Inspections for Steel and Alloy Stacks

At Industrial Access, we work on a number of different structures including quite a few industrial chimneys and smokestacks. Chimneys and stacks that are constructed from steel and alloy require specialized maintenance services that are specific to the nuances of the material. Having a periodic inspection is crucial to prolong the service life of the stack as well as keep workers safe. During an inspection, rope access technicians will review the condition of the steel stack shell, flues, coatings, linings, and other appurtenances that can affect the efficiency or operation of the structure.

Here are some details about Steel & Alloy smokestacks and what facility owners can expect during one of Industrial Access’s thorough inspection visits:

Types of Inspections

Class I Inspections are generally performed when the stack system is on-line and act as a helpful guide to whether or not an off-line inspection is warranted. A complete inspection, or a Class II Inspection, can only be accomplished with the stack system out of service as a detailed review must be performed up close and often inside of the stack. Depending on the type of facility, the environmental factors, and the production tasks performed, a steel stack may need to be inspected more frequently in order to quickly detect deterioration, corrosion, or structural vulnerabilities. After a potentially damaging event like an earthquake, severe storm, fire, etc. a Class III Inspection should be performed immediately with the stack on-line, then followed by an off-line Class II Inspection if necessary.

About Steel Stacks

There are 4 types of Steel smokestacks that we service: single wall, dual wall with internal flue, multi-flue, and cluster stacks. These stacks may be self-supporting, braced to a building, or guyed with cables. Because Steel and Alloy stacks are subject to corrosion, they are often protected with paint, galvanizing, elastomeric coatings, refractories, alloy cladding, or a special coating system. This type of stack is also known to transfer heat readily so are often provided with a means to control heat loss in order to maintain flue gas temperatures. This is often done with insulation or a lining system.

Degradation and Modes of Failure

Corrosion is the most significant failure potential for steel stacks. Having a protective coating is absolutely necessary for a long service life. Steel stacks are also subject to stress and fatigue cracks due to repetitive or excessive movement. If the shell material is thinned from corrosion, the steel stack may fail through buckling. Overheating is also another concern as it can cause deterioration or partial loss of thermal insulation or the protective coating. The stack can also be damaged by differential expansion when there is movement between components that are subject to different temperatures and are not free to expand or contract independently.

A thorough inspection annually or bi-annually is recommended so our rope access experts can determine the condition of the bolts & nuts, shell & components, appurtenances, insulation & lagging, expansion joints & seals, grounding cables, guy wires, and more. If you’d like to discuss or schedule an inspection for your Steel or Alloy Smokestack, contact us today.