Industrial chimneys and smokestacks are subject to deterioration over time and should be inspected regularly to ensure they are functioning safely and properly. Factories & plants generally have heavy production schedules which can take a toll on chimneys & smokestacks. Besides aggressive usage, a chimney or smokestack can also face degradation due to external factors such as actors such as temperature excursions, chemical attack, lightning strikes and wind loading. Having your industrial chimney regularly inspected by a chimney professional can help identify early signs of trouble before they become a health or safety hazard.
Because the most damage-prone areas are hard to see from ground level- the interior, top, & ladders & platforms- a qualified rope access chimney technician will be a great partner for keeping your industrial chimneys and smokestacks in proper working order. A regular maintenance & inspection program can help reduce costly repairs & facility down time.
If you are unfamiliar with the components or methods of an industrial chimney or smokestack inspection, this is what you can expect from a qualified chimney technician.
Visual Inspections
The very first aspect in your chimney maintenance plan is a visual inspection. Before a chimney technician can determine the necessary maintenance requirements, a preliminary visual inspection is required. There are two types of visual inspections that can be performed.
Class I inspections are performed with the system on-line. A chimney technician will inspect the structure using binoculars from ground level, and they will also get a close-up visual inspection from access ladders & platforms. These inspections should be performed once a year to identify any potential problems that require more attention.
Class II Inspections are performed with the chimney or smokestack off-line. These inspections can use rope access techniques to give the chimney technicians a close look at the structure, both inside and out. The techs will install the rigging at the top of the stack, then descend down the entire elevation of the stack. Detailed notes are taken along with photos regarding any abnormalities, damage, or safety hazards. The survey will include viewing as much of the industrial chimney or smokestack as possible from base level, access platforms, and fixed access ladders. The rope access technicians will also drop down inside the structure so they can view the condition of the flue and liner. Once the notes are compiled, the report is handed over to the facility manager to help identify any urgent concerns.
Nondestructive Testing
During a Class II Inspection, a number of nondestructive testing methods (NDT) can be performed to determine the structure integrity of an industrial chimney or smokestack. NDT methods are a means of examining the integrity of a structure without affecting the performance or usefulness of the material. Essential, NDT allows measurement of physical characteristics such as the thickness of steel or fiber reinforced plastic (FRP) or the hardness of concrete without damage to the structure. Since the inspection will not interfere with a product’s final use, nondestructive testing methods are an excellent choice for balancing quality control with cost-effectiveness, and requires little to no plant outages.
Some types of nondestructive tests include:
- Laser Surveys
- Schmidt Hammer Testing
- Ultrasonic Testing
- Hot Camera Inspection
Materials Sampling
There are a few circumstances that warrant a more detailed look at the physical condition of the chimney or smokestack. If there is an observed deficiency, materials sampling could help determine the root cause. In these instances, samples of the materials will be removed for testing and analysis.
Material Sampling Tests can include:
- Concrete Sample/Core Sample- This tests a material’s strength, the extent of any acid attack, and also corrosion resistance. The sample is collected by using a special core saw which takes a sample of the structure at various elevations. Testing the “breaking strength” of concrete cores is commonly used to determine the integrity of the structure. Petrographic analysis can also be used. This examines the physical & chemical make-up of the concrete sample to determine if should be repaired or replaced.
- FRP (Fiberglass Reinforced Plastic) Test- If the structure contains fiberglass materials, a FRP test can examine the liner layer, fiber layers, and resin to determine the condition of the material. These tests help find the remaining useful life of the chimney or stack and can spot necessary repairs.
Setting up a regular inspection & maintenance program will help to maintain lasting structural integrity, ensure a minimal maintenance expenditure, and prevent unplanned facility outages which can cost the company a great deal of money.