Technical Standards and Safety Authority (TSSA) G3 Practice Exam

For a piping system supplying an appliance having a rated input under 400,000 Btuh (120 kW), the supply line and branch line to the appliance may be purged:

1. At the main burner

2. At the drip pocket of the appliance

3. Into the combustion chamber of the appliance

4. At a readily accessible burner such as the open top burner of a gas range

The correct answer is: At a readily accessible burner such as the open top burner of a gas range

The correct answer identifies a safe and effective method of purging a gas supply line, which is essential for ensuring that any residual gas or air mixture is safely cleared before the appliance is used. Purging involves releasing gas from the supply lines to eliminate any potential hazards associated with air pockets or residual gases, which could lead to improper combustion or even hazardous situations. In this case, purging at a readily accessible burner, such as the open top burner of a gas range, is the preferred method. This is because it allows for control over the purging process in a safe environment. Accessing an open burner provides a clear exit for the gas to ignite. This is particularly important since the burner is specifically designed for combustion, reducing the risk of gas accumulation and explosion. The other options represent methods that might not comply with safety standards. Purging at the main burner or the drip pocket of the appliance may not be the safest as it could lead to a concentrated release of gas, which could be hazardous if ignited improperly. Purging directly into the combustion chamber can pose a significant risk, as it could lead to the accumulation of gas without immediate ignition, creating an unsafe situation. Thus, purging at a readily accessible burner optimally balances safety and