for controlling mechanical wastage (eq. grit and soot blower erosion) and chemical wastage (e.g. fireside corrosion, dew point corrosion) of tubing. During the design phase, the requirement design of tubes should supply details of the wastage provision for each tube design.

Membrane panel construction should be either by a fusion welded fin or integral fin method. Resistance welded fin construction will not be allowed. No tube bend should contain a circumferential weld. Parallel down-flow circuits subject to significant variations in heat absorption and/or resistance to flow between these circuits should be avoided. A staggered arrangement of tubes in the gas pass should not be used.

Durable caps suitable for transportation should be provided on each end of the tubes to prevent damage and rust on inside surface of tube and to prevent entry of debris. Corrosion or erosion margin of tube thickness should be provided for the boiler tubes.

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