Limitations of these liningsinclude:
Not oil or flame resistant
Not ozone, sunlight, or weather resistant
Temperature limited to 1408 F/608 C
Cannot be used with dilute hydrochloric acid (5–10%) or spentacids
Typical applications for soft natural rubber linings include chemical
storage tanks to handle 37% phosphorica cid, hydrofluorosilicic acid,
alum,c hlorides, and sulfateso fa mmonia, cadmium, iron, phosphorus,
and sodiumo ri norganic salts in general. Thism aterial is suitable to line
trailer tanks for transporting the abovechemicals. Soft natural rubberisalso
used to line pipes and fittings.
6.5.1.2 Multiply Natural RubberL inings
Multiply natural rubber liningsconsist of threelayers of rubber: soft natural
rubber/hard natural rubber/soft naturalr ubber. The advantages of these
linings are:
Better permeation resistance than soft natural rubber
Heat resistance to 1608 T/718 C
Ease of application, cure, and repair
Good flexibility,r educing the danger of cracking in cold weather,
rapid temperature changes,orm echanical stresses
Moderate cost
The limitations of these liningsa re:
Not oil or flame resistant
Cannot be used in transporttrucks
Refer to Table6 .4 for the compatibility of multiplyl inings with selected
corrodents. Applications for multiply linings include thosef or soft natural
rubber linings with the exceptions noted above.
6.5.1.3 Semihard Natural RubberL inings
Semihard natural rubberlinings provide:
Ease of application, cure, and repair
Excellent chemical and permeation resistance. Refer to Table 6.5.
Heat resistance to 1808 F/828 C
Moderate cost
Corrosion of Linings and Coatings
300
CAT8247—CHAPTER 6—6/10/2006—12:28—SRIDHAR—XML MODEL B–pp. 287–402