In a compressed air system, what must be true about the end-of-pipe valve?

• A. The valve at the end pipe shall be open at all times
• B. The valve at the end pipe shall be closed during operation
• C. The end pipe valve position is not specified
• D. The end pipe valve should be opened only during maintenance

Answer: (A)

In a compressed air system, the end-of-pipe valve should be kept open at all times so the terminal of the line remains vented to the atmosphere. This prevents any trapped pressure at the end of the line and allows for immediate depressurization if a hose is disconnected or a downstream valve is opened, enhancing safety for maintenance and operation. If the end valve were closed during operation, pressure in the final segment could build up or remain trapped, creating a risk of sudden energy release and making safe maintenance more difficult. Keeping the end open also avoids leaving a dead-end that could become hazardous if someone tries to connect or disconnect equipment.