1、Designation: D7492/D7492M 16D7492/D7492M 16aStandard 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,
2、 the year of last 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 selection and application of prefabricated drainage media used i
3、n conjunctionwith waterproofing systems on horizontal and vertical surfaces. Drainage media considered include rigid and semi-rigid insulationboards and rigid materials including plastics. This guide considers drainage media as it relates to the performance of thewaterproofing system, so its primary
4、 focus is draining water away from the membrane. This guide does not cover in detail otheraspects or functions of drainage system performance such as efficiency of soil dewatering. The scope of this guide does not coverother drainage media including gravel and filter fabric systems that can be const
5、ructed. The scope of this guide does not coverdrainage materials or drainage system designs used for vegetative roof systems. Vegetative roof systems require specializeddesigns.1.2 The committee with jurisdiction over this standard is not aware of any other comparable standards published by otherorg
6、anizations.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-con
7、formance with the standard.1.4 This standard may involve hazardous materials, operations and equipment. This standard does not purport to address allof the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriatesafety and healt
8、h practices and determine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C165 Test Method for Measuring Compressive Properties of Thermal InsulationsC898C898/C898M Guide for Use of High Solids Content, Cold Liquid-Applied Elastomeric Waterproofing
9、 Membrane withSeparate Wearing CourseC981 Guide for Design of Built-Up Bituminous Membrane Waterproofing Systems for Building DecksC1471C1471/C1471M Guide for the Use of High Solids Content Cold Liquid-Applied Elastomeric Waterproofing Membraneon Vertical SurfacesD896 Practice for Resistance of Adhe
10、sive Bonds to Chemical ReagentsD1079 Terminology Relating to Roofing and WaterproofingD2434 Test Method for Permeability of Granular Soils (Constant Head) (Withdrawn 2015)3D3273 Test Method for Resistance to Growth of Mold on the Surface of Interior Coatings in an Environmental ChamberD3385 Test Met
11、hod for Infiltration Rate of Soils in Field Using Double-Ring InfiltrometerD4511 Test Method for Hydraulic Conductivity of Essentially Saturated PeatD4630 Test Method for Determining Transmissivity and Storage Coefficient of Low-Permeability Rocks by In SituMeasurements Using the Constant Head Injec
12、tion TestD4716D4716/D4716M Test Method for Determining the (In-plane) Flow Rate per Unit Width and Hydraulic Transmissivity ofa Geosynthetic Using a Constant Head1 This guide is under the jurisdiction of ASTM Committee D08 on Roofing and Waterproofing and is the direct responsibility of Subcommittee
13、 D08.22 on Waterproofingand Dampproofing Systems.Current edition approved Feb. 1, 2016Dec. 1, 2016. Published March 2016December 2016. Originally approved in 2011. Last previous edition approved in 20112016 asD7492/D7492M 11.D7492/D7492M 16. DOI: 10.1520/D7492_D7492M-16. 10.1520/D7492_D7492M-16A.2 F
14、or referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is refer
15、enced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that u
16、sers consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D5898D5898/D5898M Guide fo
17、r Details for Adhered Sheet WaterproofingD6622 Guide for Application of Fully Adhered Hot-Applied Reinforced Waterproofing SystemsE154E154/E154M Test Methods for Water Vapor Retarders Used in Contact with Earth Under Concrete Slabs, on Walls, or asGround Cover3. Terminology3.1 Refer to Terminology D
18、1079 for definitions of terms used in this guide.4. Summary of Practice4.1 This guide describes a method to estimate the amount of water a drainage system may need to carry. The guide also offersdescriptions of the various drainage systems in existence today along with suggestions on how different b
19、uilding situations willrequire different performance characteristics from the drainage medium chosen. Items to be aware of during the installation ofdrainage systems is also covered along with illustrations of typical drainage systems.5. Significance and Use5.1 This guide provides information and gu
20、idelines for the selection and installation of drainage systems media that are inconjunction with waterproofing systems. This guide is intended to be used in conjunction with Guides C898C898/C898M, C981,C1471C1471/C1471M, D5898D5898/D5898M, and D6622 and to provide guidelines for the total waterproo
21、fing and drainagesystem.6. General6.1 In selecting a drainage medium for use with waterproofing, consideration should be given to the design of the waterproofingsystem. In particular orientation of the system, attachment recommendations, connections to interior and exterior drainage systemsand exter
22、nal loads applied to the system. Additional considerations include the materials and construction over the drainagemedium, installation recommendations, durability, and penetrations and joints. (See Figs. 1-3.) In all designs, the potential slipplanes should be considered.6.2 CompatibilityIt is esse
23、ntial that all components and contiguous elements of the waterproofing system are compatible andthat the design of the systems waterproofing and drainage is coordinated to form an integrated waterproofing system.6.3 Basic ComponentsThe various types of drainage media available are outlined in Sectio
24、n 12 of this guide and all consistof one or more of the following basic components. The basic components of typical drainage medium are a mounting surface thatis placed against the waterproofing membrane to prevent embedment of the media, a porous core that provides a drainage path,and a filter surf
25、ace, often a fabric bonded over the porous core to prevent clogging of the drainage paths. Fibrous and foam drainagemedia are homogeneous materials that are sufficiently dense that they can be placed directly against the waterproofing membrane.However, fibrous and foam media may not function properl
26、y in horizontal or nearly horizontal (6.61L/s (Eq X1.3 and Eq X1.4 above), another drain would be necessary to prevent water from filling up the drainage media.X1.2.2 The assumption that flow is proportional to hydraulic gradient is conservative. Flow rate has been found to more closelycorrelate wit
27、h (i)0.5 or one can use the Manning equation (below) to determine flow in drainage composites in low slope situations.Using the assumption that flow is proportional to (i)0.5, Eq X1.4 becomes:Q/length actual! 5Q/L i 5 1.0 3 i actual!#0.5! (X1.8)Q/length53.31 L/s 2m 30.0208!0.550.477 L/s 2m 2.31 gpm/
28、ft#X1.2.3 The Manning Equation provides another way to estimate flow for a low slope orientation of a drainage composite:Q 5K/n! A Rh!2/3S0.5 (X1.9)where:K = unit conversion constant, 1.49 IP/SI units; 1.0 SI/SI units,n = Gauckler-Manning coefficient, material/surface dependent,A = area for flow, pe
29、rpendicular to flow, ft2, m2,Rk = hydraulic radius = area for flow/wetted perimeter, ft, m,S = slope of surface often equal to i, the hydraulic gradient, ft/ft; m/m, andQ = volume/time, ft3/s; m3/sec.X1.2.3.1 To use the Manning equation, certain features of the drainage media must be known. In the e
30、xample above example withan egg carton type drainage composite, the additional data needed is as follows. Each cone of the drainage media will be assumedto be 12.7 mm high 12 in., 9.5 mm 38 in. wide, and the gap between each cone: 9.5 mm 12 in. wide. Thus in 0.3 m 1 ft ofdrainage composite, there wi
31、ll be 0.3048 m/(9.5 + 9.5) mm or 16 openings. As before, the slope (S) will be 0.0208. The area forflow for a single opening will be:Cone height cone spacing = 0.0127 m 0.0095 m = 1.21 10-4m2 0.0013 ft2Rh =Area for Flow/Perimeter of opening = 1.21 10-4/( 12.7 mm +9.5 mm + 12.7 mm + 9.5 mm) = 0.00272
32、 m 0.00891 ftD7492/D7492M 16a10X1.2.3.2 Gauckler-Manning coefficients can be found in various Civil Engineering text books and, in this case, a good estimatefor a composite core made of polystyrene would be 0.012. (This assumes a single opening of a drainage composite is completelysurrounded by the
33、polystyrene core; however, in a typical drainage composite one of the wetted sides of an opening would befabric, so a larger K may be appropriate. But for this example 0.012 will be used.)X1.2.3.3 Substituting the values into the Manning equation:Q 5K/n! A Rh!2/3S0.551/0.012!31.21x1024 m230.00272 m!
34、2/330.0208!0.552.8331025 m3/s 0.449 gpm! (X1.10)X1.2.3.4 This is the flow through one space between two cones and since the circumference around the drain is 0.3048 m 1 ft,see above there will be 16 of these openings thus the flow into the drain predicted by the Manning equations is:163Q 51632.83310
35、25 m3/s 54.5331024 m3/s 7.18 gpm# (X1.11)X1.2.3.5 As can be seen, the linear analysis gives the most conservative value while the Manning equation gives the highest valueof flow at the drain/drainage composite interface.All three of these analysis methods are used in water flow analysis in construct
36、iondesign.Also as mentioned above the limiting factor in plaza deck drainage in many cases will be the number and size of the drains.Thus since many areas have drain requirements for flat roofs, this drain requirement could then be used for a starting point todetermine the number of drains for a pla
37、za deck with the above analysis used to determine if for a particular plaza deck systemthat the number of drains could be reduced.X1.2.3.6 The above analysis strongly indicates that the drainage composite/drain interface will be the key design feature in manyplaza deck drainage systems and shows the
38、 water flow through this interface is affected by the diameter and number of drains, slopeof the plaza deck, and characteristics of the drainage composite (cone height and spacing). Thus the designer can manipulate thesevariables to achieve the best design.X2. USEFUL EQUATIONS FOR ESTIMATING DRAINAG
39、E REQUIREMENTS FOR VERTICAL WALLSX2.1 To determine the drainage capacity needed for a vertical orientation, decide either to size the media to handle possible waterflow before the backfill has consolidated or to base the water flow rate on the permeability ratings of the surrounding soil. If thedrai
40、nage rate needed is to be based on unconsolidated soil, the conservative approach would be similar to the approach used aboveon plaza decks. The drainage capacity would be the agreed upon rainfall rate multiplied by the area that has the potential to catchthis rain and direct it toward the vertical
41、wall. This would be very conservative as obviously some of this rain would either bypassthe drainage media and go directly into the foundation footing drainage system or be retained by the soil.X2.1.1 The approach used on consolidated soil would use Darcys equation (Eq X1.3) where Qd is the flow rat
42、e in L/s, k is thesoils permeability coefficient in mm/s, (i) is the hydraulic gradient in metre head loss/ metre loss/metre of liquid travel and A isthe area in m2 perpendicular to the flow Q. In virtually all cases, this is the surface area of drainage media on the vertical wall.Anumber ofASTM tes
43、ts are available to determine soil or rock permeability coefficients, such as see Test Methods D2434, D4511,D4630, and D3385. Once the appropriate test has determined the permeability coefficient of the soil, then a good assumption forthe hydraulic gradient is 1.0 and these numbers along with the su
44、rface area of drainage media can be substituted into Darcysequation above to determine the drainage capacity (Q) needed. Except for soils consisting of gravel or coarse sand where drainagemedia would likely be superfluous, the calculated Q will generally be quite small.Sample calculation:Qd 5kIAv (X
45、2.1)where:Qd = see Eq X1.1 (L/s),k = soil permeability constant (mm/s), see Test Methods D2434, D4511, and D4630,I = amount of head lost/length of fluid travel (in vertical flow this equals 1.0),Av = m2 of below grade wall per m of wall length, andA = area of soil/drainage media interface per metre
46、of vertical wall length, m2/m; I = 1; k determined by testing, approximately0.00167 mm/s for clay soils, approximately 1.67 mm/s for sand.D7492/D7492M 16a11X2.1.2 Assuming a 2.44 m 8 ft high piece drainage system in a clay soil: Drainage Capacity Required = kIA = 0.00167 mm/s 1 2.44 m2/m length 1.0
47、L/m2-mm = 0.00407 L/s per metre wall length; 14.9 in3/min per foot wall lengthX2.1.3 This approach will also work in areas where potential water tables may exist. In these cases, the permeability of the soillayer or layers which are below the water table or which may transport water during wet weath
48、er periods should be determinedand used in Darcys equation to size the drainage media. Of course if there are soil layers that have a higher permeability than thelayers that are in the water table, then using the higher permeability coefficient would be appropriate and conservative.X2.1.4 There are
49、other sources that can be used to determine water flows and amounts in various areas. The (NRCS) NationalResources Conservation Service (formerly the USDASoil Conservation Service) provides models such as theTR-55 which modelssmall watersheds. There are also software providers which have programs to model watersheds such as Hydrocad (trademarked)at H. Information can also be found in Section 4 of the National Engineers Handbook available from the NRCS. Theseresources can be used to refine the above analysis on
