Methods, systems, and devices for wireless communication are described. Aspects of the disclosure describe narrow beam-based channel access that enables a device to communicate in a shared radio frequency spectrum band without performing channel access procedures. Specifically, aspects of the disclosure describe techniques for defining one or more directional beams as a narrow beam, where the relative narrowness of the beam may be determined in the context of interference (e.g., as opposed to being defined from a geometric perspective). For example, a particular beam may be determined to be a narrow beam, and therefore associated with communications in shared radio frequency spectrum bands without channel access procedures, based on one or more metrics and a number of spatial streams associated with the beam. A device may use such narrow beams for communications without channel access procedures in shared radio frequency spectrum bands.