TAPPI TIP 0402-16

Abstract

This Technical Information Paper (TIP) provides guidelines for inspecting cylindrical, steam-heated pressure vessels made from gray cast iron (GCI) and used as rotating dryers in papermaking. These guidelines also apply to unheated GCI cylinders of the same construction, but large yankee dryers typically used on tissue machines are not covered. Most dryer cylinders made in North America after 1950 were designed and manufactured in accordance with ASME Boiler &Pressure Vessel Code, Section VIII (<em>1</em>). <br>These guidelines cover inspection only of the dryer pressure vessels. While inspection of related steam and condensate piping, relief valves, bearings and drive components, and doctoring devices is not covered, the inspector should report unusual symptoms and conditions in the components so they can be combined with other inspection findings of the dryers in "running" and "idle" mode (defined below), to prioritize dryers for inspection when they are in the "out of operation" mode (i.e., during an outage). This document complements the TAPPI publication, <em>Guidelines for the Safe Operation of Steam Heated Paper Machine Dryers</em> (<em>2</em>). <br>This TIP does not describe how to assess the significance of damage revealed by inspections. In that regard, API579-1/ASME FFS-1 "Fitness for service" (3), which is accepted by the National Board of Inspectors, provides post-construction code rules for assessing fitness for service of pressure vessels, including a dryer with corrosion, wear or crack damage. Guidelines in this TIP do not supersede local jurisdictional and regulatory requirements.