This specification covers four types of hydrated lime. Type N and S are suitable for use in mortar, in scratch and brown coats of cement plaster, for stucco, and for addition to Portland-cement concrete. Types NA and SA are air-entrained hydrated limes that are suitable for use in any of the above uses where the inherent properties of lime and air-entrainment are desired. The four types of lime under this specification shall be designated as Type N which is the normal hydrated lime for masonry purposes, type S which is the special hydrated lime for masonry purposes, type NA which is the normal air-entraining hydrated lime for masonry purposes and type SA which is the special air-entraining hydrated lime for masonry purposes. Hydrated lime for masonry purposes shall conform to the required chemical composition for calcium and magnesium oxides and carbon dioxide. The hydrated lime covered by Types N or S in this specification shall contain no additives for the purpose of entraining air.

1.1 This specification covers four types of hydrated lime. Types N and S are suitable for use in mortar, in scratch and brown coats of cement plaster, for stucco, and for addition to portland-cement concrete. Types NA and SA are air-entrained hydrated limes that are suitable for use in any of the above uses where the inherent properties of lime and air-entrainment are desired. The four types of lime sold under this specification shall be designated as follows:

1.1.1 Type N—Normal hydrated lime for masonry purposes.

1.1.2 Type S—Special hydrated lime for masonry purposes.

1.1.3 Type NA—Normal air-entraining hydrated lime for masonry purposes.

1.1.4 Type SA—Special air-entraining hydrated lime for masonry purposes.

Note 1—Type S, special hydrated lime, and Type SA, special air-entraining hydrated lime, are differentiated from Type N, normal hydrated lime, and Type NA, normal air-entraining hydrated lime, principally by their ability to develop high, early plasticity and higher water retentivity, and by a limitation on their unhydrated oxide content.

Note 2—For normal (Type N) and special (Type S) finishing hydrated lime, refer to Specification C206.

Note 3—Some building codes prohibit the use of air-entraining materials in mortar, because of the accompanying reduction in bond and compressive strength. Where increased freeze-thaw resistance is important, air-entraining may be beneficial. Air-entraining lime should not be used as a finishing lime.

Note 4—For lime putty, refer to Specification C1489.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.