Before work is performed in the fire, steam, or water spaces of a boiler where employees may be subject to injury from the direct escape of a high temperature medium, such as steam, or water, oil, or other medium at a high temperature entering from an interconnecting system, you must ensure that the following steps are taken:

(1) The isolation and shutoff valves connecting the dead boiler with the live system or systems must be secured, blanked, and locked or tagged, in accordance with WAC 296-304-06016, indicating that employees are working in the boiler. This tag must not be removed nor the valves unblanked until it is determined that this may be done without creating a hazard to the employees working in the boiler, or until the work in the boiler is completed. Where valves are welded instead of bolted at least two isolation and shutoff valves connecting the dead boiler with the live system or systems must be secured, locked and tagged.

(2) Drain connections to atmosphere on all of the dead interconnecting systems must be opened for visual observation of drainage.

(3) A warning sign calling attention to the fact that employees are working in the boilers must be hung in a conspicuous location in the engine room. This sign must not be removed until it is determined that the work is completed and all employees are out of the boilers.