Regulations (Standards - 29 CFR) - Table of Contents
• Part Number: 1915
• Part Title: Occup. Safety and Health Standards for Shipyard Employment
• Subpart: B
• Subpart Title: Confined and Enclosed Spaces and Other Dangerous Atmospheres in Shipyard Employment
• Standard Number: 1915.15
• Title: Maintenance of safe conditions.
• GPO Source: e-CFR

Preventing hazardous materials from entering. Pipelines that could carry hazardous materials into spaces that have been certified "Safe for Workers" or "Safe for Hot Work" shall be disconnected, blanked off, or otherwise blocked by a positive method to prevent hazardous materials from being discharged into the space.
Alteration of existing conditions. When a change that could alter conditions within a tested confined or enclosed space or other dangerous atmosphere occurs, work in the affected space or area shall be stopped. Work may not be resumed until the affected space or area is visually inspected and retested and found to comply with 1915.12, 1915.13, and 1915.14 of this part, as applicable.

Note to paragraph (b): Examples of changes that would warrant the stoppage of work include: The opening of manholes or other closures or the adjusting of a valve regulating the flow of hazardous materials.
Tests to maintain the conditions of a Marine Chemist's or Coast Guard authorized person's certificates. A competent person shall visually inspect and test each space certified as "Safe for Workers" or "Safe for Hot Work," as often as necessary to ensure that atmospheric conditions within that space are maintained within the conditions established by the c