Pneumatics System Safety

High pressure means real hazards#

A charged pneumatic system stores energy that can release violently if a fitting fails or tubing whips free. The FRC Pneumatics Manual describes a circuit with two sides: a high-pressure (storage) side at up to 120 psi and a working-pressure side at up to 60 psi. Knowing where each pressure lives — and how to bleed it to zero — is the core of pneumatics safety.

Required components on the high-pressure side#

The manual lists the components a legal FRC high-pressure side must include:

• Compressor — compresses air into the system.
• Pressure Relief Valve — relieves excess pressure if the system exceeds its set point. It is set to 125 psi and must be connected to the compressor's output port via hard fittings so it can always protect the compressor.
• Air Storage Tank(s) — store compressed air for use during a match.
• Pressure Switch — tells the controller whether to turn the compressor on or off (it cuts the compressor at ~120 psi).
• Pressure Gauges — the system must have a minimum of two gauges, indicating the stored and working pressures.
• Vent Plug (manual vent valve) — releases all stored pressure when operated by hand. This is your safety "off switch."
• Pressure Regulator — the "primary" regulator reduces pressure from the permitted storage pressure (120 psi) down to the permitted working pressure (60 psi). Only additional pressure sensors (transducers) or filters are allowed elsewhere on the high-pressure side.

Force scales with cylinder bore: a 2-inch bore cylinder at 60 psi can apply roughly 188 pounds of force — respect that energy when a mechanism actuates.

The controller#

A pneumatics controller runs the compressor and actuates the solenoid valves. Two are legal: the REV Robotics Pneumatic Hub (PH), which controls up to 16 solenoid channels (16 single-acting or 8 double-acting solenoids), and the CTR Electronics Pneumatics Control Module (PCM), which controls up to 8 solenoid channels (8 single-acting or 4 double-acting) and uses a digital pressure switch. All solenoids on a robot must be the same voltage (either 12V or 24V).

Safe assembly#

• Seal threaded (NPT) connections with PTFE thread-sealing tape (a single wrap, applied so it tightens with the threads) and snug them with wrenches.
• Cut tubing square and leave it long enough to avoid strain on the joint. To release tubing from a push-to-connect fitting, press and hold the colored collar inward, then pull the tube out.
• Validate the relief valve and run a leak test as described in the manual before relying on the system.

Safe servicing — the golden rule#

Before working on any part of the pneumatic system, follow the stored-energy procedure: open the manual vent valve to vent all compressed air to the atmosphere, and verify that every pressure gauge reads zero. Never loosen a fitting, swap a cylinder, or reach into a mechanism's path while the system holds pressure. When the robot is enabled to deploy code, charge pneumatics, or test functions, keep clear space so any mechanism can move unexpectedly to its full extent.