TY - RPRT TI - Performance tests of two cleanable impingement type air filters Airsan types AF1-30 and AF2-30 : manufactured by Air Filter Corporation Milwaukee, Wisconsin AU - Coblentz, Carl W AU - Achenbach, Paul R PY - 1958 PB - National Bureau of Standards CY - Gaithersburg, MD SN - NBS RPT 5991 DO - 10.6028/NBS.RPT.5991 ER -