The Environmental Protection Agency sets rules on the amount of emissions that an engine is allowed to produce. For non-road engines that are over 25 horsepower and are powered by gasoline, natural gas or propane, such as generators and forklifts, the regulations require low emissions, labeling, certification and testing.
The emissions standards for certification and testing on the production line are 4 grams per kilowatt hour (g/kW-hr) of hydrocarbon (HC) and nitrogen oxide (NOx), and 50 g/kW-hr of carbon dioxide (CO). For engines in use, the HC and NOx level must be 5.4 g/kW-hr and the CO level must be 50 g/kW-hr or lower. If the engine will be used for severe duty, the CO level is allowed to be higher---130 g/kW-hr for both production line testing and in-use testing.
Each engine must have its own identification number that is permanently attached to the engine. The engine label must include emission control information including the date of manufacture, the company logo and the emission control system. The type of fuel the engine runs on should also be on the label.
To receive certification, an application must be submitted to the EPA and a sample engine must be tested. The certification will be granted if the engine meets all emissions standards.
Engines must be tested for emissions both while on the production line and when in use. Records of each test must be kept on-site for one year and a report must be sent to the EPA that includes the type of engine and the results of the testing.
