A preventative insulation maintenance program, implemented in conjunction with a supplier, can allow the furnace operator, engineer and maintenance personnel to concentrate on quality heating of steel product and maintenance of the furnace equipment. Such a program should include the following:

1. Supplier sales/service be present during furnace repairs.

2. Regular inspection and mark-up of the furnace sketch as to insulation condition throughout the furnace.

3. Determination of insulation system strengths and weaknesses.

4. Record location of insulation replaced during each outage.

5. Periodically photograph insulation.

6. Keep a list of insulation designs and the quantities of each design required to insulate a full furnace in the event of an emergency or disaster.

7. Routinely take inventory of insulation spares to maintain the above.

8. Set a minimum inventory/spares level for each design.

9. Re-order when inventory/spares go below minimum level.

10. Where possible, set up a blanket order program to expedite order processing procedures for stocking programs.

11. Color code insulation types for ease of inventory, handling/stocking, installing, etc.

Tips to Prolong Service Life of Insulation

The following tips can prolong the service life of an insulation system:

1. Regular and frequent close-up inspections.

2. Seal all voids and cracks using a 3000° air setting refractory mortar or refractory patching plastic.

3. Replace damaged insulation that may not last to the next outage.

4. Wrap and seal vertical posts and crossover pipe with 1-in. thick fiber blanket.

5. The service life of highly engineered refractory products depends on a high-quality installation. Insulation designs should be installed according to suppliers’ specifications, such as:

6. Clean scale, slag, rust and debris from area to be re-insulated.

7. Observe layout of a particular section of pipe so maximum insulation coverage can be achieved without leaving large gaps.

8. Install insulation tight to the pipe so that the insulation can receive the maximum cooling effect from the water-cooled pipe.

9. Maintain proper expansion allowance between insulators and pipe structure fixtures.

10. Position joints on insulation designs away from flame.

11. Properly lock assemblies.

12. Weld areas to the pipe should be full penetration welds.

13.Weld areas should be covered with high-quality refractory mortar or patching plastic.

14. Minimize refractory thickness and width near furnace product to minimize shadowing.

15. Study furnace product push patterns or spotting of the slabs prior to outage. Position insulators on skids away from shear drag.

Reference :
Website http://www.bloomeng.com/kweldcasestudy.html#prevent

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