1、Designation: D7492/D7492M 11Standard Guide forUse of Drainage System Media with Waterproofing Systems1This standard is issued under the fixed designation D7492/D7492M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of las
2、t revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide makes recommendations for the selectionand application of prefabricated drainage media used in con-junction wi
3、th waterproofing systems on horizontal and verticalsurfaces. Drainage media considered include rigid and semi-rigid insulation boards and rigid materials including plastics.The scope of this guide does not cover other drainage mediaincluding gravel and filter fabric systems that can be con-structed.
4、 The scope of this guide does not cover drainagematerials or drainage system designs used for vegetative roofsystems. Vegetative roof systems require specialized designs.1.2 The committee with jurisdiction over this standard is notaware of any other comparable standards published by otherorganizatio
5、ns.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewi
6、th the standard.1.4 This standard may involve hazardous materials, opera-tions and equipment. This standard does not purport to addressall of the safety concerns, if any, associated with its use. It isthe responsibility of the user of this standard to establishappropriate safety and health practices
7、 and determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C165 Test Method for Measuring Compressive Propertiesof Thermal InsulationsC898 Guide for Use of High Solids Content, Cold Liquid-Applied Elastomeric Waterproofing Membrane with Sepa-rat
8、e Wearing CourseC981 Guide for Design of Built-Up Bituminous MembraneWaterproofing Systems for Building DecksC1471 Guide for the Use of High Solids Content ColdLiquid-Applied Elastomeric Waterproofing Membrane onVertical SurfacesD896 Practice for Resistance of Adhesive Bonds to Chemi-cal ReagentsD10
9、79 Terminology Relating to Roofing and WaterproofingD2434 Test Method for Permeability of Granular Soils(Constant Head)D3273 Test Method for Resistance to Growth of Mold onthe Surface of Interior Coatings in an EnvironmentalChamberD3385 Test Method for Infiltration Rate of Soils in FieldUsing Double
10、-Ring InfiltrometerD4511 Test Method for Hydraulic Conductivity of Essen-tially Saturated PeatD4630 Test Method for Determining Transmissivity andStorage Coefficient of Low-Permeability Rocks by In SituMeasurements Using the Constant Head Injection TestD4716 Test Method for Determining the (In-plane
11、) FlowRate per Unit Width and Hydraulic Transmissivity of aGeosynthetic Using a Constant HeadD5898 Guide for Details for Adhered Sheet WaterproofingD6622 Guide for Application of Fully Adhered Hot-Applied Reinforced Waterproofing SystemsE154 Test Methods for Water Vapor Retarders Used inContact with
12、 Earth Under Concrete Slabs, on Walls, or asGround Cover3. Terminology3.1 Refer to Terminology D1079 for definitions of termsused in this guide.4. Summary of Practice4.1 This guide describes a method to estimate the amount ofwater a drainage system may need to carry. The guide alsooffers description
13、s of the various drainage systems in existence1This guide is under the jurisdiction of ASTM Committee D08 on Roofing andWaterproofing and is the direct responsibility of Subcommittee D08.22 on Water-proofing and Dampproofing Systems.Current edition approved Nov. 15, 2011. Published March 2012. DOI:
14、10.1520/D7492_D7492M-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Ba
15、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.today along with suggestions on how different building situa-tions will require different performance characteristics from thedrainage medium chosen. Items to be aware of during theinstallation of drainage systems is also
16、covered along withillustrations of typical drainage systems.5. Significance and Use5.1 This guide provides information and guidelines for theselection and installation of drainage systems media that are inconjunction with waterproofing systems. This guide is intendedto be used in conjunction with Gu
17、ides C898, C981, C1471,D5898, and D6622 and to provide guidelines for the totalwaterproofing and drainage system.6. General6.1 In selecting a drainage medium for use with waterproof-ing, consideration should be given to the design of thewaterproofing system. In particular orientation of the system,a
18、ttachment recommendations, connections to interior and ex-terior drainage systems and external loads applied to thesystem. Additional considerations include the materials andconstruction over the drainage medium, installation recom-mendations, durability, and penetrations and joints. (See Figs.1-3.)
19、 In all designs, the potential slip planes should beconsidered.6.2 CompatibilityIt is essential that all components andcontiguous elements of the waterproofing system are compat-ible and that the design of the systems waterproofing anddrainage is coordinated to form an integrated waterproofingsystem
20、.6.3 Basic ComponentsThe various types of drainage me-dia available are outlined in Section 12 of this guide and allconsist of one or more of the following basic components. Thebasic components of typical drainage medium are a mountingsurface that is placed against the waterproofing membrane topreve
21、nt embedment of the media, a porous core that providesa drainage path, and a filter fabric bonded over the porous coreto prevent clogging of the drainage paths. Fibrous and foamdrainage media are homogeneous materials that are sufficientlydense that they can be placed directly against the waterproof
22、ingmembrane. Other foam boards merely provide periodicgrooves creating paths to drain water away from the water-proofed surface. However fibrous and foam media may notfunction properly in horizontal or nearly horizontal (6.61 L/s (Eq X1.3 and Eq X1.4 above), anotherdrain would be necessary to preven
23、t water from filling up thedrainage media.X1.2.2 The assumption that flow is proportional to hydrau-lic gradient is conservative. Flow rate has been found to moreclosely correlate with (i)0.5or one can use the Manningequation (below) to determine flow in drainage composites inlow slope situations. U
24、sing the assumption that flow is propor-tional to (i)0.5, Eq X1.4 becomes:Q/length actual! 5 Q/L i5 1.0 3 i actual!#0.5Q/length5 3.31 L/s2m 3 0.0208!0.55 0.477 L/s2m 2.31 gpm/ft (X1.8)X1.2.3 The Manning Equation provides another way toestimate flow for a low slope orientation of a drainagecomposite:
25、Q 5 K/n! A Rh!2/3S0.5(X1.9)where:K = unit conversion constant, 1.49 IP/SI units; 1.0 SI/SIunits,n = Gauckler-Manning coefficient, material/surface de-pendent,A = area for flow, perpendicular to flow, ft2,m2,Rk= hydraulic radius = area for flow/wetted perimeter, ft,m,S = slope of surface often equal
26、to i, the hydraulicgradient, ft/ft; m/m, andQ = volume/time, ft3/s; m3/sec.X1.2.3.1 To use the Manning equation, certain features ofthe drainage media must be known. In the example aboveexample with a egg carton type drainage composite, theadditional data needed is as follows. Each cone of the drain
27、agemedia will be assumed to be 12.7 mm high 12 in., 9.5 mm 38in. wide, and the gap between each cone: 9.5 mm 12 in. wide.Thus in 0.3 m 1 ft of drainage composite, there will be 0.3048m/(9.5 + 9.5) mm or 16 openings. As before, the slope (S) willbe 0.0208. The area for flow for a single opening will
28、be:Cone height 3 cone spacing = 0.0127 m 3 0.0095m=1.213 10-4m20.0013 ft2Rh =Area for Flow/Perimeter of opening = 1.21 3 10-4/(12.7mm+9.5 mm + 12.7 mm + 9.5 mm) = 0.00272 m 0.00891 ftX1.2.3.2 Gauckler-Manning coefficients can be found invarious Civil Engineering text books and, in this case, a goode
29、stimate for a composite core made of polystyrene would be0.012. (This assumes a single opening of a drainage compositeis completely surrounded by the polystyrene core, however ina typical drainage composite one of the wetted sides of anopening would be fabric, so a larger K may be appropriate. Butfo
30、r this example 0.012 will be used.)X1.2.3.3 Substituting the values into the Manning equation:Q 5 K/n! A Rh!2/3S0.55 1/0.012! 3 1.21x1024m23 0.00272 m!2/33 0.0208!0.55 2.83 3 1025m3/s 0.449 gpm! (X1.10)X1.2.3.4 This is the flow through one space between twocones and since the circumference around th
31、e drain is 0.3048 m1 ft, see above there will be 16 of these openings thus theflow into the drain predicted by the Manning equations is:16 3 Q 5 16 3 2.83 3 1025m3/s 5 4.53 3 1024m3/s 7.18 gpm(X1.11)X1.2.3.5 As can be seen, the linear analysis gives the mostconservative value while the Manning equat
32、ion gives thehighest value of flow at the drain/drainage composite interface.All three of these analysis methods are used in water flowanalysis in construction design. Also as mentioned above thelimiting factor in plaza deck drainage in many cases will be thenumber and size of the drains. Thus since
33、 many areas havedrain requirements for flat roofs, this drain requirement couldthen be used for a starting point to determine the number ofdrains for a plaza deck with the above analysis used todetermine if for a particular plaza deck system that the numberof drains could be reduced.D7492/D7492M 118
34、X1.2.3.6 The above analysis strongly indicates that thedrainage composite/drain interface will be the key designfeature in many plaza deck drainage systems and shows thewater flow through this interface is affected by the diameterand number of drains, slope of the plaza deck, and character-istics of
35、 the drainage composite (cone height and spacing).Thus the designer can manipulate these variables to achieve thebest design.X2. USEFUL EQUATIONS FOR ESTIMATING DRAINAGE REQUIREMENTS FOR VERTICAL WALLSX2.1 To determine the drainage capacity needed for avertical orientation, decide either to size the
36、 media to handlepossible water flow before the backfill has consolidated or tobase the water flow rate on the permeability ratings of thesurrounding soil. If the drainage rate needed is to be based onunconsolidated soil, the conservative approach would be simi-lar to the approach used above on plaza
37、 decks. The drainagecapacity would be the agreed upon rainfall rate multiplied bythe area that has the potential to catch this rain and direct ittoward the vertical wall. This would be very conservative asobviously some of this rain would either bypass the drainagemedia and go directly into the foun
38、dation footing drainagesystem or be retained by the soil.X2.1.1 The approach used on consolidated soil would useDarcys equation (Eq X1.3) where Qdis the flow rate in L/s, kis the soils permeability coefficient in mm/s., (i) is thehydraulic gradient in meter head loss/ meter of liquid travel andA is
39、the area in m2perpendicular to the flow Q. In virtually allcases, this is the surface area of drainage media on the verticalwall. A number of ASTM tests are available to determine soilor rock permeability coefficients, such as see Test MethodsD2434, D4511, D4630, and D3385. Once the appropriate test
40、has determined the permeability coefficient of the soil, then agood assumption for the hydraulic gradient is 1.0 and thesenumbers along with the surface area of drainage media can besubstituted into Darcys equation above to determine thedrainage capacity (Q) needed. Except for soils consisting ofgra
41、vel or coarse sand where drainage media would likely besuperfluous, the calculated Q will generally be quite small.Sample calculation:Qd5 kIAv(X2.1)where:Qd= see Eq X1.1 (L/s),k = soil permeability constant (mm/s), see see Test Meth-ods D2434, D4511, and D4630,I = amount of head lost/length of fluid
42、 travel (in verticalflow this equals 1.0),Av=m2of below grade wall per m of wall length, andA = area of soil/drainage media interface per metre ofvertical wall length, m2/m;I=1;kdetermined bytesting, approximately 0.00167 mm/s for clay soils,approximately 1.67 mm/s for sand.X2.1.2 Assuming an 2.44 m
43、 8 ft high piece drainagesystem in a clay soil: Drainage Capacity Required = kIA =0.00167 mm/s 3 1 3 2.44 m2/m length 3 1.0 L/m2-mm =0.00407 L/s per metre wall length; 14.9 in3/min per foot walllengthX2.1.3 This approach will also work in areas where poten-tial water tables may exist. In these cases
44、, the permeability ofthe soil layer or layers which are below the water table orwhich may transport water during wet weather periods shouldbe determined and used in Darcys equation to size thedrainage media. Of course if there are soil layers that have ahigher permeability than the layers that are i
45、n the water table,then using the higher permeability coefficient would be appro-priate and conservative.X2.1.4 There are other sources that can be used to determinewater flows and amounts in various areas. The (NRCS)National Resources Conservation Service (formerly the USDASoil Conservation Service)
46、 provides models such as the TR-55which models small watersheds. There are also softwareproviders which have programs to model watersheds such asHydrocad (trademarked) at H. Information can alsobe found in Section 4 of the National Engineers Handbookavailable from the NRCS. These resources can be us
47、ed to refinethe above analysis on vertical wall drainage systemsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any suc
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