Tennessee Construction Exit: Temporary Sediment Control Device

The Tennessee Department of Environment & Conservation (TDEC) administers the Clean Water Act (CWA) in the state of Tennessee. TDEC has partnered with the University of Tennessee, Knoxville, to produce a two level stormwater training and certification process. The Level 1 coures is a fundamentals course which equips contractors with a working knowledge of stormwater regulations and techniques to stay compliant. The Level 2 course is offered for engineers and site inspectors who need additional training for stormwater pollution management on project near Impaired or Exceptional Tennessee Waters.

Construction sites that disturb an area of 5 acres or greater are requried to obtain a NPDES stormwater permit to operate. Contractors, MS4s and Industrial sites each must obtain a permit from TDEC. A Notice of Intent (NOI) is submitted before constrution or operation begins. The TN EPSC website includes links to the TNR100000 CGP, NOI and other forms needed to aquire a stormwater permit.

Tennessee TNR100000 NDPES Stormwater Permits

To obtain a Construction Stormwater Permit, TNR100000, contractors will submit a Stormwater Pollution Prevension Plan (SWPPP) and Notice of Intent to the TDEC. The SWPPP contains a site wide plan which details Best Management Practices (BMPs) that will be used to mitigate stormwater pollution. One essential BMP is the use of a Construction Exit. These entrances are designed to minimze any polluted sediment that is tracked out of the jobsite onto impermiable surfaces like asphalt roadways. Polluted sediment on roadways will wash down stormdrains and enter protected rivers and streams.

Construction Exit Detail in Tennessee

Chapters 4 and 7 of the Tennessee Erosion And Sediment Control Handbook includes Practice 7.28: Construction Exit which states that construction exits “reduce or eliminate the transport of material from the construction area onto a public roadway by providing an area where mud and soil can be removed from the tires of construction vehicles.” The Manual also indicates that Stabilized Construction Entrances should be applied “wherever construction traffic leaves a construction site and enters a public right of way.” The handbook indicates that “Most often, construction exits are constructed of clean stone. However, several manufactured construction exits are available that do not include stone.”

Details of a stone construction entrance are included in the handbook. A 20’ by 50’ area is excavated and lined with a geotextile fabric. The area should also include a wide turning radius. The area is then filled to a depth of 8 inches with Class A-3 machined riprap. Soils that contain a high percentage of clay may require a more robust tire washing facility described in section 7.29. Lastly, contractors are instructed to manage stormwater around the entrance and avoid steep grades and exits in or near curves in public roads.

All exits must be periodically reviewed to ensure proper functionality. When dirt builds up on the rock, the top layer is scraped and replaced with clean rock. Street sweeping must be completed within 7 days or a rain event when dirt is not contained in the job site.

Manufactured construction exit have different installation and maintenance requirements because they do not use rock. FODS is a manufactured construction exit which can be installed on dirt or pavement and can be reused on multiple projects.

TDOT Construction Entrance SPecs

The Tennessee Department of Transportation has developed a SWPPP which is used on projects of all sizes across the state. The construction entrance specs are similar to what is established in the Erosion And Sediment Control Handbook. TDOT Construction Entrance standard drawings (EC-STR-25) show a 50’ x 20’ entrance that is 12’ deep of class A-3 machined rip rap.

TDOT has also pre-approved the use of FODS manufactured construction exit as a replacement for the EC-STR-25 spec. FODS Reusable Construction entrance system is a composite matting system designed to clean vehicle tires as they exit the job site. FODS do not become compacted and are ideal for high traffic volume sites.

FODS Manufactured Construction Exit

FODS Trackout Control System is composed of a single layer of reusable, composite construction exit mats which are specifically designed to remove sediment from vehicle tires. FODS is a modular device which is easy to customize for each project. The unique design of the mats traps more sediment and continues to be effective after rain events.

A standard layout is a 1x5T which provides a wide turning radius and 35’ of length. FODS are more effective than aggregate construction entrances so this layout is used to replace up to 70’ rock construction exits.

A unique advantage of using FODS is that it can be easily reused & relocated throughout various phases of a construction project. Engineered to be extremely durable, FODS mats are designed for 10+ years of service life.

The manufactured FODS construction entrance mats can be installed without excavation and over a variety of substrates. Maintenance is needed after sediment builds up to 2.5" between the pyramids. Instead of refreshing with additional rock, the system can be restored by cleaning with a street sweeper or FODS shovel.

FODS Approved For Use By The Tennessee DOT

The FODS Trackout Control System is approved for use as an alternative to the Temporary Construction Exit described in TDOT Standard Drawing EC-STR-25. The approval grants permission for local authorities to allow the use of FODS on TDOT projects across the state. The FODS reusable construction entrance system is ideal for use on highway, pipeline and other phase projects because the system highly effective and can be relocated as needed throughout the project. The rockless BMP can also increase safety by reducing the risk of rocks entering active lanes of travel.

FODS Construction Entrances on Projects In Tennessee

Since the Tennessee Department of Transportation approved FODS Reusable Construction Entrance as an alternative to traditional rock construction entrance, contractors across the state have been benefiting from the effective design and cost savings of the system. The FODS contrustion exit system was first used in Tennessee on the I-440 Highway Project. Kiewit used FODS manufactured construction exits to provide a portable solution for highway sediment and erosion control. The FODS reusable construction entrance is able to be relocated for each phase of the project, and in addition reduces the liability of introducing riprap to active roadways.

DPR Construction is also using FODS mats as they begin the sitework on the the Facebook datacenter in Gallatin. FODS reusable construction entrance mats provide industry leading ROI to contractors and dirt workers and require less ongoing maintenance costs to refresh the entrance. With FODS entrances in use, the project can keep roads clean through rain events and high traffic without additional aggregate.

Located in central Colorado, FODS LLC is proud to play a role in the protection of natural resources. FODS recyclable mats provide an environmentally friendly solution to trackout control with a service life of over 10 years. Our success in the market is an indication of the industry’s shift away from one-time use aggregate construction entrances towards reusable and sustainable alternatives. Protecting the environment is an effort that requires continuous innovation, and we are proud to offer these novel solutions to contractors around the world.

Please reach out to us for references or information about using FODS as your construction entrance in Tennessee.