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Building Product Corp.Metropolitan St. Louis Sewer District 2350 Market Street St. Louis, MO 63103-2555 (314) 768-6200 f une 26, 2009 Mr. Aron Rauls Building Products Corp. 494 North 33rd Street East St. Louis, Illinois 62205 RE: Permeable Interlocking Concrete Pavement (PICP) - A Structural BMP Dear Mr. Rauls, The Metropolitan St. Louis Sewer District (MSD) has reviewed your application of Permeable Interlocking Concrete Pavement (PICP). MSD hereby grants Provisional Use Level (PUL) approval for the PICP with a storage bed. MSD understands that the PICP enhance surface permeability by the drainage openings created by their interlocking block notched design. In some applications stormwater water quality objectives can be achieved by infiltration into the surrounding subgrade soils or filtration via an underground sand filter. In addition, the stone storage bed underlying the PICP could be designed to provide detention storage such as that needed to meet channel protection requirements. MSD has determined that PICP with storage bed systems may be used under the following conditions: 1. Proposed uses and designs of the device (specifically the Eco-Brick, as manufactured by Advanced Pavement Technology) must be in general conformance with the infouiration and methodologies provided in the Building Products Corporation application dated March 23, 2009, and strict guidelines of the Interlocking Concrete Pavement Institute (ICPI) and the requirements set forth in MSD's PICP General Design and Prequalification policy (latest edition). 2. Channel Protection Volume (CPv) storage may be provided in the base stone and subbase stone beneath the PICP and bedding layer. 3. The minimum pavement section subject to vehicular traffic shall be (from top to bottom) 3 1/8 inch thick paving units, 2-inch thick bedding stone (typically ASTM No. 8 or 9 stone), 4-inch thick layer of base stone (ASTM No. 57 or similar size), and a layer of subbase stone (ASTM No. 2 or similar size), all underlain by MSD type 4 filter fabric. The thickness of the subbase will vary depending on storage and anticipated traffic loads. However, a minimum 12-inch thick subbase will be required for all applications. 4. The post -developed curve number (CN) may be reduced. Reduced CN numbers are provided below. Soil A B C D CN 61 61 74 80 5. The PICP system will be considered as pervious area for the purpose of calculating Water Quality Volume (WQv) and 5 percent impervious when calculating the differential runoff with PI factors. However, the PICP will be considered as 100 percent impervious area for the purpose of calculating pipe sizes downstream. 6. PICP is not to be used as a standalone WQv treatment Best Management Practice (BMP). However, PICP may be used to provide WQv treatment when used in conjunction with a properly designed infiltration basin/trench, sand filter, or other supplemented BMP in order to meet MSD WQv treatment criteria. Those designs are subject to MSD review and approval. 7. The application of PICP shall be limited to low volume traffic areas. 8. Project specific design calculations and maintenance plans must be included within the project's "Stoimwater Management Facilities Report" prepared by the consulting Engineer. MSD reserves the ability to withdraw or modify this approval based on subsequent information, including information indicating that PICP with storage beds do not satisfy MSD rules, requirements, or construction and material specifications. Please provide MSD with one representative block sample of each different PICP product that each your supplying manufacture is producing. Sincerely, 3 Michael T. Buechter, P.E. Principal Engineer (BMP Committee Chainnan) Engineering/Design Metropolitan St. Louis Sewer District c o . r-- ---c k -- P c o Unique Shape, Shape, Extraordinary Quaiity The Ero-13rickTm Building pro:10as cop, & AdvariCex,i P, erer:t 7eChnob.->g, presents. a new 'shape in permeable beverzi foe use when imblementini„$ permeable interlocking concrete pavement_ iKiperior paving solution that supports storrnwater ;nor' agernent Urd bu iisgrowth, Se,f, Benefits of Eco-BriekT" ▪ Modts pedu:strian Up fe.sistunco stPridPrds [Wm the: Amer we1J DIF.iabilitie$.)i Act (ADA:. Afc,nittuifal Cluirkil;ne,2:-.;, as well as FP.,0, 5tormiNate- regoiremerm • prv, les Fir#007hsurfce W17,r1 minmJ 0nenirA5 to a ke walk ng more comfaiable • Al ovs$ for rapid ren-iialofatormwater thrmigh %/rid npening5 ▪ Elmine,es standing watefor plazas and wakways without slaoirg • %tax' mires ries gn flexibility by onabliine a wide range of creatiwe patterns • Si----iphfies stiai 70.er-farce in cm,s with ice and snow • ,,,r1'.;) points uric:ler sustainable stes and mate:lel resciame cre E00-1BriCk74 Dqr-e,4iTitv lArr, *4' —417),ELLzybo< FC.,4V Produced LxiaIPy BuittIng Prioducts Corp. OfficeltiX1,4274282 Fax; 61&27410150 wwwluilldingProductsCorororn