V4 12 Stormwater Maintenance Manual

t smooth interior corrugated HDPE pipe products. Note: Mar-Mac bands shall be installed in accordance with manufacturer's recommendations. ao Snap couplers, 4- through 8-inch (100 — 200 mm), and split band (] couplers, 10- through 30-inch (250 — 750 mm), will provide a soil- tight repair with or without gaskets. This repair method should only be used if the damaged area is in a non-trafficked green area, is cosmetic in nature, confined to a single corrugation, and is not defined as structural damage. The coupler shall be centered around the damaged area of pipe and tightened down with the bad pele nylon straps. If the damaged area is large or significant, the Seu BAND damaged area is to be cut out, and replaced with a new section of pipe. The replacement section is to be ‘spliced’ in place using snap or split band couplers. They are a convenient, low-cost tepair alternative, and are typically used to repair soil-tight smooth interior corrugated HDPE pipe products. 4640 TRUEMAN BLVD. HILLIARD, OH 43026 (800) 821-6710 www.ads-pipe.com 41

Concrete collars also provide a soil-tight repair, dependent on the integrity of the installation. Installing a concrete collar involves building a form around the area to be repaired and encasing it in concrete. A geotextile is usually wrapped around the repair area prior to pouring the collar to keep the concrete from seeping into the pipe. Typically, approximately 6” (0.15m) is excavated beneath the pipe to allow for proper application of the geotextile aan ra GEOTEXTILE and concrete encasement. If the pipe itself is damaged, WRAP the damaged area shall be removed and a replacement pipe section spliced in prior to pouririg the collar. In order to provide a greater level of joint performance, a gasket can be installed on the pipe in the concrete encasement. Concrete collars are typically more costly and time consuming than snap couplers or split band couplers but are reasonable repair options for soil-tight smooth interior corrugated HDPE pipe products. . Slip Couplings 4- through 24-inch (100 - 600 mm), \ rarataraa4 provides a watertight repair that will meet most pressure testing requirements, when installed a correctly. The slip coupling uses PVC bells with eruniifis gaskets. The gaskets are placed in the valleys on J either side of the section to be repaired and slip SLIP COUPLING couplings are then slid over the gaskets, PVC slip couplings are most commonly used with watertight smooth interior corrugated HDPE pipe products. . Internal Repairs Internal mechanical repair products generally consist of a flexible cylindrical gasket sleeve, which is expanded to conform to the inner wall of the pipe. The feasibility of this repair method depends on the size of the damaged section or joint and available access into the pipe. Internal mechanical seals slightly restrict the inside diameter of the pipe. This should be considered when assessing the risk of debris obstruction. NPC Internal Joint Seal, 18- through 60-inch (450 — 1500 mm), consists of an EPDM rubber seal and stainless steel bands. The rubber seal is inserted into the pipe and positioned over the joint. A torque wrench is used to expand the bands against the inner wall of the pipe. The Internal Joint Seal is designed to seal joints — not repair damaged pipe sections. The damaged area of the pipe must be removed and a replacement section spliced in if necessary in order to use the Internal

al Joint Seal is designed to seal joints — not repair damaged pipe sections. The damaged area of the pipe must be removed and a replacement section spliced in if necessary in order to use the Internal Joint Seal. This system may provide a watertight joint when installed as recommended. The manufacture should be contacted to verify the product meets the specific application requirements including test requirements, if specified. If pressure tests are required, NPC should be contacted to ensure that the product is suitable for the specific test criteria. Internal mechanical seals will slightly restrict the inside diameter of the pipe. This should be considered when assessing the risk of debris obstruction. Link Pipe Grouting Sleeve™, 4 through 60 inch (100 — 1500 mm), is a stainless steel grouting sleeve that is installed with an inflatable plug. The sleeve may be used to seal a joint or repair short sections of damaged pipe. The manufacture should be contacted to verify the product meets the specific application requirements including test requirements, if specified. Internal chemical sealing is another method of internal joint repair using chemically activated gel or-grout to minimize joint leakage. The grout is typically applied with specialized remote-controlled equipment. Test/seal 4640 TRUEMAN BLVD. HILLIARD, OH 43026 (800) 821-6710 www.ads-pipe.com A ANG ann

packer is used to remotely seal a joint. The grouting chemicals are forced through the joint out into the surrounding soil where they gel with the soil. The gelled mass forms a waterproof collar around the pipe. The result is significantly reduced leakage. There are several types of chemical grouts available and the manufacturer should be contacted to review the specific situation and any joint tightness or pressure test criteria. Companies such as Avanti International, Strata Tech Inc., and Carylon Corporation manufacture and/or install chemical grout. Stephen's Technologies New Life Coatings and NewLife Liner Systems as well as Avast Hydro-Lining International, are examples of companies that offer cured in place epoxy lining systems that have been effectively used with HDPE pipe. Most pipe diameters can be chemically grouted provided the grouting contractor has the appropriate equipment. Manufacturer Contact Information Contact the Regional-Engineer or Application Engineering Department for assistance with other unique conditions or for contact information regarding any companies listed in this technical note. Note: The HDPE pipe products are solely intended for the conveyance of fluids. Access into this product for maintenance, inspection, repair, or other reason should be done in strict accordance with OSHA recommendations for confined space entry. 4640 TRUEMAN BLVD, HILLIARD, OH 43026 (800) 821-6710 www.ads-pipe.com 3 ATNANS A ANG onan

> o° HDPE DETENTION SYSTEM MAINTENANCE

EDS, ! TECHNICAL NOTE Retention/Detention System Maintenance TN 6.01 February 2007 This document is provided for informational purposes only and is meant only to be a guide. Individuals using this information should make their own decisions as to suitability of this guideline for their individual projects and adjust accordingly. Introduction A retention/detention system is comprised of a series of pipes and fittings that form an underground storage area, which retains or detains storm water runoff from a given area. As sediment and debris settle out of the detained stormwater, build up occurs that requires the system to be regularly inspected and cleaned in order for the system to perform as originally designed. The following provides the available fittings and guidelines for inspection and maintenance of an HDPE underground storage system. System Accessories and Fittings Concentric Reducers Concentric Reducers are fittings that transition between two pipes, either in line with one another or at perpendicular angles. The centerlines of the two pipes are at the same elevation. When a concentric reducer is used to connect the manifold pipe to the lateral pipes, most debris will be trapped in the manifold pipe. ll ©) SIDE VIEW SECTION VIEW SIDE VIEW SECTION VIEW Eccentric Reducers Eccentric Reducers are fittings that transition between two pipes, either in line with one another or at perpendicular angles. The inverts of the two pipes are at the same elevations. When an eccentric reducer is used to connect the manifold pipe to the lateral pipes, most debris will follow the flow of the storm water into the lateral pipes. th © On SIDE VIEW SECTION VIEW l s sae] SIDE VIEW SECTION VIEW 4640 TRUEMAN BLVD. HILLIARD, OH 43026. (800) 821-6710 - www.ads-pipe.com 4 ATNEOt GADS 2007

Riser Each _retention/detention system typically has _ risers strategically placed for maintenance and inspection of the system. These risers are typically 24” in diameter or larger and are placed on the manifold fittings. Cleanouts Cleanout ports are usually 4-, 6-, or 8-in diameter pipe and are placed on the manifold fittings. They are used for entrance of RISER cLEANOUT a pipe from a vacuum truck or a water-jetting device. ‘CROSS-SECTION VIEW ‘CROSS-SECTION VIEW For a complete listing of available fittings and components please refer to the ADS Fittings Manual. Maintenance Overview of a Retention/Detention System Maintaining a clean and obstruction-free retention/detention system helps to ensure the system performs the intended function of the primary design. Build up of debris may obstruct flow through the laterals in a retention system or block the entranceway of the outlet pipe in a detention system. This may result in ineffective operation or complete failure of the system . Additionally, surrounding areas may potentially run the risk of damage due to flooding or other similar issues. Inspection/Maintenance Frequency All retention/detention systems must be cleaned and maintained. Underground systems may be maintained more cost effectively if these simple guidelines are followed. Inspection should be performed at a minimum of once per year. Cleaning should be done at the discretion of individuals responsible to maintain proper storage and flow. While maintenance can generally be performed year round, it should be scheduled during a relatively dry season. Pre-Inspection A post-installation inspection should be performed to allow the owner to measure the invert prior to accumulation of sediment. This survey will allow the monitoring of sediment build-up without requiring access to the retention/detention system. The following is the recommended procedure for pre-inspections: 1) Locate the riser section or cleanouts of the retention/detention system. The riser will typically be 24” in diameter or larger and the cleanouts are usually 4”, 6” or 8” in diameter. 2) Remove the lid of the riser or clean outs. 3) Insert a measuring device into the opening and make note to a point of reference on the stick or string. (This is done so that sediment build up can be determined in the future without having to enter the system.) 4640 TRUEMAN BLVD.

e opening and make note to a point of reference on the stick or string. (This is done so that sediment build up can be determined in the future without having to enter the system.) 4640 TRUEMAN BLVD. HILLIARD, OH 43026. (800) 821-6710 - www.ads-pipe.com I 2 |

Inspection/Maintenance A retention/detention system should be inspected at a minimum of one time a year or after major rain events if necessary. The following is the recommended procedure to inspect system in service: 1) 2) 3) 4) 5) Locate the riser section of the retention/detention system. The riser will typically be 24” in diameter or larger. Remove the lid from the riser. Measure the sediment buildup at each riser and cleanout location. Only certified confined space entry personnel having appropriate equipment should be permitted to enter the retention/detention System. Inspect each manifold, all laterals, and outlet pipes for sediment build up, obstructions, or other problems. Obstructions should be removed at this time. If measured sediment build up is between 5% - 20% of the pipe diameter, cleaning should be considered; if sediment build up exceeds 20%, cleaning should be performed at the earliest opportunity. A thorough cleaning of the system (manifolds and laterals) shall be performed by either manual methods or by a vacuum truck. 4640 TRUEMAN BLVD. HILLIARD, OH 43026. (800) 821-6710 - www.ads-pipe.com l 3

MAINTENANCE COST ESTIMATE Sub-Surface Detention Basin ...............c1ccseeeeeeeeecaeeeeeeeeneeeneeeeas $1,500 — $2,000 per year Maintenance cost estimate includes all maintenance inspections, equipment, sediment, trash and debris removal. Maintenance cost estimates are based on engineering assumptions, manufacturer’s recommendations as well as the relative frequency of maintenance. Actual costs may differ from estimate.