The revision of CAN/ULC-S573 dated May 3, 2023 is being issued to update the title page to reflect the reaffirmation of this First Edition National Standard of Canada. No changes in requirements are involved. Text that has been changed in any manner or impacted by ULSE's electronic publishing system is marked with a vertical line in the margin. The requirements are substantially in accordance with Proposal(s) on this subject dated January 27, 2023.