Glass Wool Blanket manufacturers

- Apr 28, 2019-

Glass Wool Blanket manufacturers

CORROSION PREVENTION BY DESIGN

Zaki Ahmad, in Principles of Corrosion Engineering and Corrosion Control, 2006
e) Contact with Wet Insulation Materials
Glass Wool Blanket manufacturers Produce Insulation materials, such as glass wool, glass fibers, polyurethane foam, do not cause the corrosion of steel in contact with insulation as long as the insulation material remains dry. Corrosion underneath insulation, however, assumes significant proportions if the insulation becomes wet during storage, operation or field erection. Following are the factors leading to insulation-induced corrosion:
1)Ingress of moisture in the insulation resulting in the leaching of soluble salts of low pH (about 2–3).
2)Release of chloride ions.
3)Destruction of passivity of steel by chloride ions and initiation of pits.
4)Weather cycles, such as wet-dry, hot-dry, and damp-warm cycles, which induce high corrosion rates.
5)Inadequate moisture barriers, because of inadequate spacing of insulation.


The effect of moisture ingress is shown in Figs 8.11, 8.12 and 8.13 shows the corrosion caused by ingressing of moisture in insulation in a water heater after six months of service.

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Figure 8.11. Effect of moisture ingress in insulating materials
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Figure 8.12. Insulation corrosion in water heaters

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Figure 8.13. Initiation of corrosion of water heaters by ingress of moisture in insulation
Corrosion induced by insulation can be prevented by the following measures:
1)Eliminating flat horizontal surfaces.
2)Structural designs which trap water (example, H-beams and channels) (Fig. 8.14).

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Figure 8.14. Good and bad designs for water trapping
3)Strict compliance of insulation thickness.
4)Providing an adequate moisture barrier and waterproofing.
5)Addition of sodium silicate as an inhibitor.
An idealized design to prevent insulation-induced corrosion is shown in Fig. 8.15.

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Figure 8.15. Suggested design to minimize corrosion induced by thermal insulation
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