Safety, Tools, and Jobsite Practices
Domain 9 covers safety, tools, and jobsite practices. The exam tests hazard recognition, gas detection, lockout, purging, confined spaces, and the correct use of test instruments.
Safe practice
Wear PPE: safety glasses, gloves, and hearing protection as needed. Use a calibrated combustible gas detector and soap solution for leak checks; never use a flame. Before working on gas piping, isolate and lock out the energy source, relieve pressure, and purge safely. Treat every gas leak as an emergency: eliminate ignition sources, ventilate, evacuate, and call the utility.
Tools and testing
Manometers measure gas and draft pressure; combustion analyzers measure flue gases; multimeters check electrical controls; leak detectors find small leaks. Inspect tools before use and keep calibration records. Use the right tool for the fitting to avoid damage.
Worked example
You smell gas at a meter set. You do not operate switches or use a phone inside. You evacuate, call the gas utility from a safe distance, and shut off the gas only if it is safe and you are authorized. On arrival, the utility finds a leaking service regulator. You document the event and do not re-light until the repair is approved.
Traps
- Using a lighter to check for leaks.
- Entering a confined space without testing and an attendant.
- Assuming a gas detector is calibrated because it turns on.
- Leaving a purge discharging into an occupied space.
- Working alone on a hazardous gas leak.