This test method covers determination of the air content of freshly mixed concrete containing any type of aggregate@ whether it be dense@ cellular@ or lightweight. The values stated in either inch-pound or SI units shall be regarded separately as standard. The SI units are shown in brackets. The values stated are not exact equivalents; therefore each system must be used independently of the other. Combining values from the two units may result in nonconformance. 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. Warning??Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.)