Exhaust Scrubbers and Emissions Requirements

In regards to construction equipment, “exhaust scrubbers” are aftermarket add-on devices designed to provide additional reductions to engine exhaust emissions. Certain federal agencies have regulations that suggest the use of exhaust scrubbers in specific situations. Most of the applicable regulations are for machines operated in enclosed or semi-enclosed spaces, but in some cases, can apply to machines operated outdoors.


When running equipment indoors, it is up to the employer to ensure that their employees are not exposed to more than the permissible exposure limit (PEL) or short-term exposure limit (STEL) set by the jurisdiction. Interior ventilation only circulates the exhaust air throughout the enclosure and does not remove the poisonous Carbon Monoxide (CO) gas. If CO monitors reveal a concentration higher than the PEL or STEL, customers may rent ventilation fans and air horns from Sunbelt Rentals to increase the amount of fresh outside airflow into and out of the space to decrease the amount of CO present to acceptable levels. 

In some situations, exhaust scrubbers can cause a reduction in engine performance and can cause engine damage due to excessive back-pressure. This can be caused by scrubbers that become plugged from running for extended times under low-load or due to upstream component failures. Engine manufactures will not warranty engine failures caused by exhaust scrubbers.

Sunbelt Rentals standards regarding the installation of exhaust scrubbers on our equipment are as follows:


Tier 4f

Our team does not install exhaust scrubbers on Tier 4f compliant equipment.

Machine Design

The Sunbelt Rentals team only installs scrubbers that are specifically designed for the machine.

Diesel Particulate Filters (DPF)

The Sunbelt Rentals team does not install exhaust scrubbers on units that already have Diesel Particulate Filters (DPF) included in their emission systems.

Diesel Oxidation Catalysts (DOC)

Our team does not install exhaust scrubbers on units that already have Diesel Oxidation Catalysts (DOC) included in their emission systems.

Other Diesel Engines

For all other diesel engines, our team only installs scrubbers when regulations require emissions to be lower than originally designed into the machine.

Catalytic Exhaust Products (CEP)

We only use Catalytic Exhaust Products (CEP) devices or we will contact the engine manufacturer for their recommended aftermarket exhaust scrubber suppliers

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