What is the safety timing for an appliance rated at 8 gallons per hour (gph)?

The safety timing for an appliance rated at 8 gallons per hour (gph) is established to ensure proper operation and safety during use. A timing of 15 seconds allows sufficient time for the appliance to complete its ignition sequence safely. This duration is important because it helps to prevent any potential issues related to incorrect fuel ignition or excessive fuel accumulation, which could pose fire hazards or reduce the efficiency of the appliance.

In the context of appliances operating on combustible fuels, appropriate safety timing is critical for safe functioning. The calibration of 15 seconds is consistent with industry standards which consider the flow rate of the appliance. Therefore, it ensures that the appliance can ignite effectively within the parameters set by the manufacturer, leading to a reliable and safe operation.

The other options would either provide too little time or excessive time, both of which could lead to operational inefficiencies or safety concerns depending on the appliance's specifications and the type of fuel used. Using 15 seconds strikes a balance between safety and performance, making it the most suitable answer for an appliance operating at 8 gph.