What is the primary safety procedure to observe while performing a bottom blowdown?

The primary safety procedure while performing a bottom blowdown is to ensure that you do not take your hand off the valve until it is closed. This is critical because the bottom blowdown process involves releasing potentially hot and pressurized water and sediment that has accumulated in the bottom of a boiler. By maintaining control of the valve throughout the blowdown, you can quickly stop the flow if an unexpected situation arises, such as excessive pressure release or spray of hot water. Keeping your hand on the valve helps ensure responsiveness and safety, minimizing the risk of accidents or injury.

Other safety procedures, while important, do not directly address the immediate control of the blowdown operation. For example, having a second person present can be beneficial for safety but is not a primary procedure necessary to control the blowdown process itself. Likewise, shutting down the boiler before performing the blowdown may be a good practice in some contexts, but there are procedures in place that allow blowdown to be done safely while the boiler is still operational, as long as proper control over the valve is maintained.